Added triangle drawer to the software renderer

This commit is contained in:
Magnus Norddahl 2016-10-31 06:09:46 +01:00
parent ede350ba36
commit a1ba371eed
3 changed files with 812 additions and 0 deletions

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@ -936,6 +936,7 @@ set( FASTMATH_PCH_SOURCES
r_segs.cpp
r_sky.cpp
r_things.cpp
r_triangle.cpp
s_advsound.cpp
s_environment.cpp
s_playlist.cpp

715
src/r_triangle.cpp Normal file
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@ -0,0 +1,715 @@
/*
** Triangle drawers
** Copyright (c) 2016 Magnus Norddahl
**
** This software is provided 'as-is', without any express or implied
** warranty. In no event will the authors be held liable for any damages
** arising from the use of this software.
**
** Permission is granted to anyone to use this software for any purpose,
** including commercial applications, and to alter it and redistribute it
** freely, subject to the following restrictions:
**
** 1. The origin of this software must not be misrepresented; you must not
** claim that you wrote the original software. If you use this software
** in a product, an acknowledgment in the product documentation would be
** appreciated but is not required.
** 2. Altered source versions must be plainly marked as such, and must not be
** misrepresented as being the original software.
** 3. This notice may not be removed or altered from any source distribution.
**
*/
#include <stddef.h>
#include "templates.h"
#include "doomdef.h"
#include "i_system.h"
#include "w_wad.h"
#include "r_local.h"
#include "v_video.h"
#include "doomstat.h"
#include "st_stuff.h"
#include "g_game.h"
#include "g_level.h"
#include "r_data/r_translate.h"
#include "v_palette.h"
#include "r_data/colormaps.h"
#include "r_triangle.h"
void TriangleDrawer::draw(const TriMatrix &objectToWorld, const TriVertex *vinput, int vcount, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, FTexture *texture)
{
draw_any(objectToWorld, vinput, vcount, ccw, clipleft, clipright, cliptop, clipbottom, texture, 0, &ScreenTriangleDrawer::draw);
}
void TriangleDrawer::fill(const TriMatrix &objectToWorld, const TriVertex *vinput, int vcount, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, int solidcolor)
{
draw_any(objectToWorld, vinput, vcount, ccw, clipleft, clipright, cliptop, clipbottom, nullptr, solidcolor, &ScreenTriangleDrawer::fill);
}
void TriangleDrawer::draw_any(const TriMatrix &objectToWorld, const TriVertex *vinput, int vcount, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, FTexture *texture, int solidcolor, void(*drawfunc)(const ScreenTriangleDrawerArgs *))
{
for (int i = 0; i < vcount / 3; i++)
{
TriVertex vert[3];
// Vertex shader stuff:
for (int j = 0; j < 3; j++)
{
auto &v = vert[j];
v = *(vinput++);
// Apply transform to get world coordinates:
v = objectToWorld * v;
// The software renderer world to clip transform:
double nearp = 5.0f;
double farp = 65536.f;
double tr_x = v.x - ViewPos.X;
double tr_y = v.y - ViewPos.Y;
