// 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/.

#include <cstdio>
#include <locale.h>

#include "Common/StringUtils.h"
#include "GPU/ge_constants.h"
#include "GPU/GPUState.h"
#include "Core/Config.h"

#include "GPU/Directx9/VertexShaderGeneratorHLSL.h"
#include "GPU/Common/VertexDecoderCommon.h"
#include "GPU/Common/ShaderUniforms.h"

#undef WRITE

#define WRITE p+=sprintf

static const char * const boneWeightAttrDecl[9] = {	
	"#ERROR#",
	"float  a_w1:TEXCOORD1;\n",
	"vec2 a_w1:TEXCOORD1;\n",
	"vec3 a_w1:TEXCOORD1;\n",
	"vec4 a_w1:TEXCOORD1;\n",
	"vec4 a_w1:TEXCOORD1;\n  float  a_w2:TEXCOORD2;\n",
	"vec4 a_w1:TEXCOORD1;\n  vec2 a_w2:TEXCOORD2;\n",
	"vec4 a_w1:TEXCOORD1;\n  vec3 a_w2:TEXCOORD2;\n",
	"vec4 a_w1:TEXCOORD1;\n  vec4 a_w2:TEXCOORD2;\n",
};

extern const char *hlsl_preamble_vs;

bool GenerateVertexShaderHLSL(const VShaderID &id, char *buffer, ShaderLanguage lang, std::string *errorString) {
	char *p = buffer;

	bool isModeThrough = id.Bit(VS_BIT_IS_THROUGH);
	bool lmode = id.Bit(VS_BIT_LMODE);
	bool doTexture = id.Bit(VS_BIT_DO_TEXTURE);

	GETexMapMode uvGenMode = static_cast<GETexMapMode>(id.Bits(VS_BIT_UVGEN_MODE, 2));
	bool doTextureTransform = uvGenMode == GE_TEXMAP_TEXTURE_MATRIX;

	// this is only valid for some settings of uvGenMode
	GETexProjMapMode uvProjMode = static_cast<GETexProjMapMode>(id.Bits(VS_BIT_UVPROJ_MODE, 2));
	bool doShadeMapping = uvGenMode == GE_TEXMAP_ENVIRONMENT_MAP;
	bool doFlatShading = id.Bit(VS_BIT_FLATSHADE);

	bool useHWTransform = id.Bit(VS_BIT_USE_HW_TRANSFORM);
	bool hasColor = id.Bit(VS_BIT_HAS_COLOR) || !useHWTransform;
	bool hasNormal = id.Bit(VS_BIT_HAS_NORMAL) && useHWTransform;
	bool hasTexcoord = id.Bit(VS_BIT_HAS_TEXCOORD) || !useHWTransform;
	bool enableFog = id.Bit(VS_BIT_ENABLE_FOG);
	bool flipNormal = id.Bit(VS_BIT_NORM_REVERSE);
	int ls0 = id.Bits(VS_BIT_LS0, 2);
	int ls1 = id.Bits(VS_BIT_LS1, 2);
	bool enableBones = id.Bit(VS_BIT_ENABLE_BONES);
	bool enableLighting = id.Bit(VS_BIT_LIGHTING_ENABLE);
	int matUpdate = id.Bits(VS_BIT_MATERIAL_UPDATE, 3);

	bool doBezier = id.Bit(VS_BIT_BEZIER) && !enableBones && useHWTransform;
	bool doSpline = id.Bit(VS_BIT_SPLINE) && !enableBones && useHWTransform;
	if ((doBezier || doSpline) && !hasNormal) {
		// Bad usage.
		*errorString = "Invalid flags - tess requires normal.";
		return false;
	}
	bool hasColorTess = id.Bit(VS_BIT_HAS_COLOR_TESS);
	bool hasTexcoordTess = id.Bit(VS_BIT_HAS_TEXCOORD_TESS);
	bool hasNormalTess = id.Bit(VS_BIT_HAS_NORMAL_TESS);
	bool flipNormalTess = id.Bit(VS_BIT_NORM_REVERSE_TESS);

	DoLightComputation doLight[4] = { LIGHT_OFF, LIGHT_OFF, LIGHT_OFF, LIGHT_OFF };
	if (useHWTransform) {
		int shadeLight0 = doShadeMapping ? ls0 : -1;
		int shadeLight1 = doShadeMapping ? ls1 : -1;
		for (int i = 0; i < 4; i++) {
			if (i == shadeLight0 || i == shadeLight1)
				doLight[i] = LIGHT_SHADE;
			if (enableLighting && id.Bit(VS_BIT_LIGHT0_ENABLE + i))
				doLight[i] = LIGHT_FULL;
		}
	}

	int numBoneWeights = 0;
	int boneWeightScale = id.Bits(VS_BIT_WEIGHT_FMTSCALE, 2);
	if (enableBones) {
		numBoneWeights = 1 + id.Bits(VS_BIT_BONES, 3);
	}

