raze-gles/source/common/rendering/polyrenderer/drawers/screen_triangle.cpp
2021-03-07 13:21:15 +01:00

303 lines
8.2 KiB
C++

/*
** Polygon Doom software renderer
** 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 "filesystem.h"
#include "v_video.h"
#include "poly_triangle.h"
#include "screen_triangle.h"
#include "screen_blend.h"
#include "screen_scanline_setup.h"
#include "screen_shader.h"
#include <cmath>
static void WriteDepth(int y, int x0, int x1, PolyTriangleThreadData* thread)
{
float* line = thread->depthstencil->DepthValues() + (size_t)thread->depthstencil->Width() * y;
if (thread->DepthRangeScale != 0.0f)
{
float* w = thread->scanline.W;
for (int x = x0; x < x1; x++)
{
line[x] = w[x];
}
}
else // portal fills always uses DepthRangeStart = 1 and DepthRangeScale = 0
{
for (int x = x0; x < x1; x++)
{
line[x] = 65536.0f;
}
}
}
static void WriteStencil(int y, int x0, int x1, PolyTriangleThreadData* thread)
{
uint8_t* line = thread->depthstencil->StencilValues() + (size_t)thread->depthstencil->Width() * y;
uint8_t value = thread->StencilWriteValue;
for (int x = x0; x < x1; x++)
{
line[x] = value;
}
}
static void RunFragmentShader(int y, int x0, int x1, const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread)
{
WriteVaryings(y, x0, x1, args, thread);
thread->FragmentShader(x0, x1, thread);
}
static void DrawSpan(int y, int x0, int x1, const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread)
{
if (thread->WriteColor || thread->AlphaTest)
RunFragmentShader(y, x0, x1, args, thread);
if (!thread->AlphaTest)
{
if (thread->WriteColor)
thread->WriteColorFunc(y, x0, x1, thread);
if (thread->WriteDepth)
WriteDepth(y, x0, x1, thread);
if (thread->WriteStencil)
WriteStencil(y, x0, x1, thread);
}
else
{
uint8_t* discard = thread->scanline.discard;
while (x0 < x1)
{
int xstart = x0;
while (!discard[x0] && x0 < x1) x0++;
if (xstart < x0)
{
if (thread->WriteColor)
thread->WriteColorFunc(y, xstart, x0, thread);
if (thread->WriteDepth)
WriteDepth(y, xstart, x0, thread);
if (thread->WriteStencil)
WriteStencil(y, xstart, x0, thread);
}
while (discard[x0] && x0 < x1) x0++;
}
}
}
static void NoTestSpan(int y, int x0, int x1, const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread)
{
WriteW(y, x0, x1, args, thread);
DrawSpan(y, x0, x1, args, thread);
}
static void DepthTestSpan(int y, int x0, int x1, const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread)
{
WriteW(y, x0, x1, args, thread);
float* zbufferLine = thread->depthstencil->DepthValues() + (size_t)thread->depthstencil->Width() * y;
float* w = thread->scanline.W;
float depthbias = thread->depthbias;
int x = x0;
int xend = x1;
while (x < xend)
{
int xstart = x;
while (zbufferLine[x] >= w[x] + depthbias && x < xend)
x++;
if (x > xstart)
{
DrawSpan(y, xstart, x, args, thread);
}
while (zbufferLine[x] < w[x] + depthbias && x < xend)
x++;
}
}
static void DepthStencilTestSpan(int y, int x0, int x1, const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread)
{
uint8_t* stencilLine = thread->depthstencil->StencilValues() + (size_t)thread->depthstencil->Width() * y;
uint8_t stencilTestValue = thread->StencilTestValue;
int x = x0;
int xend = x1;
while (x < xend)
{
int xstart = x;
while (stencilLine[x] == stencilTestValue && x < xend)
x++;
if (x > xstart)
{
DepthTestSpan(y, xstart, x, args, thread);
}
while (stencilLine[x] != stencilTestValue && x < xend)
x++;
}
}
static void StencilTestSpan(int y, int x0, int x1, const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread)
{
uint8_t* stencilLine = thread->depthstencil->StencilValues() + (size_t)thread->depthstencil->Width() * y;