double tr_z = v.z - ViewPos.Z;
double tx = tr_x * ViewSin - tr_y * ViewCos;
double tz = tr_x * ViewTanCos + tr_y * ViewTanSin;
v.x = (float)tx * 0.5f;
v.y = (float)tr_z * 0.5f;
v.z = (float)((-tz * (farp + nearp) / (nearp - farp) + (2.0f * farp * nearp) / (nearp - farp)));
v.w = (float)tz;
}
// Cull, clip and generate additional vertices as needed
TriVertex clippedvert[6];
int numclipvert = 0;
clipedge(vert[0], vert[1], clippedvert, numclipvert);
clipedge(vert[1], vert[2], clippedvert, numclipvert);
clipedge(vert[2], vert[0], clippedvert, numclipvert);
// Map to 2D viewport:
for (int j = 0; j < numclipvert; j++)
{
auto &v = clippedvert[j];
// Calculate normalized device coordinates:
v.w = 1.0f / v.w;
v.x *= v.w;
v.y *= v.w;
v.z *= v.w;
// Apply viewport scale to get screen coordinates:
v.x = (float)(CenterX + v.x * 2.0f * CenterX);
v.y = (float)(CenterY - v.y * 2.0f * InvZtoScale);
}
// Draw screen triangles
ScreenTriangleDrawerArgs args;
args.dest = dc_destorg;
args.pitch = dc_pitch;
args.clipleft = clipleft;
args.clipright = clipright;
args.cliptop = cliptop;
args.clipbottom = clipbottom;
if (texture)
{
args.textureWidth = texture->GetWidth();
args.textureHeight = texture->GetHeight();
args.texturePixels = texture->GetPixels();
}
else
{
args.textureWidth = 0;
args.textureHeight = 0;
args.texturePixels = nullptr;
}
args.solidcolor = solidcolor;
if (ccw)
{
for (int i = numclipvert; i > 1; i--)
{
args.v1 = &clippedvert[numclipvert - 1];
args.v2 = &clippedvert[i - 1];
args.v3 = &clippedvert[i - 2];
drawfunc(&args);
}
}
else
{
for (int i = 2; i < numclipvert; i++)
{
args.v1 = &clippedvert[0];
args.v2 = &clippedvert[i - 1];
args.v3 = &clippedvert[i];
drawfunc(&args);
}
}
}
}
bool TriangleDrawer::cullhalfspace(float clipdistance1, float clipdistance2, float &t1, float &t2)
{
float d1 = clipdistance1 * (1.0f - t1) + clipdistance2 * t1;
float d2 = clipdistance1 * (1.0f - t2) + clipdistance2 * t2;
if (d1 < 0.0f && d2 < 0.0f)
return true;
if (d1 < 0.0f)
t1 = MAX(-clipdistance1 / (clipdistance2 - clipdistance1), t1);
if (d2 < 0.0f)
t2 = MIN(1.0f + clipdistance2 / (clipdistance1 - clipdistance2), t2);
return false;
}
void TriangleDrawer::clipedge(const TriVertex &v1, const TriVertex &v2, TriVertex *clippedvert, int &numclipvert)
{
// Clip and cull so that the following is true for all vertices:
// -v.w <= v.x <= v.w
// -v.w <= v.y <= v.w
// -v.w <= v.z <= v.w
float t1 = 0.0f, t2 = 1.0f;
bool culled =
cullhalfspace(v1.x + v1.w, v2.x + v2.w, t1, t2) ||
cullhalfspace(v1.w - v1.x, v2.w - v2.x, t1, t2) ||
cullhalfspace(v1.y + v1.w, v2.y + v2.w, t1, t2) ||
cullhalfspace(v1.w - v1.y, v2.w - v2.y, t1, t2) ||
cullhalfspace(v1.z + v1.w, v2.z + v2.w, t1, t2) ||
cullhalfspace(v1.w - v1.z, v2.w - v2.z, t1, t2);
if (culled)
return;
if (t1 == 0.0f)
{
clippedvert[numclipvert++] = v1;
}
else
{
auto &v = clippedvert[numclipvert++];
v.x = v1.x * (1.0f - t1) + v2.x * t1;
v.y = v1.y * (1.0f - t1) + v2.y * t1;
v.z = v1.z * (1.0f - t1) + v2.z * t1;
v.w = v1.w * (1.0f - t1) + v2.w * t1;
