Games with a build per 3D card: Glide, ATI3DCIF and the S3D Toolkit

What to know

Before Direct3D settled, many games shipped one executable per 3D card: a software build, a 3dfx Glide build, an ATI Rage build, an S3 ViRGE build, sometimes an MMX build. The builds share most of their code. Pick one reference build and match the others to it. Then trace only what differs. Read the imports first. They name the API. They also show how much each build hands to the card.

• Find the API. Run peinfo GAME.EXE --imports. glide.dll or glide2x.dll is Glide 2.x, glide3x.dll is Glide 3, ati3dcif.dll is ATI3DCIF, S3DTKW.dll is the S3D Toolkit. Some builds load the DLL with LoadLibrary. Search the strings for those builds (docs/hardware/card-apis.md).
• Clues in the imports. A Glide build that does not import ddraw.dll draws everything through the Voodoo. An ATI3DCIF build without ATI3DCIF_TextureReg never gives the chip a texture.
• Match the builds. Run match_functions.py on two builds to carry labels from the reference build to the others. Then list which data files each build reads. Another build may read a field that the reference build skips.
• Pick the reference. The software build is usually the one to copy exactly. The card builds show what was drawn differently. Record which build each finding comes from.
• Measure what the card gets. A build named after a card does not always give the card the scene. POD's ATI Rage and S3 ViRGE builds draw the textured track and cars with the game's software renderer, into DirectDraw surfaces at 640 × 480. They give the chip only the untextured faces: shadows and light beams (measured: in one race the S3 build made 15,000 S3DTK_TriangleSet calls, all Gouraud. It never made a texture surface). Redrawing such a build's card calls at a higher resolution sharpens only what the card drew. Count the card calls by kind in one real scene, and check whether texture surfaces are ever made, before choosing between scaling the finished frame and redrawing it.
• Running a card build today. Glide needs a wrapper that translates it to a modern API (dgVoodoo 2 or nGlide on Windows), or a virtual machine with an emulated Voodoo card (86Box). Wine has none of the card libraries, so a build that imports one does not start (missing card library). Another way is a replacement written for the game (a Glide 2 replacement, S3D Toolkit return values, ViRGE pixels). Start with the software build.
• MMX builds. docs/hardware/simd.md covers a separate MMX executable and a path chosen by CPUID.