melonDS/GPU3D_Soft.cpp

883 lines
28 KiB
C++

/*
Copyright 2016-2017 StapleButter
This file is part of melonDS.
melonDS is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your option)
any later version.
melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with melonDS. If not, see http://www.gnu.org/licenses/.
*/
#include <stdio.h>
#include <string.h>
#include "NDS.h"
#include "GPU.h"
namespace GPU3D
{
namespace SoftRenderer
{
u32 DispCnt;
u32 AlphaRef;
u32 ColorBuffer[256*192];
u32 DepthBuffer[256*192];
u32 AttrBuffer[256*192];
// attribute buffer:
// bit0-5: polygon ID
// bit8: fog enable
bool Init()
{
return true;
}
void DeInit()
{
}
void Reset()
{
memset(ColorBuffer, 0, 256*192 * 4);
memset(DepthBuffer, 0, 256*192 * 4);
memset(AttrBuffer, 0, 256*192 * 4);
}
void TextureLookup(u32 texparam, u32 texpal, s16 s, s16 t, u16* color, u8* alpha)
{
u32 vramaddr = (texparam & 0xFFFF) << 3;
u32 width = 8 << ((texparam >> 20) & 0x7);
u32 height = 8 << ((texparam >> 23) & 0x7);
s >>= 4;
t >>= 4;
// texture wrapping
// TODO: optimize this somehow
if (texparam & (1<<16))
{
if (texparam & (1<<18))
{
if (s & width) s = (width-1) - (s & (width-1));
else s = (s & (width-1));
}
else
s &= width-1;
}
else
{
if (s < 0) s = 0;
else if (s >= width) s = width-1;
}
if (texparam & (1<<17))
{
if (texparam & (1<<19))
{
if (t & height) t = (height-1) - (t & (height-1));
else t = (t & (height-1));
}
else
t &= height-1;
}
else
{
if (t < 0) t = 0;
else if (t >= height) t = height-1;
}
u8 alpha0;
if (texparam & (1<<29)) alpha0 = 0;
else alpha0 = 31;
switch ((texparam >> 26) & 0x7)
{
case 1: // A3I5
{
vramaddr += ((t * width) + s);
u8 pixel = GPU::ReadVRAM_Texture<u8>(vramaddr);
texpal <<= 4;
*color = GPU::ReadVRAM_TexPal<u16>(texpal + ((pixel&0x1F)<<1));
*alpha = ((pixel >> 3) & 0x1C) + (pixel >> 6);
}
break;
case 2: // 4-color
{
vramaddr += (((t * width) + s) >> 2);
u8 pixel = GPU::ReadVRAM_Texture<u8>(vramaddr);
pixel >>= ((s & 0x3) << 1);
pixel &= 0x3;
texpal <<= 3;
*color = GPU::ReadVRAM_TexPal<u16>(texpal + (pixel<<1));
*alpha = (pixel==0) ? alpha0 : 31;
}
break;
case 3: // 16-color
{
vramaddr += (((t * width) + s) >> 1);
u8 pixel = GPU::ReadVRAM_Texture<u8>(vramaddr);
if (s & 0x1) pixel >>= 4;
else pixel &= 0xF;
texpal <<= 4;
*color = GPU::ReadVRAM_TexPal<u16>(texpal + (pixel<<1));
*alpha = (pixel==0) ? alpha0 : 31;
}
break;
case 4: // 256-color
{
vramaddr += ((t * width) + s);
u8 pixel = GPU::ReadVRAM_Texture<u8>(vramaddr);
texpal <<= 4;
*color = GPU::ReadVRAM_TexPal<u16>(texpal + (pixel<<1));
*alpha = (pixel==0) ? alpha0 : 31;
}
break;
case 5: // compressed
{
vramaddr += ((t & 0x3FC) * (width>>2)) + (s & 0x3FC);
vramaddr += (t & 0x3);
u32 slot1addr = 0x20000 + ((vramaddr & 0x1FFFC) >> 1);
if (vramaddr >= 0x40000)
slot1addr += 0x10000;
u8 val = GPU::ReadVRAM_Texture<u8>(vramaddr);
val >>= (2 * (s & 0x3));
u16 palinfo = GPU::ReadVRAM_Texture<u16>(slot1addr);
u32 paloffset = (palinfo & 0x3FFF) << 2;