for (int i = 0; i < TriVertex::NumVarying; i++)
v.varying[i] = v1.varying[i] * (1.0f - t1) + v2.varying[i] * t1;
}
if (t2 != 1.0f)
{
auto &v = clippedvert[numclipvert++];
v.x = v1.x * (1.0f - t2) + v2.x * t2;
v.y = v1.y * (1.0f - t2) + v2.y * t2;
v.z = v1.z * (1.0f - t2) + v2.z * t2;
v.w = v1.w * (1.0f - t2) + v2.w * t2;
for (int i = 0; i < TriVertex::NumVarying; i++)
v.varying[i] = v1.varying[i] * (1.0f - t2) + v2.varying[i] * t2;
}
}
/////////////////////////////////////////////////////////////////////////////
void ScreenTriangleDrawer::draw(const ScreenTriangleDrawerArgs *args)
{
uint8_t *dest = args->dest;
int pitch = args->pitch;
const TriVertex &v1 = *args->v1;
const TriVertex &v2 = *args->v2;
const TriVertex &v3 = *args->v3;
int clipleft = args->clipleft;
int clipright = args->clipright;
const short *cliptop = args->cliptop;
const short *clipbottom = args->clipbottom;
const uint8_t *texturePixels = args->texturePixels;
int textureWidth = args->textureWidth;
int textureHeight = args->textureHeight;
// 28.4 fixed-point coordinates
const int Y1 = (int)round(16.0f * v1.y);
const int Y2 = (int)round(16.0f * v2.y);
const int Y3 = (int)round(16.0f * v3.y);
const int X1 = (int)round(16.0f * v1.x);
const int X2 = (int)round(16.0f * v2.x);
const int X3 = (int)round(16.0f * v3.x);
// Deltas
const int DX12 = X1 - X2;
const int DX23 = X2 - X3;
const int DX31 = X3 - X1;
const int DY12 = Y1 - Y2;
const int DY23 = Y2 - Y3;
const int DY31 = Y3 - Y1;
// Fixed-point deltas
const int FDX12 = DX12 << 4;
const int FDX23 = DX23 << 4;
const int FDX31 = DX31 << 4;
const int FDY12 = DY12 << 4;
const int FDY23 = DY23 << 4;
const int FDY31 = DY31 << 4;
// Bounding rectangle
int clipymin = cliptop[clipleft];
int clipymax = clipbottom[clipleft];
for (int i = clipleft + 1; i <= clipright; i++)
{
clipymin = MIN(clipymin, (int)cliptop[i]);
clipymax = MAX(clipymax, (int)clipbottom[i]);
}
int minx = MAX((MIN(MIN(X1, X2), X3) + 0xF) >> 4, clipleft);
int maxx = MIN((MAX(MAX(X1, X2), X3) + 0xF) >> 4, clipright);
int miny = MAX((MIN(MIN(Y1, Y2), Y3) + 0xF) >> 4, clipymin);
int maxy = MIN((MAX(MAX(Y1, Y2), Y3) + 0xF) >> 4, clipymax - 1);
if (minx >= maxx || miny >= maxy)
return;
// Block size, standard 8x8 (must be power of two)
const int q = 8;
// Start in corner of 8x8 block
minx &= ~(q - 1);
miny &= ~(q - 1);
dest += miny * pitch;
// Half-edge constants
int C1 = DY12 * X1 - DX12 * Y1;
int C2 = DY23 * X2 - DX23 * Y2;
int C3 = DY31 * X3 - DX31 * Y3;
// Correct for fill convention
if (DY12 < 0 || (DY12 == 0 && DX12 > 0)) C1++;
if (DY23 < 0 || (DY23 == 0 && DX23 > 0)) C2++;
if (DY31 < 0 || (DY31 == 0 && DX31 > 0)) C3++;
// Gradients
float gradWX = gradx(v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, v1.w, v2.w, v3.w);
float gradWY = grady(v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, v1.w, v2.w, v3.w);
float startW = v1.w + gradWX * (minx - v1.x) + gradWY * (miny - v1.y);
float gradVaryingX[TriVertex::NumVarying], gradVaryingY[TriVertex::NumVarying], startVarying[TriVertex::NumVarying];
