Level-specific downgrades

Hot Shelter downgrades

October 16, 2017November 11, 2023PkR

Hot Shelter received fewer downgrades in SADX than other levels, with some lighting issues and only several effects removed. Compared to Final Egg, this level is not broken at least. Let’s have a look at some problems with the SADX redesign of Hot Shelter.

The first area in Amy’s stage has a different lighting setup and some texture changes. If you’ve read previous comparisons, you know SADX doesn’t seem to like glass surfaces with environment mapping, and this level is no exception. In this particular area the glass wasn’t removed or made a solid texture, but the UVs were edited to make it look more pixelated.

From a quick look the lighting change doesn’t seem bad. SADX gets rid of the green tinge of the Dreamcast level, although it readds it in some areas as vertex colors. SADX already has dark green lighting in Speed Highway, Casinopolis and Final Egg, so it’s nice to have something a little different. It’s hard to say whether this area is an improvement over the Dreamcast version – it’s just different.

The area outside the elevator has also received some redesign. The carpet texture is different, the shadows on the door and the statues are stronger, and wood textures are replaced with metal, which looks slightly low resolution but still acceptable. This is one of the few areas that hold up relatively well:

The green glass problem is also present in the aquarium section, adding a pixelated blob on aquarium walls:

The water doesn’t render behind the glass walls in SADX, which leads to an awkward black space (the water is still there but it doesn’t show up due to transparency issues).

The issue with unnecessary processing of material colors specific to the PC port shows up again here, adding a strange orange color to the floating platform:

The floor in the above screenshots has more detailed lighting on the Gamecube, but not all areas in the level have better lighting. For example, the room with the water drainage switch has more basic lighting than on the Dreamcast:

There is also a problem with the water drain animation. The model used in that animation had its mesh order swapped to avoid rendering issues, however the code to animate the UVs was not updated accordingly. Because of that, part of the water mesh near the top isn’t animated:

Dreamcast	Gamecube

The green light you see in some rooms in Acts 2 and 3 has the actual light part missing in SADX. The PC version also broke some UVs in the area because of texture mirroring.

Here’s a closer look at the messed-up UVs. You can also notice that the water is no longer transparent, which isn’t a major issue, but can’t be called an enhancement either:

The mirrors, which had different textures for male and female bathrooms, are now replaced with a solid color:

Fog in this area was reduced, and the background’s UVs were adjusted to make the distant mechanisms look smaller. The replacement texture’s resolution is half the resolution of the Dreamcast texture, although both are included in the game data. A similar downgrade happened with the background in Final Egg Act 2.

The lighting in this area is relatively good in SADX, although the bright yellow parts that are supposed to be lit up aren’t bright enough.

Something’s wrong with the bridge texture in the PC version, however. It looks more blurry than its console counterparts:

If it was a simple texture recompression/mirroring problem, it would be easy to fix by replacing the texture. However, the UVs on the model were also adjusted to make the texture look more washed out. To restore the proper look of the bridge, the entire model had to be replaced with its Dreamcast counterpart.

When the rocket takes you above this area on the Dreamcast, the level fades in as you fall down, while in SADX there’s no fog so you can see everything right away. It’s hard to say whether removing it was a good or a bad change because it was probably there originally for performance reasons, but one could also argue it’s an artistic element.

Dreamcast	Gamecube	PC

The floor in the room with colored cubes is brighter and more opaque in SADX. It replaces the environment mapping effect on the floor with solid green and makes the bottom layer barely visible. The lights coming from below tend to pop in or disappear in SADX when you turn the camera or walk around.

Gamma’s level loses its dark yellow and orange tones and gets dark green (again) instead. Note the simplified lighting on Gamma himself as well:

This area doesn’t look too bad with vertex colors if you don’t take into account the overuse of green elsewhere in the game. A minor annoyance is that Gamma’s eyes aren’t lit up at all times, but that problem is specific to his model – read more on this in the Characters section.

This area has a transparency glitch, which only happens in the PC version:

Dreamcast	Gamecube	PC

This area has received some new textures, which doesn’t look too bad, but now the green glass covering the mechanisms is almost invisible:

Lighting in this area is different, making the Gamecube/PC version slightly darker and less colorful:

The entrance to the final area looks a bit richer on the Dreamcast thanks to its more complex lighting:

To avoid (possibly) rendering issues involving transparent models, the middle part of the slope was made opaque in SADX, which also made the lights inside the slope invisible:

The room where you fight E-105 Zeta has lost neon blue decorations, and Zeta’s textures suffer from recompression. In addition, Zeta’s base animation (the tubes that move vertically) is missing in SADX.

Illumination decorations have been removed in several other areas in Hot Shelter, for example Big’s level has a few of them missing:

The upper segment of Big’s level also has some changes. Fog color is different, you can see farther and the background is changed. Dreamcast fog made the surroundings fade in as you moved around, while in SADX you can see almost everything but with washed out colors. As usual, the fog is thicker in the PC version, but here it doesn’t help the atmosphere too much:

Compared to Final Egg, Hot Shelter doesn’t seem too bad even with all the downgrades. There are quite a few areas in this level where the lighting comes close to looking on par with the Dreamcast original, or even better. It would’ve been an acceptable redesign if it wasn’t for removed decorations, fog changes and low texture quality. If you want to revert this level to the original version on PC, you can install the Dreamcast Conversion mod, and if you only want to restore the original lighting, you can use the Lantern Engine mod. More in the “Fixing the PC version of SADX” section of this blog.

Final Egg downgrades

October 15, 2017November 11, 2023PkR

If there was a “top 10” list of SADX downgrades, Final Egg would probably be #1. This level suffers from removed lighting, bad fog settings, missing effects, missing object animations, new bugs introduced in SADX, loss of transparency in some level pieces, broken models that wash out backgrounds and poor texture quality. Let’s compare the levels side by side to find out what’s been lost in the transition.

The starting location reveals a different lighting setup. Although the textures have similar design, the SADX version of the level loses the original’s colors and makes it dark green. Dark green would’ve been fine in this level perhaps, but the original’s color variety was removed in favor of colors that are already abundant across the game. Speed Highway and Casinopolis also have green vertex colors. The lighting on Sonic is also dark green in this level, which is a nice change because SADX character lighting seldom matches the environment. The Egg Keeper is missing (although it comes back in the Steam version), and the PC version adds grey fog that doesn’t fit the level too well – black would’ve worked better.

The lasers look different in SADX. Their models are the same in all versions but SADX is unable to render their brighter inner layer properly, making them look like a dark purple line. Rearranging the model hierarchy was enough to restore the original look of the lasers.

The little standing lights are broken in all ports. On the Dreamcast, they consist of one light (vertical or horizontal) that rotates as you walk around it – a subtle effect that enhances the atmosphere of the level. In SADX, the lights have both the horizontal and vertical meshes, making it look strange with two layers, they don’t vary in size and are completely static – they don’t react to camera or player movement.

