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 dstAlphaEnable)
{
	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)dstAlphaEnable << 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, bool HLSL);
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, bool dstAlphaEnable, bool HLSL)
{
	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 (texcoord < numTexgen) {
                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");
                }
            }
            else {
                WRITE(p, "float3 indtex%d=tex2D(samp%d,float2(0.0f,0.0f));\n", i, bpmem.tevindref.getTexMap(i));
            }
        }
    }

    // HACK to handle cases where the tex gen is not enabled
    if (numTexgen == 0) {
        WRITE(p, "float3 uv0 = float3(0.0f,0.0f,0.0f);\n");
    }

    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, HLSL)) {
        // 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) {
            if (dstAlphaEnable) {
                WRITE(p, "  ocol0 = float4(prev.rgb,"I_ALPHA"[0].w);\n");
            } else {			  
                WriteFog(p, bOutputZ);
                WRITE(p, "  ocol0 = prev;\n");
            }
		} else {
			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 bHasTexCoord = (u32)texcoord < bpmem.genMode.numtexgens;
    bool bHasIndStage = bpmem.tevind[n].IsActive() && bpmem.tevind[n].bt < bpmem.genMode.numindstages;

    // HACK to handle cases where the tex gen is not enabled
    if (!bHasTexCoord) {
        texcoord = 0;
    }

    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 && bHasTexCoord) { // 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 && bHasTexCoord) { // 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;
            if(bHasTexCoord) {
                if (texture_mask & (1<<texmap)) {
                    // nonpow2
                    if (texfun == XF_TEXPROJ_STQ )
                        WRITE(p, "tevcoord.xy = uv%d.xy / uv%d.z;\n", texcoord, texcoord);
                    else
                        WRITE(p, "tevcoord.xy = uv%d.xy;\n", texcoord);
                    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, texcoord , texcoord );
                    else 
                        WRITE(p, "tevcoord.xy = "I_TEXDIMS"[%d].xy * uv%d.xy;\n", texmap, texcoord);
                }
            } else {
                // donkopunchstania - check that this is correct when there are no tex gens
                WRITE(p, "tevcoord.xy = float2(0.0f,0.0f);\n");
            }
        }
        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, bool HLSL)
{
    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;
    }

	// Seems we need discard for Cg and clip for d3d. sigh.
	if (HLSL) 
		WRITE(p, "clip( ");
	else {
		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");
    }
}