From 3cf8a1fa944ccce44cece51b372c49b7b48d3c3f Mon Sep 17 00:00:00 2001
From: gm-matthew <108370479+gm-matthew@users.noreply.github.com>
Date: Fri, 5 Jul 2024 15:57:25 +0100
Subject: [PATCH] Implementing texture NP values For some reason Model 3 uses
 vertex coordinates rather than texel coordinates to calculate mipmap levels
 Revised microtexture implementation; results are very close to real hardware
 when running at native resolution with supersampling disabled

---
 Src/Graphics/New3D/Model.h              |  6 +-
 Src/Graphics/New3D/New3D.cpp            | 10 +++-
 Src/Graphics/New3D/New3D.h              |  1 +
 Src/Graphics/New3D/PolyHeader.cpp       |  5 ++
 Src/Graphics/New3D/PolyHeader.h         |  5 +-
 Src/Graphics/New3D/R3DShader.cpp        | 10 ++--
 Src/Graphics/New3D/R3DShader.h          |  4 +-
 Src/Graphics/New3D/R3DShaderCommon.h    | 80 +++++++++++--------------
 Src/Graphics/New3D/R3DShaderQuads.h     | 11 +++-
 Src/Graphics/New3D/R3DShaderTriangles.h |  6 +-
 10 files changed, 79 insertions(+), 59 deletions(-)

diff --git a/Src/Graphics/New3D/Model.h b/Src/Graphics/New3D/Model.h
index 6707733..795831b 100644
--- a/Src/Graphics/New3D/Model.h
+++ b/Src/Graphics/New3D/Model.h
@@ -52,6 +52,7 @@ struct R3DPoly
 	Vertex v[4];			// just easier to have them as an array
 	float faceNormal[3];	// we need this to help work out poly winding, i assume the h/w uses this instead of calculating normals itself
 	UINT8 faceColour[4];	// per face colour
+	float textureNP;
 	int number = 4;
 };
 
@@ -59,6 +60,7 @@ struct FVertex : Vertex			// full vertex including face attributes
 {
 	float faceNormal[3];
 	UINT8 faceColour[4];
+	float textureNP;
 
 	FVertex& operator=(const Vertex& vertex) 
 	{
@@ -71,6 +73,7 @@ struct FVertex : Vertex			// full vertex including face attributes
 	{
 		for (int i = 0; i < 4; i++) { faceColour[i] = r3dPoly.faceColour[i]; }
 		for (int i = 0; i < 3; i++) { faceNormal[i] = r3dPoly.faceNormal[i]; }
+		textureNP = r3dPoly.textureNP;
 
 		*this = r3dPoly.v[index];
 	}
@@ -82,6 +85,7 @@ struct FVertex : Vertex			// full vertex including face attributes
 		// copy face attributes
 		for (int i = 0; i < 4; i++) { faceColour[i] = r3dPoly.faceColour[i]; }
 		for (int i = 0; i < 3; i++) { faceNormal[i] = r3dPoly.faceNormal[i]; }
+		textureNP = r3dPoly.textureNP;
 	}
 
 	static void Average(const FVertex& p1, const FVertex& p2, FVertex& p3)
@@ -142,7 +146,7 @@ struct Mesh
 	// microtexture
 	bool	microTexture		= false;
 	int		microTextureID		= 0;
-	float	microTextureScale	= 0;
+	float	microTextureMinLOD	= 0;
 
 	// attributes
 	bool textured		= false;
diff --git a/Src/Graphics/New3D/New3D.cpp b/Src/Graphics/New3D/New3D.cpp
index 6abe615..4f01be3 100644
--- a/Src/Graphics/New3D/New3D.cpp
+++ b/Src/Graphics/New3D/New3D.cpp
@@ -55,6 +55,7 @@ CNew3D::CNew3D(const Util::Config::Node &config, const std::string& gameName) :
 	glEnableVertexAttribArray(m_r3dShader.GetVertexAttribPos("inColour"));
 	glEnableVertexAttribArray(m_r3dShader.GetVertexAttribPos("inFaceNormal"));
 	glEnableVertexAttribArray(m_r3dShader.GetVertexAttribPos("inFixedShade"));
+	glEnableVertexAttribArray(m_r3dShader.GetVertexAttribPos("inTextureNP"));
 