uint8_t stencilTestValue = thread->StencilTestValue;
int x = x0;
int xend = x1;
while (x < xend)
{
int xstart = x;
while (stencilLine[x] == stencilTestValue && x < xend)
x++;
if (x > xstart)
{
WriteW(y, x0, x1, args, thread);
DrawSpan(y, xstart, x, args, thread);
}
while (stencilLine[x] != stencilTestValue && x < xend)
x++;
}
}
static void SortVertices(const TriDrawTriangleArgs* args, ScreenTriVertex** sortedVertices)
{
sortedVertices[0] = args->v1;
sortedVertices[1] = args->v2;
sortedVertices[2] = args->v3;
if (sortedVertices[1]->y < sortedVertices[0]->y)
std::swap(sortedVertices[0], sortedVertices[1]);
if (sortedVertices[2]->y < sortedVertices[0]->y)
std::swap(sortedVertices[0], sortedVertices[2]);
if (sortedVertices[2]->y < sortedVertices[1]->y)
std::swap(sortedVertices[1], sortedVertices[2]);
}
void ScreenTriangle::Draw(const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread)
{
// Sort vertices by Y position
ScreenTriVertex* sortedVertices[3];
SortVertices(args, sortedVertices);
int clipleft = thread->clip.left;
int cliptop = MAX(thread->clip.top, thread->numa_start_y);
int clipright = thread->clip.right;
int clipbottom = MIN(thread->clip.bottom, thread->numa_end_y);
int topY = (int)(sortedVertices[0]->y + 0.5f);
int midY = (int)(sortedVertices[1]->y + 0.5f);
int bottomY = (int)(sortedVertices[2]->y + 0.5f);
topY = MAX(topY, cliptop);
midY = MIN(midY, clipbottom);
bottomY = MIN(bottomY, clipbottom);
if (topY >= bottomY)
return;
SelectFragmentShader(thread);
SelectWriteColorFunc(thread);
void(*testfunc)(int y, int x0, int x1, const TriDrawTriangleArgs * args, PolyTriangleThreadData * thread);
int opt = 0;
if (thread->DepthTest) opt |= SWTRI_DepthTest;
if (thread->StencilTest) opt |= SWTRI_StencilTest;
testfunc = ScreenTriangle::TestSpanOpts[opt];
topY += thread->skipped_by_thread(topY);
int num_cores = thread->num_cores;
// Find start/end X positions for each line covered by the triangle:
int y = topY;
float longDX = sortedVertices[2]->x - sortedVertices[0]->x;
float longDY = sortedVertices[2]->y - sortedVertices[0]->y;
float longStep = longDX / longDY;
float longPos = sortedVertices[0]->x + longStep * (y + 0.5f - sortedVertices[0]->y) + 0.5f;
longStep *= num_cores;
if (y < midY)
{
float shortDX = sortedVertices[1]->x - sortedVertices[0]->x;
float shortDY = sortedVertices[1]->y - sortedVertices[0]->y;
float shortStep = shortDX / shortDY;
float shortPos = sortedVertices[0]->x + shortStep * (y + 0.5f - sortedVertices[0]->y) + 0.5f;
shortStep *= num_cores;
while (y < midY)
{
int x0 = (int)shortPos;
int x1 = (int)longPos;
if (x1 < x0) std::swap(x0, x1);
x0 = clamp(x0, clipleft, clipright);
x1 = clamp(x1, clipleft, clipright);
testfunc(y, x0, x1, args, thread);
shortPos += shortStep;
longPos += longStep;
y += num_cores;
}
}
if (y < bottomY)
{
float shortDX = sortedVertices[2]->x - sortedVertices[1]->x;
float shortDY = sortedVertices[2]->y - sortedVertices[1]->y;
float shortStep = shortDX / shortDY;
float shortPos = sortedVertices[1]->x + shortStep * (y + 0.5f - sortedVertices[1]->y) + 0.5f;
shortStep *= num_cores;
while (y < bottomY)
{
int x0 = (int)shortPos;
int x1 = (int)longPos;
if (x1 < x0) std::swap(x0, x1);
x0 = clamp(x0, clipleft, clipright);
x1 = clamp(x1, clipleft, clipright);
testfunc(y, x0, x1, args, thread);
shortPos += shortStep;
longPos += longStep;
y += num_cores;
}
}
}
void(*ScreenTriangle::TestSpanOpts[])(int y, int x0, int x1, const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread) =
{
&NoTestSpan,
&DepthTestSpan,
&StencilTestSpan,
&DepthStencilTestSpan
};