	// Output some compatibility defines
	WRITE(p, "%s", hlsl_preamble_vs);

	if (lang == HLSL_D3D9) {
		WRITE(p, "#pragma warning( disable : 3571 )\n");
		if (isModeThrough) {
			WRITE(p, "float4x4 u_proj_through : register(c%i);\n", CONST_VS_PROJ_THROUGH);
		} else {
			WRITE(p, "float4x4 u_proj : register(c%i);\n", CONST_VS_PROJ);
			// Add all the uniforms we'll need to transform properly.
		}

		if (enableFog) {
			WRITE(p, "vec2 u_fogcoef : register(c%i);\n", CONST_VS_FOGCOEF);
		}
		if (useHWTransform || !hasColor)
			WRITE(p, "vec4 u_matambientalpha : register(c%i);\n", CONST_VS_MATAMBIENTALPHA);  // matambient + matalpha

		if (useHWTransform) {
			// When transforming by hardware, we need a great deal more uniforms...
			WRITE(p, "mat3x4 u_world : register(c%i);\n", CONST_VS_WORLD);
			WRITE(p, "mat3x4 u_view : register(c%i);\n", CONST_VS_VIEW);
			if (doTextureTransform)
				WRITE(p, "mat3x4 u_texmtx : register(c%i);\n", CONST_VS_TEXMTX);
			if (enableBones) {
#ifdef USE_BONE_ARRAY
				WRITE(p, "mat3x4 u_bone[%i] : register(c%i);\n", numBones, CONST_VS_BONE0);
#else
				for (int i = 0; i < numBoneWeights; i++) {
					WRITE(p, "mat3x4 u_bone%i : register(c%i);\n", i, CONST_VS_BONE0 + i * 3);
				}
#endif
			}
			if (doTexture) {
				WRITE(p, "vec4 u_uvscaleoffset : register(c%i);\n", CONST_VS_UVSCALEOFFSET);
			}
			for (int i = 0; i < 4; i++) {
				if (doLight[i] != LIGHT_OFF) {
					// This is needed for shade mapping
					WRITE(p, "vec3 u_lightpos%i : register(c%i);\n", i, CONST_VS_LIGHTPOS + i);
				}
				if (doLight[i] == LIGHT_FULL) {
					GELightType type = static_cast<GELightType>(id.Bits(VS_BIT_LIGHT0_TYPE + 4 * i, 2));
					GELightComputation comp = static_cast<GELightComputation>(id.Bits(VS_BIT_LIGHT0_COMP + 4 * i, 2));

					if (type != GE_LIGHTTYPE_DIRECTIONAL)
						WRITE(p, "vec3 u_lightatt%i : register(c%i);\n", i, CONST_VS_LIGHTATT + i);

					if (type == GE_LIGHTTYPE_SPOT || type == GE_LIGHTTYPE_UNKNOWN) {
						WRITE(p, "vec3 u_lightdir%i : register(c%i);\n", i, CONST_VS_LIGHTDIR + i);
						WRITE(p, "vec4 u_lightangle_spotCoef%i : register(c%i);\n", i, CONST_VS_LIGHTANGLE_SPOTCOEF + i);
					}
					WRITE(p, "vec3 u_lightambient%i : register(c%i);\n", i, CONST_VS_LIGHTAMBIENT + i);
					WRITE(p, "vec3 u_lightdiffuse%i : register(c%i);\n", i, CONST_VS_LIGHTDIFFUSE + i);

					if (comp == GE_LIGHTCOMP_BOTH) {
						WRITE(p, "vec3 u_lightspecular%i : register(c%i);\n", i, CONST_VS_LIGHTSPECULAR + i);
					}
				}
			}
			if (enableLighting) {
				WRITE(p, "vec4 u_ambient : register(c%i);\n", CONST_VS_AMBIENT);
				if ((matUpdate & 2) == 0 || !hasColor)
					WRITE(p, "vec3 u_matdiffuse : register(c%i);\n", CONST_VS_MATDIFFUSE);
				// if ((matUpdate & 4) == 0)
				WRITE(p, "vec4 u_matspecular : register(c%i);\n", CONST_VS_MATSPECULAR);  // Specular coef is contained in alpha
				WRITE(p, "vec3 u_matemissive : register(c%i);\n", CONST_VS_MATEMISSIVE);
			}
		}

