Files
melonDS/GPU3D_Soft.cpp
2017-02-15 17:49:14 +01:00

335 lines
10 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 "GPU3D.h"
namespace GPU3D
{
namespace SoftRenderer
{
u8 ColorBuffer[256*192 * 4];
u32 DepthBuffer[256*192];
bool Init()
{
return true;
}
void DeInit()
{
//
}
void Reset()
{
memset(ColorBuffer, 0, 256*192 * 4);
memset(DepthBuffer, 0, 256*192 * 4);
}
void RenderPixel(u32 attr, s32 x, s32 y, s32 z, u8 vr, u8 vg, u8 vb)
{
u32* depth = &DepthBuffer[(256*y) + x];
bool passdepth = false;
if (attr & (1<<14))
{
s32 diff = *depth - z;
if ((u32)(diff + 0x200) <= 0x400)
passdepth = true;
}
else
if (z < *depth)
passdepth = true;
if (!passdepth) return;
u8* pixel = &ColorBuffer[((256*y) + x) * 4];
pixel[0] = vr;
pixel[1] = vg;
pixel[2] = vb;
pixel[3] = 31; // TODO: alpha
// TODO: optional update for translucent pixels
*depth = z;
}
void RenderPolygon(Polygon* polygon)
{
int nverts = polygon->NumVertices;
int vtop = 0, vbot = 0;
s32 ytop = 191, ybot = 0;
s32 scrcoords[10][4];
// find the topmost and bottommost vertices of the polygon
for (int i = 0; i < nverts; i++)
{
Vertex* vtx = polygon->Vertices[i];
s32 posX, posY, posZ, posW;
s32 w = vtx->Position[3];
if (w == 0)
{
posX = 0;
posY = 0;
posZ = 0;
posW = 0x1000;
}
else
{
// TODO: find a way to avoid doing 3 divisions :/
posX = ((s64)vtx->Position[0] << 12) / w;
posY = ((s64)vtx->Position[1] << 12) / w;
posZ = ((s64)vtx->Position[2] << 12) / w;
posW = w;
}
s32 scrX = (((posX + 0x1000) * Viewport[2]) >> 13) + Viewport[0];
s32 scrY = (((posY + 0x1000) * Viewport[3]) >> 13) + Viewport[1];
s32 scrZ = (((s64)(posZ + 0x1000) * 0xFFFFFF) >> 13);
if (scrX > 255) scrX = 255;
if (scrY > 191) scrY = 191;
if (scrZ > 0xFFFFFF) scrZ = 0xFFFFFF;
if (scrX < 0) { printf("!! bad X %d\n", scrX); scrX = 0;}
if (scrY < 0) { printf("!! bad Y %d\n", scrY); scrY = 0;}
if (scrZ < 0) { printf("!! bad Z %d %d\n", scrZ, vtx->Position[2]); scrZ = 0;}
scrcoords[i][0] = scrX;
scrcoords[i][1] = 191 - scrY;
scrcoords[i][2] = scrZ;
scrcoords[i][3] = posW;
if (scrcoords[i][1] < ytop)
{
ytop = scrcoords[i][1];
vtop = i;
}
if (scrcoords[i][1] > ybot)
{
ybot = scrcoords[i][1];
vbot = i;
}
//if (vtx->Color[0]==63 && vtx->Color[1]==0 && vtx->Color[2]==0)
//printf("v%d: %d,%d Z=%f W=%f %d %d\n", i, scrX, 191-scrY, vtx->Position[2]/4096.0f, vtx->Position[3]/4096.0f,
// polygon->FacingView, vtx->Clipped);
}
// draw, line per line
int lcur = vtop, rcur = vtop;
int lnext, rnext;
s32 lstep, rstep;
//s32 xmin, xmax;
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 ((scrcoords[lnext][1] - scrcoords[lcur][1]) == 0) lstep = 0; else
