dolphin/Source/Core/VideoCommon/Src/PixelShaderGen.cpp

// Copyright (C) 2003-2008 Dolphin 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.

// 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 SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/

#include <stdio.h>
#include <cmath>
#include <assert.h>

#include "Profiler.h"
#include "PixelShaderGen.h"
#include "XFMemory.h"  // for texture projection mode
#include "BPMemory.h"

// Mash together all the inputs that contribute to the code of a generated pixel shader into
// a unique identifier, basically containing all the bits. Yup, it's a lot ....
void GetPixelShaderId(PIXELSHADERUID &uid, u32 s_texturemask, u32 zbufrender, u32 zBufRenderToCol0)
{
	u32 projtexcoords = 0;
	for (u32 i = 0; i < (u32)bpmem.genMode.numtevstages + 1; i++) {
		if (bpmem.tevorders[i/2].getEnable(i&1)) {
			int texcoord = bpmem.tevorders[i/2].getTexCoord(i&1);
			if (xfregs.texcoords[texcoord].texmtxinfo.projection )
				projtexcoords |= 1 << texcoord;
		}
	}
	uid.values[0] = (u32)bpmem.genMode.numtevstages |
				   ((u32)bpmem.genMode.numindstages << 4) |
				   ((u32)bpmem.genMode.numtexgens << 7) |
				   ((u32)bpmem.dstalpha.enable << 11) |
				   ((u32)((bpmem.alphaFunc.hex >> 16) & 0xff) << 12) |
				   (projtexcoords << 20) |
				   ((u32)bpmem.ztex2.op << 28) |
				   (zbufrender << 30) |
				   (zBufRenderToCol0 << 31);

	uid.values[0] = (uid.values[0] & ~0x0ff00000) | (projtexcoords << 20);
	// swap table
	for (int i = 0; i < 8; i += 2)
		((u8*)&uid.values[1])[i/2] = (bpmem.tevksel[i].hex & 0xf) | ((bpmem.tevksel[i + 1].hex & 0xf) << 4);

	uid.values[2] = s_texturemask;

    uid.values[3] = (u32)bpmem.fog.c_proj_fsel.fsel |
                   ((u32)bpmem.fog.c_proj_fsel.proj << 3);

	int hdr = 4;
	u32* pcurvalue = &uid.values[hdr];
	for (u32 i = 0; i < (u32)bpmem.genMode.numtevstages+1; ++i) {
		TevStageCombiner::ColorCombiner &cc = bpmem.combiners[i].colorC;
		TevStageCombiner::AlphaCombiner &ac = bpmem.combiners[i].alphaC;

		u32 val0 = cc.hex&0xffffff;
		u32 val1 = ac.hex&0xffffff;
		val0 |= bpmem.tevksel[i/2].getKC(i&1)<<24;
		val1 |= bpmem.tevksel[i/2].getKA(i&1)<<24;
		pcurvalue[0] = val0;
		pcurvalue[1] = val1;
		pcurvalue += 2;
	}

	for (u32 i = 0; i < ((u32)bpmem.genMode.numtevstages+1)/2; ++i) {
		u32 val0, val1;
		if (bpmem.tevorders[i].hex & 0x40)
			val0 = bpmem.tevorders[i].hex & 0x3ff;
		else
			val0 = bpmem.tevorders[i].hex & 0x380;
		if (bpmem.tevorders[i].hex & 0x40000)
			val1 = (bpmem.tevorders[i].hex & 0x3ff000) >> 12;
		else
			val1 = (bpmem.tevorders[i].hex & 0x380000) >> 12;

		switch (i % 3) {
			case 0: pcurvalue[0] = val0|(val1<<10); break;
			case 1: pcurvalue[0] |= val0<<20; pcurvalue[1] = val1; pcurvalue++; break;
			case 2: pcurvalue[1] |= (val0<<10)|(val1<<20); pcurvalue++; break;
		}
	}

	if ((bpmem.genMode.numtevstages + 1) & 1) { // odd
		u32 val0;
		if (bpmem.tevorders[bpmem.genMode.numtevstages/2].hex & 0x40)
			val0 = bpmem.tevorders[bpmem.genMode.numtevstages/2].hex&0x3ff;
		else
			val0 = bpmem.tevorders[bpmem.genMode.numtevstages/2].hex & 0x380;

		switch (bpmem.genMode.numtevstages % 3) {
			case 0: pcurvalue[0] = val0; break;
			case 1: pcurvalue[0] |= val0 << 20; break;
			case 2: pcurvalue[1] |= val0 << 10; pcurvalue++; break;
		}
	}

	if ((bpmem.genMode.numtevstages % 3) != 2)
		++pcurvalue;

	uid.tevstages = (u32)(pcurvalue-&uid.values[0]-hdr);

	for (u32 i = 0; i < bpmem.genMode.numindstages; ++i) {
		u32 val = bpmem.tevind[i].hex & 0x1fffff; // 21 bits
		switch (i%3) {
			case 0: pcurvalue[0] = val; break;
			case 1: pcurvalue[0] |= val << 21; pcurvalue[1] = val >> 11; ++pcurvalue; break;
			case 2: pcurvalue[0] |= val << 10; ++pcurvalue; break;
		}
	}

	// yeah, well ....
	uid.indstages = (u32)(pcurvalue - &uid.values[0] - (hdr - 1) - uid.tevstages);
}

//   old tev->pixelshader notes
//
//   color for this stage (alpha, color) is given by bpmem.tevorders[0].colorchan0
//   konstant for this stage (alpha, color) is given by bpmem.tevksel   
//   inputs are given by bpmem.combiners[0].colorC.a/b/c/d     << could be current chan color
//   according to GXTevColorArg table above
//   output is given by .outreg
//   tevtemp is set according to swapmodetables and 

static void WriteStage(char *&p, int n, u32 texture_mask);
static void WrapNonPow2Tex(char* &p, const char* var, int texmap, u32 texture_mask);
static void WriteAlphaCompare(char *&p, int num, int comp);
static bool WriteAlphaTest(char *&p);
static void WriteFog(char *&p, bool bOutputZ);

const float epsilon8bit = 1.0f / 255.0f;