Dreamcast	Gamecube

The rotation effect was subtle, but the loss of light size adjustment is noticeable in areas like these:

The Dreamcast version has more complex lighting on enemies and objects in this level, much like in the rest of the game. The SADX redesign of this particular area compensates for the removal of lighting with vertex colors, which add more lighting detail compared to the flat look of the original (object lighting is simpler, however). The PC version’s lighting is brighter and more washed out:

The ceiling in this and many other areas has lost the yellow light, but the objects and the walls have vertex colors. Again, dark green is the most used color, which takes away from the color variety of the original game. The fog in the PC version doesn’t help the atmosphere:

The loss of lighting is noticeable on objects like conveyor belts, and if you look closely you can see loss of texture quality, which is particularly noticeable in the PC port:

This area near the end of Act 1 has received a new texture, which looks lower quality than the original:

Act 2 has vertex colors that aren’t all dark green, which is a good change. The start area looks darker on the Gamecube and brighter on PC, but fog settings aside it doesn’t appear to have been downgraded:

However, SADX added a bug that allows you to spindash backwards and fall through the level, which you coudn’t do on the Dreamcast. This bug was never fixed in later ports.

Dreamcast	Gamecube

All ports have changed fog settings for this level, which makes the bottom of the level visible from above. The Dreamcast version had thick black fog obscuring this area, but in the ports you can see the characters walking around at the bottom after they die:

Here’s another example of this problem. The fog in the original version also enhances the overall look of the scene, although the Gamecube version would have ended up looking just as good (if not better) if it had proper fog settings for this area:

The high-speed sections that take you through blue glass tubes are less impressive in SADX. Let’s have a quick look at the first one:

Dreamcast	Gamecube

There are several problems with the SADX redesign of these tubes:

The blue glass pieces were redesigned to be less transparent, so you barely see anything through them in SADX.
The UVs on those blue glass pieces were adjusted to make the environment mapping effect less prominent. The tubes are less shiny/colorful as a result.
The multi-colored tubes have been removed in the areas where they overlapped the glass, and they are also not as bright in the areas where they still remain. The whole scene looks darker and less colorful as a result.
The large background object behind the glass was adjusted (deliberately) to be darker and more washed out, so you can barely even see it. The texture itself is also darker, lower resolution and has less detail.

Here’s the second section, at the end of which you can see the washed-out background closer:

Dreamcast	Gamecube

Here’s what the background object appears like in fullbright (no lighting) if you look at it from the start coordinate (we can do that thanks to the hacking tools made by MainMemory and other talented SA1/SADX hackers):

And here’s what the textures for this object look like (using Gamecube textures; the ones used in the PC port are the same but recompressed):

Not only are the Gamecube textures 4 times smaller (half the resolution) than the originals, but they also have the middle part blackened out. If you look closer you’ll notice that the Gamecube textures use the same artwork as the original Dreamcast textures, but with altered colors and rearranged pieces. Interestingly the original Dreamcast textures are still in the files. This particular level piece looks darker and washed out even with Dreamcast textures because of added dark vertex colors. The UVs also don’t seem to work well with the Dreamcast texture. While the resolution downgrade could have been done for performance reasons (but let’s remember that this is supposed to be an “enhanced” port), there is no way the added dark vertex colors and all the editing were accidental. The developers deliberately reworked this level to make it look uglier.

This area was also downgraded with washed out background and simplified UVs on the blue glass. The plasma effect on the spinning electric cylinders was replaced with a choppy animation, which we will discuss later.

To avoid issues with rendering transparent things (probably), this elevator was redesigned to use opaque textures:

Final Egg also suffers from alpha rejection (you can read more on it and its side effects in the Transparency section). In this level, the blue lights don’t reach as far as their Dreamcast counterparts, and they don’t look as vibrant as the originals, which makes the game miss out on some scenes:

This is particularly visible in Act 3, where much of the ambience is lost in Gamma’s level. The washed out lighting doesn’t help, especially in the PC version:

There is an area where the light was supposed to follow Sonic climbing up a ladder, making it another impressive looking moment in the game, but in SADX you don’t get to see it because of alpha rejection and the edited light model:

In the original game, the light has a low resolution texture that gets scaled to the length of the light, and the noise from upscaling a low resolution texture creates a cool looking rainbow effect that you can see in the Dreamcast screenshot. However, the light’s texture also has an alpha channel. To mask rendering issues with transparent things, the Gamecube/PC ports don’t show transparent pixels if their transparency is beyond a certain threshold, which is what happens here. Simply editing the texture’s alpha channel to make it pass the alpha rejection test makes the lights much more vibrant. However, in addition to alpha rejection issues, the SADX light model was adjusted to make the light shorter, so even with an edited texture or disabled alpha rejection it wouldn’t look as good as the Dreamcast original. To bring back the proper look of these lights, both the texture and the Dreamcast model for the light had to be restored.

Here’s another area that illustrates how much ambience is lost in SADX because of missing effects, lower resolution textures and thicker fog:

Another problem caused by alpha rejection is roughness of particle effects, such as smoke or dust. In this level there aren’t too many (apart from the effect that shows up when breaking item capsules, which you see in most levels), but Amy’s level suffers from it. Admittedly it’s not the worst looking case (for some bad looking particles, check out the articles for Ice Cap or Lost World):

In the starting area of Sonic’s Act 3, the yellow lights don’t extend, the glass is less transparent and no longer has clear blue/green color variation, and the background is barely visible behind the glass:

The badnik throwers in this section have a shiny effect on the Dreamcast, while in SADX the effect was replaced with a low-resolution texture. The PC version’s processing of unnecessary material colors makes their lids almost entirely black. The blue illumination effect is also missing in SADX:

Finally, let’s talk about those electric cylinders. In the Dreamcast version they had a smooth “plasma” animation, but in the ports the effect was replaced with an animation that consists of 6 frames. For a port that claims to be an improved version of the original, this is quite an embarrassing replacement:

The electric traps in Act 3 also used this effect, and they got the same treatment in SADX. The Dreamcast original does a more convincing job at conveying the atmosphere of the level with its lighting and effects:

The SADX redesign of Final Egg arguably doesn’t convey the original level’s atmosphere, nor does it hold up well on its own. Reduced lighting and fog settings, removed special effects and lower quality textures make it one of the worst downgraded levels in the game. In a port that is supposed to be a better version of the original game, these downgrades are hard to justify. Thankfully on PC this level can be reverted to the original state with the Dreamcast Conversion mod, and its lighting can be brought back with the Lantern Engine mod. Find out more in the section dedicated to fixing the PC port.

Casinopolis downgrades

October 13, 2017November 11, 2023PkR

On a surface level, Casinopolis doesn’t seem to have downgrades in SADX. There is some lighting detail added around the level, and some areas have new textures. It might be tempting to call this level an improvement over the Dreamcast original. However, like with other levels in SADX, the improvements in this level are somewhat superficial, and many aspects of the level are broken in the ports, intentionally or otherwise.