		if (!isModeThrough && gstate_c.Supports(GPU_ROUND_DEPTH_TO_16BIT)) {
			WRITE(p, "vec4 u_depthRange : register(c%i);\n", CONST_VS_DEPTHRANGE);
		}
		if (!isModeThrough) {
			WRITE(p, "vec4 u_cullRangeMin : register(c%i);\n", CONST_VS_CULLRANGEMIN);
			WRITE(p, "vec4 u_cullRangeMax : register(c%i);\n", CONST_VS_CULLRANGEMAX);
		}
	} else {
		WRITE(p, "cbuffer base : register(b0) {\n%s};\n", cb_baseStr);
		WRITE(p, "cbuffer lights: register(b1) {\n%s};\n", cb_vs_lightsStr);
		WRITE(p, "cbuffer bones : register(b2) {\n%s};\n", cb_vs_bonesStr);
	}

	bool scaleUV = !isModeThrough && (uvGenMode == GE_TEXMAP_TEXTURE_COORDS || uvGenMode == GE_TEXMAP_UNKNOWN);

	// And the "varyings".
	bool texCoordInVec3 = false;
	if (useHWTransform) {
		WRITE(p, "struct VS_IN {                              \n");
		if ((doSpline || doBezier) && lang == HLSL_D3D11) {
			WRITE(p, "  uint instanceId : SV_InstanceID;\n");
		}
		if (enableBones) {
			WRITE(p, "  %s", boneWeightAttrDecl[numBoneWeights]);
		}
		if (doTexture && hasTexcoord) {
			WRITE(p, "  vec2 texcoord : TEXCOORD0;\n");
		}
		if (hasColor)  {
			WRITE(p, "  vec4 color0 : COLOR0;\n");
		}
		if (hasNormal) {
			WRITE(p, "  vec3 normal : NORMAL;\n");
		}
		WRITE(p, "  vec3 position : POSITION;\n");
		WRITE(p, "};\n");
		
	} else {
		WRITE(p, "struct VS_IN {\n");
		WRITE(p, "  vec4 position : POSITION;\n");
		if (doTexture && hasTexcoord) {
			if (doTextureTransform && !isModeThrough) {
				texCoordInVec3 = true;
				WRITE(p, "  vec3 texcoord : TEXCOORD0;\n");
			}
			else
				WRITE(p, "  vec2 texcoord : TEXCOORD0;\n");
		}
		if (hasColor) {
			WRITE(p, "  vec4 color0 : COLOR0;\n");
		}
		// only software transform supplies color1 as vertex data
		if (lmode) {
			WRITE(p, "  vec4 color1 : COLOR1;\n");
		}
		WRITE(p, "};\n");
	}

	WRITE(p, "struct VS_OUT {\n");
	if (doTexture) {
		WRITE(p, "  vec3 v_texcoord : TEXCOORD0;\n");
	}
	const char *colorInterpolation = doFlatShading && lang == HLSL_D3D11 ? "nointerpolation " : "";
	WRITE(p, "  %svec4 v_color0    : COLOR0;\n", colorInterpolation);
	if (lmode)
		WRITE(p, "  vec3 v_color1    : COLOR1;\n");

	if (enableFog) {
		WRITE(p, "  float v_fogdepth: TEXCOORD1;\n");
	}
	if (lang == HLSL_D3D9) {
		WRITE(p, "  vec4 gl_Position   : POSITION;\n");
	} else {
		WRITE(p, "  vec4 gl_Position   : SV_Position;\n");
	}
	WRITE(p, "};\n");

	// Confirmed: Through mode gets through exactly the same in GL and D3D in Phantasy Star: Text is 38023.0 in the test scene.

	if (!isModeThrough && gstate_c.Supports(GPU_ROUND_DEPTH_TO_16BIT)) {
		// Apply the projection and viewport to get the Z buffer value, floor to integer, undo the viewport and projection.
		// The Z range in D3D is different but we compensate for that using parameters.
		WRITE(p, "\nvec4 depthRoundZVP(vec4 v) {\n");
		WRITE(p, "  float z = v.z / v.w;\n");
		WRITE(p, "  z = (z * u_depthRange.x + u_depthRange.y);\n");
		WRITE(p, "  z = floor(z);\n");
		WRITE(p, "  z = (z - u_depthRange.z) * u_depthRange.w;\n");
		WRITE(p, "  return vec4(v.x, v.y, z * v.w, v.w);\n");
		WRITE(p, "}\n\n");
	}

	// Hardware tessellation
	if (doSpline || doBezier) {
		if (lang == HLSL_D3D11) {
			WRITE(p, "struct TessData {\n");
			WRITE(p, "  vec3 pos; float pad1;\n");
			WRITE(p, "  vec2 tex; vec2 pad2;\n");
			WRITE(p, "  vec4 col;\n");
			WRITE(p, "};\n");
			WRITE(p, "StructuredBuffer<TessData> tess_data : register(t0);\n");