texpal <<= 4;
switch (val & 0x3)
{
case 0:
*color = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset);
*alpha = 31;
break;
case 1:
*color = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset + 2);
*alpha = 31;
break;
case 2:
if ((palinfo >> 14) == 1)
{
u16 color0 = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset);
u16 color1 = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset + 2);
u32 r0 = color0 & 0x001F;
u32 g0 = color0 & 0x03E0;
u32 b0 = color0 & 0x7C00;
u32 r1 = color1 & 0x001F;
u32 g1 = color1 & 0x03E0;
u32 b1 = color1 & 0x7C00;
u32 r = (r0 + r1) >> 1;
u32 g = ((g0 + g1) >> 1) & 0x03E0;
u32 b = ((b0 + b1) >> 1) & 0x7C00;
*color = r | g | b;
}
else if ((palinfo >> 14) == 3)
{
u16 color0 = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset);
u16 color1 = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset + 2);
u32 r0 = color0 & 0x001F;
u32 g0 = color0 & 0x03E0;
u32 b0 = color0 & 0x7C00;
u32 r1 = color1 & 0x001F;
u32 g1 = color1 & 0x03E0;
u32 b1 = color1 & 0x7C00;
u32 r = (r0*5 + r1*3) >> 3;
u32 g = ((g0*5 + g1*3) >> 3) & 0x03E0;
u32 b = ((b0*5 + b1*3) >> 3) & 0x7C00;
*color = r | g | b;
}
else
*color = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset + 4);
*alpha = 31;
break;
case 3:
if ((palinfo >> 14) == 2)
{
*color = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset + 6);
*alpha = 31;
}
else if ((palinfo >> 14) == 3)
{
u16 color0 = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset);
u16 color1 = GPU::ReadVRAM_TexPal<u16>(texpal + paloffset + 2);
u32 r0 = color0 & 0x001F;
u32 g0 = color0 & 0x03E0;
u32 b0 = color0 & 0x7C00;
u32 r1 = color1 & 0x001F;
u32 g1 = color1 & 0x03E0;
u32 b1 = color1 & 0x7C00;
u32 r = (r0*3 + r1*5) >> 3;
u32 g = ((g0*3 + g1*5) >> 3) & 0x03E0;
u32 b = ((b0*3 + b1*5) >> 3) & 0x7C00;
*color = r | g | b;
*alpha = 31;
}
else
{
*color = 0;
*alpha = 0;
}
break;
}
}
break;
case 6: // A5I3
{
vramaddr += ((t * width) + s);
u8 pixel = GPU::ReadVRAM_Texture<u8>(vramaddr);
texpal <<= 4;
*color = GPU::ReadVRAM_TexPal<u16>(texpal + ((pixel&0x7)<<1));
*alpha = (pixel >> 3);
}
break;
case 7: // direct color
{
vramaddr += (((t * width) + s) << 1);
*color = GPU::ReadVRAM_Texture<u16>(vramaddr);
*alpha = (*color & 0x8000) ? 31 : 0;
}
break;
}
}
bool DepthTest(Polygon* polygon, s32 x, s32 y, s32 z)
{
u32 oldz = DepthBuffer[(256*y) + x];
if (polygon->Attr & (1<<14))
{
s32 diff = oldz - z;
if ((u32)(diff + 0x200) <= 0x400)
return true;
}
else
if (z < oldz)
return true;
return false;
}
u32 RenderPixel(Polygon* polygon, s32 x, s32 y, s32 z, u8 vr, u8 vg, u8 vb, s16 s, s16 t)
{
u32 attr = polygon->Attr;
u8 r, g, b, a;
u32 polyalpha = (polygon->Attr >> 16) & 0x1F;
bool wireframe = (polyalpha == 0);
if ((DispCnt & (1<<0)) && (((polygon->TexParam >> 26) & 0x7) != 0))
{
u8 tr, tg, tb;
u16 tcolor; u8 talpha;
TextureLookup(polygon->TexParam, polygon->TexPalette, s, t, &tcolor, &talpha);
