ppsspp/GPU/GLES/FragmentShaderGenerator.cpp

311 lines
9.8 KiB
C++

// Copyright (c) 2012- PPSSPP Project.
// This program 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, version 2.0 or later versions.
// This program 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 2.0 for more details.
// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/
// Official git repository and contact information can be found at
// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.
#if defined(USING_GLES2)
#define GLSL_ES_1_0
#else
#define GLSL_1_3
// SDL 1.2 on Apple does not have support for OpenGL 3 and hence needs
// special treatment in the shader generator.
#if defined(__APPLE__)
#define FORCE_OPENGL_2_0
#endif
#endif
#include "FragmentShaderGenerator.h"
#include "../ge_constants.h"
#include "../GPUState.h"
#include <cstdio>
#define WRITE p+=sprintf
// #define DEBUG_SHADER
// GL_NV_shader_framebuffer_fetch looks interesting....
static bool IsAlphaTestTriviallyTrue() {
int alphaTestFunc = gstate.alphatest & 7;
int alphaTestRef = (gstate.alphatest >> 8) & 0xFF;
switch (alphaTestFunc) {
case GE_COMP_ALWAYS:
return true;
case GE_COMP_GEQUAL:
if (alphaTestRef == 0)
return true;
// This breaks the trees in MotoGP, for example.
// case GE_COMP_GREATER:
//if (alphaTestRef == 0 && (gstate.alphaBlendEnable & 1) && gstate.getBlendFuncA() == GE_SRCBLEND_SRCALPHA && gstate.getBlendFuncB() == GE_SRCBLEND_INVSRCALPHA)
// return true;
case GE_COMP_LEQUAL:
if (alphaTestRef == 255)
return true;
default:
return false;
}
}
static bool IsColorTestTriviallyTrue() {
int colorTestFunc = gstate.colortest & 3;
switch (colorTestFunc) {
case GE_COMP_ALWAYS:
return true;
default:
return false;
}
}
static bool CanDoubleSrcBlendMode() {
if (!gstate.isAlphaBlendEnabled()) {
return false;
}
int funcA = gstate.getBlendFuncA();
int funcB = gstate.getBlendFuncB();
if (funcA != GE_SRCBLEND_DOUBLESRCALPHA) {
funcB = funcA;
funcA = gstate.getBlendFuncB();
}
if (funcA != GE_SRCBLEND_DOUBLESRCALPHA) {
return false;
}
// One side should be doubled. Let's check the other side.
// LittleBigPlanet, for example, uses 2.0 * src, 1.0 - src, which can't double.
switch (funcB) {
case GE_DSTBLEND_SRCALPHA:
case GE_DSTBLEND_INVSRCALPHA:
return false;
default:
return true;
}
}
// Here we must take all the bits of the gstate that determine what the fragment shader will
// look like, and concatenate them together into an ID.
void ComputeFragmentShaderID(FragmentShaderID *id) {
memset(&id->d[0], 0, sizeof(id->d));
if (gstate.clearmode & 1) {
// We only need one clear shader, so let's ignore the rest of the bits.
id->d[0] = 1;
} else {
int lmode = (gstate.lmode & 1) && gstate.isLightingEnabled();
bool enableFog = gstate.isFogEnabled() && !gstate.isModeThrough();
bool enableAlphaTest = gstate.isAlphaTestEnabled() && !IsAlphaTestTriviallyTrue();
bool enableColorTest = gstate.isColorTestEnabled() && !IsColorTestTriviallyTrue();
bool enableColorDoubling = (gstate.texfunc & 0x10000) != 0;
// This isn't really correct, but it's a hack to get doubled blend modes to work more correctly.
bool enableAlphaDoubling = CanDoubleSrcBlendMode();
bool doTextureProjection = gstate.getUVGenMode() == 1;
bool doTextureAlpha = (gstate.texfunc & 0x100) != 0;
// All texfuncs except replace are the same for RGB as for RGBA with full alpha.