			WRITE(p, "struct TessWeight {\n");
			WRITE(p, "  vec4 basis;\n");
			WRITE(p, "  vec4 deriv;\n");
			WRITE(p, "};\n");
			WRITE(p, "StructuredBuffer<TessWeight> tess_weights_u : register(t1);\n");
			WRITE(p, "StructuredBuffer<TessWeight> tess_weights_v : register(t2);\n");
		}

		const char *init[3] = { "0.0, 0.0", "0.0, 0.0, 0.0", "0.0, 0.0, 0.0, 0.0" };
		for (int i = 2; i <= 4; i++) {
			// Define 3 types vec2, vec3, vec4
			WRITE(p, "float%d tess_sample(in float%d points[16], float4x4 weights) {\n", i, i);
			WRITE(p, "  float%d pos = float%d(%s);\n", i, i, init[i - 2]);
			for (int v = 0; v < 4; ++v) {
				for (int u = 0; u < 4; ++u) {
					WRITE(p, "  pos += weights[%i][%i] * points[%i];\n", v, u, v * 4 + u);
				}
			}
			WRITE(p, "  return pos;\n");
			WRITE(p, "}\n");
		}

		WRITE(p, "float4x4 outerProduct(vec4 u, vec4 v) {\n");
		WRITE(p, "  return mul((float4x1)v, (float1x4)u);\n");
		WRITE(p, "}\n");

		WRITE(p, "struct Tess {\n");
		WRITE(p, "  vec3 pos;\n");
		if (doTexture)
			WRITE(p, "  vec2 tex;\n");
		WRITE(p, "  vec4 col;\n");
		if (hasNormalTess)
			WRITE(p, "  vec3 nrm;\n");
		WRITE(p, "};\n");

		WRITE(p, "void tessellate(in VS_IN In, out Tess tess) {\n");
		WRITE(p, "  int2 point_pos = int2(In.position.z, In.normal.z)%s;\n", doBezier ? " * 3" : "");
		WRITE(p, "  int2 weight_idx = int2(In.position.xy);\n");
		// Load 4x4 control points
		WRITE(p, "  vec3 _pos[16];\n");
		WRITE(p, "  vec2 _tex[16];\n");
		WRITE(p, "  vec4 _col[16];\n");
		WRITE(p, "  int index;\n");
		for (int i = 0; i < 4; i++) {
			for (int j = 0; j < 4; j++) {
				WRITE(p, "  index = (%i + point_pos.y) * u_spline_counts + (%i + point_pos.x);\n", i, j);
				WRITE(p, "  _pos[%i] = tess_data[index].pos;\n", i * 4 + j);
				if (doTexture && hasTexcoordTess)
					WRITE(p, "  _tex[%i] = tess_data[index].tex;\n", i * 4 + j);
				if (hasColorTess)
					WRITE(p, "  _col[%i] = tess_data[index].col;\n", i * 4 + j);
			}
		}

		// Basis polynomials as weight coefficients
		WRITE(p, "  vec4 basis_u = tess_weights_u[weight_idx.x].basis;\n");
		WRITE(p, "  vec4 basis_v = tess_weights_v[weight_idx.y].basis;\n");
		WRITE(p, "  float4x4 basis = outerProduct(basis_u, basis_v);\n");

		// Tessellate
		WRITE(p, "  tess.pos = tess_sample(_pos, basis);\n");
		if (doTexture) {
			if (hasTexcoordTess)
				WRITE(p, "  tess.tex = tess_sample(_tex, basis);\n");
			else
				WRITE(p, "  tess.tex = In.normal.xy;\n");
		}
		if (hasColorTess)
			WRITE(p, "  tess.col = tess_sample(_col, basis);\n");
		else
			WRITE(p, "  tess.col = u_matambientalpha;\n");
		if (hasNormalTess) {
			// Derivatives as weight coefficients
			WRITE(p, "  vec4 deriv_u = tess_weights_u[weight_idx.x].deriv;\n");
			WRITE(p, "  vec4 deriv_v = tess_weights_v[weight_idx.y].deriv;\n");

			WRITE(p, "  vec3 du = tess_sample(_pos, outerProduct(deriv_u, basis_v));\n");
			WRITE(p, "  vec3 dv = tess_sample(_pos, outerProduct(basis_u, deriv_v));\n");
			WRITE(p, "  tess.nrm = normalize(cross(du, dv));\n");
		}
		WRITE(p, "}\n");
	}

