3 textures blending fix for OpenGL.

Engine/source/terrain/glsl/terrFeatureGLSL.cpp

@@ -458,7 +458,7 @@ void TerrainDetailMapFeatGLSL::processPix(   Vector<ShaderComponent*> &component
    }
 
    // Add to the blend total.
-   meta->addStatement( new GenOp( "   @ = max( @, @ );\r\n", blendTotal, blendTotal, detailBlend ) );
+   meta->addStatement( new GenOp( "   @ += @;\r\n", blendTotal, detailBlend ) );
 
    // If we had a parallax feature... then factor in the parallax
    // amount so that it fades out with the layer blending.

Templates/Empty/game/shaders/common/terrain/terrain.glsl

@@ -32,10 +32,12 @@ float calcBlend( float texId, vec2 layerCoord, float layerSize, vec4 layerSample
    vec4 diff = clamp( abs( layerSample - texId ), 0.0, 1.0 );
    float noBlend = float(any( bvec4(1 - diff) ));
 
-   // Use step to see if any of the layer samples 
    // match the current texture id.
-   vec4 factors = step( texId, layerSample );
-
+   vec4 factors = vec4(0);
+   for(int i = 0; i < 4; i++)
+      if(layerSample[i] == texId)
+         factors[i] = 1;
+ 
    // This is a custom bilinear filter.
 
    vec2 uv = layerCoord * layerSize;

Templates/Full/game/shaders/common/terrain/terrain.glsl

@@ -32,10 +32,12 @@ float calcBlend( float texId, vec2 layerCoord, float layerSize, vec4 layerSample
    vec4 diff = clamp( abs( layerSample - texId ), 0.0, 1.0 );
    float noBlend = float(any( bvec4(1 - diff) ));
 
-   // Use step to see if any of the layer samples 
    // match the current texture id.
-   vec4 factors = step( texId, layerSample );
-
+   vec4 factors = vec4(0);
+   for(int i = 0; i < 4; i++)
+      if(layerSample[i] == texId)
+         factors[i] = 1;
+ 
    // This is a custom bilinear filter.
 
    vec2 uv = layerCoord * layerSize;