tr = (tcolor << 1) & 0x3E; if (tr) tr++;
tg = (tcolor >> 4) & 0x3E; if (tg) tg++;
tb = (tcolor >> 9) & 0x3E; if (tb) tb++;
// TODO: other blending modes
r = ((tr+1) * (vr+1) - 1) >> 6;
g = ((tg+1) * (vg+1) - 1) >> 6;
b = ((tb+1) * (vb+1) - 1) >> 6;
a = ((talpha+1) * (polyalpha+1) - 1) >> 5;
}
else
{
r = vr;
g = vg;
b = vb;
a = polyalpha;
}
if (wireframe) a = 31;
return r | (g << 8) | (b << 16) | (a << 24);
}
void RenderPolygon(Polygon* polygon, u32 wbuffer)
{
int nverts = polygon->NumVertices;
bool isline = false;
int vtop = 0, vbot = 0;
s32 ytop = 192, ybot = 0;
s32 xtop = 256, xbot = 0;
// process the vertices, transform to screen coordinates
// find the topmost and bottommost vertices of the polygon
for (int i = 0; i < nverts; i++)
{
Vertex* vtx = polygon->Vertices[i];
if (!vtx->ViewportTransformDone)
{
s32 posX, posY, posZ;
s32 w = vtx->Position[3];
if (w == 0)
{
posX = 0;
posY = 0;
posZ = 0;
w = 0x1000;
}
else
{
posX = (((s64)(vtx->Position[0] + w) * Viewport[2]) / (((s64)w) << 1)) + Viewport[0];
posY = (((s64)(-vtx->Position[1] + w) * Viewport[3]) / (((s64)w) << 1)) + Viewport[1];
if (wbuffer) posZ = w;
else posZ = (((s64)vtx->Position[2] * 0x800000) / w) + 0x7FFEFF;
}
if (posX < 0) posX = 0;
else if (posX > 256) posX = 256;
if (posY < 0) posY = 0;
else if (posY > 192) posY = 192;
if (posZ < 0) posZ = 0;
else if (posZ > 0xFFFFFF) posZ = 0xFFFFFF;
vtx->FinalPosition[0] = posX;
vtx->FinalPosition[1] = posY;
vtx->FinalPosition[2] = posZ;
vtx->FinalPosition[3] = w;
vtx->FinalColor[0] = vtx->Color[0] >> 12;
if (vtx->FinalColor[0]) vtx->FinalColor[0] = ((vtx->FinalColor[0] << 4) + 0xF);
vtx->FinalColor[1] = vtx->Color[1] >> 12;
if (vtx->FinalColor[1]) vtx->FinalColor[1] = ((vtx->FinalColor[1] << 4) + 0xF);
vtx->FinalColor[2] = vtx->Color[2] >> 12;
if (vtx->FinalColor[2]) vtx->FinalColor[2] = ((vtx->FinalColor[2] << 4) + 0xF);
vtx->ViewportTransformDone = true;
}
if (vtx->FinalPosition[1] < ytop || (vtx->FinalPosition[1] == ytop && vtx->FinalPosition[0] < xtop))
{
xtop = vtx->FinalPosition[0];
ytop = vtx->FinalPosition[1];
vtop = i;
}
if (vtx->FinalPosition[1] > ybot || (vtx->FinalPosition[1] == ybot && vtx->FinalPosition[0] > xbot))
{
xbot = vtx->FinalPosition[0];
ybot = vtx->FinalPosition[1];
vbot = i;
}
}
if (ytop > 191) return;
// draw, line per line
u32 polyalpha = (polygon->Attr >> 16) & 0x1F;
bool wireframe = (polyalpha == 0);
int lcur = vtop, rcur = vtop;
int lnext, rnext;
s32 dxl, dxr;
s32 lslope, rslope;
bool l_xmajor, r_xmajor;
if (ybot == ytop)
{
ybot++;
isline = true;
vtop = 0; vbot = 0;
xtop = 256; xbot = 0;
int i;
i = 1;
if (polygon->Vertices[i]->FinalPosition[0] < polygon->Vertices[vtop]->FinalPosition[0]) vtop = i;
if (polygon->Vertices[i]->FinalPosition[0] > polygon->Vertices[vbot]->FinalPosition[0]) vbot = i;
i = nverts - 1;
if (polygon->Vertices[i]->FinalPosition[0] < polygon->Vertices[vtop]->FinalPosition[0]) vtop = i;