	WRITE(p, "VS_OUT main(VS_IN In) {\n");
	WRITE(p, "  VS_OUT Out;\n");
	if (doTexture) {
		if (texCoordInVec3) {
			WRITE(p, "  vec3 texcoord = In.texcoord;\n");
		} else {
			WRITE(p, "  vec2 texcoord = In.texcoord;\n");
		}
	}
	if (hasColor) {
		WRITE(p, "  vec4 color0 = In.color0;\n");
		if (lmode && !useHWTransform) {
			WRITE(p, "  vec4 color1 = In.color1;\n");
		}
	}
	if (hasNormal) {
		WRITE(p, "  vec3 normal = In.normal;\n");
	}
	if (useHWTransform) {
		WRITE(p, "  vec3 position = In.position;\n");
	} else {
		WRITE(p, "  vec4 position = In.position;\n");
	}

	if (!useHWTransform) {
		// Simple pass-through of vertex data to fragment shader
		if (doTexture) {
			if (texCoordInVec3) {
				WRITE(p, "  Out.v_texcoord = texcoord;\n");
			} else {
				WRITE(p, "  Out.v_texcoord = vec3(texcoord, 1.0);\n");
			}
		}
		if (hasColor) {
			WRITE(p, "  Out.v_color0 = color0;\n");
			if (lmode)
				WRITE(p, "  Out.v_color1 = color1.rgb;\n");
		} else {
			WRITE(p, "  Out.v_color0 = u_matambientalpha;\n");
			if (lmode)
				WRITE(p, "  Out.v_color1 = vec3(0.0);\n");
		}
		if (enableFog) {
			WRITE(p, "  Out.v_fogdepth = position.w;\n");
		}
		if (isModeThrough) {
			WRITE(p, "  vec4 outPos = mul(u_proj_through, vec4(In.position.xyz, 1.0));\n");
		} else {
			if (gstate_c.Supports(GPU_ROUND_DEPTH_TO_16BIT)) {
				WRITE(p, "  vec4 outPos = depthRoundZVP(mul(u_proj, vec4(In.position.xyz, 1.0)));\n");
			} else {
				WRITE(p, "  vec4 outPos = mul(u_proj, vec4(In.position.xyz, 1.0));\n");
			}
		}
	}  else {
		// Step 1: World Transform / Skinning
		if (!enableBones) {
			if (doSpline || doBezier) {
				// Hardware tessellation
				WRITE(p, "  Tess tess;\n");
				WRITE(p, "  tessellate(In, tess);\n");

				WRITE(p, "  vec3 worldpos = mul(vec4(tess.pos.xyz, 1.0), u_world).xyz;\n");
				if (hasNormalTess)
					WRITE(p, "  vec3 worldnormal = normalize(mul(vec4(%stess.nrm, 0.0), u_world)).xyz;\n", flipNormalTess ? "-" : "");
				else
					WRITE(p, "  mediump vec3 worldnormal = vec3(0.0, 0.0, 1.0);\n");
			} else {
				// No skinning, just standard T&L.
				WRITE(p, "  vec3 worldpos = mul(vec4(position.xyz, 1.0), u_world).xyz;\n");
				if (hasNormal)
					WRITE(p, "  mediump vec3 worldnormal = normalize(mul(vec4(%snormal, 0.0), u_world).xyz);\n", flipNormal ? "-" : "");
				else
					WRITE(p, "  mediump vec3 worldnormal = vec3(0.0, 0.0, 1.0);\n");
			}
		} else {
			static const char * const boneWeightAttr[8] = {
				"a_w1.x", "a_w1.y", "a_w1.z", "a_w1.w",
				"a_w2.x", "a_w2.y", "a_w2.z", "a_w2.w",
			};

			if (lang == HLSL_D3D11) {
				if (numBoneWeights == 1)
					WRITE(p, "  mat3x4 skinMatrix = mul(In.a_w1, u_bone[0])");
				else
					WRITE(p, "  float4x3 skinMatrix = mul(In.a_w1.x, u_bone[0])");
				for (int i = 1; i < numBoneWeights; i++) {
					const char *weightAttr = boneWeightAttr[i];
					// workaround for "cant do .x of scalar" issue
					if (numBoneWeights == 1 && i == 0) weightAttr = "a_w1";
					if (numBoneWeights == 5 && i == 4) weightAttr = "a_w2";
					WRITE(p, " + mul(In.%s, u_bone[%i])", weightAttr, i);
				}
			} else {
				if (numBoneWeights == 1)
					WRITE(p, "  float4x3 skinMatrix = mul(In.a_w1, u_bone0)");
				else
					WRITE(p, "  float4x3 skinMatrix = mul(In.a_w1.x, u_bone0)");
				for (int i = 1; i < numBoneWeights; i++) {
					const char *weightAttr = boneWeightAttr[i];
					// workaround for "cant do .x of scalar" issue
					if (numBoneWeights == 1 && i == 0) weightAttr = "a_w1";
					if (numBoneWeights == 5 && i == 4) weightAttr = "a_w2";
					WRITE(p, " + mul(In.%s, u_bone%i)", weightAttr, i);
				}
			}

			WRITE(p, ";\n");

