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attempt to optimize quotient/remainder calc

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This commit is contained in:
Jaklyy
2024-03-17 14:00:49 -04:00
parent ee91d7f8f3
commit 9ee9389ee1
2 changed files with 41 additions and 30 deletions
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43
src/GPU3D_Soft.h
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@ -69,23 +69,33 @@ private:
{
public:
constexpr Interpolator() {}
constexpr Interpolator(s32 x0, s32 x1, s32 w0, s32 w1)
constexpr Interpolator(s32 x0, s32 x1, s32 w0, s32 w1, bool wbuffer, s32 z0, s32 z1)
{
Setup(x0, x1, w0, w1);
Setup(x0, x1, w0, w1, wbuffer, z0, z1);
}
constexpr void Setup(s32 x0, s32 x1, s32 w0, s32 w1)
constexpr void Setup(s32 x0, s32 x1, s32 w0, s32 w1, bool wbuffer, s32 z0 = 0, s32 z1 = 0)
{
this->x0 = x0;
this->x1 = x1;
this->xdiff = x1 - x0;
this->wbuffer = wbuffer;
// calculate reciprocal for Z interpolation
// TODO eventually: use a faster reciprocal function?
if (this->xdiff != 0)
this->xrecip_z = (1<<22) / this->xdiff;
else
this->xrecip_z = 0;
// calculate quotient and remainder for Z interpolation
if (!dir && !wbuffer && xdiff != 0)
{
if (z0 < z1)
{
// remainder is unused for this path
this->zquo = ((z1 - z0) >> 1) / xdiff;
}
else
{
// should optimize down to one divide instruction
this->zquo = ((z0 - z1) >> 1) / xdiff;
this->zrem = ((z0 - z1) >> 1) % xdiff;
}
}
// linear mode is used if both W values are equal and have
// low-order bits cleared (0-6 along X, 1-6 along Y)
@ -164,7 +174,7 @@ private:
}
}
constexpr s32 InterpolateZ(s32 z0, s32 z1, bool wbuffer) const
constexpr s32 InterpolateZ(s32 z0, s32 z1) const
{
if (xdiff == 0 || z0 == z1) return z0;
@ -194,9 +204,9 @@ private:
{
// these algorithms are weiiird but i can't argue with the results
if (z0 < z1)
return z0 + ((z1-z0 >> 1) / xdiff * x << 1);
return z0 + ((zquo * x) << 1);
else
return z1 + (((z0-z1 >> 1) / xdiff * (xdiff-x)) + ((z0-z1 >> 1) % xdiff) << 1);
return z1 + ((zquo * (xdiff-x) + zrem) << 1);
}
}
}
@ -206,8 +216,9 @@ private:
int shift;
bool linear;
bool wbuffer;
s32 xrecip_z;
s32 zquo, zrem;
s32 w0n, w0d, w1d;
u32 yfactor;
@ -231,7 +242,7 @@ private:
Increment = 0;
XMajor = false;
Interp.Setup(0, 0, 0, 0);
Interp.Setup(0, 0, 0, 0, false);
Interp.SetX(0);
xcov_incr = 0;
@ -239,7 +250,7 @@ private:
return x0;
}
constexpr s32 Setup(s32 x0, s32 x1, s32 y0, s32 y1, s32 w0, s32 w1, s32 y)
constexpr s32 Setup(s32 x0, s32 x1, s32 y0, s32 y1, s32 w0, s32 w1, s32 y, bool wbuffer)
{
this->x0 = x0;
this->y = y;
@ -305,7 +316,7 @@ private:
s32 x = XVal();
int interpoffset = (Increment >= 0x40000) && (side ^ Negative);
Interp.Setup(y0-interpoffset, y1-interpoffset, w0, w1);
Interp.Setup(y0-interpoffset, y1-interpoffset, w0, w1, wbuffer);
Interp.SetX(y);
// used for calculating AA coverage