static const char *tevKSelTableC[] = // KCSEL
{
    "1.0f,1.0f,1.0f",            //1   = 0x00
    "0.875,0.875,0.875",//7_8 = 0x01
    "0.75,0.75,0.75",	//3_4 = 0x02
    "0.625,0.625,0.625",//5_8 = 0x03
    "0.5,0.5,0.5",      //1_2 = 0x04
    "0.375,0.375,0.375",//3_8 = 0x05
    "0.25,0.25,0.25",   //1_4 = 0x06
    "0.125,0.125,0.125",//1_8 = 0x07
    "ERROR", //0x08
    "ERROR", //0x09
    "ERROR", //0x0a
    "ERROR", //0x0b
    I_KCOLORS"[0].rgb",//K0 = 0x0C
    I_KCOLORS"[1].rgb",//K1 = 0x0D
    I_KCOLORS"[2].rgb",//K2 = 0x0E
    I_KCOLORS"[3].rgb",//K3 = 0x0F
    I_KCOLORS"[0].rrr",//K0_R = 0x10
    I_KCOLORS"[1].rrr",//K1_R = 0x11
    I_KCOLORS"[2].rrr",//K2_R = 0x12
    I_KCOLORS"[3].rrr",//K3_R = 0x13
    I_KCOLORS"[0].ggg",//K0_G = 0x14 
    I_KCOLORS"[1].ggg",//K1_G = 0x15
    I_KCOLORS"[2].ggg",//K2_G = 0x16
    I_KCOLORS"[3].ggg",//K3_G = 0x17
    I_KCOLORS"[0].bbb",//K0_B = 0x18
    I_KCOLORS"[1].bbb",//K1_B = 0x19
    I_KCOLORS"[2].bbb",//K2_B = 0x1A
    I_KCOLORS"[3].bbb",//K3_B = 0x1B
    I_KCOLORS"[0].aaa",//K0_A = 0x1C
    I_KCOLORS"[1].aaa",//K1_A = 0x1D
    I_KCOLORS"[2].aaa",//K2_A = 0x1E
    I_KCOLORS"[3].aaa",//K3_A = 0x1F
};

static const char *tevKSelTableA[] = // KASEL
{
    "1.0f",    //1   = 0x00
    "0.875f",//7_8 = 0x01
    "0.75f",	//3_4 = 0x02
    "0.625f",//5_8 = 0x03
    "0.5f",  //1_2 = 0x04
    "0.375f",//3_8 = 0x05
    "0.25f", //1_4 = 0x06
    "0.125f",//1_8 = 0x07
    "ERROR", //0x08
    "ERROR", //0x09
    "ERROR", //0x0a
    "ERROR", //0x0b
    "ERROR", //0x0c
    "ERROR", //0x0d
    "ERROR", //0x0e
    "ERROR", //0x0f
    I_KCOLORS"[0].r",//K0_R = 0x10
    I_KCOLORS"[1].r",//K1_R = 0x11
    I_KCOLORS"[2].r",//K2_R = 0x12
    I_KCOLORS"[3].r",//K3_R = 0x13
    I_KCOLORS"[0].g",//K0_G = 0x14
    I_KCOLORS"[1].g",//K1_G = 0x15
    I_KCOLORS"[2].g",//K2_G = 0x16
    I_KCOLORS"[3].g",//K3_G = 0x17
    I_KCOLORS"[0].b",//K0_B = 0x18
    I_KCOLORS"[1].b",//K1_B = 0x19
    I_KCOLORS"[2].b",//K2_B = 0x1A
    I_KCOLORS"[3].b",//K3_B = 0x1B
    I_KCOLORS"[0].a",//K0_A = 0x1C
    I_KCOLORS"[1].a",//K1_A = 0x1D
    I_KCOLORS"[2].a",//K2_A = 0x1E
    I_KCOLORS"[3].a",//K3_A = 0x1F
};

static const char *tevScaleTable[] = // CS
{
    "1.0f",   //SCALE_1
    "2.0f", //SCALE_2
    "4.0f", //SCALE_4
    "0.5f",//DIVIDE_2
};

static const char *tevBiasTable[] = // TB
{
    "",      //ZERO,
    "+0.5f",  //ADDHALF,
    "-0.5f",  //SUBHALF,
    "",
};

static const char *tevOpTable[] = { // TEV
    "+",      //TEVOP_ADD = 0,
    "-",      //TEVOP_SUB = 1,
};

//static const char *tevCompOpTable[] = { ">", "==" };

#define TEVCMP_R8    0
#define TEVCMP_GR16  1
#define TEVCMP_BGR24 2
#define TEVCMP_RGB8  3

static const char *tevCInputTable[] = // CC
{
    "prev.rgb",         //CPREV,
    "prev.aaa",           //APREV,
    "c0.rgb",           //C0,
    "c0.aaa",             //A0,
    "c1.rgb",           //C1,
    "c1.aaa",             //A1,
    "c2.rgb",           //C2,
    "c2.aaa",             //A2,
    "textemp.rgb",      //TEXC,
    "textemp.aaa",        //TEXA,
    "rastemp.rgb",    //RASC,
    "rastemp.aaa",      //RASA,
    "float3(1.0f,1.0f,1.0f)",              //ONE,
    "float3(.5f,.5f,.5f)",              //HALF,
    "konsttemp.rgb",    //KONST,
    "float3(0.0f,0.0f,0.0f)",              //ZERO
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
};

static const char *tevCInputTable2[] = // CC
{
    "prev",         //CPREV,
    "(prev.aaa)",           //APREV,
    "c0",           //C0,
    "(c0.aaa)",             //A0,
    "c1",           //C1,
    "(c1.aaa)",             //A1,
    "c2",           //C2,
    "(c2.aaa)",             //A2,
    "textemp",      //TEXC,
    "(textemp.aaa)",        //TEXA,
    "rastemp",    //RASC,
    "(rastemp.aaa)",      //RASA,
    "float3(1.0f,1.0f,1.0f)",              //ONE,
    "float3(.5f,.5f,.5f)",              //HALF,
    "konsttemp", //"konsttemp.rgb",    //KONST,
    "float3(0.0f,0.0f,0.0f)",              //ZERO
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
    "PADERROR",	"PADERROR",	"PADERROR",	"PADERROR",
};

static const char *tevAInputTable[] = // CA
{
    "prev.a",           //APREV,
    "c0.a",             //A0,
    "c1.a",             //A1,
    "c2.a",             //A2,
    "textemp.a",        //TEXA,
    "rastemp.a",        //RASA,
    "konsttemp.a",      //KONST
    "0.0", //ZERO
    "PADERROR", "PADERROR", "PADERROR", "PADERROR",
    "PADERROR", "PADERROR", "PADERROR", "PADERROR",
    "PADERROR", "PADERROR", "PADERROR", "PADERROR",
    "PADERROR", "PADERROR", "PADERROR",
};	

