Fixed gl_FragCoord.y calculation

src/common/version.h

 #define MAJOR_VERSION 1
 #define MINOR_VERSION 0
 #define BUILD_VERSION 0
-#define BUILD_REVISION 924
+#define BUILD_REVISION 925
 
 #define STRINGIFY(x) #x
 #define MACRO_STRINGIFY(x) STRINGIFY(x)

src/compiler/OutputHLSL.cpp

@@ -188,7 +188,7 @@ void OutputHLSL::header()
 
         if (mUsesFragCoord)
         {
-            out << "uniform float4 dx_Viewport;\n"
+            out << "uniform float4 dx_Coord;\n"
                    "uniform float2 dx_Depth;\n";
         }
 

src/libGLESv2/Context.cpp

@@ -1798,11 +1798,13 @@ bool Context::applyRenderTarget(bool ignoreViewport)
         GLfloat xy[2] = {1.0f / viewport.Width, -1.0f / viewport.Height};
         programObject->setUniform2fv(halfPixelSize, 1, xy);
 
-        GLint viewport = programObject->getDxViewportLocation();
-        GLfloat whxy[4] = {mState.viewportWidth / 2.0f, mState.viewportHeight / 2.0f, 
+        // These values are used for computing gl_FragCoord in Program::linkVaryings(). The approach depends on Shader Model 3.0 support.
+        GLint coord = programObject->getDxCoordLocation();
+        float h = mSupportsShaderModel3 ? mRenderTargetDesc.Height : mState.viewportHeight / 2.0f;
+        GLfloat whxy[4] = {mState.viewportWidth / 2.0f, h, 
                           (float)mState.viewportX + mState.viewportWidth / 2.0f, 
                           (float)mState.viewportY + mState.viewportHeight / 2.0f};
-        programObject->setUniform4fv(viewport, 1, whxy);
+        programObject->setUniform4fv(coord, 1, whxy);
 
         GLint depth = programObject->getDxDepthLocation();
         GLfloat dz[2] = {(zFar - zNear) / 2.0f, (zNear + zFar) / 2.0f};

src/libGLESv2/Context.h

@@ -65,7 +65,7 @@ enum
     MAX_TEXTURE_IMAGE_UNITS = 16,
     MAX_VERTEX_TEXTURE_IMAGE_UNITS_VTF = 4,   // For devices supporting vertex texture fetch
     MAX_COMBINED_TEXTURE_IMAGE_UNITS_VTF = MAX_TEXTURE_IMAGE_UNITS + MAX_VERTEX_TEXTURE_IMAGE_UNITS_VTF,    
-    MAX_FRAGMENT_UNIFORM_VECTORS_SM2 = 32 - 3,    // Reserve space for dx_Viewport, dx_Depth, and dx_DepthRange. dx_PointOrLines and dx_FrontCCW use separate bool registers.
+    MAX_FRAGMENT_UNIFORM_VECTORS_SM2 = 32 - 3,    // Reserve space for dx_Coord, dx_Depth, and dx_DepthRange. dx_PointOrLines and dx_FrontCCW use separate bool registers.
     MAX_FRAGMENT_UNIFORM_VECTORS_SM3 = 224 - 3,
     MAX_DRAW_BUFFERS = 1,
 

src/libGLESv2/Program.cpp

@@ -1600,13 +1600,20 @@ bool Program::linkVaryings()
     if (mFragmentShader->mUsesFragCoord)
     {
         mPixelHLSL += "    float rhw = 1.0 / input.gl_FragCoord.w;\n";
-        if (sm3) {
+        
+        if (sm3)
+        {
+            // dx_Coord.y contains the render target height. See Context::applyRenderTarget()
             mPixelHLSL += "    gl_FragCoord.x = input.dx_VPos.x + 0.5;\n"
-                          "    gl_FragCoord.y = 2.0 * dx_Viewport.y - input.dx_VPos.y - 0.5;\n";
-        } else {
-            mPixelHLSL += "    gl_FragCoord.x = (input.gl_FragCoord.x * rhw) * dx_Viewport.x + dx_Viewport.z;\n"
-                          "    gl_FragCoord.y = -(input.gl_FragCoord.y * rhw) * dx_Viewport.y + dx_Viewport.w;\n";
+                          "    gl_FragCoord.y = dx_Coord.y - input.dx_VPos.y - 0.5;\n";
+        }
+        else
+        {
+            // dx_Coord contains the viewport width/2, height/2, center.x and center.y. See Context::applyRenderTarget()
+            mPixelHLSL += "    gl_FragCoord.x = (input.gl_FragCoord.x * rhw) * dx_Coord.x + dx_Coord.z;\n"
+                          "    gl_FragCoord.y = -(input.gl_FragCoord.y * rhw) * dx_Coord.y + dx_Coord.w;\n";
         }
+        
         mPixelHLSL += "    gl_FragCoord.z = (input.gl_FragCoord.z * rhw) * dx_Depth.x + dx_Depth.y;\n"
                       "    gl_FragCoord.w = rhw;\n";
     }
@@ -1732,7 +1739,7 @@ void Program::link()
             // are reserved prefixes, and do not receive additional decoration
             mDxDepthRangeLocation = getUniformLocation("dx_DepthRange");
             mDxDepthLocation = getUniformLocation("dx_Depth");
-            mDxViewportLocation = getUniformLocation("dx_Viewport");
+            mDxCoordLocation = getUniformLocation("dx_Coord");
             mDxHalfPixelSizeLocation = getUniformLocation("dx_HalfPixelSize");
             mDxFrontCCWLocation = getUniformLocation("dx_FrontCCW");
             mDxPointsOrLinesLocation = getUniformLocation("dx_PointsOrLines");
@@ -2420,7 +2427,7 @@ void Program::unlink(bool destroy)
 
     mDxDepthRangeLocation = -1;
     mDxDepthLocation = -1;
-    mDxViewportLocation = -1;
+    mDxCoordLocation = -1;
     mDxHalfPixelSizeLocation = -1;
     mDxFrontCCWLocation = -1;
     mDxPointsOrLinesLocation = -1;
@@ -2841,9 +2848,9 @@ GLint Program::getDxDepthLocation() const
     return mDxDepthLocation;
 }
 
-GLint Program::getDxViewportLocation() const
+GLint Program::getDxCoordLocation() const
 {
-    return mDxViewportLocation;
+    return mDxCoordLocation;
 }
 
 GLint Program::getDxHalfPixelSizeLocation() const

src/libGLESv2/Program.h

@@ -103,7 +103,7 @@ class Program
 
     GLint getDxDepthRangeLocation() const;
     GLint getDxDepthLocation() const;
-    GLint getDxViewportLocation() const;
+    GLint getDxCoordLocation() const;
     GLint getDxHalfPixelSizeLocation() const;
     GLint getDxFrontCCWLocation() const;
     GLint getDxPointsOrLinesLocation() const;
@@ -207,7 +207,7 @@ class Program
 
     GLint mDxDepthRangeLocation;
     GLint mDxDepthLocation;
-    GLint mDxViewportLocation;
+    GLint mDxCoordLocation;
     GLint mDxHalfPixelSizeLocation;
     GLint mDxFrontCCWLocation;
     GLint mDxPointsOrLinesLocation;