lstep = ((scrcoords[lnext][0] - scrcoords[lcur][0]) << 12) / (scrcoords[lnext][1] - scrcoords[lcur][1]);
if ((scrcoords[rnext][1] - scrcoords[rcur][1]) == 0) rstep = 0; else
rstep = ((scrcoords[rnext][0] - scrcoords[rcur][0]) << 12) / (scrcoords[rnext][1] - scrcoords[rcur][1]);*/
//xmin = scrcoords[lcur][0] << 12;
//xmax = scrcoords[rcur][0] << 12;
for (s32 y = ytop; y <= ybot; y++)
{
if (y < ybot)
{
while (y == scrcoords[lnext][1])
{
lcur = lnext;
if (polygon->FacingView)
{
lnext = lcur + 1;
if (lnext >= nverts) lnext = 0;
}
else
{
lnext = lcur - 1;
if (lnext < 0) lnext = nverts - 1;
}
//lstep = ((scrcoords[lnext][0] - scrcoords[lcur][0]) << 12) / (scrcoords[lnext][1] - scrcoords[lcur][1]);
//xmin = scrcoords[lcur][0] << 12;
if (lcur == vbot) break;
}
while (y == scrcoords[rnext][1])
{
rcur = rnext;
if (polygon->FacingView)
{
rnext = rcur - 1;
if (rnext < 0) rnext = nverts - 1;
}
else
{
rnext = rcur + 1;
if (rnext >= nverts) rnext = 0;
}
//rstep = ((scrcoords[rnext][0] - scrcoords[rcur][0]) << 12) / (scrcoords[rnext][1] - scrcoords[rcur][1]);
//xmax = scrcoords[rcur][0] << 12;
if (rcur == vbot) break;
}
}
Vertex* vlcur = polygon->Vertices[lcur];
Vertex* vlnext = polygon->Vertices[lnext];
Vertex* vrcur = polygon->Vertices[rcur];
Vertex* vrnext = polygon->Vertices[rnext];
s32 lfactor, rfactor;
if (scrcoords[lnext][1] == scrcoords[lcur][1])
lfactor = 0;
else
lfactor = ((y - scrcoords[lcur][1]) << 12) / (scrcoords[lnext][1] - scrcoords[lcur][1]);
if (scrcoords[rnext][1] == scrcoords[rcur][1])
rfactor = 0;
else
rfactor = ((y - scrcoords[rcur][1]) << 12) / (scrcoords[rnext][1] - scrcoords[rcur][1]);
s32 xl = scrcoords[lcur][0] + (((scrcoords[lnext][0] - scrcoords[lcur][0]) * lfactor) >> 12);
s32 xr = scrcoords[rcur][0] + (((scrcoords[rnext][0] - scrcoords[rcur][0]) * rfactor) >> 12);
if (xl<0 || xr>255) continue; // hax
s32 zl = scrcoords[lcur][2] + (((s64)(scrcoords[lnext][2] - scrcoords[lcur][2]) * lfactor) >> 12);
s32 zr = scrcoords[rcur][2] + (((s64)(scrcoords[rnext][2] - scrcoords[rcur][2]) * rfactor) >> 12);
s32 wl = scrcoords[lcur][3] + (((s64)(scrcoords[lnext][3] - scrcoords[lcur][3]) * lfactor) >> 12);
s32 wr = scrcoords[rcur][3] + (((s64)(scrcoords[rnext][3] - scrcoords[rcur][3]) * rfactor) >> 12);
s64 perspfactorl1 = ((s64)(0x1000 - lfactor) << 12) / scrcoords[lcur][3];
s64 perspfactorl2 = ((s64)lfactor << 12) / scrcoords[lnext][3];
s64 perspfactorr1 = ((s64)(0x1000 - rfactor) << 12) / scrcoords[rcur][3];
s64 perspfactorr2 = ((s64)rfactor << 12) / scrcoords[rnext][3];
