MarkEHenderson
commented
1 month ago Note: I suspect these draw calls would work if they were categorized as terrain, but since the colorTexture1 is unstable (dynamically generated on the cpu), there's no way to reliably categorize them.
I suspect we'll need to enable categorization and replacement by colorTexture2 to really make this effect work.
Alternatively, @Arrokoth7323 would it be possible to get the game to swap the textures, so that colorTexture1 is the stable texture (either the grid or the grass texture) and colorTexture2 is the mask? If so, you could probably label them as terrain to get stuff to work properly.
Arrokoth7323
NV-LL
Describe the bug
Context:
For the game Star Wars Empire at War (Directx9.0c), we have a odd issue. There is multiple shaders which use fixed function calls to blend textures to produce one output.
Space Fog of War: A fog of war mask texture is generated by the CPU to indicate in real time using a alpha channel, where units can see on a 2d plane. This is seen as a corresponding white texture with an alpha of where units can see is generated. This is combined with a generic diffuse texture for a grid which should have its color and alpha "blended" with the fog of war texture.
Land Terrain Textures: A mask texture is generated by the CPU to indicate on a cell of the map where a certain terrain texture should be painted. This is seen as a corresponding white texture. This is combined with a generic diffuse texture for the type of terrain (grass/rock/dirt/etc.) which should have its color "blended" with the mask texture. The game splits a "cell" of a terrain into chunks based on where a certain terrain texture is painted. Hence a separate grid like mesh to created, split from the original square cell. The texture is then painted onto the new mesh within the now split cell.
Issue Observed:
When handling two color textures. Remix will read colorTexture1 and will display said colorTexture1 without blending the color or alpha of colorTexture2.
For Space Fog of War this means the white mask texture (colorTexture1) with the alpha which indicates where units currently see, becomes the only visible texture. The grid texture's (colorTexture2) color and alpha is not blended with the mask texture.
For Land Terrain Textures the mask texture (colorTexture1) generated to indicate where to display a terrain diffuse texture (colorTexture2) within a cell becomes the only visible texture. The terrain diffuse texture color is not blended with the mask texture.
colorTexture1 & colorTexture2 will be read by Remix and present in the list of textures on the side for Space Fog of War. However for Land Terrain Texture only colorTexture1 will be present. If you ignore the skydome texture, then mark the terrain white mask texture as Skybox, the proper blended Terrain Texture becomes visible. However it is not read by Remix at said point and hence no render calls (lighting) are made on it, so this "workaround" is pointless.
I ultimately believe these two issues are very similar in scope and hence could share a single fix.
Code:
As mentioned prior, Empire at Wars shaders are all purpose built with fallback fixed function techniques to ensure compatibility with less-powerful graphics cards of the time. See below for each of the above issues, the corresponding shader technique code, to get an idea of the fixed function calls used.
Space Fog of War (Shader Name: SpaceFogOfWar.fx):
}
technique t3 < string LOD="FIXEDFUNCTION";
}