for (int i = 0; i < TriVertex::NumVarying; i++)
{
gradVaryingX[i] = gradx(v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, v1.varying[i] * v1.w, v2.varying[i] * v2.w, v3.varying[i] * v3.w);
gradVaryingY[i] = grady(v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, v1.varying[i] * v1.w, v2.varying[i] * v2.w, v3.varying[i] * v3.w);
startVarying[i] = v1.varying[i] * v1.w + gradVaryingX[i] * (minx - v1.x) + gradVaryingY[i] * (miny - v1.y);
}
// Loop through blocks
for (int y = miny; y < maxy; y += q)
{
for (int x = minx; x < maxx; x += q)
{
// Corners of block
int x0 = x << 4;
int x1 = (x + q - 1) << 4;
int y0 = y << 4;
int y1 = (y + q - 1) << 4;
// Evaluate half-space functions
bool a00 = C1 + DX12 * y0 - DY12 * x0 > 0;
bool a10 = C1 + DX12 * y0 - DY12 * x1 > 0;
bool a01 = C1 + DX12 * y1 - DY12 * x0 > 0;
bool a11 = C1 + DX12 * y1 - DY12 * x1 > 0;
int a = (a00 << 0) | (a10 << 1) | (a01 << 2) | (a11 << 3);
bool b00 = C2 + DX23 * y0 - DY23 * x0 > 0;
bool b10 = C2 + DX23 * y0 - DY23 * x1 > 0;
bool b01 = C2 + DX23 * y1 - DY23 * x0 > 0;
bool b11 = C2 + DX23 * y1 - DY23 * x1 > 0;
int b = (b00 << 0) | (b10 << 1) | (b01 << 2) | (b11 << 3);
bool c00 = C3 + DX31 * y0 - DY31 * x0 > 0;
bool c10 = C3 + DX31 * y0 - DY31 * x1 > 0;
bool c01 = C3 + DX31 * y1 - DY31 * x0 > 0;
bool c11 = C3 + DX31 * y1 - DY31 * x1 > 0;
int c = (c00 << 0) | (c10 << 1) | (c01 << 2) | (c11 << 3);
// Skip block when outside an edge
if (a == 0x0 || b == 0x0 || c == 0x0) continue;
// Check if block needs clipping
int clipcount = 0;
for (int ix = x; ix < x + q; ix++)
{
clipcount += (clipleft > ix) || (clipright < ix) || (cliptop[ix] > y) || (clipbottom[ix] <= y + q - 1);
}
// Calculate varying variables for affine block
float offx0 = (x - minx) + 0.5f;
float offy0 = (y - miny) + 0.5f;
float offx1 = offx0 + q;
float offy1 = offy0 + q;
float rcpWTL = 1.0f / (startW + offx0 * gradWX + offy0 * gradWY);
float rcpWTR = 1.0f / (startW + offx1 * gradWX + offy0 * gradWY);
float rcpWBL = 1.0f / (startW + offx0 * gradWX + offy1 * gradWY);
float rcpWBR = 1.0f / (startW + offx1 * gradWX + offy1 * gradWY);
float varyingTL[TriVertex::NumVarying];
float varyingTR[TriVertex::NumVarying];
float varyingBL[TriVertex::NumVarying];
float varyingBR[TriVertex::NumVarying];
for (int i = 0; i < TriVertex::NumVarying; i++)
{
varyingTL[i] = (startVarying[i] + offx0 * gradVaryingX[i] + offy0 * gradVaryingY[i]) * rcpWTL;
varyingTR[i] = (startVarying[i] + offx1 * gradVaryingX[i] + offy0 * gradVaryingY[i]) * rcpWTR;
varyingBL[i] = ((startVarying[i] + offx0 * gradVaryingX[i] + offy1 * gradVaryingY[i]) * rcpWBL - varyingTL[i]) * (1.0f / q);
varyingBR[i] = ((startVarying[i] + offx1 * gradVaryingX[i] + offy1 * gradVaryingY[i]) * rcpWBR - varyingTR[i]) * (1.0f / q);
}
uint8_t *buffer = dest;
// Accept whole block when totally covered
if (a == 0xF && b == 0xF && c == 0xF && clipcount == 0)
{
for (int iy = 0; iy < q; iy++)
{
float varying[TriVertex::NumVarying], varyingStep[TriVertex::NumVarying];