static const char *tevAInputTable2[] = // CA
{
    "prev",           //APREV,
    "c0",             //A0,
    "c1",             //A1,
    "c2",             //A2,
    "textemp",        //TEXA,
    "rastemp",        //RASA,
    "konsttemp",      //KONST,  (hw1 had quarter)
    "float4(0,0,0,0)", //ZERO
    "PADERROR", "PADERROR", "PADERROR", "PADERROR",
    "PADERROR", "PADERROR", "PADERROR", "PADERROR",
    "PADERROR", "PADERROR", "PADERROR", "PADERROR",
    "PADERROR", "PADERROR", "PADERROR", "PADERROR",
};	

static const char *tevRasTable[] =
{
    "colors[0]",
    "colors[1]",
    "ERROR", //2
    "ERROR", //3
    "ERROR", //4
    "alphabump", // use bump alpha
    "(alphabump*(255.0f/248.0f))", //normalized
    "float4(0,0,0,0)", // zero
};

static const char *alphaRef[2] = 
{
    I_ALPHA"[0].x",
    I_ALPHA"[0].y"
};

//static const char *tevTexFunc[] = { "tex2D", "texRECT" };

static const char *tevCOutputTable[]  = { "prev.rgb", "c0.rgb", "c1.rgb", "c2.rgb" };
static const char *tevAOutputTable[]  = { "prev.a", "c0.a", "c1.a", "c2.a" };
static const char *tevIndAlphaSel[]   = {"", "x", "y", "z"};
static const char *tevIndAlphaScale[] = {"", "*32","*16","*8"};
static const char *tevIndBiasField[]  = {"", "x", "y", "xy", "z", "xz", "yz", "xyz"}; // indexed by bias
static const char *tevIndBiasAdd[]    = {"-128.0f", "1.0f", "1.0f", "1.0f" }; // indexed by fmt
static const char *tevIndWrapStart[]  = {"0", "256", "128", "64", "32", "16", "0.001" };
static const char *tevIndFmtScale[]   = {"255.0f", "31.0f", "15.0f", "8.0f" };

#define WRITE p+=sprintf

static const char *swapColors = "rgba";
static char swapModeTable[4][5];

static char text[16384];

static void BuildSwapModeTable()
{
    //bpmem.tevregs[0].
    for (int i = 0; i < 4; i++)
    {
        swapModeTable[i][0] = swapColors[bpmem.tevksel[i*2].swap1];
        swapModeTable[i][1] = swapColors[bpmem.tevksel[i*2].swap2];
        swapModeTable[i][2] = swapColors[bpmem.tevksel[i*2+1].swap1];
        swapModeTable[i][3] = swapColors[bpmem.tevksel[i*2+1].swap2];
        swapModeTable[i][4] = 0;
    }
}

const char *GeneratePixelShader(u32 texture_mask, bool has_zbuffer_target, bool bRenderZToCol0)
{
	text[sizeof(text) - 1] = 0x7C;  // canary
    DVSTARTPROFILE();

    BuildSwapModeTable();
    int numStages = bpmem.genMode.numtevstages + 1;
    int numTexgen = bpmem.genMode.numtexgens;

    char *p = text;
    WRITE(p, "//Pixel Shader for TEV stages\n");
    WRITE(p, "//%i TEV stages, %i texgens, %i IND stages\n",
		numStages, numTexgen, bpmem.genMode.numindstages);

    bool bRenderZ = has_zbuffer_target && bpmem.zmode.updateenable;
    bool bOutputZ = bpmem.ztex2.op != ZTEXTURE_DISABLE;
    bool bInputZ = bpmem.ztex2.op==ZTEXTURE_ADD || bRenderZ || bpmem.fog.c_proj_fsel.fsel != 0;

    // bool bRenderZToCol0 = ; // output z and alpha to color0
    assert( !bRenderZToCol0 || bRenderZ );

    int nIndirectStagesUsed = 0;
    if (bpmem.genMode.numindstages > 0) {
        for (int i = 0; i < numStages; ++i) {
            if (bpmem.tevind[i].IsActive() && bpmem.tevind[i].bt < bpmem.genMode.numindstages) {
                nIndirectStagesUsed |= 1<<bpmem.tevind[i].bt;
            }
        }
    }

    // Declare samplers
    if (texture_mask) {
        WRITE(p, "uniform samplerRECT ");
        bool bfirst = true;
        for (int i = 0; i < 8; ++i) {
            if (texture_mask & (1<<i)) {
                WRITE(p, "%s samp%d : register(s%d)", bfirst?"":",", i, i);
                bfirst = false;
            }
        }
        WRITE(p, ";\n");
    }

    if (texture_mask != 0xff) {
        WRITE(p, "uniform sampler2D ");
        bool bfirst = true;
        for (int i = 0; i < 8; ++i) {
            if (!(texture_mask & (1<<i))) {
                WRITE(p, "%s samp%d : register(s%d)", bfirst?"":",",i, i);
                bfirst = false;
            }
        }
        WRITE(p, ";\n");
    }

    WRITE(p, "\n");

    WRITE(p, "uniform float4 "I_COLORS"[4] : register(c%d);\n", C_COLORS);
    WRITE(p, "uniform float4 "I_KCOLORS"[4] : register(c%d);\n", C_KCOLORS);
    WRITE(p, "uniform float4 "I_ALPHA"[1] : register(c%d);\n", C_ALPHA);
    WRITE(p, "uniform float4 "I_TEXDIMS"[8] : register(c%d);\n", C_TEXDIMS);
    WRITE(p, "uniform float4 "I_ZBIAS"[2] : register(c%d);\n", C_ZBIAS);
    WRITE(p, "uniform float4 "I_INDTEXSCALE"[2] : register(c%d);\n", C_INDTEXSCALE);
    WRITE(p, "uniform float4 "I_INDTEXMTX"[6] : register(c%d);\n", C_INDTEXMTX);
    WRITE(p, "uniform float4 "I_FOG"[2] : register(c%d);\n", C_FOG);

    WRITE(p, "void main(\n");

