diff options
Diffstat (limited to 'src/code')
| -rw-r--r-- | src/code/PreRender.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/src/code/PreRender.c b/src/code/PreRender.c index dc12fd2a5..0a1b0f2cf 100644 --- a/src/code/PreRender.c +++ b/src/code/PreRender.c @@ -361,7 +361,11 @@ void PreRender_FetchFbufCoverage(PreRender* this, Gfx** gfxp) { Gfx* gfx = *gfxp; gDPPipeSync(gfx++); - // Set the blend color to full white and set maximum depth + // Set the blend color to full white and set maximum depth. + // It is important that at least dz is set to full here as the blender will shift memory alpha values based on the + // value of dz even if depth compare is disabled. If per-pixel depth was enabled, fill rectangle always uses 0 z/dz, + // causing a maximal shift of 4 to be applied to the memory alpha value. Full dz results in no shift, which is + // desired here. gDPSetBlendColor(gfx++, 255, 255, 255, 8); gDPSetPrimDepth(gfx++, 0xFFFF, 0xFFFF); @@ -372,9 +376,10 @@ void PreRender_FetchFbufCoverage(PreRender* this, Gfx** gfxp) { // FORCE_BL : Apply the blender to all pixels rather than just edges, skip the division step of the blend formula // (G_BL_CLR_IN * G_BL_0 + G_BL_CLR_BL * G_BL_A_MEM) = G_BL_CLR_BL * G_BL_A_MEM // - // G_BL_A_MEM ("memory alpha") is coverage, therefore this blender configuration emits only the coverage (up to a - // constant factor determined by blend color) and discards any pixel colors. For an RGBA16 framebuffer, each of the - // three color channels r,g,b will receive the coverage value individually. + // G_BL_A_MEM ("memory alpha") is coverage (shifted into the most significant 3 bits of the 5-bit blender alpha + // input), therefore this blender configuration emits only the coverage (up to a constant factor determined by + // blend color) and discards any pixel colors. For an RGBA16 framebuffer, each of the three color channels r,g,b + // will receive the coverage value individually. // // Also disables other modes such as alpha compare and texture perspective correction gDPSetOtherMode(gfx++, |