if (polygon->Vertices[i]->FinalPosition[0] > polygon->Vertices[vbot]->FinalPosition[0]) vbot = i;
lcur = vtop; lnext = vtop;
rcur = vbot; rnext = vbot;
lslope = 0; l_xmajor = false;
rslope = 0; r_xmajor = false;
}
else
{
//while (polygon->Vertices[lnext]->FinalPosition[1] )
if (polygon->FacingView)
{
lnext = lcur + 1;
if (lnext >= nverts) lnext = 0;
rnext = rcur - 1;
if (rnext < 0) rnext = nverts - 1;
}
else
{
lnext = lcur - 1;
if (lnext < 0) lnext = nverts - 1;
rnext = rcur + 1;
if (rnext >= nverts) rnext = 0;
}
if (polygon->Vertices[lnext]->FinalPosition[1] == polygon->Vertices[lcur]->FinalPosition[1])
lslope = 0;
else
lslope = ((polygon->Vertices[lnext]->FinalPosition[0] - polygon->Vertices[lcur]->FinalPosition[0]) << 12) /
(polygon->Vertices[lnext]->FinalPosition[1] - polygon->Vertices[lcur]->FinalPosition[1]);
if (polygon->Vertices[rnext]->FinalPosition[1] == polygon->Vertices[rcur]->FinalPosition[1])
rslope = 0;
else
rslope = ((polygon->Vertices[rnext]->FinalPosition[0] - polygon->Vertices[rcur]->FinalPosition[0]) << 12) /
(polygon->Vertices[rnext]->FinalPosition[1] - polygon->Vertices[rcur]->FinalPosition[1]);
l_xmajor = (lslope < -0x1000) || (lslope > 0x1000);
r_xmajor = (rslope < -0x1000) || (rslope > 0x1000);
}
if (l_xmajor) dxl = (lslope > 0) ? 0x800 : (-lslope-0x800)+0x1000;
else if (lslope) dxl = (lslope > 0) ? 0 : 0x1000;
else dxl = 0;
if (r_xmajor) dxr = (rslope > 0) ? rslope-0x800 : 0x800+0x1000;
else if (rslope) dxr = (rslope > 0) ? 0 : 0x1000;
else dxr = 0x1000;
if (ybot > 191) ybot = 191;
for (s32 y = ytop; y < ybot; y++)
{
if (!isline)
{
if (y >= polygon->Vertices[lnext]->FinalPosition[1] && lcur != vbot)
{
while (y >= polygon->Vertices[lnext]->FinalPosition[1] && lcur != vbot)
{
lcur = lnext;
if (polygon->FacingView)
{
lnext = lcur + 1;
if (lnext >= nverts) lnext = 0;
}
else
{
lnext = lcur - 1;
if (lnext < 0) lnext = nverts - 1;
}
}
if (polygon->Vertices[lnext]->FinalPosition[1] == polygon->Vertices[lcur]->FinalPosition[1])
lslope = 0;
else
lslope = ((polygon->Vertices[lnext]->FinalPosition[0] - polygon->Vertices[lcur]->FinalPosition[0]) << 12) /
(polygon->Vertices[lnext]->FinalPosition[1] - polygon->Vertices[lcur]->FinalPosition[1]);
l_xmajor = (lslope < -0x1000) || (lslope > 0x1000);
if (l_xmajor) dxl = (lslope > 0) ? 0x800 : (-lslope-0x800)+0x1000;
else if (lslope) dxl = (lslope > 0) ? 0 : 0x1000;
else dxl = 0;
}
if (y >= polygon->Vertices[rnext]->FinalPosition[1] && rcur != vbot)
{
while (y >= polygon->Vertices[rnext]->FinalPosition[1] && rcur != vbot)
{
rcur = rnext;
if (polygon->FacingView)
{
rnext = rcur - 1;
if (rnext < 0) rnext = nverts - 1;
}
else
{
rnext = rcur + 1;
if (rnext >= nverts) rnext = 0;
}
}
if (polygon->Vertices[rnext]->FinalPosition[1] == polygon->Vertices[rcur]->FinalPosition[1])
rslope = 0;
else
rslope = ((polygon->Vertices[rnext]->FinalPosition[0] - polygon->Vertices[rcur]->FinalPosition[0]) << 12) /
(polygon->Vertices[rnext]->FinalPosition[1] - polygon->Vertices[rcur]->FinalPosition[1]);