for (int i = 0; i < TriVertex::NumVarying; i++)
{
varying[i] = varyingTL[i] + varyingBL[i] * iy;
varyingStep[i] = (varyingTR[i] + varyingBR[i] * iy - varying[i]) * (1.0f / q);
}
for (int ix = x; ix < x + q; ix++)
{
uint32_t ufrac = (uint32_t)((varying[0] - floor(varying[0])) * 0x100000000LL);
uint32_t vfrac = (uint32_t)((varying[1] - floor(varying[1])) * 0x100000000LL);
//uint32_t light = (uint32_t)clamp(varying[2] * 255.0f + 0.5f, 0.0f, 255.0f);
uint32_t upos = ((ufrac >> 16) * textureWidth) >> 16;
uint32_t vpos = ((vfrac >> 16) * textureHeight) >> 16;
uint32_t uvoffset = upos * textureHeight + vpos;
buffer[ix] = texturePixels[uvoffset];
for (int i = 0; i < TriVertex::NumVarying; i++)
varying[i] += varyingStep[i];
}
buffer += pitch;
}
}
else // Partially covered block
{
int CY1 = C1 + DX12 * y0 - DY12 * x0;
int CY2 = C2 + DX23 * y0 - DY23 * x0;
int CY3 = C3 + DX31 * y0 - DY31 * x0;
for (int iy = 0; iy < q; iy++)
{
int CX1 = CY1;
int CX2 = CY2;
int CX3 = CY3;
float varying[TriVertex::NumVarying], varyingStep[TriVertex::NumVarying];
for (int i = 0; i < TriVertex::NumVarying; i++)
{
varying[i] = varyingTL[i] + varyingBL[i] * iy;
varyingStep[i] = (varyingTR[i] + varyingBR[i] * iy - varying[i]) * (1.0f / q);
}
for (int ix = x; ix < x + q; ix++)
{
bool visible = ix >= clipleft && ix <= clipright && (cliptop[ix] <= y + iy) && (clipbottom[ix] > y + iy);
if (CX1 > 0 && CX2 > 0 && CX3 > 0 && visible)
{
uint32_t ufrac = (uint32_t)((varying[0] - floor(varying[0])) * 0x100000000LL);
uint32_t vfrac = (uint32_t)((varying[1] - floor(varying[1])) * 0x100000000LL);
//uint32_t light = (uint32_t)clamp(varying[2] * 255.0f + 0.5f, 0.0f, 255.0f);
uint32_t upos = ((ufrac >> 16) * textureWidth) >> 16;
uint32_t vpos = ((vfrac >> 16) * textureHeight) >> 16;
uint32_t uvoffset = upos * textureHeight + vpos;
buffer[ix] = texturePixels[uvoffset];
}
for (int i = 0; i < TriVertex::NumVarying; i++)
varying[i] += varyingStep[i];
CX1 -= FDY12;
CX2 -= FDY23;
CX3 -= FDY31;
}
CY1 += FDX12;
CY2 += FDX23;
CY3 += FDX31;
buffer += pitch;
}
}
}
dest += q * pitch;
}
}
void ScreenTriangleDrawer::fill(const ScreenTriangleDrawerArgs *args)
{
uint8_t *dest = args->dest;
int pitch = args->pitch;
const TriVertex &v1 = *args->v1;
const TriVertex &v2 = *args->v2;
const TriVertex &v3 = *args->v3;
int clipleft = args->clipleft;
int clipright = args->clipright;
const short *cliptop = args->cliptop;
const short *clipbottom = args->clipbottom;
int solidcolor = args->solidcolor;
// 28.4 fixed-point coordinates
const int Y1 = (int)round(16.0f * v1.y);
const int Y2 = (int)round(16.0f * v2.y);
const int Y3 = (int)round(16.0f * v3.y);
const int X1 = (int)round(16.0f * v1.x);
const int X2 = (int)round(16.0f * v2.x);
const int X3 = (int)round(16.0f * v3.x);
// Deltas
const int DX12 = X1 - X2;
const int DX23 = X2 - X3;
const int DX31 = X3 - X1;
const int DY12 = Y1 - Y2;
const int DY23 = Y2 - Y3;
const int DY31 = Y3 - Y1;
// Fixed-point deltas
const int FDX12 = DX12 << 4;
const int FDX23 = DX23 << 4;