			// Trying to simplify this results in bugs in LBP...
			WRITE(p, "  vec3 skinnedpos = mul(float4(position.xyz, 1.0), skinMatrix).xyz;\n");
			WRITE(p, "  vec3 worldpos = mul(float4(skinnedpos, 1.0), u_world).xyz;\n");

			if (hasNormal) {
				WRITE(p, "  vec3 skinnednormal = mul(float4(%snormal, 0.0), skinMatrix).xyz;\n", flipNormal ? "-" : "");
			} else {
				WRITE(p, "  vec3 skinnednormal = mul(float4(0.0, 0.0, %s1.0, 0.0), skinMatrix).xyz;\n", flipNormal ? "-" : "");
			}
			WRITE(p, "  mediump vec3 worldnormal = normalize(mul(float4(skinnednormal, 0.0), u_world).xyz);\n");
		}

		WRITE(p, "  vec4 viewPos = vec4(mul(vec4(worldpos, 1.0), u_view).xyz, 1.0);\n");

		// Final view and projection transforms.
		if (gstate_c.Supports(GPU_ROUND_DEPTH_TO_16BIT)) {
			WRITE(p, "  vec4 outPos = depthRoundZVP(mul(u_proj, viewPos));\n");
		} else {
			WRITE(p, "  vec4 outPos = mul(u_proj, viewPos);\n");
		}

		// TODO: Declare variables for dots for shade mapping if needed.

		const char *ambientStr = (matUpdate & 1) && hasColor ? "color0" : "u_matambientalpha";
		const char *diffuseStr = (matUpdate & 2) && hasColor ? "color0.rgb" : "u_matdiffuse";
		const char *specularStr = (matUpdate & 4) && hasColor ? "color0.rgb" : "u_matspecular.rgb";
		if (doBezier || doSpline) {
			// TODO: Probably, should use hasColorTess but FF4 has a problem with drawing the background.
			ambientStr = (matUpdate & 1) && hasColor ? "tess.col" : "u_matambientalpha";
			diffuseStr = (matUpdate & 2) && hasColor ? "tess.col.rgb" : "u_matdiffuse";
			specularStr = (matUpdate & 4) && hasColor ? "tess.col.rgb" : "u_matspecular.rgb";
		}

		bool diffuseIsZero = true;
		bool specularIsZero = true;
		bool distanceNeeded = false;
		bool anySpots = false;
		if (enableLighting) {
			WRITE(p, "  vec4 lightSum0 = u_ambient * %s + float4(u_matemissive, 0.0);\n", ambientStr);

			for (int i = 0; i < 4; i++) {
				GELightType type = static_cast<GELightType>(id.Bits(VS_BIT_LIGHT0_TYPE + 4 * i, 2));
				GELightComputation comp = static_cast<GELightComputation>(id.Bits(VS_BIT_LIGHT0_COMP + 4 * i, 2));
				if (doLight[i] != LIGHT_FULL)
					continue;
				diffuseIsZero = false;
				if (comp == GE_LIGHTCOMP_BOTH)
					specularIsZero = false;
				if (type != GE_LIGHTTYPE_DIRECTIONAL)
					distanceNeeded = true;
				if (type == GE_LIGHTTYPE_SPOT || type == GE_LIGHTTYPE_UNKNOWN)
					anySpots = true;
			}

			if (!specularIsZero) {
				WRITE(p, "  vec3 lightSum1 = 0;\n");
			}
			if (!diffuseIsZero) {
				WRITE(p, "  vec3 toLight;\n");
				WRITE(p, "  vec3 diffuse;\n");
			}
			if (distanceNeeded) {
				WRITE(p, "  float distance;\n");
				WRITE(p, "  float lightScale;\n");
			}
			WRITE(p, "  float ldot;\n");
			if (anySpots) {
				WRITE(p, "  float angle;\n");
			}
		}

		// Calculate lights if needed. If shade mapping is enabled, lights may need to be
		// at least partially calculated.
		for (int i = 0; i < 4; i++) {
			if (doLight[i] != LIGHT_FULL)
				continue;

			GELightType type = static_cast<GELightType>(id.Bits(VS_BIT_LIGHT0_TYPE + 4 * i, 2));
			GELightComputation comp = static_cast<GELightComputation>(id.Bits(VS_BIT_LIGHT0_COMP + 4 * i, 2));

			if (type == GE_LIGHTTYPE_DIRECTIONAL) {
				// We prenormalize light positions for directional lights.
				WRITE(p, "  toLight = u_lightpos%i;\n", i);
			} else {
				WRITE(p, "  toLight = u_lightpos%i - worldpos;\n", i);
				WRITE(p, "  distance = length(toLight);\n");
				WRITE(p, "  toLight /= distance;\n");
			}

			bool doSpecular = comp == GE_LIGHTCOMP_BOTH;
			bool poweredDiffuse = comp == GE_LIGHTCOMP_ONLYPOWDIFFUSE;