r_xmajor = (rslope < -0x1000) || (rslope > 0x1000);
if (r_xmajor) dxr = (rslope > 0) ? rslope-0x800 : 0x800+0x1000;
else if (rslope) dxr = (rslope > 0) ? 0 : 0x1000;
else dxr = 0x1000;
}
}
Vertex *vlcur, *vlnext, *vrcur, *vrnext;
s32 xstart, xend;
s32 xstart_int, xend_int;
s32 slope_start, slope_end;
if (lslope == 0 && rslope == 0 &&
polygon->Vertices[lcur]->FinalPosition[0] == polygon->Vertices[rcur]->FinalPosition[0])
{
xstart = polygon->Vertices[lcur]->FinalPosition[0];
xend = xstart;
}
else
{
if (lslope > 0)
{
xstart = polygon->Vertices[lcur]->FinalPosition[0] + (dxl >> 12);
if (xstart < polygon->Vertices[lcur]->FinalPosition[0])
xstart = polygon->Vertices[lcur]->FinalPosition[0];
else if (xstart > polygon->Vertices[lnext]->FinalPosition[0]-1)
xstart = polygon->Vertices[lnext]->FinalPosition[0]-1;
}
else if (lslope < 0)
{
xstart = polygon->Vertices[lcur]->FinalPosition[0] - (dxl >> 12);
if (xstart < polygon->Vertices[lnext]->FinalPosition[0])
xstart = polygon->Vertices[lnext]->FinalPosition[0];
else if (xstart > polygon->Vertices[lcur]->FinalPosition[0]-1)
xstart = polygon->Vertices[lcur]->FinalPosition[0]-1;
}
else
xstart = polygon->Vertices[lcur]->FinalPosition[0];
if (rslope > 0)
{
xend = polygon->Vertices[rcur]->FinalPosition[0] + (dxr >> 12);
if (xend < polygon->Vertices[rcur]->FinalPosition[0])
xend = polygon->Vertices[rcur]->FinalPosition[0];
else if (xend > polygon->Vertices[rnext]->FinalPosition[0]-1)
xend = polygon->Vertices[rnext]->FinalPosition[0]-1;
}
else if (rslope < 0)
{
xend = polygon->Vertices[rcur]->FinalPosition[0] - (dxr >> 12);
if (xend < polygon->Vertices[rnext]->FinalPosition[0])
xend = polygon->Vertices[rnext]->FinalPosition[0];
else if (xend > polygon->Vertices[rcur]->FinalPosition[0]-1)
xend = polygon->Vertices[rcur]->FinalPosition[0]-1;
}
else
xend = polygon->Vertices[rcur]->FinalPosition[0] - 1;
}
// if the left and right edges are swapped, render backwards.
// note: we 'forget' to swap the xmajor flags, on purpose
// the hardware has the same bug
if (xstart > xend)
{
vlcur = polygon->Vertices[rcur];
vlnext = polygon->Vertices[rnext];
vrcur = polygon->Vertices[lcur];
vrnext = polygon->Vertices[lnext];
slope_start = rslope;
slope_end = lslope;
s32 tmp = xstart; xstart = xend; xend = tmp;
}
else
{
vlcur = polygon->Vertices[lcur];
vlnext = polygon->Vertices[lnext];
vrcur = polygon->Vertices[rcur];
vrnext = polygon->Vertices[rnext];
slope_start = lslope;
slope_end = rslope;
}
// interpolate attributes along Y
s64 lfactor1, lfactor2;
s64 rfactor1, rfactor2;
if (l_xmajor)
{
lfactor1 = (vlnext->FinalPosition[0] - xstart) * vlnext->FinalPosition[3];
lfactor2 = (xstart - vlcur->FinalPosition[0]) * vlcur->FinalPosition[3];
}
else
{
lfactor1 = (vlnext->FinalPosition[1] - y) * vlnext->FinalPosition[3];
lfactor2 = (y - vlcur->FinalPosition[1]) * vlcur->FinalPosition[3];
}
s64 ldenom = lfactor1 + lfactor2;
if (ldenom == 0)
