- safety check in msaa sample weight computation

- add msaa shaders

git-svn-id: http://www.openflipper.org/svnrepo/OpenFlipper/branches/Free@18437 383ad7c9-94d9-4d36-a494-682f7c89f535

Shaders/MSAA/msaa.glsl

+// methods for resolving multisampled textures
+
+
+vec4 ReadMultisampledTexture(in sampler2DMS tex, in ivec2 pos, in int numSamples)
+{
+  vec4 texel = vec4(0,0,0,0);
+  for (int i = 0; i < numSamples; ++i)
+  {
+	vec4 sample = texelFetch(tex, pos, i);
+	
+	texel += sample;
+  }
+  
+  return texel / float(numSamples);
+}
+
+vec4 ReadMultisampledTexture(in sampler2DMS tex, in vec2 texcood, in int numSamples)
+{
+  ivec2 pos = int(floor(texcoord));
+  return ReadMultisampledTexture(tex, pos, numSamples);
+}
+
+
+vec4 ReadMultisampledTexture(in sampler2DMS tex, in ivec2 pos, in int numSamples, in samplerBuffer filterWeights)
+{
+  vec4 texel = vec4(0,0,0,0);
+  for (int i = 0; i < numSamples; ++i)
+  {
+    float filterWeight = texelFetch(filterWeights, i).x;
+	vec4 sample = texelFetch(tex, pos, i);
+	
+	texel += filterWeight * sample;
+  }
+  
+  return texel;
+}
+
+vec4 ReadMultisampledTexture(in sampler2DMS tex, in vec2 texcood, in int numSamples, in samplerBuffer filterWeights)
+{
+  ivec2 pos = int(floor(texcoord));
+  return ReadMultisampledTexture(tex, pos, numSamples, filterWeights);
+}
+
+
+vec4 FilterMultisampledTextureBilinear(in sampler2DMS tex, in vec2 texcoord, in int numSamples)
+{
+  ivec2 texSize = textureSize(tex);
+  
+  // top-left texel position
+  vec2 pos00 = floor( texSize * texcoord );
+  ivec2 loc00 = ivec2(pos00);
+  
+  // lerp weights
+  vec2 alpha = fract( texSize * texcoord );
+
+  // bilinear filtering
+
+  // lerp in u-direction top
+  vec4 sampleX0 = mix(
+    ReadMultisampledTexture(tex, loc00, numSamples),
+    ReadMultisampledTexture(tex, loc00 + ivec2(1,0), numSamples),
+	alpha.x);
+			
+  // lerp in u-direction bottom
+  vec4 sampleX1 = mix(
+    ReadMultisampledTexture(tex, loc00 + ivec2(0,1), numSamples),
+    ReadMultisampledTexture(tex, loc00 + ivec2(1,1), numSamples),
+	alpha.x);
+  
+  // lerp in v direction
+  return mix(sampleX0, sampleX1, alpha.y);
+}
+
+
+vec4 FilterMultisampledTextureBilinear(in sampler2DMS tex, in vec2 texcoord, in int numSamples, in samplerBuffer filterWeights)
+{
+  ivec2 texSize = textureSize(tex);
+  
+  // top-left texel position
+  vec2 pos00 = floor( texSize * texcoord );
+  ivec2 loc00 = ivec2(pos00);
+  
+  // lerp weights
+  vec2 alpha = fract( texSize * texcoord );
+
+  // bilinear filtering
+
+  // lerp in u-direction top
+  vec4 sampleX0 = mix(
+    ReadMultisampledTexture(tex, loc00, numSamples, filterWeights),
+    ReadMultisampledTexture(tex, loc00 + ivec2(1,0), numSamples, filterWeights),
+	alpha.x);
+			
+  // lerp in u-direction bottom
+  vec4 sampleX1 = mix(
+    ReadMultisampledTexture(tex, loc00 + ivec2(0,1), numSamples, filterWeights),
+    ReadMultisampledTexture(tex, loc00 + ivec2(1,1), numSamples, filterWeights),
+	alpha.x);
+  
+  // lerp in v direction
+  return mix(sampleX0, sampleX1, alpha.y);
+}
\ No newline at end of file

Shaders/MSAA/sample_linear.glsl

+#version 150
+
+#include "msaa.glsl"
+
+
+uniform sampler2DMS inputTex;
+uniform int numSamples;
+
+in vec2 vTexCoord;
+out vec4 outFragment;
+
+
+void main()
+{
+  outFragment = FilterMultisampledTextureBilinear(inputTex, vTexCoord, numSamples);
+}
\ No newline at end of file

Shaders/MSAA/sample_nearest.glsl

+#version 150
+
+#include "msaa.glsl"
+
+
+uniform sampler2DMS inputTex;
+uniform int numSamples;
+
+in vec2 vTexCoord;
+out vec4 outFragment;
+
+
+void main()
+{
+  outFragment = ReadMultisampledTexture(inputTex, vTexCoord, numSamples);
+}
\ No newline at end of file