 	// before draw, specify vertex and index arrays with their offsets, offsetof is maybe evil ..
 	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inVertex"), 4, GL_FLOAT, GL_FALSE, sizeof(FVertex), 0);
@@ -63,6 +64,7 @@ CNew3D::CNew3D(const Util::Config::Node &config, const std::string& gameName) :
 	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inColour"), 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(FVertex), (void*)offsetof(FVertex, faceColour));
 	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inFaceNormal"), 3, GL_FLOAT, GL_FALSE, sizeof(FVertex), (void*)offsetof(FVertex, faceNormal));
 	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inFixedShade"), 1, GL_FLOAT, GL_FALSE, sizeof(FVertex), (void*)offsetof(FVertex, fixedShade));
+	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inTextureNP"), 1, GL_FLOAT, GL_FALSE, sizeof(FVertex), (void*)offsetof(FVertex, textureNP));
 
 	glBindVertexArray(0);
 	m_vbo.Bind(false);
@@ -102,10 +104,12 @@ void CNew3D::SetStepping(int stepping)
 	if (m_step > 0x10) {
 		m_offset = 0;							// culling nodes are 10 words
 		m_vertexFactor = (1.0f / 2048.0f);		// vertices are in 13.11 format
+		m_textureNPFactor = (1.0f / 16384.0f);	// texture NP values are in 10.14 format
 	}
 	else {
 		m_offset = 2;							// 8 words
 		m_vertexFactor = (1.0f / 128.0f);		// 17.7
+		m_textureNPFactor = (1.0f / 4096.0f);	// 12.12
 	}
 }
 
@@ -1287,10 +1291,8 @@ void CNew3D::SetMeshValues(SortingMesh *currentMesh, PolyHeader &ph)
 
 		if (currentMesh->microTexture) {
 
-			static const float microTexScale[] = { 2.f, 4.f, 16.f, 256.f };
-
 			currentMesh->microTextureID = ph.MicroTextureID();
-			currentMesh->microTextureScale = microTexScale[ph.MicroTextureMinLOD()];
+			currentMesh->microTextureMinLOD = (float)ph.MicroTextureMinLOD();
 		}
 	}
 }
@@ -1396,6 +1398,8 @@ void CNew3D::CacheModel(Model *m, const UINT32 *data)
 			p.v[i].normal[2] = p.faceNormal[2];
 		}
 
+		p.textureNP = ph.TextureNP() * m_textureNPFactor;
+
 		UINT32* vData = ph.StartOfData();	// vertex data starts here
 
 		// remaining vertices are new and defined here
diff --git a/Src/Graphics/New3D/New3D.h b/Src/Graphics/New3D/New3D.h
index 90f4065..614e2d6 100644
--- a/Src/Graphics/New3D/New3D.h
+++ b/Src/Graphics/New3D/New3D.h
@@ -244,6 +244,7 @@ private:
 	int		m_step;
 	int		m_offset;			// offset to subtract for words 3 and higher of culling nodes
 	float	m_vertexFactor;		// fixed-point conversion factor for vertices
+	float	m_textureNPFactor;	// fixed-point conversion factor for texture NP values
 
 	// Memory (passed from outside)
 	const UINT32	*m_cullingRAMLo;	// 4 MB
diff --git a/Src/Graphics/New3D/PolyHeader.cpp b/Src/Graphics/New3D/PolyHeader.cpp
index 543e9c1..4274074 100644
--- a/Src/Graphics/New3D/PolyHeader.cpp
+++ b/Src/Graphics/New3D/PolyHeader.cpp
@@ -306,6 +306,11 @@ int PolyHeader::Y()
 	return y;
 }
 
+float PolyHeader::TextureNP()
+{
+	return (float)(header[5] >> 8);
+}
+
 //
 // header 6
 //
diff --git a/Src/Graphics/New3D/PolyHeader.h b/Src/Graphics/New3D/PolyHeader.h
index b6b572e..c10f339 100644
--- a/Src/Graphics/New3D/PolyHeader.h
+++ b/Src/Graphics/New3D/PolyHeader.h
@@ -55,7 +55,7 @@ xxxxxxxx xxxxxxxx xxxxxxxx --------		Color (RGB888 or two 12-bit indexes, sensor
 -------- -------- -------- ---xxxxx		Upper 5 bits of texture U coordinate
 