Let’s start with a basic comparison of the dynamic light effect in the start area. The Gamecube version removes the slight purple coloration on Sonic’s model, adds green vertex colors to the level and is darker overall. The light transitions on Sonic’s model aren’t smooth in the PC version, and the scene is brighter than on the Gamecube:

Dreamcast	Gamecube	PC

The lack of smoothness in the PC port is caused by two factors. The Gamecube version uses per-pixel lighting for characters, while the Dreamcast uses per-vertex lighting. The PC version switches back to per-vertex lighting which combined with exceedingly high specular values on character models makes it accentuate the polygons stronger. This results in jerky light transitions.

If you look around the level, you may notice that some objects have lost their animation. For example, the roof of the Card Pinball entrance is no longer animated in the ports:

Dreamcast	Gamecube	PC

To be fair, this also happens on the Dreamcast with the slot machines: the blue ones are properly animated, while the red ones have frozen UVs. Neither of the ports fixes that; instead, the red machines in SADX are broken as well:

Dreamcast	Gamecube	PC

Similar to Windy Valley and Ice Cap, the glow effect on the “goal” emerald is missing in the ports:

Dreamcast	Gamecube	PC

There are also visual glitches the original game didn’t have. Some of such glitches are specific to the PC version*, such as this problem with the “Pinball” sign:

From the Lighting section you may remember that the PC version ignores vertex colors on objects. The above comparison is one instance where the PC version’s lighting is more broken than on the Gamecube, but the problem with ignoring vertex colors on anything that isn’t part of the level model persists across the entire game. The problem was not fixed in later ports (fixed in the Mod Loader though), so the Gamecube version is effectively the only port where the SADX lighting system is fully functional.

Other glitches happen in both ports, such as this problem with the “Casinopolis” billboard on the second floor:

As a workaround for transparency-related issues in the ports, this light object is rendered in such a way that its base becomes too bright and its layering gets broken:

The shiny letters on top of the shower room entrance were replaced with a low-resolution texture:

The letters on the “Information” billboard still have the environment mapping effect, but the textures and/or normals were adjusted to make it look like a solid color, which makes them look less colorful.

The Dreamcast version has several unique glass textures in different stages, while SADX uses one texture almost everywhere. The same glass texture can be seen reused in SADX Station Square, Speed Highway and Chaos 0.

The shower room was redesigned as well, which doesn’t appear to be worse than the original, but something is wrong with the wall lights on the Gamecube:

Knuckles’ stage has also had a fair share of downgrades. For example, many lights in the fountain are missing:

The gears in this area, which have survived the Gamecube transition, are broken in the PC port:

Dreamcast	Gamecube	PC

One of the spinning cylinders doesn’t render properly in the ports:

Dreamcast	Gamecube	PC

The lion on the second floor has lost some texture animations:

Dreamcast	Gamecube	PC

The sewers area looks quite different in SADX. The water is no longer animated, the lighting is replaced with green vertex colors, yellow fog is replaced with blue, and you can’t see as far as in the Dreamcast version. While SADX has better draw distance in some levels, it’s certainly not the case with this level:

The static water looks passable with the Gamecube’s distortion effect, however it’s hard to say if the static low-resolution texture is an improvement over the animated green wave texture in the Dreamcast version:

The giant fan areas have also been redesigned slightly. Other than reduced lighting, the change does not involve any particular downgrades (or improvements for that matter). Looking at these screenshots side by side makes it hard to tell which is the supposedly enhanced version, especially considering the original game’s richer color scheme and more vibrant character lighting.

The lights in the sewers were supposed to dim, which you can tell from the sound they make, but this doesn’t happen in the ports because of the way their models are rendered (the blinking code is still active in the ports):

Dreamcast	Gamecube	PC

The strange-looking square on the floor near the end of the level is supposed to be a light texture. It is using an incorrect blending mode, which makes it look like grating. Note how the big ceiling light is also missing in SADX.

The pinball area has also lost some lighting detail in the ports, but SADX adds other details to compensate – for example, the borders of the pinball are animated and more colorful than in the original game. The PC version looks brighter, but that isn’t how it was intended to look. It’s a side effect of the PC version’s poor rendering setup that makes it unable to replicate the Gamecube version’s lighting.

Sonic’s lighting doesn’t change when entering pinball areas in SADX, while in the original game Sonic used a different palette:

The NiGHTS board has received a minor redesign, with the glass area made green and less shiny. Texture quality degradation is quite noticeable in the whole area. The ports also add some strange dotted lines around the borders:

*The problem with the blue arrows above the “MARE” sign is caused by a glitch in the Dreamcast emulator, it looks fine on real hardware and on the emulator at 1x internal resolution

The second NiGHTS area also has some lighting differences. The scrolling effect on the walls breaks further with each port for some reason. The rings NiGHTS takes Sonic through in this area are supposed to play a sound as you go through them, but this is also missing in the ports.

Sonic isn’t lit up in this stage, which is an improvement because the white palette looked strange in the original level. Texture quality reduction in the ports is visible again in this part of the level:

Finally, the dome in this area has some transparency problems. The PC version also makes the background darker than intended:

From a quick look Casino doesn’t seem heavily downgraded in SADX. However, some detail is lost in the supposedly enhanced ports, and some parts of the level are broken. This level, particularly the second act, benefits greatly from Dreamcast lighting (restored in the PC version by the Lantern Engine mod) and fixed level models (Dreamcast Conversion mod). Find out how to install the mods in the section dedicated to fixing the PC version of SADX.

Ice Cap downgrades

October 12, 2017November 11, 2023PkR

Ice Cap is a level that received a strange redesign in SADX. The textures were made less colorful, some effects were removed, and the lighting, especially in Big’s level, looks more basic.

Sonic’s starting location reveals several lighting and texture differences. The crystals are also no longer translucent, which makes the small sparkle effect less visible. Note how the shadows are more pronounced in the Dreamcast screenshot.

As for the textures, those are the same exact textures as in SA1 but desaturated:

Another visible difference is Sonic’s lighting, which loses all its detail in SADX. The Dreamcast version had a “frost” effect on characters, while in SADX character lighting in Ice Cap barely differs from the normal glossy look:

Ice Cap’s air effects suffer from alpha rejection, which makes them look lower quality than they are (more on that in the Transparency section):

Dreamcast	Gamecube

Note how the particle sprites blend well with the background in the Dreamcast version, but in SADX they get raw edges, which makes them stand out and gives them a low-res look:

The freezer badnik has a similar problem. The particle effect also suffers from lack of rotation, which makes it look less dynamic compared to the original version.

The Dreamcast version has bright white fog in this area. SADX Gamecube adjusts fog distances and color to show farther and adds some shadows on the ground. The PC version washes out the shadows and reduces fog distances back to SA1 levels:

The icicles in the cave, as well as the ceiling they’re hanging from, have lost the shiny effect (environment mapping). Also note how the base part of the icicles has one of its layers missing because of transparency issues:

The first cave in Act 2 is missing lighting in SADX:

The bottom of the following area has a darker and less vibrant selection of colors, in addition the PC version breaks it with material colors that are normally ignored in other versions:

Several transparent pieces with environment mapping were removed or made opaque throughout the level, such as the ice walls in this area:

Like in Act 1, the icicles have lost the environment mapping:

There is a problem with the big icicle that you stand on near the end of the level. If you walk around, you’ll notice transparency glitches happening with its bottom part. This doesn’t happen in the original game:

Dreamcast	Gamecube

Act 3 has lost its bluish bits and is now blindingly white – the result of different lighting and reduced color saturation in textures. In addition, the particle effect in front of the avalanche looks like a white blob most of the time. While some may prefer this look, it’s caused by a bug – the game doesn’t set the correct blending mode for the particle, which blends with the avalanche behind it and washes out the details with solid white.