{
lfactor1 = 0x1000;
lfactor2 = 0;
ldenom = 0x1000;
}
if (r_xmajor)
{
rfactor1 = (vrnext->FinalPosition[0] - xend+1) * vrnext->FinalPosition[3];
rfactor2 = (xend+1 - vrcur->FinalPosition[0]) * vrcur->FinalPosition[3];
}
else
{
rfactor1 = (vrnext->FinalPosition[1] - y) * vrnext->FinalPosition[3];
rfactor2 = (y - vrcur->FinalPosition[1]) * vrcur->FinalPosition[3];
}
s64 rdenom = rfactor1 + rfactor2;
if (rdenom == 0)
{
rfactor1 = 0x1000;
rfactor2 = 0;
rdenom = 0x1000;
}
s32 zl = ((lfactor1 * vlcur->FinalPosition[2]) + (lfactor2 * vlnext->FinalPosition[2])) / ldenom;
s32 zr = ((rfactor1 * vrcur->FinalPosition[2]) + (rfactor2 * vrnext->FinalPosition[2])) / rdenom;
s32 wl = ((lfactor1 * vlcur->FinalPosition[3]) + (lfactor2 * vlnext->FinalPosition[3])) / ldenom;
s32 wr = ((rfactor1 * vrcur->FinalPosition[3]) + (rfactor2 * vrnext->FinalPosition[3])) / rdenom;
s32 rl = ((lfactor1 * vlcur->FinalColor[0]) + (lfactor2 * vlnext->FinalColor[0])) / ldenom;
s32 gl = ((lfactor1 * vlcur->FinalColor[1]) + (lfactor2 * vlnext->FinalColor[1])) / ldenom;
s32 bl = ((lfactor1 * vlcur->FinalColor[2]) + (lfactor2 * vlnext->FinalColor[2])) / ldenom;
s32 sl = ((lfactor1 * vlcur->TexCoords[0]) + (lfactor2 * vlnext->TexCoords[0])) / ldenom;
s32 tl = ((lfactor1 * vlcur->TexCoords[1]) + (lfactor2 * vlnext->TexCoords[1])) / ldenom;
s32 rr = ((rfactor1 * vrcur->FinalColor[0]) + (rfactor2 * vrnext->FinalColor[0])) / rdenom;
s32 gr = ((rfactor1 * vrcur->FinalColor[1]) + (rfactor2 * vrnext->FinalColor[1])) / rdenom;
s32 br = ((rfactor1 * vrcur->FinalColor[2]) + (rfactor2 * vrnext->FinalColor[2])) / rdenom;
s32 sr = ((rfactor1 * vrcur->TexCoords[0]) + (rfactor2 * vrnext->TexCoords[0])) / rdenom;
s32 tr = ((rfactor1 * vrcur->TexCoords[1]) + (rfactor2 * vrnext->TexCoords[1])) / rdenom;
// calculate edges
s32 l_edgeend, r_edgestart;
if (l_xmajor)
{
if (slope_start > 0) l_edgeend = vlcur->FinalPosition[0] + ((dxl + slope_start) >> 12);
else l_edgeend = vlcur->FinalPosition[0] - ((dxl - slope_start) >> 12);
if (l_edgeend == xstart) l_edgeend++;
}
else
l_edgeend = xstart + 1;
if (r_xmajor)
{
if (slope_end > 0) r_edgestart = vrcur->FinalPosition[0] + ((dxr + slope_end) >> 12);
else r_edgestart = vrcur->FinalPosition[0] - ((dxr - slope_end) >> 12);
if (r_edgestart == xend_int) r_edgestart--;
}
else
r_edgestart = xend - 1;
// edge fill rules for opaque pixels:
// * right edge is filled if slope > 1
// * left edge is filled if slope <= 1
// * edges with slope = 0 are always filled
// edges are always filled if the pixels are translucent
// in wireframe mode, there are special rules for equal Z (TODO)
for (s32 x = xstart; x <= xend; x++)
{
if (x < 0) continue;
if (x > 255) break;
int edge = 0;
if (y == ytop) edge |= 0x4;
else if (y == ybot-1) edge |= 0x8;
if (x < l_edgeend) edge |= 0x1;
else if (x > r_edgestart) edge |= 0x2;
// wireframe polygons. really ugly, but works
if (wireframe && edge==0) continue;