 0x05 : 
-xxxxxxxx xxxxxxxx xxxxxxxx --------		Texture NP ?
+xxxxxxxx xxxxxxxx xxxxxxxx --------		Texture NP
 -------- -------- -------- x-------		Low bit of texture U coordinate
 -------- -------- -------- ---xxxxx		Low 5 bits of texture V coordinate
 
@@ -115,7 +115,7 @@ public:
 	bool	TexVMirror();
 	bool	MicroTexture();
 	int		MicroTextureID();
-	int		MicroTextureMinLOD();	// basically how many times it repeats compared to the base texture (i assume)
+	int		MicroTextureMinLOD();
 
 	// header 3
 	int		TexWidth();
@@ -133,6 +133,7 @@ public:
 	// header 5
 	int		X();
 	int		Y();
+	float	TextureNP();
 
 	//header 6
 	bool	Layered();
diff --git a/Src/Graphics/New3D/R3DShader.cpp b/Src/Graphics/New3D/R3DShader.cpp
index fe7c302..5855b5d 100644
--- a/Src/Graphics/New3D/R3DShader.cpp
+++ b/Src/Graphics/New3D/R3DShader.cpp
@@ -36,7 +36,7 @@ void R3DShader::Start()
 	m_nodeAlpha			= 1.0f;
 	m_shininess			= 0;
 	m_specularValue		= 0;
-	m_microTexScale		= 0;
+	m_microTexMinLOD	= 0;
 	m_microTexID		= -1;
 	m_texturePage		= -1;
 
@@ -108,7 +108,7 @@ bool R3DShader::LoadShader(const char* vertexShader, const char* fragmentShader)
 	m_locTexture2Enabled	= glGetUniformLocation(m_shaderProgram, "microTexture");
 	m_locTextureAlpha		= glGetUniformLocation(m_shaderProgram, "textureAlpha");
 	m_locAlphaTest			= glGetUniformLocation(m_shaderProgram, "alphaTest");
-	m_locMicroTexScale		= glGetUniformLocation(m_shaderProgram, "microTextureScale");
+	m_locMicroTexMinLOD		= glGetUniformLocation(m_shaderProgram, "microTextureMinLOD");
 	m_locMicroTexID			= glGetUniformLocation(m_shaderProgram, "microTextureID");
 	m_locBaseTexInfo		= glGetUniformLocation(m_shaderProgram, "baseTexInfo");
 	m_locBaseTexType		= glGetUniformLocation(m_shaderProgram, "baseTexType");
@@ -224,9 +224,9 @@ void R3DShader::SetMeshUniforms(const Mesh* m)
 		m_texturePage = (m->page ^ m_transPage);
 	}
 
-	if (m_dirtyMesh || m->microTextureScale != m_microTexScale) {
-		glUniform1f(m_locMicroTexScale, m->microTextureScale);
-		m_microTexScale = m->microTextureScale;
+	if (m_dirtyMesh || m->microTextureMinLOD != m_microTexMinLOD) {
+		glUniform1f(m_locMicroTexMinLOD, m->microTextureMinLOD);
+		m_microTexMinLOD = m->microTextureMinLOD;
 	}
 
 	if (m_dirtyMesh || m->microTextureID != m_microTexID) {
diff --git a/Src/Graphics/New3D/R3DShader.h b/Src/Graphics/New3D/R3DShader.h
index ac849fb..610b8d0 100644
--- a/Src/Graphics/New3D/R3DShader.h
+++ b/Src/Graphics/New3D/R3DShader.h
@@ -46,7 +46,7 @@ private:
 	GLint m_locTexturePage;
 	GLint m_locTextureAlpha;
 	GLint m_locAlphaTest;
-	GLint m_locMicroTexScale;
+	GLint m_locMicroTexMinLOD;
 	GLint m_locMicroTexID;
 	GLint m_locBaseTexInfo;
 	GLint m_locBaseTexType;
@@ -73,7 +73,7 @@ private:
 
 	bool	m_layered;
 	bool	m_noLosReturn;
-	float	m_microTexScale;
+	float	m_microTexMinLOD;
 	int		m_microTexID;
 	int		m_baseTexInfo[4];
 	int		m_baseTexType;
diff --git a/Src/Graphics/New3D/R3DShaderCommon.h b/Src/Graphics/New3D/R3DShaderCommon.h
index 44cddc7..ec335d8 100644
--- a/Src/Graphics/New3D/R3DShaderCommon.h
+++ b/Src/Graphics/New3D/R3DShaderCommon.h
@@ -119,13 +119,13 @@ ivec2 GetMicroTexturePos(int id)
 	return ivec2(xCoords[id],yCoords[id]);
 }
 