The goal emerald at the end of the stage is missing the glow effect, like the Windy Valley emerald:

One of the most radical changes happened to Big’s area. Since the palette lighting system played the main role in creating the night look of Big’s level in the original game, it’s no wonder the level was changed from night to day when the palette lighting for stages was removed in SADX.

The water surface opacity in some areas was reduced to such a low level in SADX it looks like a hole in the terrain with something missing:

Combined with reduced visibility of water wave effects on the walls, the level looks more barebones in SADX, especially in the PC version, which lacks the Gamecube’s distortion effect:

As can be seen from above, it is hard to regard Ice Cap in SADX an upgrade to the original version of the level. Thankfully it’s possible to revert to the original (including palettized lighting!) with mods. Check out this section to learn more about mods for the PC version.

Lost World downgrades

October 11, 2017November 10, 2023PkR

Lost World has gone through fewer quality downgrades than other levels in SADX. There are several areas that can be called improvements over the Dreamcast version. There are also some problems with lighting and transparency, and several new textures in the ports. Let’s take a closer look at the SADX redesign of this level.

The start location reveals a somewhat different mood for the stage. Distant areas were shrouded in white fog on the Dreamcast, while the Gamecube version uses dark grey. In general, the level appears darker and more “withered”. If we forget for a moment that the original game was all about being a colorful spectacle at any given time, this change is not bad. It fits the “ruin” theme of the level quite well. The darker atmosphere also helps accentuate the lights* coming from those stone pillars:

* While not immediately noticeable, the majority of fire sprites in SADX are broken slightly because of changes to the particle system. More on that in the Miscellaneous section.

The area below has also received some redesign. The new model for plants looks more detailed than its rougher Dreamcast counterpart. The colors are duller, but for a ruin-themed level perhaps this is what the designers were going for:

Some redesigns appear a bit strange, though. This area was flat on the Dreamcast, but now it has blocks with empty spaces. These blocks were likely supposed to be filled with water (SADX “Preview” prototype has water here), but it was removed for reasons unknown, leaving them empty:

The snake room entrance is presented more effectively on the Gamecube. The darker theme works well with the lights. The fog is perhaps too thick in the PC version, but it still looks acceptable:

The problems begin after entering the snake room. The collision on the snake is glitchy in all versions of the game, however only in SADX the snake parts have a jittery position readjustment happening every few frames, which is noticeable enough to get annoying. The Gamecube’s distortion effect makes it difficult to navigate underwater, although some people might prefer that:

Dreamcast	Gamecube

There are 3 buttons to press in the snake room, which open the door leading to the next area. In the Dreamcast version each of those buttons was illuminated by a light coming from the ceiling. The lights are still there in SADX, but they aren’t as bright and their texture has noticeable color banding:

An interesting detail about those lights is that their intensity depends on how far away you are from them – you can see that in the Dreamcast screenshot. When you get closer to the light, it becomes more transparent and less white. This effect is missing in both versions of SADX. In addition, the lights no longer reach far enough so they don’t go all the way to show the location of the button, which appears to have been their main purpose. Note a pretty nasty object draw distance limitation that makes the platform under the button disappear in the Dreamcast version, which was not fixed in the ports:

When you pressed one of those buttons, the game would show the door with three signs above it. The signs corresponded to the three buttons, and they would light up as you pressed them. It looked fine in the Dreamcast and Gamecube versions, but can you tell which button is pressed in the PC version?):

The starting area in Act 2 also received some redesign. The area around the first checkpoint is one of the few places in the entire game where the Gamecube’s lighting surpasses the original game:

The areas before and after the checkpoint have also had redesigns. The stone floor was replaced with a sand texture that has visible seams on the right side, and the rocks on the wall are slightly more repetitive than the original texture:

The mirror room is where things start breaking again. When it goes dark, the Gamecube version has some minor artifacts in the distance, while the PC version glitches out and displays the sky texture. This happens because of reduced draw distance in the ports. This doesn’t fix itself until you get far enough into the mirror room:

The mirror room has long been one of the biggest complaints among PC players because it never gets dark enough. It’s so well lit you could skip the whole room without activating a single mirror, but you can see even farther if you do activate one:

Particle effects such as water splashes have visible quality degradation in SADX because of alpha rejection and texture recompression. You can read more on alpha rejection in the Transparency section. Here’s what the water particles look like in SA1 and SADX:

The rocks in this area have slightly better UVs in SADX. Also note how SADX made all plants the same color:

This area was re-textured, using the same textures in places where it was previously using unique textures.

The panel glitch present in the original version (caused by a duplicate object entry in the SET file) was not fixed in the ports. Note how the transparent part of the panel’s texture got progressively worse with each port, and how the PC version’s texture lacks proper mirroring:

The PC version demonstrates massive texture quality reduction. You can see the box looks about the same in the Dreamcast and Gamecube versions, but loses a lot of detail in the PC version:

In conclusion, it is safe to say this level didn’t suffer as many issues in the Dreamcast-Gamecube transition as some other levels. Some issues seen in this level are general issues with SADX rather than level-specific problems. As Lost World didn’t have complex lighting or special effects, there wasn’t much the developers could break in it (but when there was, they did – like the mirror room in the PC version or ceiling lights in Act 1). You can play the original Dreamcast version of this level (which fixes issues with the mirror room, particles etc.) on PC with the Dreamcast Conversion mod. Find out more in the section on fixing the PC version of SADX.

Sky Deck downgrades

October 10, 2017November 10, 2023PkR

Like other Sonic games, every level in Sonic Adventure is designed around a certain theme. There is also some feature or special effect that is specific to a particular level. For Emerald Coast that is the ocean waves effect (removed in SADX), for Windy Valley it is the tornado etc. Sky Deck, a sky-themed level, also has a unique gimmick: every once in a while the Egg Carrier changes altitude, and the environment descends into darkness. The wind also gets stronger, sometimes blowing things away. Like other levels in Sonic Adventure, it was made to be visually impressive. The SADX version is missing several special effects, and the sky, which was the highlight of the original level, is mostly static. Let’s have a look at some of the most visible problems with this level.

In Sonic’s Act 1, you may notice that UVs on some models were stretched, but the textures remained the same resolution. This degrades the visuals slightly and makes the bottom of the cannon appear misaligned. Also note the near-complete absence of lighting in SADX screenshots:

The cloud layers in Sky Deck are completely static in SADX. Although making the layers scroll can be achieved with a simple hack, the sky is not moving in the ports. The lack of cloud movement makes the level feel empty and unfinished. The actual reason the clouds are static is a bug: the game still has code to adjust UVs but it uses the wrong model pointer.