    WRITE(p, "out half4 ocol0 : COLOR0,\n");
    if (bRenderZ && !bRenderZToCol0 )
        WRITE(p, "out half4 ocol1 : COLOR1,\n");

    if (bOutputZ )
        WRITE(p, "  out float depth : DEPTH,\n");

    // compute window position if needed because binding semantic WPOS is not widely supported
	if (numTexgen < 7) {
		for (int i = 0; i < numTexgen; ++i)
			WRITE(p, "  in float3 uv%d : TEXCOORD%d, \n", i, i);
		WRITE(p, "  in float4 clipPos : TEXCOORD%d, \n", numTexgen);
	} else {
		// wpos is in w of first 4 texcoords
		for (int i = 0; i < numTexgen; ++i)
			WRITE(p, "  in float%d uv%d : TEXCOORD%d, \n", i<4?4:3, i, i);
	}

    WRITE(p, "  in float4 colors[2] : COLOR0){\n");

    char* pmainstart = p;

    WRITE(p, "float4 c0="I_COLORS"[1],c1="I_COLORS"[2],c2="I_COLORS"[3],prev=float4(0.0f,0.0f,0.0f,0.0f),textemp,rastemp,konsttemp=float4(0.0f,0.0f,0.0f,0.0f);\n"
            "float3 comp16 = float3(1,255,0), comp24 = float3(1,255,255*255);\n"
            "float4 alphabump=0;\n"
            "float3 tevcoord;\n"
            "float2 wrappedcoord, tempcoord;\n");

    //if (bOutputZ ) WRITE(p, "  float depth;\n");
//    WRITE(p, "return 1;}\n");
//    return PixelShaderMngr::CompilePixelShader(ps, text);

    // indirect texture map lookup
    for(u32 i = 0; i < bpmem.genMode.numindstages; ++i) {
        if (nIndirectStagesUsed & (1<<i)) {
            // perform indirect texture map lookup
            // note that we have to scale by the regular texture map's coordinates since this is a texRECT call
            // (and we have to match with the game's texscale calls)
            int texcoord = bpmem.tevindref.getTexCoord(i);
            if (texture_mask & (1<<bpmem.tevindref.getTexMap(i))) {
                // TODO: I removed a superfluous argument, please check that the resulting expression is correct. (mthuurne 2008-08-27)
                WRITE(p, "float2 induv%d=uv%d.xy * "I_INDTEXSCALE"[%d].%s;\n", i, texcoord, i/2, (i&1)?"zw":"xy"); //, bpmem.tevindref.getTexMap(i)

                char str[16];
                sprintf(str, "induv%d", i);
                WrapNonPow2Tex(p, str, bpmem.tevindref.getTexMap(i), texture_mask);
                WRITE(p, "float3 indtex%d=texRECT(samp%d,induv%d.xy).abg;\n", i, bpmem.tevindref.getTexMap(i), i);
            }
            else {
                WRITE(p, "float3 indtex%d=tex2D(samp%d,uv%d.xy*"I_INDTEXSCALE"[%d].%s).abg;\n", i, bpmem.tevindref.getTexMap(i), texcoord, i/2, (i&1)?"zw":"xy");
            }
        }
    }

    for (int i = 0; i < numStages; i++)
        WriteStage(p, i, texture_mask); //build the equation for this stage

	if (numTexgen >= 7) {
		WRITE(p, "float4 clipPos = float4(uv0.w, uv1.w, uv2.w, uv3.w);\n");
	}

	if (bInputZ) {
		// the screen space depth value = far z + (clip z / clip w) * z range		
		WRITE(p, "float zCoord = "I_ZBIAS"[1].x + (clipPos.z / clipPos.w) * "I_ZBIAS"[1].y;\n");
	}

    if (bOutputZ) {
        // use the texture input of the last texture stage (textemp), hopefully this has been read and is in correct format...
        if (bpmem.ztex2.op == ZTEXTURE_ADD) {
            WRITE(p, "depth = frac(dot("I_ZBIAS"[0].xyzw, textemp.xyzw) + "I_ZBIAS"[1].w + zCoord);\n");
        }
        else {
            _assert_(bpmem.ztex2.op == ZTEXTURE_REPLACE);
            WRITE(p, "depth = frac(dot("I_ZBIAS"[0].xyzw, textemp.xyzw) + "I_ZBIAS"[1].w);\n");			
        }
    }

    //if (bpmem.genMode.numindstages ) WRITE(p, "prev.rg = indtex0.xy;\nprev.b = 0;\n");

    if (!WriteAlphaTest(p)) {
        // alpha test will always fail, so restart the shader and just make it an empty function
        p = pmainstart;
		WRITE(p, "discard;\n");
        WRITE(p, "ocol0 = 0;\n");
    }
    else {
        if (!bRenderZToCol0) {
            /* donkopunchstania: NEEDS FIX - dstalpha does not change how fragments are blended with the EFB
			   once the blending is done, the dstalpha is written to the EFB in place of the
			   fragment alpha if dstalpha is enabled. this only matters if the EFB supports alpha.
               Commenting this out fixed Metroids but causes glitches in Super Mario Sunshine.

			if (bpmem.dstalpha.enable)
                WRITE(p, "  ocol0 = float4(prev.rgb,"I_ALPHA"[0].w);\n");
            else
			   */
            WriteFog(p, bOutputZ);
            WRITE(p, "  ocol0 = prev;\n");
        }
    }

    if (bRenderZ) {
        // write depth as color
        if (bRenderZToCol0) {
            if (bOutputZ )
                WRITE(p, "ocol0.xyz = frac(float3(256.0f*256.0f, 256.0f, 1.0f) * depth);\n");
            else
                WRITE(p, "ocol0.xyz = frac(float3(256.0f*256.0f, 256.0f, 1.0f) * zCoord);\n");
            WRITE(p, "ocol0.w = prev.w;\n");
        }
        else {
            if (bOutputZ)
                WRITE(p, "ocol1 = frac(float4(256.0f*256.0f, 256.0f, 1.0f, 0.0f) * depth);\n");
            else
                WRITE(p, "ocol1 = frac(float4(256.0f*256.0f, 256.0f, 1.0f, 0.0f) * zCoord);\n");
        }
    }
    WRITE(p, "}\n");
	if (text[sizeof(text) - 1] != 0x7C)
		PanicAlert("PixelShader generator - buffer too small, canary has been eaten!");
    return text;
}