-float mip_map_level(in vec2 texture_coordinate) // in texel units
+float mip_map_level(in vec3 coordinate)
 {
-    vec2  dx_vtc        = dFdx(texture_coordinate);
-    vec2  dy_vtc        = dFdy(texture_coordinate);
-    float delta_max_sqr = max(dot(dx_vtc, dx_vtc), dot(dy_vtc, dy_vtc));
-    float mml = 0.5 * log2(delta_max_sqr);
-    return max( 0.0, mml );
+	// Real3D uses vertex coordinates rather than texel coordinates to calculate mipmap levels
+	vec3 dx_vtc = dFdx(coordinate);
+	vec3 dy_vtc = dFdy(coordinate);
+	float delta_max_sqr = max(dot(dx_vtc, dx_vtc), dot(dy_vtc, dy_vtc));
+	return log2(delta_max_sqr / (fsTextureNP * fsTextureNP)) * 0.5;			// result not clamped
 }
 
 float LinearTexLocations(int wrapMode, float size, float u, out float u0, out float u1)
@@ -207,59 +207,51 @@ vec4 texBiLinear(usampler2D texSampler, ivec2 wrapMode, vec2 texSize, ivec2 texP
     return mix( pInterp_q0, pInterp_q1, b ); // Interpolate in Y direction.
 }
 
-vec4 textureR3D(usampler2D texSampler, ivec2 wrapMode, ivec2 texSize, ivec2 texPos, vec2 texCoord)
+vec4 GetTextureValue()
 {
-	float numLevels	= floor(log2(min(float(texSize.x), float(texSize.y))));				// r3d only generates down to 1:1 for square textures, otherwise its the min dimension
-	float fLevel	= min(mip_map_level(texCoord * vec2(texSize)), numLevels);
-
-	if(alphaTest) fLevel *= 0.5;
-	else fLevel *= 0.8;
+	float lod = mip_map_level(fsViewVertex);
+	float numLevels = floor(log2(min(float(baseTexInfo.z), float(baseTexInfo.w))));		// r3d only generates down to 1:1 for square textures, otherwise its the min dimension
+	float fLevel = clamp(lod, 0.0, numLevels);
 
 	int iLevel = int(fLevel);
 
-	ivec2 texPos0 = GetTexturePosition(iLevel,texPos);
-	ivec2 texSize0 = GetTextureSize(iLevel, texSize);
+	ivec2 tex1Pos = GetTexturePosition(iLevel, ivec2(baseTexInfo.xy));
+	ivec2 tex1Size = GetTextureSize(iLevel, ivec2(baseTexInfo.zw));
+	vec4 tex1Data = texBiLinear(textureBank[texturePage], textureWrapMode, vec2(tex1Size), tex1Pos, fsTexCoord, iLevel);
 
-	if (fLevel > 0)
+	// init second texel with blank data to avoid any potentially undefined behavior
+	vec4 tex2Data = vec4(0.0);
+
+	float blendFactor = 0.0;
+
+	// if LOD < 0, no need to blend with next mipmap level; slight performance boost
+	if (lod > 0.0)
 	{
-		ivec2 texPos1 = GetTexturePosition(iLevel+1,texPos);
-		ivec2 texSize1 = GetTextureSize(iLevel+1, texSize); 
+		ivec2 tex2Pos = GetTexturePosition(iLevel+1, ivec2(baseTexInfo.xy));
+		ivec2 tex2Size = GetTextureSize(iLevel+1, ivec2(baseTexInfo.zw));
+		tex2Data = texBiLinear(textureBank[texturePage], textureWrapMode, vec2(tex2Size), tex2Pos, fsTexCoord, iLevel+1);
 