Dreamcast	Gamecube

The first act has several areas where platforms are broken into pieces that fly off the screen. Broken platform debris are misrotated in SADX. While not a major issue, it makes the destroyed platforms look strange. Here’s what it looks like right after the cannon hits the platform:

As you progress through the level, you can notice that the sky gets darker when the Egg Carrier descends into the clouds. In the Dreamcast version the entire environment, including characters and objects, reacts to this by switching to a different lighting palette. In SADX, most of the environment ignores lighting changes. The PC version also adds fog that is too thick for this area and has a color that doesn’t fit too well because it makes things brighter when they are supposed to be darker:

Areas like these look a lot worse without proper lighting:

On the Dreamcast, the transition between “normal” and “dark” versions of the sky was smoother: before the sky changed texture, it faded out to white with an additive effect, and then faded back in with the new texture. Fog also became brighter and thicker during the transition, then it went back to “normal” mode, which also had a “dark” and a “light” version. All of the above details are lost in SADX. The sky texture changes abruptly, there is no fog adjustment, and the additive blending of the sky is missing.
*The PC version had the HD GUI mod enabled. This does not affect the visuals compared here.

Dreamcast	Gamecube	PC

In the original game you can hear Eggman’s announcements “Descending into the clouds, slow the ship down!” and “Go up – full speed ahead!” whenever the ship changes altitude in the first section of Act 2. These announcements are never heard in SADX because they were removed from the level’s soundbanks, even though the game still has the code to play them*. We can only speculate why, but my guess is they were removed after the SADX sound system was retooled to use fewer soundbanks. The Dreamcast version had Japanese and English soundbanks for some levels, while SADX only has the separate language versions of character voice soundbanks.

*The code to play the announcements is buggy and the announcements get cut off before they finish playing. This also happens in the Dreamcast version, but the problem got worse in SADX because the code was not adjusted for 60 FPS. The Sound Overhaul mod fixes both problems, and the announcements play properly at any framerate.

All three acts of Sky Deck have some texture changes. Some of the new textures look passable, others look less detailed and more washed out. The PC version suffers the most from this because the textures were mirrored and recompressed:

Act 3 has also had some retexturing work done in SADX. Some of the textures are recycled: for example, in the screenshots below the level piece uses a texture that is also used for the elevator in both versions of the game. There are also some yellow vertex colors placed sparsely around various level pieces, which arguably don’t fit the level’s theme:

The crane in the screenshots below survived the Gamecube transition, but got slightly broken in the PC version due to a texture mirroring issue. While in this particular instance there is no major issue, it’s worth pointing out what the crane is supposed to look like:

Some objects have lost their effects in the ports. For example, the cannon you fight at the end of Act 1 has simpler texturing and lacks its shiny metal surface in SADX. A similar change happened to the cannon at the end of Act 2:

The sky in Act 3 also looks different because all of its effects were removed in the ports. The Dreamcast version has a sky with moving clouds, which looks quite impressive in the scene where Sonic descends to the lower segment of the level. The Gamecube version doesn’t have moving clouds and you can only see the background. Both Gamecube and PC versions have skybox scale and draw distance issues that make the sky look broken. You can also see the metal struts have lost their transparency in SADX:

Here’s a video of this effect in motion. The visible cutoff is caused by reduced skybox draw distance in the ports.

Dreamcast	Gamecube

The glass walls inside cargo holds in Act 3 are supposed to be transparent, but the Dreamcast version is the only one that renders them correctly. SADX makes them opaque, which looks strange:

Minor but funny issue: the code for rendering the robot maid cleaning the floor behind the blue glass is broken and disables the glowing piece under her skirt (left – normal, right – disabled). It disappears only in one of her animations, and shows up if you pause the game. This happens because the variables in the function are in the wrong order.

An overview of Knuckles’ level shows the broken skybox again and a strange looking green fog that doesn’t fit the theme of the level too well. This is also likely the only area in the game where the PC version’s unnecessary processing of material colors fixes a problem – the bottom of the lever is no longer white:

Sky Deck doesn’t have too many downgrades from SA1 in terms of quantity, but quality-wise those downgrades are certainly some of the worst in the entire game – with lack of lighting, missing cloud movement and a broken skybox in Act 3. This level can be fixed with Dreamcast Conversion, where cloud movement is restored and various effects, such as additive blending for skybox transitions, are reimplemented. The Lantern Engine mod restores the vibrant palette lighting, and the Sound Overhaul mod adds back missing announcements in Act 2. To learn more how to install the mods, head over to the “Fixing the PC version of SADX” section.

Red Mountain downgrades

October 9, 2017November 10, 2023PkR

Red Mountain, particularly its first and third acts, was reworked in SADX to a more noticeable degree than other stages. Acts 1 and 3 have new textures and at least one new texture is higher resolution than the textures used in the Dreamcast level. Many people seem to genuinely prefer the SADX redesign, and perhaps Acts 1/3 are not the worst when it comes to SADX downgrades – unlike Act 2, which is a downgrade from the original in every aspect. However, even Acts 1/3 have some noticeable changes that can be seen as inferior to the Dreamcast version.

From a quick look it may seem that the SADX version of Red Mountain has higher resolution textures than its Dreamcast counterpart, but that isn’t entirely true. If you compare the textures between the Gamecube and Dreamcast versions, you’ll notice that there’s only one texture in the Gamecube/PC version that is 512×512, and the rest of the textures are mostly the same resolution as on the Dreamcast or lower. SADX replaces one 128×128 texture with a 256×256 one, but four 256×256 textures were also replaced with 16×16 textures in SADX. In addition, there are two extra textures on the Gamecube/PC.

Textures	Dreamcast	Gamecube
Total	45	47
512×512	0	1
256×256	10	9
128×128	11	9
64×64	19	19
32×32	3	3
16×16	0	4
8×8	2	2

Despite the increased total number of textures, the variety of them suffered a little bit. In the Dreamcast version there are three mountain textures: one used before the zipline (ai256_iwa31), one used after the zipline (ai256_iwa26) and one used near the end of the stage (d128side8a). In SADX there are only two: one before (ai256_iwa28) and one after the zipline (d128side8a). Both of them are less varied/colorful than their Dreamcast counterparts, and only the second texture is higher resolution than the Dreamcast version (and the only texture that is 512×512):

In Act 1 in particular, something happened to several textures in SADX: their resolution was reduced to 16×16, and their hue was shifted to make them blue. Two other textures were not shrunk but still received the blue coloration. These textures appear to be unused, which means that the SADX version of the level actually uses less textures than its Dreamcast counterpart.