if (gstate_c.textureFullAlpha && (gstate.texfunc & 0x7) != GE_TEXFUNC_REPLACE)
doTextureAlpha = false;
// id->d[0] |= (gstate.clearmode & 1);
if (gstate.isTextureMapEnabled()) {
id->d[0] |= 1 << 1;
id->d[0] |= (gstate.texfunc & 0x7) << 2;
id->d[0] |= (doTextureAlpha & 1) << 5; // rgb or rgba
}
id->d[0] |= (lmode & 1) << 7;
id->d[0] |= gstate.isAlphaTestEnabled() << 8;
if (enableAlphaTest)
id->d[0] |= (gstate.alphatest & 0x7) << 9; // alpha test func
id->d[0] |= gstate.isColorTestEnabled() << 12;
if (enableColorTest)
id->d[0] |= (gstate.colortest & 0x3) << 13; // color test func
id->d[0] |= (enableFog & 1) << 15;
id->d[0] |= (doTextureProjection & 1) << 16;
id->d[0] |= (enableColorDoubling & 1) << 17;
id->d[0] |= (enableAlphaDoubling & 1) << 18;
}
}
// Missing: Z depth range
// Also, logic ops etc, of course. Urgh.
void GenerateFragmentShader(char *buffer) {
char *p = buffer;
#if defined(GLSL_ES_1_0)
WRITE(p, "precision lowp float;\n");
#elif !defined(FORCE_OPENGL_2_0)
WRITE(p, "#version 110\n");
#endif
int lmode = (gstate.lmode & 1) && gstate.isLightingEnabled();
int doTexture = gstate.isTextureMapEnabled() && !gstate.isModeClear();
bool enableFog = gstate.isFogEnabled() && !gstate.isModeThrough() && !gstate.isModeClear();
bool enableAlphaTest = gstate.isAlphaTestEnabled() && !IsAlphaTestTriviallyTrue() && !gstate.isModeClear();
bool enableColorTest = gstate.isColorTestEnabled() && !IsColorTestTriviallyTrue() && !gstate.isModeClear();
bool enableColorDoubling = (gstate.texfunc & 0x10000) != 0;
// This isn't really correct, but it's a hack to get doubled blend modes to work more correctly.
bool enableAlphaDoubling = CanDoubleSrcBlendMode();
bool doTextureProjection = gstate.getUVGenMode() == 1;
bool doTextureAlpha = (gstate.texfunc & 0x100) != 0;
if (gstate_c.textureFullAlpha && (gstate.texfunc & 0x7) != GE_TEXFUNC_REPLACE)
doTextureAlpha = false;
if (doTexture)
WRITE(p, "uniform sampler2D tex;\n");
if (enableAlphaTest || enableColorTest) {
WRITE(p, "uniform vec4 u_alphacolorref;\n");
WRITE(p, "uniform vec4 u_colormask;\n");
}
if (gstate.isTextureMapEnabled())
WRITE(p, "uniform vec3 u_texenv;\n");
WRITE(p, "varying vec4 v_color0;\n");
if (lmode)
WRITE(p, "varying vec3 v_color1;\n");
if (enableFog) {
WRITE(p, "uniform vec3 u_fogcolor;\n");
#if defined(GLSL_ES_1_0)
WRITE(p, "varying mediump float v_fogdepth;\n");
#else
WRITE(p, "varying float v_fogdepth;\n");
#endif
}
if (doTexture)
{
if (doTextureProjection)
WRITE(p, "varying vec3 v_texcoord;\n");
else
WRITE(p, "varying vec2 v_texcoord;\n");
}
if (enableAlphaTest) {
WRITE(p, "float roundAndScaleTo255f(in float x) { return floor(x * 255.0 + 0.5); }\n");
}
if (enableColorTest) {
WRITE(p, "vec3 roundAndScaleTo255v(in vec3 x) { return floor(x * 255.0 + 0.5); }\n");
}
WRITE(p, "void main() {\n");
if (gstate.isModeClear()) {
// Clear mode does not allow any fancy shading.
