mirror of
https://github.com/DrBeef/Raze.git
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124 lines
4.1 KiB
C++
124 lines
4.1 KiB
C++
/*
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** Polygon Doom software renderer
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** Copyright (c) 2016 Magnus Norddahl
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**
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** This software is provided 'as-is', without any express or implied
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** warranty. In no event will the authors be held liable for any damages
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** arising from the use of this software.
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**
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** Permission is granted to anyone to use this software for any purpose,
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** including commercial applications, and to alter it and redistribute it
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** freely, subject to the following restrictions:
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**
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** 1. The origin of this software must not be misrepresented; you must not
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** claim that you wrote the original software. If you use this software
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** in a product, an acknowledgment in the product documentation would be
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** appreciated but is not required.
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** 2. Altered source versions must be plainly marked as such, and must not be
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** misrepresented as being the original software.
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** 3. This notice may not be removed or altered from any source distribution.
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**
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*/
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#pragma once
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#include <cstdint>
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#include <vector>
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#include <float.h>
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#include "renderstyle.h"
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//#include "rendering/swrenderer/drawers/r_draw.h"
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class FString;
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class PolyTriangleThreadData;
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struct ScreenTriVertex
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{
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float x, y, z, w;
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float u, v;
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float worldX, worldY, worldZ;
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float a, r, g, b;
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float gradientdistZ;
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};
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struct ScreenTriangleStepVariables
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{
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float W, U, V;
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float WorldX, WorldY, WorldZ;
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float A, R, G, B;
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float GradientdistZ;
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};
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struct TriDrawTriangleArgs
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{
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ScreenTriVertex *v1;
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ScreenTriVertex *v2;
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ScreenTriVertex *v3;
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ScreenTriangleStepVariables gradientX;
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ScreenTriangleStepVariables gradientY;
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bool CalculateGradients()
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{
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float bottomX = (v2->x - v3->x) * (v1->y - v3->y) - (v1->x - v3->x) * (v2->y - v3->y);
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float bottomY = (v1->x - v3->x) * (v2->y - v3->y) - (v2->x - v3->x) * (v1->y - v3->y);
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if ((bottomX >= -FLT_EPSILON && bottomX <= FLT_EPSILON) || (bottomY >= -FLT_EPSILON && bottomY <= FLT_EPSILON))
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return false;
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gradientX.W = FindGradientX(bottomX, 1.0f, 1.0f, 1.0f);
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gradientX.U = FindGradientX(bottomX, v1->u, v2->u, v3->u);
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gradientX.V = FindGradientX(bottomX, v1->v, v2->v, v3->v);
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gradientX.WorldX = FindGradientX(bottomX, v1->worldX, v2->worldX, v3->worldX);
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gradientX.WorldY = FindGradientX(bottomX, v1->worldY, v2->worldY, v3->worldY);
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gradientX.WorldZ = FindGradientX(bottomX, v1->worldZ, v2->worldZ, v3->worldZ);
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gradientX.A = FindGradientX(bottomX, v1->a, v2->a, v3->a);
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gradientX.R = FindGradientX(bottomX, v1->r, v2->r, v3->r);
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gradientX.G = FindGradientX(bottomX, v1->g, v2->g, v3->g);
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gradientX.B = FindGradientX(bottomX, v1->b, v2->b, v3->b);
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gradientX.GradientdistZ = FindGradientX(bottomX, v1->gradientdistZ, v2->gradientdistZ, v3->gradientdistZ);
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gradientY.W = FindGradientY(bottomY, 1.0f, 1.0f, 1.0f);
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gradientY.U = FindGradientY(bottomY, v1->u, v2->u, v3->u);
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gradientY.V = FindGradientY(bottomY, v1->v, v2->v, v3->v);
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gradientY.WorldX = FindGradientY(bottomY, v1->worldX, v2->worldX, v3->worldX);
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gradientY.WorldY = FindGradientY(bottomY, v1->worldY, v2->worldY, v3->worldY);
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gradientY.WorldZ = FindGradientY(bottomY, v1->worldZ, v2->worldZ, v3->worldZ);
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gradientY.A = FindGradientY(bottomY, v1->a, v2->a, v3->a);
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gradientY.R = FindGradientY(bottomY, v1->r, v2->r, v3->r);
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gradientY.G = FindGradientY(bottomY, v1->g, v2->g, v3->g);
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gradientY.B = FindGradientY(bottomY, v1->b, v2->b, v3->b);
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gradientY.GradientdistZ = FindGradientY(bottomY, v1->gradientdistZ, v2->gradientdistZ, v3->gradientdistZ);
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return true;
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}
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private:
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float FindGradientX(float bottomX, float c0, float c1, float c2)
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{
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c0 *= v1->w;
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c1 *= v2->w;
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c2 *= v3->w;
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return ((c1 - c2) * (v1->y - v3->y) - (c0 - c2) * (v2->y - v3->y)) / bottomX;
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}
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float FindGradientY(float bottomY, float c0, float c1, float c2)
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{
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c0 *= v1->w;
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c1 *= v2->w;
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c2 *= v3->w;
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return ((c1 - c2) * (v1->x - v3->x) - (c0 - c2) * (v2->x - v3->x)) / bottomY;
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}
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};
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class ScreenTriangle
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{
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public:
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static void Draw(const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread);
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private:
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static void(*TestSpanOpts[])(int y, int x0, int x1, const TriDrawTriangleArgs* args, PolyTriangleThreadData* thread);
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};
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enum SWTestSpan
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{
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SWTRI_DepthTest = 1,
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SWTRI_StencilTest = 2
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};
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