Of course this is barely relevant without comparing the actual look of the level ingame, so let’s compare the start location between versions. The grass textures look more detailed in SADX, but the overall look is less colorful and the lighting is darker and less complex if you look at the badniks and objects:

The Dreamcast version conveys a more coherent impression of the “volcanic” nature of the area:

The ports have transparency and material color issues with cloud layers. In the Dreamcast version there are two layers of white clouds that move with different speeds, creating a “parallax” effect. This effect is barely noticeable in the Gamecube version (and the clouds move in a different direction), and completely gone in the PC version, which also gives the clouds a dirty grey color because of unnecessary processing of material colors:

Dreamcast	Gamecube	PC

All versions of SADX are also struggling with draw distance in this level, and the clouds don’t go far enough. They are also placed lower in SADX. In addition, the PC version has thick purple fog, which conflicts with the atmosphere because the color is a bit out of place:

The clouds not reaching far enough is particularly an issue in Knuckles’ level, where the exposed bottom part of the mountains looks like a black void. It becomes a noticeable problem when you go to the lower segments of the level:

The clouds also look less impressive from above in the PC version (which all the later console ports are based on), you can also see how the Dreamcast version of the level is generally brighter and more colorful than its SADX counterpart. Some levels (Big’s Ice Cap for example) changed from night to day, for this one you could say it changed from summer to late fall (Left: Dreamcast, Middle: Gamecube, Right: PC):

A recurrent problem with the ports is loss of detail in character lighting. The characters in the Dreamcast version often had palettes that matched the level’s theme, or had an otherwise unique effect. For example, in Red Mountain Act 1 Sonic is illuminated from one side with a yellow specular light. Although the Gamecube version had a character lighting system that could’ve been as capable as the Dreamcast version, the characters seldom have noticeable differences from the ordinary glossy look. The PC version’s character lighting is even worse than on the Gamecube because it disregards half of the coloration values left over from the console port.

Dreamcast	Gamecube	PC

In many levels in the Dreamcast version level geometry loaded in once you got close enough, much like objects in all versions of the game. In some cases, such as Windy Valley Act 3, the pop-in was noticeable enough to get annoying. SADX increases draw distance for some levels and changes the pop-in to work in a different way: instead of drawing the entire level geometry piece when the camera is within its range, the game only shows parts of it gradually as the camera gets closer. This can work well in combination with fog, but Red Mountain ended up getting problems that the Dreamcast version didn’t have. Here’s a video comparison of level geometry pop-in between versions. You can clearly see that the Dreamcast has no pop-in in this area, while SADX has a strange looking mountain partially showing and hiding itself in the background:

Dreamcast	Gamecube

This becomes noticeable enough once you climb up the mountain. This particular instance of pop-in was even reported as a bug with SADX mods!

The Dreamcast version doesn’t have this problem because it doesn’t draw the problematic level pieces at this distance. Also note the much better lighting and the subtle white fog that enhances the look of distant mountains.

The last area in Act 1 has some lighting detail removed. Note how the subtle glare is missing on the machinery and the surroundings:

Let’s end the discussion of Act 1 with a texture quality comparison. This is what the sky looks like in all 3 versions, the PC version again being the worst of all:

Act 2 is missing many lighting detail in SADX, although some vertex colors were added. The Dreamcast version’s lighting affected both the objects and the environment around them. Objects such as skulls, gravestones, boxes, badniks etc. are no longer tinted red on the Gamecube. Note how even the rings have some faint red glow in the Dreamcast version. The lighting system used in SADX does not allow for this kind of ambience:

The level itself has also largely lost its “red” theme, with the SADX version being darker and less colorful overall:

The following screenshot demonstrates how the loss of lighting affects the ambience of the level. Note how the skull becomes less distinguishable from the wall with each port:

The “redness” of the original level also worked quite well in motion. Here is a comparison of a section with rocks falling into lava, which has lost quite a bit of ambience in SADX:

Dreamcast	Gamecube

In the section outside the caves, the skybox is stretched and the clouds don’t go far enough:

One major change about the SADX redesign of Red Mountain is the new lava texture, which looks more detailed. The lava is less bright in the PC version because of unnecessary processing of material colors.

Red Mountain is one of the bigger redesigns in SADX, both due to its texture changes and different lighting. To get the original lighting back you can install the Lantern Engine mod, and to fix other downgrades you can use the Dreamcast Conversion mod. If you prefer the SADX redesign of the level, you can turn off Red Mountain in Dreamcast Conversion config in the Mod Loader and use the Gamecube Project mod. For more, check out the section about fixing the PC version of SADX.

Speed Highway downgrades

October 8, 2017November 10, 2023PkR

In the original Sonic Adventure, Speed Highway was one of levels that showcased the graphical capabilities of the Dreamcast to the fullest. When playing this level, you could feel that every little detail in it was designed to be a visual spectacle – much like in the rest of the game, but this particular level just pushed the hardware to the very limit. It was gorgeous to look at, with all the crazy lights, the roads going upside down, with helicopters and the police chasing after you. The scene with Sonic running down the side of a building is one of the most memorable moments in the entire game.

The SADX version of the level has had a number of changes, some arguably conflicting with the original atmosphere from the Dreamcast version. From the start you can see how the lighting sets a completely different tone for the stage, making it darker and eerie green. The PC version’s lighting is almost non-existent:

The windows are lit up in the Dreamcast version, while on the Gamecube/PC they use the “lit up” texture but lack brightness. This could be considered an oversight, as it would’ve been simple to make the windows brighter – it’s a single material flag. On the Dreamcast, there are buildings (see the helicopter comparison) where only some of the lights are lit up, which creates original looking patterns. This is missing in later versions of the game.

The breakable glass has almost completely lost its environment mapping effect, as well as its unique texture. It is now using a green texture similar to the rest of glass surfaces elsewhere in SADX.

In all versions except the Dreamcast original there is a bug with the red transporter. Its model has a material flag that enables transparency on an opaque mesh, which breaks the game’s draw queue system and makes parts of level geometry visible through the mesh. It’s especially noticeable in motion.

Dreamcast	Gamecube

The grabber basket that brings Sonic to the upper level has lost its shiny surface (environment mapping) and is now properly textured instead.

Dreamcast	Gamecube

The helicopter went through a similar transformation, only retaining the shiny effect on its windows. A building with partially lit windows is present in the Dreamcast version. The window pattern is gone in later versions.

Here’s another example of this change from Act 3: the cars are no longer shiny and use the same green glass texture as many other areas in SADX:

The Dreamcast models for cars use a low-resolution texture and distort it to get a “metallic” looking surface. This effect is used by many models in SA1 and SADX – the lion in Casinopolis, icicles (SA1 only), window reflections in Station Square, cars (full models in SA1, windows only in SADX) etc. The Dreamcast version certainly relied a lot on this effect.

The removal of environment mapping in this particular case can be considered both a good and a bad change: although the textures allow for more detail, the “metallic” effect is gone.

Speed Highway has several objects with blinking lights, which are seen more often in Tails’ level. This radar/satellite dish tower has a glowing light at the top, for example. In SADX its light was disabled.

Dreamcast	Gamecube

Another missing effect is the rotating lights inside the bottom part of this type of platform in Tails’ stage:

Dreamcast	Gamecube

The lights are still there, but you can’t see them because SADX is struggling with transparency.