			WRITE(p, "  ldot = dot(toLight, worldnormal);\n");
			if (poweredDiffuse) {
				// pow(0.0, 0.0) may be undefined, but the PSP seems to treat it as 1.0.
				// Seen in Tales of the World: Radiant Mythology (#2424.)
				WRITE(p, "  if (u_matspecular.a <= 0.0) {\n");
				WRITE(p, "    ldot = 1.0;\n");
				WRITE(p, "  } else {\n");
				WRITE(p, "    ldot = pow(max(ldot, 0.0), u_matspecular.a);\n");
				WRITE(p, "  }\n");
			}

			const char *timesLightScale = " * lightScale";

			// Attenuation
			switch (type) {
			case GE_LIGHTTYPE_DIRECTIONAL:
				timesLightScale = "";
				break;
			case GE_LIGHTTYPE_POINT:
				WRITE(p, "  lightScale = clamp(1.0 / dot(u_lightatt%i, vec3(1.0, distance, distance*distance)), 0.0, 1.0);\n", i);
				break;
			case GE_LIGHTTYPE_SPOT:
			case GE_LIGHTTYPE_UNKNOWN:
				WRITE(p, "  angle = length(u_lightdir%i) == 0.0 ? 0.0 : dot(normalize(u_lightdir%i), toLight);\n", i, i);
				WRITE(p, "  if (angle >= u_lightangle_spotCoef%i.x) {\n", i);
				WRITE(p, "    lightScale = clamp(1.0 / dot(u_lightatt%i, vec3(1.0, distance, distance*distance)), 0.0, 1.0) * (u_lightangle_spotCoef%i.y <= 0.0 ? 1.0 : pow(angle, u_lightangle_spotCoef%i.y));\n", i, i, i);
				WRITE(p, "  } else {\n");
				WRITE(p, "    lightScale = 0.0;\n");
				WRITE(p, "  }\n");
				break;
			default:
				// ILLEGAL
				break;
			}

			WRITE(p, "  diffuse = (u_lightdiffuse%i * %s) * max(ldot, 0.0);\n", i, diffuseStr);
			if (doSpecular) {
				WRITE(p, "  if (ldot >= 0.0) {\n");
				WRITE(p, "    ldot = dot(normalize(toLight + vec3(0.0, 0.0, 1.0)), worldnormal);\n");
				WRITE(p, "    if (u_matspecular.a <= 0.0) {\n");
				WRITE(p, "      ldot = 1.0;\n");
				WRITE(p, "    } else {\n");
				WRITE(p, "      ldot = pow(max(ldot, 0.0), u_matspecular.a);\n");
				WRITE(p, "    }\n");
				WRITE(p, "    if (ldot > 0.0)\n");
				WRITE(p, "      lightSum1 += u_lightspecular%i * %s * ldot %s;\n", i, specularStr, timesLightScale);
				WRITE(p, "  }\n");
			}
			WRITE(p, "  lightSum0.rgb += (u_lightambient%i * %s.rgb + diffuse)%s;\n", i, ambientStr, timesLightScale);
		}

		if (enableLighting) {
			// Sum up ambient, emissive here.
			if (lmode) {
				WRITE(p, "  Out.v_color0 = clamp(lightSum0, 0.0, 1.0);\n");
				// v_color1 only exists when lmode = 1.
				if (specularIsZero) {
					WRITE(p, "  Out.v_color1 = splat3(0.0);\n");
				} else {
					WRITE(p, "  Out.v_color1 = clamp(lightSum1, 0.0, 1.0);\n");
				}
			} else {
				if (specularIsZero) {
					WRITE(p, "  Out.v_color0 = clamp(lightSum0, 0.0, 1.0);\n");
				} else {
					WRITE(p, "  Out.v_color0 = clamp(clamp(lightSum0, 0.0, 1.0) + float4(lightSum1, 0.0), 0.0, 1.0);\n");
				}
			}
		} else {
			// Lighting doesn't affect color.
			if (hasColor) {
				if (doBezier || doSpline)
					WRITE(p, "  Out.v_color0 = tess.col;\n");
				else
					WRITE(p, "  Out.v_color0 = color0;\n");
			} else {
				WRITE(p, "  Out.v_color0 = u_matambientalpha;\n");
			}
			if (lmode)
				WRITE(p, "  Out.v_color1 = splat3(0.0);\n");
		}