const int FDX31 = DX31 << 4;
const int FDY12 = DY12 << 4;
const int FDY23 = DY23 << 4;
const int FDY31 = DY31 << 4;
// Bounding rectangle
int clipymin = cliptop[clipleft];
int clipymax = clipbottom[clipleft];
for (int i = clipleft + 1; i <= clipright; i++)
{
clipymin = MIN(clipymin, (int)cliptop[i]);
clipymax = MAX(clipymax, (int)clipbottom[i]);
}
int minx = MAX((MIN(MIN(X1, X2), X3) + 0xF) >> 4, clipleft);
int maxx = MIN((MAX(MAX(X1, X2), X3) + 0xF) >> 4, clipright);
int miny = MAX((MIN(MIN(Y1, Y2), Y3) + 0xF) >> 4, clipymin);
int maxy = MIN((MAX(MAX(Y1, Y2), Y3) + 0xF) >> 4, clipymax - 1);
if (minx >= maxx || miny >= maxy)
return;
// Block size, standard 8x8 (must be power of two)
const int q = 8;
// Start in corner of 8x8 block
minx &= ~(q - 1);
miny &= ~(q - 1);
dest += miny * pitch;
// Half-edge constants
int C1 = DY12 * X1 - DX12 * Y1;
int C2 = DY23 * X2 - DX23 * Y2;
int C3 = DY31 * X3 - DX31 * Y3;
// Correct for fill convention
if (DY12 < 0 || (DY12 == 0 && DX12 > 0)) C1++;
if (DY23 < 0 || (DY23 == 0 && DX23 > 0)) C2++;
if (DY31 < 0 || (DY31 == 0 && DX31 > 0)) C3++;
// Loop through blocks
for (int y = miny; y < maxy; y += q)
{
for (int x = minx; x < maxx; x += q)
{
// Corners of block
int x0 = x << 4;
int x1 = (x + q - 1) << 4;
int y0 = y << 4;
int y1 = (y + q - 1) << 4;
// Evaluate half-space functions
bool a00 = C1 + DX12 * y0 - DY12 * x0 > 0;
bool a10 = C1 + DX12 * y0 - DY12 * x1 > 0;
bool a01 = C1 + DX12 * y1 - DY12 * x0 > 0;
bool a11 = C1 + DX12 * y1 - DY12 * x1 > 0;
int a = (a00 << 0) | (a10 << 1) | (a01 << 2) | (a11 << 3);
bool b00 = C2 + DX23 * y0 - DY23 * x0 > 0;
bool b10 = C2 + DX23 * y0 - DY23 * x1 > 0;
bool b01 = C2 + DX23 * y1 - DY23 * x0 > 0;
bool b11 = C2 + DX23 * y1 - DY23 * x1 > 0;
int b = (b00 << 0) | (b10 << 1) | (b01 << 2) | (b11 << 3);
bool c00 = C3 + DX31 * y0 - DY31 * x0 > 0;
bool c10 = C3 + DX31 * y0 - DY31 * x1 > 0;
bool c01 = C3 + DX31 * y1 - DY31 * x0 > 0;
bool c11 = C3 + DX31 * y1 - DY31 * x1 > 0;
int c = (c00 << 0) | (c10 << 1) | (c01 << 2) | (c11 << 3);
// Skip block when outside an edge
if (a == 0x0 || b == 0x0 || c == 0x0) continue;
// Check if block needs clipping
int clipcount = 0;
for (int ix = x; ix < x + q; ix++)
{
clipcount += (clipleft > ix) || (clipright < ix) || (cliptop[ix] > y) || (clipbottom[ix] <= y + q - 1);
}
uint8_t *buffer = dest;
// Accept whole block when totally covered
if (a == 0xF && b == 0xF && c == 0xF && clipcount == 0)
{
for (int iy = 0; iy < q; iy++)
{
for (int ix = x; ix < x + q; ix++)
{
buffer[ix] = solidcolor;
}
buffer += pitch;
}
}
else // Partially covered block
{
int CY1 = C1 + DX12 * y0 - DY12 * x0;
int CY2 = C2 + DX23 * y0 - DY23 * x0;
int CY3 = C3 + DX31 * y0 - DY31 * x0;
for (int iy = 0; iy < q; iy++)
{
int CX1 = CY1;
int CX2 = CY2;
int CX3 = CY3;
for (int ix = x; ix < x + q; ix++)
{
bool visible = ix >= clipleft && ix <= clipright && (cliptop[ix] <= y + iy) && (clipbottom[ix] > y + iy);
if (CX1 > 0 && CX2 > 0 && CX3 > 0 && visible)
{
buffer[ix] = solidcolor;
}
CX1 -= FDY12;