u32 rl = (((perspfactorl1 * vlcur->Color[0]) + (perspfactorl2 * vlnext->Color[0])) << 12) / (perspfactorl1 + perspfactorl2);
u32 gl = (((perspfactorl1 * vlcur->Color[1]) + (perspfactorl2 * vlnext->Color[1])) << 12) / (perspfactorl1 + perspfactorl2);
u32 bl = (((perspfactorl1 * vlcur->Color[2]) + (perspfactorl2 * vlnext->Color[2])) << 12) / (perspfactorl1 + perspfactorl2);
u32 rr = (((perspfactorr1 * vrcur->Color[0]) + (perspfactorr2 * vrnext->Color[0])) << 12) / (perspfactorr1 + perspfactorr2);
u32 gr = (((perspfactorr1 * vrcur->Color[1]) + (perspfactorr2 * vrnext->Color[1])) << 12) / (perspfactorr1 + perspfactorr2);
u32 br = (((perspfactorr1 * vrcur->Color[2]) + (perspfactorr2 * vrnext->Color[2])) << 12) / (perspfactorr1 + perspfactorr2);
s32 xdiv;
if (xr == xl)
xdiv = 0;
else
xdiv = 0x1000 / (xr - xl);
for (s32 x = xl; x <= xr; x++)
{
s32 xfactor = (x - xl) * xdiv;
s32 z = zl + (((s64)(zr - zl) * xfactor) >> 12);
s32 perspfactor1 = ((0x1000 - xfactor) << 12) / wl;
s32 perspfactor2 = (xfactor << 12) / wr;
// possible optimization: only do color interpolation if the depth test passes
u32 vr = (s64)((perspfactor1 * rl) + (perspfactor2 * rr)) / (perspfactor1 + perspfactor2);
u32 vg = (s64)((perspfactor1 * gl) + (perspfactor2 * gr)) / (perspfactor1 + perspfactor2);
u32 vb = (s64)((perspfactor1 * bl) + (perspfactor2 * br)) / (perspfactor1 + perspfactor2);
RenderPixel(polygon->Attr, x, y, z, vr>>12, vg>>12, vb>>12);
// Z debug
/*u8 zerp = (w * 63) / 0xFFFFFF;
pixel[0] = zerp;
pixel[1] = zerp;
pixel[2] = zerp;*/
}
}
// DEBUG CODE
/*for (int i = 0; i < nverts; i++)
{
s32 x = scrcoords[i][0];
s32 y = scrcoords[i][1];
u8* pixel = &ColorBuffer[((256*y) + x) * 4];
pixel[0] = 63;
pixel[1] = 63;
pixel[2] = 63;
pixel[3] = 31;
}*/
}
void RenderFrame(Vertex* vertices, Polygon* polygons, int npolys)
{
// TODO: render translucent polygons last
// TODO proper clear color/depth support!
for (int i = 0; i < 256*192; i++)
{
((u32*)ColorBuffer)[i] = 0x00000000;
DepthBuffer[i] = 0xFFFFFF;
}
for (int i = 0; i < npolys; i++)
{
/*printf("polygon %d: %d %d %d\n", i, polygons[i].Vertices[0]->Color[0], polygons[i].Vertices[0]->Color[1], polygons[i].Vertices[0]->Color[2]);
for (int j = 0; j < polygons[i].NumVertices; j++)
printf(" %d: %f %f %f\n",
j,
polygons[i].Vertices[j]->Position[0]/4096.0f,
polygons[i].Vertices[j]->Position[1]/4096.0f,
polygons[i].Vertices[j]->Position[2]/4096.0f);
*/
//printf("polygon %d\n", i);
//if (!polygons[i].Vertices[0]->Clipped) continue;
//printf("polygon %d\n", i);
RenderPolygon(&polygons[i]);
}
}
u8* GetLine(int line)
{
return &ColorBuffer[line * 256 * 4];
}
}
}