The lights on Eggman’s missile were not removed, but for some reason their blinking is broken in the PC version:

Dreamcast	Gamecube	PC

If you look closely, you can see that the smoke effect looks lower resolution in the PC version. This is caused by alpha rejection, more on that in the Transparency section.

Texture quality suffers again, especially in the PC version, where some textures are half of their original resolution in addition to having been recompressed multiple times:

Act 2 has also lost some ambience: the red fog near the bottom is gone, and the updated glass texture doesn’t seem to fit the level’s theme:

The colorful ambience of the original level is darker in the ports:

Strangely, at the end of Act 2, there are no rings to collect using the magnetic shield that you get slightly earlier.

The buildings in Act 3 had two effects in the Dreamcast version: you could see the skybox and parts of the level through the windows because they were semi-transparent (so it looked like a reflection), and the texture on the windows themselves had environment mapping:

Dreamcast	PC (same as Gamecube)

The SADX version of the level has no such effects. Although all versions of the game still support environment mapping, the windows in this stage use a static opaque green texture that never changes regardless of where the camera is.

Act 3 in general appears to have lost a lot of its original atmosphere. Here’s a comparison of the starting point as Knuckles. The Dreamcast version sets a different tone for this level. The PC version adds fog that washes out the details even more:

If you walk around the stage a little bit, you’ll notice that the advertisement boards on the roof look strange in SADX. The model is rendered in an incorrect order:

Since the PC version processes material colors, broken container bottoms now have a green tint.

The fountain uses a different model in SADX, possibly to mask issues with self-blending objects and transparency order.

The Dreamcast version had dynamic fog in this level, which got thicker in some areas (possibly to improve framerate), but reduced in other areas to improve visibility. Even when the fog got thicker, the areas close to the player were not obscured by it. The Gamecube version gets rid of the fog altogether in this level, while the PC version brings it back, but fog distance is never adjusted on PC, which makes it wash out the colors:

Here’s an area where the fog goes away on the Dreamcast. As you can see, the colors in the level are constantly washed out in the PC version because the distance where fog begins is much closer to the player:

The Master Emerald pieces have lost their shading in SADX and look a lot brighter and less transparent overall.

Speed Highway is one of the levels in SADX that received a large number of changes. Some of these changes, such as the green vertex coloring in Act 1, go in a completely different direction than the original Dreamcast level.

With Lantern Engine you can play this level with original lighting, and with Dreamcast Conversion you can have this level reverted to the original version with all transparency effects restored, as well as tweaked fog for better visuals. Check out the “Fixing the PC version of SADX” to find out how to install these mods.

Twinkle Park downgrades

October 6, 2017November 10, 2023PkR1 Comment

Twinkle Park is one of the areas that received a heavier redesign in SADX. When compared against the Dreamcast original, it almost looks like a different stage. However, there are many areas where this stage falls short of being a decent improvement over its previous version.

Right from the start you can see the dramatic difference in lighting. The Gamecube version sets a completely different mood for the stage. The variety of colors is reduced significantly, and the lighting on Sonic and the level itself doesn’t have much variety. The PC version takes the Gamecube’s already simple lighting and reduces it further.

A close-up of Sonic’s model in the Dreamcast version reveals an impressive amount of lighting detail (for a 1998 game) that was made possible thanks to the Dreamcast version’s LANTERN engine. Note the overall coloration of the model and how the bottom of Sonic’s quills is shaded differently than the rest of his body. A similar look could’ve been achieved with the character lighting system in the Gamecube version, but for some reason the lighting on characters is toned down. The PC version is even less capable than the Gamecube version when it comes to character lighting:

The original version of Twinkle Park had a bright solid ceiling for this area, which was replaced with a glass ceiling in SADX. We know SADX has problems with transparent things, and this part is no exception. As a result, the redesigned ceiling is suffering from issues the original one didn’t have:

The brightness of neon lights was reduced in the ports. All lights in Twinkle Park Act 1 have had their brightness reduced in SADX, the PC version having the dimmest lights. Note how the ceiling lights are also suffering from transparency issues in SADX. The light texture, which was already low resolution in the original game, has visible quality degradation in SADX:

This light in particular has suffered the most, it seems:

As you progress through the kart race, you see some planets and asteroids spinning in the air. An interesting detail about the asteroids in SA1 is that they have the same lighting as the characters, which illuminates them softly from the bottom. While this is technically still in SADX, you can’t see it because character lighting has been simplified. Also note how the wall texture is stretched out more in SADX despite having a similar overall design:

The second act also has lighting differences. A brief glimpse over this area reveals how much ambience was lost in the Gamecube version, and how the PC version reduces it even further. To be fair, the Gamecube version looks different, but it’s not completely broken, and at least it looks like it has lighting, whereas the PC version is almost entirely fullbright. Not even the objects are lit properly in the PC version:

There are vivid color transitions in the Dreamcast version’s lighting, which are more subtle on the Gamecube, although in some areas it has more detail:

With all its differences, some people may prefer the Gamecube version’s redesign of Twinkle Park. At the same time there are some changes that make the level look lower quality due to the usage of low resolution textures. This one, for example:

The potted plants from the Dreamcast version were redesigned to use higher-poly models with a simpler object hierarchy, likely to work around transparency problems, but even the replacement models are suffering from transparency issues:

Some issues in this level plague all versions of SADX, and some are specific to the PC version. For example, the crown that you see after each bowling area has broken UVs only in SADX PC:

This is caused by an inconsistent change in the PC version related to texture mirroring (more on that in the Textures section). For some reason the developers mirrored some textures manually and adjusted UVs on some models to accommodate for the change. The textures were mirrored horizontally, vertically or in both directions. This is what it looks like:

As you can see, texture mirroring had a negative impact on texture quality because the mirrored texture had to be stretched or squeezed. When applied to the model, the trap door texture (bottom) is only quarter of its original size (half the resolution of the original texture). However, manual mirroring is unnecessary in the PC port. The PC version’s native mirroring works fine and is still used for a lot of models that weren’t updated. The crown happens to be one of such models – the developers updated the UVs for other models that use the same texture, but didn’t update the crown model.

Here’s another example of broken UV mapping. The textures on this object were consistent with the rest of the roof on the Dreamcast, but somehow it broke in both PC and Gamecube versions – which is relatively rare as most UV issues are PC-specific:

Another PC-specific issue causes some models to be colored incorrectly. For example the Buyon badnik has different colors only in the PC version:

While this might seem like a minor change, there’s a technical reason behind this issue, and it causes loss of detail in many cases. When rendering a model, console versions of SADX usually ignore the model’s material colors. The PC version and later ports don’t ignore them, and the models end up colored in strange ways. For example, Chaos 0 is blue only in the PC version and later ports (even though his textures are still green), and the jungle in the Mystic Ruins looks broken partially because the PC version and later ports process its material colors. There are many cases like these throughout the game.