-		vec4 texLevel0 = texBiLinear(texSampler, wrapMode, vec2(texSize0), texPos0, texCoord, iLevel);
-		vec4 texLevel1 = texBiLinear(texSampler, wrapMode, vec2(texSize1), texPos1, texCoord, iLevel+1);
-
-		return mix(texLevel0, texLevel1, fract(fLevel));	// linear blend between our mipmap levels
+		blendFactor = fract(fLevel);
 	}
-	else
+	else if (microTexture && lod < -microTextureMinLOD)
 	{
-		// if fLevel is 0, no need to mix with next mipmap level; slight performance boost
-		return texBiLinear(texSampler, wrapMode, vec2(texSize0), texPos0, texCoord, iLevel);
-	}
-}
+		vec4 scaleIndex = vec4(2.0, 4.0, 16.0, 256.0);		// unsure if minLOD=4 has 256x scale? No games appear to use it
+		vec2 scale = (vec2(baseTexInfo.zw) / 128.0) * scaleIndex[int(microTextureMinLOD)];
 
-vec4 GetTextureValue()
-{
-	vec4 tex1Data = textureR3D(textureBank[texturePage], textureWrapMode, ivec2(baseTexInfo.zw), ivec2(baseTexInfo.xy), fsTexCoord);
+		// microtextures are always 128x128 and only use LOD 0 mipmap
+		ivec2 tex2Pos = GetMicroTexturePos(microTextureID);
+		tex2Data = texBiLinear(textureBank[(texturePage+1)&1], ivec2(0), ivec2(128), tex2Pos, fsTexCoord * scale, 0);
+
+		blendFactor = -(lod + microTextureMinLOD) * 0.25;
+		blendFactor = clamp(blendFactor, 0.0, 0.5);
+	}
+
+	tex1Data = mix(tex1Data, tex2Data, blendFactor);
 
 	if(textureInverted) {
 		tex1Data.rgb = vec3(1.0) - vec3(tex1Data.rgb);
 	}
 
-	if (microTexture) {
-		vec2 scale			= (vec2(baseTexInfo.zw) / 128.0) * microTextureScale;
-		ivec2 pos			= GetMicroTexturePos(microTextureID);
-	
-		vec4 tex2Data		= textureR3D(textureBank[(texturePage+1)&1], ivec2(0), ivec2(128), pos, fsTexCoord * scale);
-
-		float lod			= mip_map_level(fsTexCoord * scale * vec2(128.0));
-
-		float blendFactor	= max(lod - 1.5, 0.0);			// bias -1.5
-		blendFactor			= min(blendFactor, 1.0);		// clamp to max value 1
-		blendFactor			= (blendFactor + 1.0) / 2.0;	// 0.5 - 1 range
-
-		tex1Data			= mix(tex2Data, tex1Data, blendFactor);
-	}
-
 	if (alphaTest) {
 		if (tex1Data.a < (32.0/255.0)) {
 			discard;
diff --git a/Src/Graphics/New3D/R3DShaderQuads.h b/Src/Graphics/New3D/R3DShaderQuads.h
index 5ae1dee..33866c7 100644
--- a/Src/Graphics/New3D/R3DShaderQuads.h
+++ b/Src/Graphics/New3D/R3DShaderQuads.h
@@ -19,6 +19,7 @@ in vec2		inTexCoord;
 in vec3		inFaceNormal;		// used to emulate r3d culling 
 in float	inFixedShade;
 in vec4		inColour;
+in float	inTextureNP;
 
 // outputs to geometry shader
 
@@ -29,6 +30,7 @@ out VS_OUT
 	vec2	texCoord;
 	vec4	color;
 	float	fixedShade;
+	float	textureNP;
 	float	discardPoly;	// can't have varying bool (glsl spec)
 } vs_out;
 
@@ -62,6 +64,7 @@ void main(void)
 	vs_out.color    	= GetColour(inColour);
 	vs_out.texCoord		= inTexCoord;
 	vs_out.fixedShade	= inFixedShade;
+	vs_out.textureNP	= inTextureNP * modelScale;
 	gl_Position			= projMat * modelMat * inVertex;
 }
 )glsl";
@@ -80,6 +83,7 @@ in VS_OUT
 	vec2	texCoord;
 	vec4	color;
 	float	fixedShade;
+	float	textureNP;
 	float	discardPoly;	// can't have varying bool (glsl spec)
 } gs_in[4];
 