s64 factor1 = (xend+1 - x) * wr;
s64 factor2 = (x - xstart) * wl;
s64 denom = factor1 + factor2;
if (denom == 0)
{
factor1 = 0x1000;
factor2 = 0;
denom = 0x1000;
}
s32 z = ((factor1 * zl) + (factor2 * zr)) / denom;
if (!DepthTest(polygon, x, y, z)) continue;
u32 vr = ((factor1 * rl) + (factor2 * rr)) / denom;
u32 vg = ((factor1 * gl) + (factor2 * gr)) / denom;
u32 vb = ((factor1 * bl) + (factor2 * br)) / denom;
s16 s = ((factor1 * sl) + (factor2 * sr)) / denom;
s16 t = ((factor1 * tl) + (factor2 * tr)) / denom;
u32 color = RenderPixel(polygon, x, y, z, vr>>3, vg>>3, vb>>3, s, t);
u32 attr = 0;
u8 alpha = color >> 24;
// alpha test
if (DispCnt & (1<<2))
{
if (alpha <= AlphaRef) continue;
}
// alpha blending disable
// TODO: check alpha test when blending is disabled
if (!(DispCnt & (1<<3)))
alpha = 31;
if (alpha == 31)
{
if (!wireframe)
{
if ((edge & 0x1) && slope_start > 0x1000)
continue;
if ((edge & 0x2) && (slope_end != 0 && slope_end <= 0x1000))
continue;
}
DepthBuffer[(y*256) + x] = z;
}
else if (alpha > 0)
{
//
// TODO: conditional Z-buffer update
DepthBuffer[(y*256) + x] = z;
}
ColorBuffer[(y*256) + x] = color;
AttrBuffer[(y*256) + x] = attr;
}
if (lslope > 0) dxl += lslope;
else dxl -= lslope;
if (rslope > 0) dxr += rslope;
else dxr -= rslope;
}
}
void RenderFrame(u32 attr, Vertex* vertices, Polygon* polygons, int npolys)
{
// TODO: render translucent polygons last
u32 polyid = (ClearAttr1 >> 24) & 0x3F;
if (DispCnt & (1<<14))
{
u8 xoff = (ClearAttr2 >> 16) & 0xFF;
u8 yoff = (ClearAttr2 >> 24) & 0xFF;
for (int y = 0; y < 256*192; y += 256)
{
for (int x = 0; x < 256; x++)
{
u16 val2 = GPU::ReadVRAM_Texture<u16>(0x40000 + (yoff << 9) + (xoff << 1));
u16 val3 = GPU::ReadVRAM_Texture<u16>(0x60000 + (yoff << 9) + (xoff << 1));
// TODO: confirm color conversion
u32 r = (val2 << 1) & 0x3E; if (r) r++;
u32 g = (val2 >> 4) & 0x3E; if (g) g++;
u32 b = (val2 >> 9) & 0x3E; if (b) b++;
u32 a = (val2 & 0x8000) ? 0x1F000000 : 0;
u32 color = r | (g << 8) | (b << 16) | a;
u32 z = ((val3 & 0x7FFF) * 0x200) + 0x1FF;
if (z >= 0x10000 && z < 0xFFFFFF) z++;
ColorBuffer[y+x] = color;
DepthBuffer[y+x] = z;
AttrBuffer[y+x] = polyid | ((val3 & 0x8000) >> 7);
xoff++;
}
yoff++;
}
}
else
{
// TODO: confirm color conversion
u32 r = (ClearAttr1 << 1) & 0x3E; if (r) r++;
u32 g = (ClearAttr1 >> 4) & 0x3E; if (g) g++;
u32 b = (ClearAttr1 >> 9) & 0x3E; if (b) b++;
u32 a = (ClearAttr1 >> 16) & 0x1F;
u32 color = r | (g << 8) | (b << 16) | (a << 24);
u32 z = ((ClearAttr2 & 0x7FFF) * 0x200) + 0x1FF;
if (z >= 0x10000 && z < 0xFFFFFF) z++;
polyid |= ((ClearAttr1 & 0x8000) >> 7);
for (int i = 0; i < 256*192; i++)
{
ColorBuffer[i] = color;
DepthBuffer[i] = z;
AttrBuffer[i] = polyid;
}
}
for (int i = 0; i < npolys; i++)
{//if (i<npolys-6) continue;//printf("poly %d\n", i);
//if (i<npolys-2)continue;
RenderPolygon(&polygons[i], attr&0x2);
}
}
u32* GetLine(int line)
{
return &ColorBuffer[line * 256];
}
}
}