rewrite of aa code

should behave identically
This commit is contained in:
Jaklyy 2023-10-18 00:36:53 -04:00
parent ed79b1772c
commit 0c8095c1bb
2 changed files with 19 additions and 36 deletions

View File

@ -1063,14 +1063,11 @@ void SoftRenderer::RenderPolygonScanline(RendererPolygon* rp, s32 y)
if (x < 0) x = 0;
s32 xlimit;
s32 xcov = 0;
// part 1: left edge
edge = yedge | 0x1;
xlimit = xstart+l_edgelen;
if (xlimit > xend+1) xlimit = xend+1;
if (xlimit > 256) xlimit = 256;
if (l_edgecov & (1<<31)) xcov = (l_edgecov >> 12) & 0x3FF;
if (!l_filledge) x = xlimit;
else
@ -1129,14 +1126,12 @@ void SoftRenderer::RenderPolygonScanline(RendererPolygon* rp, s32 y)
// anti-aliasing: all edges are rendered
// calculate coverage
s32 cov = l_edgecov;
if (cov & (1<<31))
attr |= (l_edgecov >> 5) << 8;
if (x < xlimit-1)
{
cov = xcov >> 5;
if (cov > 31) cov = 31;
xcov += (l_edgecov & 0x3FF);
l_edgecov += rp->SlopeL.XCov_Incr;
if (l_edgecov > 0x3FF) l_edgecov = 0x3FF;
}
attr |= (cov << 8);
// push old pixel down if needed
if (pixeladdr < BufferSize)
@ -1255,7 +1250,6 @@ void SoftRenderer::RenderPolygonScanline(RendererPolygon* rp, s32 y)
edge = yedge | 0x2;
xlimit = xend+1;
if (xlimit > 256) xlimit = 256;
if (r_edgecov & (1<<31)) xcov = (r_edgecov >> 12) & 0x3FF;
if (r_filledge)
for (; x < xlimit; x++)
@ -1313,14 +1307,12 @@ void SoftRenderer::RenderPolygonScanline(RendererPolygon* rp, s32 y)
// anti-aliasing: all edges are rendered
// calculate coverage
s32 cov = r_edgecov;
if (cov & (1<<31))
attr |= (r_edgecov >> 5) << 8;
if (x < xlimit-1)
{
cov = 0x1F - (xcov >> 5);
if (cov < 0) cov = 0;
xcov += (r_edgecov & 0x3FF);
r_edgecov -= rp->SlopeR.XCov_Incr;
if (r_edgecov < 0) r_edgecov = 0;
}
attr |= (cov << 8);
// push old pixel down if needed
if (pixeladdr < BufferSize)

View File

@ -246,7 +246,7 @@ private:
Interp.Setup(0, 0, 0, 0);
Interp.SetX(0);
xcov_incr = 0;
XCov_Incr = 0;
return x0;
}
@ -322,7 +322,7 @@ private:
Interp.SetX(y);
// used for calculating AA coverage
if (XMajor) xcov_incr = (ylen << 10) / xlen;
if (XMajor) XCov_Incr = ((ylen << 10) / xlen) & 0x3FF;
return x;
}
@ -373,9 +373,11 @@ private:
// fix the y value for negative slopes
s32 ycoord = Negative ? (ylen << 10) - startcov >> 10 : startcov >> 10;
// if yvalue is not equal to actual y value, invert coverage value
if (ycoord != y - y0) startcov = 0x3FF - (startcov & 0x3FF);
startcov &= 0x3FF;
if (ycoord != y - y0) startcov = 0x3FF - startcov;
if (side ^ swapped) startcov = 0x3FF - startcov;
*coverage = (1<<31) | (startcov << 12) | (xcov_incr & 0x3FF);
*coverage = startcov;
if constexpr (swapped) *length = 1;
}
@ -389,26 +391,17 @@ private:
{
// for some reason vertical edges' aa values
// are inverted too when the edges are swapped
if constexpr (swapped)
*coverage = 0;
else
*coverage = 31;
*coverage = swapped ? 0 : 31 << 5;
}
else
{
s32 cov = ((dx >> 9) + (Increment >> 10)) >> 4;
if ((cov >> 5) != (dx >> 18)) cov = 31;
cov &= 0x1F;
if constexpr (swapped)
{
if (side ^ Negative) cov = 0x1F - cov;
}
else
{
if (!(side ^ Negative)) cov = 0x1F - cov;
}
if (side ^ !Negative ^ swapped) cov = 0x1F - cov;
*coverage = cov;
// shift left 5 just to make it align with xmajor coverage values
*coverage = cov << 5;
}
}
@ -425,15 +418,13 @@ private:
bool Negative;
bool XMajor;
Interpolator<1> Interp;
s32 XCov_Incr;
private:
s32 x0, y0, xmin, xmax;
s32 xlen, ylen;
s32 dx;
s32 y;
s32 xcov_incr;
s32 ycoverage, ycov_incr;
};
template <typename T>