Improve batching by binding up to 8 simultaneous textures.

glsl/shp.frag

@@ -1,4 +1,12 @@
-uniform sampler2D DiffuseTexture, Palette;
+uniform sampler2D Texture0;
+uniform sampler2D Texture1;
+uniform sampler2D Texture2;
+uniform sampler2D Texture3;
+uniform sampler2D Texture4;
+uniform sampler2D Texture5;
+uniform sampler2D Texture6;
+uniform sampler2D Texture7;
+uniform sampler2D Palette;
 
 uniform bool EnableDepthPreview;
 uniform float DepthTextureScale;
@@ -7,6 +15,7 @@ varying vec4 vTexCoord;
 varying vec2 vTexMetadata;
 varying vec4 vChannelMask;
 varying vec4 vDepthMask;
+varying vec2 vTexSampler;
 
 varying vec4 vColorFraction;
 varying vec4 vRGBAFraction;
@@ -27,9 +36,29 @@ float jet_b(float x)
 	return x < 0.3 ? 4.0 * x + 0.5 : -4.0 * x + 2.5;
 }
 
+vec4 Sample(float samplerIndex, vec2 pos)
+{
+	if (samplerIndex < 1.0)
+		return texture2D(Texture0, pos);
+	else if (samplerIndex < 2.0)
+		return texture2D(Texture1, pos);
+	else if (samplerIndex < 3.0)
+		return texture2D(Texture2, pos);
+	else if (samplerIndex < 4.0)
+		return texture2D(Texture3, pos);
+	else if (samplerIndex < 5.0)
+		return texture2D(Texture4, pos);
+	else if (samplerIndex < 6.0)
+		return texture2D(Texture5, pos);
+	else if (samplerIndex < 7.0)
+		return texture2D(Texture6, pos);
+
+	return texture2D(Texture7, pos);
+}
+
 void main()
 {
-	vec4 x = texture2D(DiffuseTexture, vTexCoord.st);
+	vec4 x = Sample(vTexSampler.s, vTexCoord.st);
 	vec2 p = vec2(dot(x, vChannelMask), vTexMetadata.s);
 	vec4 c = vPalettedFraction * texture2D(Palette, p) + vRGBAFraction * x + vColorFraction * vTexCoord;
 
@@ -40,7 +69,7 @@ void main()
 	float depth = gl_FragCoord.z;
 	if (length(vDepthMask) > 0.0)
 	{
-		vec4 y = texture2D(DiffuseTexture, vTexCoord.pq);
+		vec4 y = Sample(vTexSampler.t, vTexCoord.pq);
 		depth = depth + DepthTextureScale * dot(y, vDepthMask);
 	}
 

glsl/shp.vert

@@ -9,15 +9,18 @@ varying vec4 vTexCoord;
 varying vec2 vTexMetadata;
 varying vec4 vChannelMask;
 varying vec4 vDepthMask;
+varying vec2 vTexSampler;
 
 varying vec4 vColorFraction;
 varying vec4 vRGBAFraction;
 varying vec4 vPalettedFraction;
 
-vec2 UnpackChannelAttributes(float x)
+vec4 UnpackChannelAttributes(float x)
 {
 	// The channel attributes float encodes a set of attributes
 	// stored as flags in the mantissa of the unnormalized float value.
+	// Bits 9-11 define the sampler index (0-7) that the secondary texture is bound to
+	// Bits 6-8 define the sampler index (0-7) that the primary texture is bound to
 	// Bits 3-5 define the behaviour of the secondary texture channel:
 	//    000: Channel is not used
 	//    001, 011, 101, 111: Sample depth sprite from channel R,G,B,A
@@ -26,6 +29,16 @@ vec2 UnpackChannelAttributes(float x)
 	//    010: Sample RGBA sprite from all four channels
 	//    001, 011, 101, 111: Sample paletted sprite from channel R,G,B,A
 
+	float secondarySampler = 0.0;
+	if (x >= 2048.0) { x -= 2048.0;  secondarySampler += 4.0; }
+	if (x >= 1024.0) { x -= 1024.0;  secondarySampler += 2.0; }
+	if (x >= 512.0) { x -= 512.0;  secondarySampler += 1.0; }
+
+	float primarySampler = 0.0;
+	if (x >= 256.0) { x -= 256.0;  primarySampler += 4.0; }
+	if (x >= 128.0) { x -= 128.0;  primarySampler += 2.0; }
+	if (x >= 64.0) { x -= 64.0;  primarySampler += 1.0; }
+
 	float secondaryChannel = 0.0;
 	if (x >= 32.0) { x -= 32.0;  secondaryChannel += 4.0; }
 	if (x >= 16.0) { x -= 16.0;  secondaryChannel += 2.0; }
@@ -36,7 +49,7 @@ vec2 UnpackChannelAttributes(float x)
 	if (x >= 2.0) { x -= 2.0;  primaryChannel += 2.0; }
 	if (x >= 1.0) { x -= 1.0;  primaryChannel += 1.0; }
 
-	return vec2(primaryChannel, secondaryChannel);
+	return vec4(primaryChannel, secondaryChannel, primarySampler, secondarySampler);
 }
 
 vec4 SelectChannelMask(float x)
@@ -85,10 +98,11 @@ void main()
 	vTexCoord = aVertexTexCoord;
 	vTexMetadata = aVertexTexMetadata;
 	
-	vec2 attrib = UnpackChannelAttributes(aVertexTexMetadata.t);
+	vec4 attrib = UnpackChannelAttributes(aVertexTexMetadata.t);
 	vChannelMask = SelectChannelMask(attrib.s);
 	vColorFraction = SelectColorFraction(attrib.s);
 	vRGBAFraction = SelectRGBAFraction(attrib.s);
 	vPalettedFraction = SelectPalettedFraction(attrib.s);
 	vDepthMask = SelectChannelMask(attrib.t);
+	vTexSampler = attrib.pq;
 }