static void WriteStage(char *&p, int n, u32 texture_mask)
{
    char *rasswap = swapModeTable[bpmem.combiners[n].alphaC.rswap];
    char *texswap = swapModeTable[bpmem.combiners[n].alphaC.tswap];


    int texcoord = bpmem.tevorders[n/2].getTexCoord(n&1);
    int texfun = xfregs.texcoords[texcoord].texmtxinfo.projection;
    bool bHasIndStage = bpmem.tevind[n].IsActive() && bpmem.tevind[n].bt < bpmem.genMode.numindstages;

    if (bHasIndStage) {
        // perform the indirect op on the incoming regular coordinates using indtex%d as the offset coords
        bHasIndStage = true;
        int texmap = bpmem.tevorders[n/2].getEnable(n&1) ? bpmem.tevorders[n/2].getTexMap(n&1) : bpmem.tevindref.getTexMap(bpmem.tevind[n].bt);

		if (bpmem.tevind[n].bs != ITBA_OFF) {
            // write the bump alpha

			if (bpmem.tevind[n].fmt == ITF_8) {
				WRITE(p, "alphabump = indtex%d.%s %s;\n", bpmem.tevind[n].bt, 
					tevIndAlphaSel[bpmem.tevind[n].bs], tevIndAlphaScale[bpmem.tevind[n].fmt]);
			}
			else {			
				// donkopunchstania: really bad way to do this
				// cannot always use fract because fract(1.0) is 0.0 when it needs to be 1.0
				// omitting fract seems to work as well
				WRITE(p, "if (indtex%d.%s >= 1.0f )\n", bpmem.tevind[n].bt, 
					tevIndAlphaSel[bpmem.tevind[n].bs]);
				WRITE(p, "   alphabump = 1.0f;\n");
				WRITE(p, "else\n");
				WRITE(p, "   alphabump = fract ( indtex%d.%s %s );\n", bpmem.tevind[n].bt, 
					tevIndAlphaSel[bpmem.tevind[n].bs], tevIndAlphaScale[bpmem.tevind[n].fmt]);
			}
		}

        // bias
        WRITE(p, "float3 indtevcrd%d = indtex%d;\n", n, bpmem.tevind[n].bt);
        WRITE(p, "indtevcrd%d.xyz *= %s;\n", n, tevIndFmtScale[bpmem.tevind[n].fmt]);
        if (bpmem.tevind[n].bias != ITB_NONE )
            WRITE(p, "indtevcrd%d.%s += %s;\n", n, tevIndBiasField[bpmem.tevind[n].bias], tevIndBiasAdd[bpmem.tevind[n].fmt]);

        // multiply by offset matrix and scale
        if (bpmem.tevind[n].mid != 0) {
            if (bpmem.tevind[n].mid <= 3) {
                int mtxidx = 2*(bpmem.tevind[n].mid-1);
                WRITE(p, "float2 indtevtrans%d = float2(dot("I_INDTEXMTX"[%d].xyz, indtevcrd%d), dot("I_INDTEXMTX"[%d].xyz, indtevcrd%d));\n",
                    n, mtxidx, n, mtxidx+1, n);
            }
            else if (bpmem.tevind[n].mid <= 5) { // s matrix
                int mtxidx = 2*(bpmem.tevind[n].mid-5);
                WRITE(p, "float2 indtevtrans%d = "I_INDTEXMTX"[%d].ww * uv%d.xy * indtevcrd%d.xx;\n", n, mtxidx, texcoord, n);
            }
            else if (bpmem.tevind[n].mid <= 9) { // t matrix
                int mtxidx = 2*(bpmem.tevind[n].mid-9);
                WRITE(p, "float2 indtevtrans%d = "I_INDTEXMTX"[%d].ww * uv%d.xy * indtevcrd%d.yy;\n", n, mtxidx, texcoord, n);
            }
            else {
                // TODO: I removed a superfluous argument, please check that the resulting expression is correct. (mthuurne 2008-08-27)
                WRITE(p, "float2 indtevtrans%d = 0;\n", n); //, n
            }
        }
        else {
            // TODO: I removed a superfluous argument, please check that the resulting expression is correct. (mthuurne 2008-08-27)
            WRITE(p, "float2 indtevtrans%d = 0;\n", n); //, n
        }

        // wrapping
        if (!bpmem.tevorders[n/2].getEnable(n&1) || (texture_mask & (1<<texmap))) {
            // non pow2

            if (bpmem.tevind[n].sw != ITW_OFF || bpmem.tevind[n].tw != ITW_OFF) {
                if (bpmem.tevind[n].sw == ITW_0) {
                    if (bpmem.tevind[n].tw == ITW_0) {
                        // zero out completely
                        WRITE(p, "wrappedcoord = float2(0.0f,0.0f);\n");
                    }
                    else {
                        WRITE(p, "wrappedcoord.x = fmod( (uv%d.x+%s)*"I_TEXDIMS"[%d].x*"I_TEXDIMS"[%d].z, %s);\n"
                            "wrappedcoord.y = 0;\n", texcoord, tevIndWrapStart[bpmem.tevind[n].sw], texmap, texmap, tevIndWrapStart[bpmem.tevind[n].sw]);
                    }
                }
                else if (bpmem.tevind[n].tw == ITW_0) {
                    WRITE(p, "wrappedcoord.y = fmod( (uv%d.y+%s)*"I_TEXDIMS"[%d].y*"I_TEXDIMS"[%d].w, %s);\n"
                        "wrappedcoord.x = 0;\n", texcoord, tevIndWrapStart[bpmem.tevind[n].tw], texmap, texmap, tevIndWrapStart[bpmem.tevind[n].tw]);
                }
                else {
                    WRITE(p, "wrappedcoord = fmod( (uv%d.xy+float2(%s,%s))*"I_TEXDIMS"[%d].xy*"I_TEXDIMS"[%d].zw, float2(%s,%s));\n", texcoord,
                        tevIndWrapStart[bpmem.tevind[n].sw], tevIndWrapStart[bpmem.tevind[n].tw],texmap,texmap,
                        tevIndWrapStart[bpmem.tevind[n].sw], tevIndWrapStart[bpmem.tevind[n].tw]);
                }
            }
            else {
                WRITE(p, "wrappedcoord = uv%d.xy*"I_TEXDIMS"[%d].xy;\n", texcoord, texmap);
            }
        }
        else {
            // pow of 2
            WRITE(p, "indtevtrans%d.xy *= "I_TEXDIMS"[%d].xy * "I_TEXDIMS"[%d].zw;\n", n, texmap, texmap);