CX2 -= FDY23;
CX3 -= FDY31;
}
CY1 += FDX12;
CY2 += FDX23;
CY3 += FDX31;
buffer += pitch;
}
}
}
dest += q * pitch;
}
}
float ScreenTriangleDrawer::gradx(float x0, float y0, float x1, float y1, float x2, float y2, float c0, float c1, float c2)
{
float top = (c1 - c2) * (y0 - y2) - (c0 - c2) * (y1 - y2);
float bottom = (x1 - x2) * (y0 - y2) - (x0 - x2) * (y1 - y2);
return top / bottom;
}
float ScreenTriangleDrawer::grady(float x0, float y0, float x1, float y1, float x2, float y2, float c0, float c1, float c2)
{
float top = (c1 - c2) * (x0 - x2) - (c0 - c2) * (x1 - x2);
float bottom = -((x1 - x2) * (y0 - y2) - (x0 - x2) * (y1 - y2));
return top / bottom;
}
/////////////////////////////////////////////////////////////////////////////
TriMatrix TriMatrix::null()
{
TriMatrix m;
memset(m.matrix, 0, sizeof(m.matrix));
return m;
}
TriMatrix TriMatrix::identity()
{
TriMatrix m = null();
m.matrix[0] = 1.0f;
m.matrix[5] = 1.0f;
m.matrix[10] = 1.0f;
m.matrix[15] = 1.0f;
return m;
}
TriMatrix TriMatrix::translate(float x, float y, float z)
{
TriMatrix m = identity();
m.matrix[0 + 3 * 4] = x;
m.matrix[1 + 3 * 4] = y;
m.matrix[2 + 3 * 4] = z;
return m;
}
TriMatrix TriMatrix::scale(float x, float y, float z)
{
TriMatrix m = null();
m.matrix[0 + 0 * 4] = x;
m.matrix[1 + 1 * 4] = y;
m.matrix[2 + 2 * 4] = z;
m.matrix[3 + 3 * 4] = 1;
return m;
}
TriMatrix TriMatrix::rotate(float angle, float x, float y, float z)
{
float c = cosf(angle);
float s = sinf(angle);
TriMatrix m = null();
m.matrix[0 + 0 * 4] = (x*x*(1.0f - c) + c);
m.matrix[0 + 1 * 4] = (x*y*(1.0f - c) - z*s);
m.matrix[0 + 2 * 4] = (x*z*(1.0f - c) + y*s);
m.matrix[1 + 0 * 4] = (y*x*(1.0f - c) + z*s);
m.matrix[1 + 1 * 4] = (y*y*(1.0f - c) + c);
m.matrix[1 + 2 * 4] = (y*z*(1.0f - c) - x*s);
m.matrix[2 + 0 * 4] = (x*z*(1.0f - c) - y*s);
m.matrix[2 + 1 * 4] = (y*z*(1.0f - c) + x*s);
m.matrix[2 + 2 * 4] = (z*z*(1.0f - c) + c);
m.matrix[3 + 3 * 4] = 1.0f;
return m;
}
TriMatrix TriMatrix::operator*(const TriMatrix &mult) const
{
TriMatrix result;
for (int x = 0; x < 4; x++)
{
for (int y = 0; y < 4; y++)
{
result.matrix[x + y * 4] =
matrix[0 * 4 + x] * mult.matrix[y * 4 + 0] +
matrix[1 * 4 + x] * mult.matrix[y * 4 + 1] +
matrix[2 * 4 + x] * mult.matrix[y * 4 + 2] +
matrix[3 * 4 + x] * mult.matrix[y * 4 + 3];
}
}
return result;
}
TriVertex TriMatrix::operator*(TriVertex v) const
{
float vx = matrix[0 * 4 + 0] * v.x + matrix[1 * 4 + 0] * v.y + matrix[2 * 4 + 0] * v.z + matrix[3 * 4 + 0] * v.w;
float vy = matrix[0 * 4 + 1] * v.x + matrix[1 * 4 + 1] * v.y + matrix[2 * 4 + 1] * v.z + matrix[3 * 4 + 1] * v.w;
float vz = matrix[0 * 4 + 2] * v.x + matrix[1 * 4 + 2] * v.y + matrix[2 * 4 + 2] * v.z + matrix[3 * 4 + 2] * v.w;
float vw = matrix[0 * 4 + 3] * v.x + matrix[1 * 4 + 3] * v.y + matrix[2 * 4 + 3] * v.z + matrix[3 * 4 + 3] * v.w;
v.x = vx;
v.y = vy;
v.z = vz;
v.w = vw;
return v;
}

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/*