		// Step 3: UV generation
		if (doTexture) {
			switch (uvGenMode) {
			case GE_TEXMAP_TEXTURE_COORDS:  // Scale-offset. Easy.
			case GE_TEXMAP_UNKNOWN: // Not sure what this is, but Riviera uses it.  Treating as coords works.
				if (scaleUV) {
					if (hasTexcoord) {
						if (doBezier || doSpline)
							WRITE(p, "  Out.v_texcoord = vec3(tess.tex.xy * u_uvscaleoffset.xy + u_uvscaleoffset.zw, 0.0);\n");
						else
							WRITE(p, "  Out.v_texcoord = vec3(texcoord.xy * u_uvscaleoffset.xy, 0.0);\n");
					} else {
						WRITE(p, "  Out.v_texcoord = splat3(0.0);\n");
					}
				} else {
					if (hasTexcoord) {
						WRITE(p, "  Out.v_texcoord = vec3(texcoord.xy * u_uvscaleoffset.xy + u_uvscaleoffset.zw, 0.0);\n");
					} else {
						WRITE(p, "  Out.v_texcoord = vec3(u_uvscaleoffset.zw, 0.0);\n");
					}
				}
				break;

			case GE_TEXMAP_TEXTURE_MATRIX:  // Projection mapping.
				{
					std::string temp_tc;
					switch (uvProjMode) {
					case GE_PROJMAP_POSITION:  // Use model space XYZ as source
						temp_tc = "vec4(position.xyz, 1.0)";
						break;
					case GE_PROJMAP_UV:  // Use unscaled UV as source
						{
							if (hasTexcoord) {
								temp_tc = StringFromFormat("vec4(texcoord.xy, 0.0, 1.0)");
							} else {
								temp_tc = "vec4(0.0, 0.0, 0.0, 1.0)";
							}
						}
						break;
					case GE_PROJMAP_NORMALIZED_NORMAL:  // Use normalized transformed normal as source
						if (hasNormal)
							temp_tc = flipNormal ? "vec4(normalize(-normal), 1.0)" : "vec4(normalize(normal), 1.0)";
						else
							temp_tc = "vec4(0.0, 0.0, 1.0, 1.0)";
						break;
					case GE_PROJMAP_NORMAL:  // Use non-normalized transformed normal as source
						if (hasNormal)
							temp_tc =  flipNormal ? "vec4(-normal, 1.0)" : "vec4(normal, 1.0)";
						else
							temp_tc = "vec4(0.0, 0.0, 1.0, 1.0)";
						break;
					}
					// Transform by texture matrix. XYZ as we are doing projection mapping.
					WRITE(p, "  Out.v_texcoord.xyz = mul(%s, u_texmtx) * vec3(u_uvscaleoffset.xy, 1.0);\n", temp_tc.c_str());
				}
				break;

			case GE_TEXMAP_ENVIRONMENT_MAP:  // Shade mapping - use dots from light sources.
				{
					std::string lightFactor0 = StringFromFormat("(length(u_lightpos%i) == 0.0 ? worldnormal.z : dot(normalize(u_lightpos%i), worldnormal))", ls0, ls0);
					std::string lightFactor1 = StringFromFormat("(length(u_lightpos%i) == 0.0 ? worldnormal.z : dot(normalize(u_lightpos%i), worldnormal))", ls1, ls1);
					WRITE(p, "  Out.v_texcoord = vec3(u_uvscaleoffset.xy * vec2(1.0 + %s, 1.0 + %s) * 0.5, 1.0);\n", lightFactor0.c_str(), lightFactor1.c_str());
				}
				break;

			default:
				// Should be unreachable.
				_assert_(false);
				return false;
			}
		}

		// Compute fogdepth
		if (enableFog) {
			WRITE(p, "  Out.v_fogdepth = (viewPos.z + u_fogcoef.x) * u_fogcoef.y;\n");
		}
	}

	if (!isModeThrough && gstate_c.Supports(GPU_SUPPORTS_VS_RANGE_CULLING)) {
		WRITE(p, "  vec3 projPos = outPos.xyz / outPos.w;\n");
		// Vertex range culling doesn't happen when depth is clamped, so only do this if in range.
		WRITE(p, "  if (u_cullRangeMin.w <= 0.0 || (projPos.z >= u_cullRangeMin.z && projPos.z <= u_cullRangeMax.z)) {\n");
		const char *outMin = "projPos.x < u_cullRangeMin.x || projPos.y < u_cullRangeMin.y || projPos.z < u_cullRangeMin.z";
		const char *outMax = "projPos.x > u_cullRangeMax.x || projPos.y > u_cullRangeMax.y || projPos.z > u_cullRangeMax.z";
		WRITE(p, "    if (%s || %s) {\n", outMin, outMax);
		WRITE(p, "      outPos.w = u_cullRangeMax.w;\n");
		WRITE(p, "    }\n");
		WRITE(p, "  }\n");
	}
	WRITE(p, "  Out.gl_Position = outPos;\n");

	WRITE(p, "  return Out;\n");
	WRITE(p, "}\n");
	return true;
}