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fog

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This commit is contained in:
StapleButter
2017-05-26 15:14:22 +02:00
parent a63ab24447
commit 6f4d835c7f
3 changed files with 89 additions and 12 deletions
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75
src/GPU3D_Soft.cpp
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@ -1027,6 +1027,9 @@ void RenderPolygonScanline(RendererPolygon* rp, s32 y)
if ((dstattr & 0x7F000000) == (attr & 0x7F000000))
continue;
if (!(dstattr & (1<<15)))
attr &= ~(1<<15);
u32 dstcolor = ColorBuffer[pixeladdr];
u32 dstalpha = dstcolor >> 24;
@ -1106,6 +1109,78 @@ void RenderScanline(s32 y, int npolys)
if (y >= polygon->YTop && (y < polygon->YBottom || (y == polygon->YTop && polygon->YBottom == polygon->YTop)))
RenderPolygonScanline(rp, y);
}
if (RenderDispCnt & (1<<7))
{
// fog
// hardware testing shows that the fog step is 0x80000>>SHIFT
// basically, the depth values used in GBAtek need to be
// multiplied by 0x200 to match Z-buffer values
bool fogcolor = !(RenderDispCnt & (1<<6));
u32 fogshift = (RenderDispCnt >> 8) & 0xF;
u32 fogoffset = RenderFogOffset * 0x200;
u32 fogR = (RenderFogColor << 1) & 0x3E; if (fogR) fogR++;
u32 fogG = (RenderFogColor >> 4) & 0x3E; if (fogG) fogG++;
u32 fogB = (RenderFogColor >> 9) & 0x3E; if (fogB) fogB++;
u32 fogA = (RenderFogColor >> 16) & 0x1F;
for (int x = 0; x < 256; x++)
{
u32 pixeladdr = (y*256) + x;
u32 attr = AttrBuffer[pixeladdr];
if (!(attr & (1<<15))) continue;
u32 z = DepthBuffer[pixeladdr];
u32 densityid, densityfrac;
if (z < fogoffset)
{
densityid = 0;
densityfrac = 0;
}
else
{
z = (z - fogoffset) << fogshift;
densityid = z >> 19;
if (densityid >= 32)
{
densityid = 32;
densityfrac = 0;
}
else
densityfrac = z & 0x7FFFF;
}
// checkme
u32 density =
((RenderFogDensityTable[densityid] * (0x80000-densityfrac)) +
(RenderFogDensityTable[densityid+1] * densityfrac)) >> 19;
if (density >= 127) density = 128;
u32 srccolor = ColorBuffer[pixeladdr];
u32 srcR = srccolor & 0x3F;
u32 srcG = (srccolor >> 8) & 0x3F;
u32 srcB = (srccolor >> 16) & 0x3F;
u32 srcA = (srccolor >> 24) & 0x1F;
if (fogcolor)
{
srcR = ((fogR * density) + (srcR * (128-density))) >> 7;
srcG = ((fogG * density) + (srcG * (128-density))) >> 7;
srcB = ((fogB * density) + (srcB * (128-density))) >> 7;
}
if (densityid > 0)
srcA = ((fogA * density) + (srcA * (128-density))) >> 7;
else
srcA = ((0x1F * density) + (srcA * (128-density))) >> 7; // checkme
ColorBuffer[pixeladdr] = srcR | (srcG << 8) | (srcB << 16) | (srcA << 24);
}
}
}
void ClearBuffers()