There are supposed to be two Sweep badniks in the second act of Twinkle Park, but only one shows up in SADX despite being included in the game’s SET file. There is a programming error preventing it from spawning properly, which can be avoided by moving the badnik’s position slightly.

Amy’s stage has also suffered from downgrades in SADX in several aspects. First, the fog that enhances the spooky atmosphere in the original level is reduced in the ports. You can now see all the way till the end of the corridor, which is brightly lit too:

The mirror halls have also been reworked in the ports. On the Dreamcast, there are three layers of mirrors on each side. In SADX there are only two layers of mirrors on each side, and even those glitch out randomly as you make your way through the corridor:

Note how the Dreamcast version also manages to render more reflected paths and doesn’t reveal level geometry from another area. The differences in lighting are also noticeable here.

This is what the mirror rooms look like from above. The SA1 version (right) has six mirror layers in total for each room, while the SADX version (left) has only four. You can also see that the distant paths, which “reflect” in the mirrors on the Dreamcast, are missing in SADXю

In SADX the mirrors disappear randomly as you progress through the hall, which is noticeable during regular gameplay, but here’s a more clear illustration using first-person camera in the Gamecube version. This doesn’t happen in the original game as the Dreamcast doesn’t have to deal with transparency sorting issues.

The trap door uses a simpler tiling pattern and is more obvious in SADX. The noticeably low texture quality in the PC version is the result of recompression and texture mirroring:

In the Dreamcast version several trap doors were placed underneath the floor near the end of this area, which gave the bottom of the stage a strange look. In SADX those were removed and the floor model was updated to no longer be hollow on the inside. Although the platforms created a sense of depth in the original game, the replacement isn’t a bad alternative overall.

On the note of transparency issues, Amy’s escape balloon is no longer transparent in SADX, but it can’t be helped as such objects are difficult to render properly with the game’s engine limitations:

As a redeeming factor, the vertex colors in this area create a convincing corridor lit up by candles. The corridor in the Dreamcast version doesn’t have this kind of lighting. The PC version again looks brighter, but at least it retains the shadowing:

Another improvement in SADX is the pirate ships. Rather than using a low-resolution environment map they are now properly textured:

Apart from the above improvements, the SADX version of Twinkle Park suffers from downgrades in comparison to the original game. The majority of these downgrades are fixed in the Dreamcast Conversion mod, which reverts the level to its original Dreamcast version while fixing some parts of it to work properly in SADX. For those who prefer the SADX look of the level, the Lantern Engine mod adds back Dreamcast lighting that blends together with the vertex colors in the SADX level, and the Gamecube Project mod improves texture quality. Learn more about the mods in the “Fixing the PC version of SADX” section of this blog.

Windy Valley downgrades

October 6, 2017November 10, 2023PkR

From a quick look it might seem that Windy Valley didn’t change from SA1 to SADX. The first two acts are short, and the last act doesn’t have complex lighting or any particularly difficult special effects. Unfortunately even Windy Valley has some serious issues in the ports.

Act 1 is the area where you can notice the ports’ inferior texture quality. This is what you see right after entering the stage. The PC version screenshot has mipmaps enabled in the Mod Loader, normally it looks even worse.

Notice how the Gamecube version’s fake lighting, which admittedly looks pretty good in this area, didn’t carry over to the PC port. To compensate for the loss of the Dreamcast’s palettized lighting, some textures, such as the rocky walls, were made darker. In addition, there’s a color mismatch between the grass and the path texture’s edge in SADX, which could be either a design inconsistency or a side effect of texture recompression in the ports.

The textures in the PC version also lack mipmaps, which makes distant areas look problematic, especially in motion. Any movement reduces distant textures into a pixelated mess. It can be made to look better with anisotropic filtering, but it won’t look as good as real mipmaps. Thankfully SADX Mod Loader has automatic mipmap generation to correct that, and before the Mod Loader there were mods that added mipmaps to the PC version. Back when the PC port came out it looked like this (You can read more on it in the Textures section):

Several parts of the scenery are missing throughout the whole Act 1. For example, most of the wind turbines in the screenshots below are present in the Dreamcast version, but gone in SADX Gamecube and PC:

An interesting detail about the Dreamcast Windy Valley is its transparent skybox. The level pieces that are suspended in the air look like they are partially submerged in water. In the ports the skybox was made bigger and the effect was removed. It seems that the developers have tried to compensate for it by adding greenish vertex colors to the pieces involved, but it doesn’t look too convincing because the skybox is still far away. In addition, because the skybox is bigger and lacks transparency in SADX, the “parallax” effect seen in the original game when multiple layers scroll at different speeds is gone in SADX as the bottom layer of the skybox is invisible.

The Dreamcast version has dynamic fog that changes color and intensity depending on where you are in the level. When the tornado appears, the fog is supposed to get darker and thicker, but this effect is broken in the ports.

In the Dreamcast version, fog is often used to enhance the overall ambience of an area. For example, in Windy Valley Act 2 there is greyish-blue fog – a subtle, but effective touch to create the feeling of being inside a tornado. This effect is gone in SADX because fog is turned off for the area:

The following area has missing textures in SADX because of unnecessary material flags and/or incorrect texture conversion. The original Dreamcast level also has these wrong flags but the game processes the meshes correctly.

All later ports have strange-looking overhanging ropes on the collapsing bridge. Interestingly similar bridges in Ice Cap and Red Mountain (which use the same code) are unaffected. Some time ago I found out this is caused by a model change – for some reason the developers stretched the model used for vertical ropes. The UVs on the ropes are also stretched, which suggests it may have been done by accident. Also notice how the lighting on Sonic and the objects fits the environment in the Dreamcast version, while the Gamecube version’s lighting is more generic.

Act 3 begins with color banding in the sky, which looks odd in all versions of the game, but each more makes it more apparent.

Issues with transparency shows up on a few paths in this act. To work around transparency problems, the ports use alpha rejection – a feature that doesn’t let the engine display pixels whose transparency is beyond a certain threshold. It’s not the worst solution for its time, and it would’ve been an okay compromise if it didn’t break a substantial amount of unrelated special effects. The Dreamcast version didn’t have any drawbacks associated with transparency and alpha rejection. More on this in the Transparency section. Here’s what alpha rejection is used for in this level:

The third act also had a subtle white fog effect, which made it look like the area was bathing in sunshine. The effect is gone in SADX – while the fog is still there, its color was changed to a duller one, and fog distances were adjusted farther so there is no visible coloration on nearby objects and level geometry. This would’ve worked better in Emerald Coast to prevent washing out the sand color in the PC version.

Finally, the “goal” emerald’s pulsating glow is missing in SADX.

The removal of the glow effect is a relatively minor issue. However, as this blog demonstrates, the entire game has many details removed in every level, and after so many downgrades it ends up losing its charm. Together with the removed lighting and reduced texture quality the “enhanced port” does not compare favorably to the Dreamcast original. In the PC version, this level can be improved significantly by reverting to the original Dreamcast version of level models, fixing texture quality by using textures from the original game, and adding back fog effects and palettized lighting from the Dreamcast. More on that in the “Fixing the PC version of SADX” section.