            // mult by bitdepth / tex dimensions
            if (bpmem.tevind[n].sw != ITW_OFF || bpmem.tevind[n].tw != ITW_OFF) {
                if (bpmem.tevind[n].sw == ITW_0) {
                    if (bpmem.tevind[n].tw == ITW_0) {
                        // zero out completely
                        WRITE(p, "wrappedcoord = float2(0.0f,0.0f);\n");
                    }
                    else {
                        WRITE(p, "wrappedcoord.x = "I_TEXDIMS"[%d].x * fmod( uv%d.x+%s, "I_TEXDIMS"[%d].z*%s);\n"
                            "wrappedcoord.y = 0;\n", texmap, texcoord, tevIndWrapStart[bpmem.tevind[n].sw], texmap, tevIndWrapStart[bpmem.tevind[n].sw]);
                    }
                }
                else if (bpmem.tevind[n].tw == ITW_0) {
                    WRITE(p, "wrappedcoord.y = "I_TEXDIMS"[%d].y * fmod( uv%d.y+%s, "I_TEXDIMS"[%d].w*%s);\n"
                        "wrappedcoord.x = 0;\n", texmap, texcoord, tevIndWrapStart[bpmem.tevind[n].tw], texmap, tevIndWrapStart[bpmem.tevind[n].tw]);
                }
                else {
                    // have to add an offset or else might get negative values!
                    WRITE(p, "wrappedcoord = "I_TEXDIMS"[%d].xy * fmod( uv%d.xy+float2(%s,%s), "I_TEXDIMS"[%d].zw*float2(%s,%s));\n", texmap, texcoord,
                        tevIndWrapStart[bpmem.tevind[n].sw], tevIndWrapStart[bpmem.tevind[n].tw], texmap, 
                        tevIndWrapStart[bpmem.tevind[n].sw], tevIndWrapStart[bpmem.tevind[n].tw]);
                }
            }
            else {
                WRITE(p, "wrappedcoord = uv%d.xy;\n", texcoord);
            }
        }

        if (bpmem.tevind[n].fb_addprev) {
            // add previous tevcoord

            if (texfun == XF_TEXPROJ_STQ) {
                WRITE(p, "tevcoord.xy += wrappedcoord/uv%d.z + indtevtrans%d;\n", texcoord, n);
                //WRITE(p, "tevcoord.z += uv%d.z;\n", texcoord);
            }
            else {
                WRITE(p, "tevcoord.xy += wrappedcoord + indtevtrans%d;\n", n);
            }
        }
        else {
            WRITE(p, "tevcoord.xy = wrappedcoord/uv%d.z + indtevtrans%d;\n", texcoord, n);
            //if (texfun == XF_TEXPROJ_STQ )
            //    WRITE(p, "tevcoord.z = uv%d.z;\n", texcoord);
        }
    }

    WRITE(p, "rastemp=%s.%s;\n",tevRasTable[bpmem.tevorders[n/2].getColorChan(n&1)],rasswap);

    if (bpmem.tevorders[n/2].getEnable(n&1)) {
        int texmap = bpmem.tevorders[n/2].getTexMap(n&1);
        if(!bHasIndStage) {
            // calc tevcord
            //tevcoord.xy = texdim[1].xy * uv1.xy / uv1.z;
            int OurTexCoord = 0;
            if(bpmem.genMode.numtexgens)
                OurTexCoord = texcoord;
            else
                OurTexCoord = 0;
            if (texture_mask & (1<<texmap)) {
                // nonpow2
                if (texfun == XF_TEXPROJ_STQ )
                    WRITE(p, "tevcoord.xy = uv%d.xy / uv%d.z;\n", texcoord, OurTexCoord);
                else
                    WRITE(p, "tevcoord.xy = uv%d.xy;\n", OurTexCoord);
                WrapNonPow2Tex(p, "tevcoord", texmap, texture_mask);
            }
            else {
                if (texfun == XF_TEXPROJ_STQ ) 
                    WRITE(p, "tevcoord.xy = "I_TEXDIMS"[%d].xy * uv%d.xy / uv%d.z;\n", texmap, OurTexCoord , OurTexCoord );
                else 
                    WRITE(p, "tevcoord.xy = "I_TEXDIMS"[%d].xy * uv%d.xy;\n", texmap, OurTexCoord);

            }
        }
        else if (texture_mask & (1<<texmap)) {
            // if non pow 2, have to manually repeat
            //WrapNonPow2Tex(p, "tevcoord", texmap);
            bool bwraps = !!(texture_mask & (0x100<<texmap));
            bool bwrapt = !!(texture_mask & (0x10000<<texmap));
                
            if (bwraps || bwrapt) {
                const char* field = bwraps ? (bwrapt ? "xy" : "x") : "y";
                WRITE(p, "tevcoord.%s = fmod(tevcoord.%s+32*"I_TEXDIMS"[%d].%s,"I_TEXDIMS"[%d].%s);\n", field, field, texmap, field, texmap, field);
            }
        }

        if (texture_mask & (1<<texmap) )
            WRITE(p, "textemp=texRECT(samp%d,tevcoord.xy).%s;\n", texmap, texswap);
        else
            WRITE(p, "textemp=tex2D(samp%d,tevcoord.xy).%s;\n", texmap, texswap);
    }
    else
        WRITE(p, "textemp=float4(1,1,1,1);\n");

    int kc = bpmem.tevksel[n/2].getKC(n&1);
    int ka = bpmem.tevksel[n/2].getKA(n&1);

    TevStageCombiner::ColorCombiner &cc = bpmem.combiners[n].colorC;
    TevStageCombiner::AlphaCombiner &ac = bpmem.combiners[n].alphaC;

    bool bCKonst = cc.a == TEVCOLORARG_KONST || cc.b == TEVCOLORARG_KONST || cc.c == TEVCOLORARG_KONST || cc.d == TEVCOLORARG_KONST;
    bool bAKonst = ac.a == TEVALPHAARG_KONST || ac.b == TEVALPHAARG_KONST || ac.c == TEVALPHAARG_KONST || ac.d == TEVALPHAARG_KONST;
    if (bCKonst || bAKonst )
        WRITE(p, "konsttemp=float4(%s,%s);\n",tevKSelTableC[kc],tevKSelTableA[ka]);  