WRITE(p, " gl_FragColor = v_color0;\n");
} else {
const char *secondary = "";
// Secondary color for specular on top of texture
if (lmode) {
WRITE(p, " vec4 s = vec4(v_color1, 0.0);\n");
secondary = " + s";
} else {
secondary = "";
}
if (gstate.textureMapEnable & 1) {
if (doTextureProjection) {
WRITE(p, " vec4 t = texture2DProj(tex, v_texcoord);\n");
} else {
WRITE(p, " vec4 t = texture2D(tex, v_texcoord);\n");
}
WRITE(p, " vec4 p = v_color0;\n");
if (doTextureAlpha) { // texfmt == RGBA
switch (gstate.texfunc & 0x7) {
case GE_TEXFUNC_MODULATE:
WRITE(p, " vec4 v = p * t%s;\n", secondary); break;
case GE_TEXFUNC_DECAL:
WRITE(p, " vec4 v = vec4(mix(p.rgb, t.rgb, t.a), p.a)%s;\n", secondary); break;
case GE_TEXFUNC_BLEND:
WRITE(p, " vec4 v = vec4(mix(p.rgb, u_texenv.rgb, t.rgb), p.a * t.a)%s;\n", secondary); break;
case GE_TEXFUNC_REPLACE:
WRITE(p, " vec4 v = t%s;\n", secondary); break;
case GE_TEXFUNC_ADD:
WRITE(p, " vec4 v = vec4(p.rgb + t.rgb, p.a * t.a)%s;\n", secondary); break;
default:
WRITE(p, " vec4 v = p;\n"); break;
}
} else { // texfmt == RGB
switch (gstate.texfunc & 0x7) {
case GE_TEXFUNC_MODULATE:
WRITE(p, " vec4 v = vec4(t.rgb * p.rgb, p.a)%s;\n", secondary); break;
case GE_TEXFUNC_DECAL:
WRITE(p, " vec4 v = vec4(t.rgb, p.a)%s;\n", secondary); break;
case GE_TEXFUNC_BLEND:
WRITE(p, " vec4 v = vec4(mix(p.rgb, u_texenv.rgb, t.rgb), p.a)%s;\n", secondary); break;
case GE_TEXFUNC_REPLACE:
WRITE(p, " vec4 v = vec4(t.rgb, p.a)%s;\n", secondary); break;
case GE_TEXFUNC_ADD:
WRITE(p, " vec4 v = vec4(p.rgb + t.rgb, p.a)%s;\n", secondary); break;
default:
WRITE(p, " vec4 v = p;\n"); break;
}
}
} else {
// No texture mapping
WRITE(p, " vec4 v = v_color0 %s;\n", secondary);
}
if (enableAlphaTest) {
int alphaTestFunc = gstate.alphatest & 7;
const char *alphaTestFuncs[] = { "#", "#", " != ", " == ", " >= ", " > ", " <= ", " < " }; // never/always don't make sense
if (alphaTestFuncs[alphaTestFunc][0] != '#') {
WRITE(p, " if (roundAndScaleTo255f(v.a) %s u_alphacolorref.a) discard;\n", alphaTestFuncs[alphaTestFunc]);
}
}
// TODO: Before or after the color test?
if (enableColorDoubling && enableAlphaDoubling) {
WRITE(p, " v = v * 2.0;\n");
} else if (enableColorDoubling) {
WRITE(p, " v.rgb = v.rgb * 2.0;\n");
} else if (enableAlphaDoubling) {
WRITE(p, " v.a = v.a * 2.0;\n");
}
if (enableColorTest) {
int colorTestFunc = gstate.colortest & 3;
const char *colorTestFuncs[] = { "#", "#", " != ", " == " }; // never/always don't make sense
int colorTestMask = gstate.colormask;
if (colorTestFuncs[colorTestFunc][0] != '#') {
WRITE(p, "if (roundAndScaleTo255v(v.rgb) %s u_alphacolorref.rgb) discard;\n", colorTestFuncs[colorTestFunc]);
}
}
if (enableFog) {
WRITE(p, " float fogCoef = clamp(v_fogdepth, 0.0, 1.0);\n");
WRITE(p, " gl_FragColor = mix(vec4(u_fogcolor, v.a), v, fogCoef);\n");
// WRITE(p, " v.x = v_depth;\n");
} else {
WRITE(p, " gl_FragColor = v;\n");
}
}
#ifdef DEBUG_SHADER
if (doTexture) {
WRITE(p, " gl_FragColor = texture2D(tex, v_texcoord.xy);\n");
} else {
WRITE(p, " gl_FragColor = vec4(1,0,1,1);\n");
}
#endif
WRITE(p, "}\n");
}