@@ -95,6 +99,7 @@ out GS_OUT
 	flat vec2	texCoord[4];
 	flat vec4	color;
 	flat float	fixedShade[4];
+	flat float	textureNP;
 } gs_out;
 
 //a*b - c*d, computed in a stable fashion (Kahan)
@@ -128,6 +133,7 @@ void main(void)
 
 	// flat attributes
 	gs_out.color = gs_in[0].color;
+	gs_out.textureNP = gs_in[0].textureNP;
 
 	// precompute crossproducts for all vertex combinations to be looked up in loop below for area computation
 	precise float cross[4][4];
@@ -180,7 +186,7 @@ uniform usampler2D textureBank[2];			// entire texture sheet
 // texturing
 uniform bool	textureEnabled;
 uniform bool	microTexture;
-uniform float	microTextureScale;
+uniform float	microTextureMinLOD;
 uniform int		microTextureID;
 uniform ivec4	baseTexInfo;		// x/y are x,y positions in the texture sheet. z/w are with and height
 uniform int		baseTexType;
@@ -231,6 +237,7 @@ in GS_OUT
 	flat vec2	texCoord[4];
 	flat vec4	color;
 	flat float	fixedShade[4];
+	flat float	textureNP;
 } fs_in;
 
 //our calculated vertex attributes from the above
@@ -239,6 +246,7 @@ vec3	fsViewNormal;
 vec2	fsTexCoord;
 float	fsFixedShade;
 vec4	fsColor;
+float	fsTextureNP;
 
 //outputs
 layout(location = 0) out vec4 out0;		// opaque
@@ -323,6 +331,7 @@ void QuadraticInterpolation()
 	fsTexCoord		= vec2(0.0);
 	fsFixedShade	= 0.0;
 	fsColor			= fs_in.color;
+	fsTextureNP		= fs_in.textureNP;
 	
 	for (int i=0; i<4; i++) {
 		fsViewVertex	+= lambda[i] * fs_in.viewVertex[i];
diff --git a/Src/Graphics/New3D/R3DShaderTriangles.h b/Src/Graphics/New3D/R3DShaderTriangles.h
index f8971bd..e6968d7 100644
--- a/Src/Graphics/New3D/R3DShaderTriangles.h
+++ b/Src/Graphics/New3D/R3DShaderTriangles.h
@@ -19,6 +19,7 @@ in  vec2	inTexCoord;
 in  vec4	inColour;
 in  vec3	inFaceNormal;		// used to emulate r3d culling 
 in  float	inFixedShade;
+in  float	inTextureNP;
 
 // outputs to fragment shader
 out vec3	fsViewVertex;
@@ -27,6 +28,7 @@ out vec2	fsTexCoord;
 out vec4	fsColor;
 out float	fsDiscard;			// can't have varying bool (glsl spec)
 out float	fsFixedShade;
+out float	fsTextureNP;
 
 vec4 GetColour(vec4 colour)
 {
@@ -58,6 +60,7 @@ void main(void)
 	fsColor    		= GetColour(inColour);
 	fsTexCoord		= inTexCoord;
 	fsFixedShade	= inFixedShade;
+	fsTextureNP		= inTextureNP * modelScale;
 	gl_Position		= projMat * modelMat * inVertex;
 }
 )glsl";
@@ -71,7 +74,7 @@ uniform usampler2D textureBank[2];			// entire texture sheet
 // texturing
 uniform bool	textureEnabled;
 uniform bool	microTexture;
-uniform float	microTextureScale;
+uniform float	microTextureMinLOD;
 uniform int		microTextureID;
 uniform ivec4	baseTexInfo;		// x/y are x,y positions in the texture sheet. z/w are with and height
 uniform int		baseTexType;
@@ -115,6 +118,7 @@ in  vec4	fsColor;
 in  vec2	fsTexCoord;
 in  float	fsDiscard;
 in  float	fsFixedShade;
+in	float	fsTextureNP;
 
 //outputs
 layout(location = 0) out vec4 out0;		// opaque