    WRITE(p, "%s= ", tevCOutputTable[cc.dest]); 

    // combine the color channel
    if (cc.bias != 3) {  // if not compare
        //normal color combiner goes here
        WRITE(p, "   %s*(%s%s",tevScaleTable[cc.shift],tevCInputTable[cc.d],tevOpTable[cc.op]);
        WRITE(p, "lerp(%s,%s,%s) %s);\n",
              tevCInputTable[cc.a], tevCInputTable[cc.b],
              tevCInputTable[cc.c], tevBiasTable[cc.bias]);
    }
    else {
        int cmp = (cc.shift<<1)|cc.op|8; // comparemode stored here
        switch(cmp) {
        case TEVCMP_R8_GT:
        case TEVCMP_RGB8_GT: // per component compares
            WRITE(p, "   %s + ((%s.%s > %s.%s) ? %s : float3(0.0f,0.0f,0.0f));\n",
                tevCInputTable[cc.d], tevCInputTable2[cc.a], cmp==TEVCMP_R8_GT?"r":"rgb", tevCInputTable2[cc.b], cmp==TEVCMP_R8_GT?"r":"rgb", tevCInputTable[cc.c]);
            break;
        case TEVCMP_R8_EQ:
        case TEVCMP_RGB8_EQ:
            WRITE(p, "   %s + (abs(%s.r - %s.r)<%f ? %s : float3(0.0f,0.0f,0.0f));\n",
                tevCInputTable[cc.d], tevCInputTable2[cc.a], tevCInputTable2[cc.b], epsilon8bit, tevCInputTable[cc.c]);
            break;
        
        case TEVCMP_GR16_GT: // 16 bit compares: 255*g+r (probably used for ztextures, so make sure in ztextures, g is the most significant byte)
        case TEVCMP_BGR24_GT: // 24 bit compares: 255*255*b+255*g+r
            WRITE(p, "   %s + (( dot(%s.rgb-%s.rgb, comp%s) > 0) ? %s : float3(0.0f,0.0f,0.0f));\n",
                tevCInputTable[cc.d], tevCInputTable2[cc.a], tevCInputTable2[cc.b], cmp==TEVCMP_GR16_GT?"16":"24", tevCInputTable[cc.c]);
            break;
        case TEVCMP_GR16_EQ:
        case TEVCMP_BGR24_EQ:
            WRITE(p, "   %s + (abs(dot(%s.rgb - %s.rgb, comp%s))<%f ? %s : float3(0.0f,0.0f,0.0f));\n",
                tevCInputTable[cc.d], tevCInputTable2[cc.a], tevCInputTable2[cc.b], cmp==TEVCMP_GR16_EQ?"16":"24", epsilon8bit, tevCInputTable[cc.c]);
            break;
        default:
            WRITE(p, "float3(0.0f,0.0f,0.0f);\n");
            break;
        }
    }
    
    if (cc.clamp)
        WRITE(p, "%s = clamp(%s,0.0f,1.0f);\n", tevCOutputTable[cc.dest],tevCOutputTable[cc.dest]);

    // combine the alpha channel
    WRITE(p, "%s= ", tevAOutputTable[ac.dest]);

    if (ac.bias != 3) { // if not compare
        //normal alpha combiner goes here
        WRITE(p, "   %s*(%s%s",tevScaleTable[ac.shift],tevAInputTable[ac.d],tevOpTable[ac.op]);
        WRITE(p, "lerp(%s,%s,%s) %s)\n",
            tevAInputTable[ac.a],tevAInputTable[ac.b],
            tevAInputTable[ac.c],tevBiasTable[ac.bias]);
    }
    else {
        //compare alpha combiner goes here
        int cmp = (ac.shift<<1)|ac.op|8; // comparemode stored here
        switch(cmp) {
        case TEVCMP_R8_GT:
        case TEVCMP_A8_GT:
            WRITE(p, "   %s + ((%s.%s > %s.%s) ? %s : 0)\n",
                tevAInputTable[ac.d],tevAInputTable2[ac.a], cmp==TEVCMP_R8_GT?"r":"a", tevAInputTable2[ac.b], cmp==TEVCMP_R8_GT?"r":"a", tevAInputTable[ac.c]);
            break;
        case TEVCMP_R8_EQ:
        case TEVCMP_A8_EQ:
            WRITE(p, "   %s + (abs(%s.r - %s.r)<%f ? %s : 0)\n",
                tevAInputTable[ac.d],tevAInputTable2[ac.a], tevAInputTable2[ac.b],epsilon8bit,tevAInputTable[ac.c]);
            break;
        
        case TEVCMP_GR16_GT: // 16 bit compares: 255*g+r (probably used for ztextures, so make sure in ztextures, g is the most significant byte)
        case TEVCMP_BGR24_GT: // 24 bit compares: 255*255*b+255*g+r
            WRITE(p, "   %s + (( dot(%s.rgb-%s.rgb, comp%s) > 0) ? %s : 0)\n",
                tevAInputTable[ac.d],tevAInputTable2[ac.a], tevAInputTable2[ac.b], cmp==TEVCMP_GR16_GT?"16":"24", tevAInputTable[ac.c]);
            break;
        case TEVCMP_GR16_EQ:
        case TEVCMP_BGR24_EQ:
            WRITE(p, "   %s + (abs(dot(%s.rgb - %s.rgb, comp%s))<%f ? %s : 0)\n",
                tevAInputTable[ac.d],tevAInputTable2[ac.a], tevAInputTable2[ac.b],cmp==TEVCMP_GR16_EQ?"16":"24",epsilon8bit,tevAInputTable[ac.c]);
            break;
        default:
            WRITE(p, "0)\n");
            break;
        }
    }