** Triangle drawers
** Copyright (c) 2016 Magnus Norddahl
**
** This software is provided 'as-is', without any express or implied
** warranty. In no event will the authors be held liable for any damages
** arising from the use of this software.
**
** Permission is granted to anyone to use this software for any purpose,
** including commercial applications, and to alter it and redistribute it
** freely, subject to the following restrictions:
**
** 1. The origin of this software must not be misrepresented; you must not
** claim that you wrote the original software. If you use this software
** in a product, an acknowledgment in the product documentation would be
** appreciated but is not required.
** 2. Altered source versions must be plainly marked as such, and must not be
** misrepresented as being the original software.
** 3. This notice may not be removed or altered from any source distribution.
**
*/
#ifndef __R_TRIANGLE__
#define __R_TRIANGLE__
#include "r_draw.h"
class FTexture;
struct ScreenTriangleDrawerArgs;
struct TriVertex
{
TriVertex() { }
TriVertex(float x, float y, float z, float w, float u, float v, float light) : x(x), y(y), z(z), w(w) { varying[0] = u; varying[1] = v; varying[2] = light; }
enum { NumVarying = 3 };
float x, y, z, w;
float varying[NumVarying];
};
struct TriMatrix
{
static TriMatrix null();
static TriMatrix identity();
static TriMatrix translate(float x, float y, float z);
static TriMatrix scale(float x, float y, float z);
static TriMatrix rotate(float angle, float x, float y, float z);
TriVertex operator*(TriVertex v) const;
TriMatrix operator*(const TriMatrix &m) const;
float matrix[16];
};
class TriangleDrawer
{
public:
static void draw(const TriMatrix &objectToWorld, const TriVertex *vinput, int vcount, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, FTexture *texture);
static void fill(const TriMatrix &objectToWorld, const TriVertex *vinput, int vcount, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, int solidcolor);
private:
static void draw_any(const TriMatrix &objectToWorld, const TriVertex *vinput, int vcount, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, FTexture *texture, int solidcolor, void(*drawfunc)(const ScreenTriangleDrawerArgs *));
static bool cullhalfspace(float clipdistance1, float clipdistance2, float &t1, float &t2);
static void clipedge(const TriVertex &v1, const TriVertex &v2, TriVertex *clippedvert, int &numclipvert);
};
struct ScreenTriangleDrawerArgs
{
uint8_t *dest;
int pitch;
TriVertex *v1;
TriVertex *v2;
TriVertex *v3;
int clipleft;
int clipright;
const short *cliptop;
const short *clipbottom;
const uint8_t *texturePixels;
int textureWidth;
int textureHeight;
int solidcolor;
};
class ScreenTriangleDrawer
{
public:
static void draw(const ScreenTriangleDrawerArgs *args);
static void fill(const ScreenTriangleDrawerArgs *args);
private:
static float gradx(float x0, float y0, float x1, float y1, float x2, float y2, float c0, float c1, float c2);
static float grady(float x0, float y0, float x1, float y1, float x2, float y2, float c0, float c1, float c2);
};
#endif