    WRITE(p, ";\n");

    if (ac.clamp)
        WRITE(p, "%s = clamp(%s,0.0f,1.0f);\n", tevAOutputTable[ac.dest],tevAOutputTable[ac.dest]);
    WRITE(p, "\n");
}

void WrapNonPow2Tex(char* &p, const char* var, int texmap, u32 texture_mask)
{
    _assert_(texture_mask & (1<<texmap));
    bool bwraps = !!(texture_mask & (0x100<<texmap));
    bool bwrapt = !!(texture_mask & (0x10000<<texmap));
        
    if (bwraps || bwrapt) {
        const char* field = bwraps ? (bwrapt ? "xy" : "x") : "y";
        const char* wrapfield = bwraps ? (bwrapt ? "zw" : "z") : "w";
        WRITE(p, "%s.%s = "I_TEXDIMS"[%d].%s*frac(%s.%s*"I_TEXDIMS"[%d].%s+32);\n", var, field, texmap, field, var, field, texmap, wrapfield);

        if (!bwraps )
            WRITE(p, "%s.x *= "I_TEXDIMS"[%d].x * "I_TEXDIMS"[%d].z;\n", var, texmap, texmap);
        if (!bwrapt )
            WRITE(p, "%s.y *= "I_TEXDIMS"[%d].y * "I_TEXDIMS"[%d].w;\n", var, texmap, texmap);
    }
    else {
        WRITE(p, "%s.xy *= "I_TEXDIMS"[%d].xy * "I_TEXDIMS"[%d].zw;\n", var, texmap, texmap);
    }
}

static void WriteAlphaCompare(char *&p, int num, int comp)
{
    switch(comp) {
    case ALPHACMP_ALWAYS:  WRITE(p, "(false)");	break;
    case ALPHACMP_NEVER:   WRITE(p, "(true)");	break;
    case ALPHACMP_LEQUAL:  WRITE(p, "(prev.a > %s)",alphaRef[num]);	break;
    case ALPHACMP_LESS:    WRITE(p, "(prev.a >= %s - %f)",alphaRef[num],epsilon8bit*0.5f);break;
    case ALPHACMP_GEQUAL:  WRITE(p, "(prev.a < %s)",alphaRef[num]);	break;
    case ALPHACMP_GREATER: WRITE(p, "(prev.a <= %s + %f)",alphaRef[num],epsilon8bit*0.5f);break;
    case ALPHACMP_EQUAL:   WRITE(p, "(abs(prev.a-%s)>%f)",alphaRef[num],epsilon8bit*2); break;
    case ALPHACMP_NEQUAL:  WRITE(p, "(abs(prev.a-%s)<%f)",alphaRef[num],epsilon8bit*2); break;
    }
}

static bool WriteAlphaTest(char *&p)
{
    u32 op = bpmem.alphaFunc.logic;
    u32 comp[2] = {bpmem.alphaFunc.comp0,bpmem.alphaFunc.comp1};

    //first kill all the simple cases
    switch(op) {
    case 0: // and
        if (comp[0] == ALPHACMP_ALWAYS && comp[1] == ALPHACMP_ALWAYS) return true;
        if (comp[0] == ALPHACMP_NEVER || comp[1] == ALPHACMP_NEVER) {
            WRITE(p, "discard;\n");
            return false;
        }
        break;
    case 1: // or
        if (comp[0] == ALPHACMP_ALWAYS || comp[1] == ALPHACMP_ALWAYS) return true;
        if (comp[0] == ALPHACMP_NEVER && comp[1] == ALPHACMP_NEVER) {
            WRITE(p, "discard;\n");
            return false;
        }
        break;
    case 2: // xor
        if ( (comp[0] == ALPHACMP_ALWAYS && comp[1] == ALPHACMP_NEVER) || (comp[0] == ALPHACMP_NEVER && comp[1] == ALPHACMP_ALWAYS) ) return true;
        if ( (comp[0] == ALPHACMP_ALWAYS && comp[1] == ALPHACMP_ALWAYS) || (comp[0] == ALPHACMP_NEVER && comp[1] == ALPHACMP_NEVER)) {
            WRITE(p, "discard;\n");
            return false;
        }
        break;
    case 3: // xnor
        if ( (comp[0] == ALPHACMP_ALWAYS && comp[1] == ALPHACMP_NEVER) || (comp[0] == ALPHACMP_NEVER && comp[1] == ALPHACMP_ALWAYS)) {
            WRITE(p, "discard;\n");
            return false;
        }
        if ( (comp[0] == ALPHACMP_ALWAYS && comp[1] == ALPHACMP_ALWAYS) || (comp[0] == ALPHACMP_NEVER && comp[1] == ALPHACMP_NEVER) )
            return true;
        break;
    }

    WRITE(p, "discard( ");
    WriteAlphaCompare(p, 0, bpmem.alphaFunc.comp0);
    
    // negated because testing the inverse condition
    switch(bpmem.alphaFunc.logic) {
    case 0: WRITE(p, " || "); break; // and
    case 1: WRITE(p, " && "); break; // or
    case 2: WRITE(p, " == "); break; // xor
    case 3: WRITE(p, " != "); break; // xnor
    }
    WriteAlphaCompare(p, 1, bpmem.alphaFunc.comp1);
    WRITE(p, ");\n");
    return true;
}

static void WriteFog(char *&p, bool bOutputZ)
{
	bool enabled = bpmem.fog.c_proj_fsel.fsel == 0 ? false : true;

    if (enabled) {
        if (bpmem.fog.c_proj_fsel.proj == 0) {
            // perspective
            // ze = A/(B - Zs)
            WRITE (p, "  float ze = "I_FOG"[1].x / ("I_FOG"[1].y - %s);\n", bOutputZ ? "depth" : "zCoord");
        } else {
            // orthographic
            // ze = a*Zs
            WRITE (p, "  float ze = "I_FOG"[1].x * %s;\n", bOutputZ ? "depth" : "zCoord");
        }

        WRITE (p, "  float fog = clamp(ze - "I_FOG"[1].z, 0.0f, 1.0f);\n");
    }

    switch (bpmem.fog.c_proj_fsel.fsel) {       
        case 2: // linear
            // empty
            break;
        case 4: // exp
            WRITE(p, "  fog = 1.0f - pow(2, -8.0f * fog);\n");
            break;
        case 5: // exp2
            WRITE(p, "  fog = 1.0f - pow(2, -8.0f * fog * fog);\n");
            break;
        case 6: // backward exp
            WRITE(p, "  fog = 1.0f - fog;\n");
            WRITE(p, "  fog = pow(2, -8.0f * fog);\n");
            break;
        case 7: // backward exp2
            WRITE(p, "  fog = 1.0f - fog;\n");
            WRITE(p, "  fog = pow(2, -8.0f * fog * fog);\n");
            break;
    }

    if (enabled) {
        WRITE(p, "  prev.rgb = (1.0f - fog) * prev.rgb + (fog * "I_FOG"[0].rgb);\n");
    }
}