Using ARB_explicit_uniform_location in shaders.

The backwards compatibility fully kills the purpose, but at least I can
test the feature somewhere :-)

src/Shaders/FlatShader.cpp

@@ -65,8 +65,14 @@ template<std::uint8_t dimensions> FlatShader<dimensions>::FlatShader() {
 
     link();
 
-    transformationProjectionMatrixUniform = uniformLocation("transformationProjectionMatrix");
-    colorUniform = uniformLocation("color");
+    #ifndef MAGNUM_TARGET_GLES
+    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::explicit_uniform_location>()) {
+    #else
+    {
+    #endif
+        transformationProjectionMatrixUniform = uniformLocation("transformationProjectionMatrix");
+        colorUniform = uniformLocation("color");
+    }
 }
 
 template class FlatShader<2>;

src/Shaders/FlatShader.h

@@ -61,8 +61,8 @@ template<std::uint8_t dimensions> class MAGNUM_SHADERS_EXPORT FlatShader: public
         }
 
     private:
-        GLint transformationProjectionMatrixUniform,
-            colorUniform;
+        GLint transformationProjectionMatrixUniform = 0,
+            colorUniform = 1;
 };
 
 /** @brief 2D flat shader */

src/Shaders/FlatShader2D.frag

@@ -2,7 +2,11 @@
 #define fragmentColor gl_FragColor
 #endif
 
+#ifdef EXPLICIT_UNIFORM_LOCATION
+layout(location = 1) uniform vec3 color;
+#else
 uniform lowp vec3 color;
+#endif
 
 #ifdef NEW_GLSL
 out lowp vec4 fragmentColor;

src/Shaders/FlatShader2D.vert

@@ -2,7 +2,11 @@
 #define in attribute
 #endif
 
+#ifdef EXPLICIT_UNIFORM_LOCATION
+layout(location = 0) uniform mat3 transformationProjectionMatrix;
+#else
 uniform highp mat3 transformationProjectionMatrix;
+#endif
 
 #ifdef EXPLICIT_ATTRIB_LOCATION
 layout(location = 0) in highp vec3 position;

src/Shaders/PhongShader.cpp

@@ -52,15 +52,21 @@ PhongShader::PhongShader() {
 
     link();
 
-    ambientColorUniform = uniformLocation("ambientColor");
-    diffuseColorUniform = uniformLocation("diffuseColor");
-    specularColorUniform = uniformLocation("specularColor");
-    shininessUniform = uniformLocation("shininess");
-    transformationMatrixUniform = uniformLocation("transformationMatrix");
-    projectionMatrixUniform = uniformLocation("projectionMatrix");
-    normalMatrixUniform = uniformLocation("normalMatrix");
-    lightUniform = uniformLocation("light");
-    lightColorUniform = uniformLocation("lightColor");
+    #ifndef MAGNUM_TARGET_GLES
+    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::explicit_uniform_location>()) {
+    #else
+    {
+    #endif
+        transformationMatrixUniform = uniformLocation("transformationMatrix");
+        projectionMatrixUniform = uniformLocation("projectionMatrix");
+        normalMatrixUniform = uniformLocation("normalMatrix");
+        lightUniform = uniformLocation("light");
+        diffuseColorUniform = uniformLocation("diffuseColor");
+        ambientColorUniform = uniformLocation("ambientColor");
+        specularColorUniform = uniformLocation("specularColor");
+        lightColorUniform = uniformLocation("lightColor");
+        shininessUniform = uniformLocation("shininess");
+    }
 
     /* Set defaults in OpenGL ES (for desktop they are set in shader code itself) */
     #ifdef MAGNUM_TARGET_GLES

src/Shaders/PhongShader.frag

@@ -3,13 +3,22 @@
 #define color gl_FragColor
 #endif
 
-uniform lowp vec3 diffuseColor;
 #ifndef GL_ES
-uniform lowp vec3 ambientColor = vec3(0.0, 0.0, 0.0);
-uniform lowp vec3 specularColor = vec3(1.0, 1.0, 1.0);
-uniform lowp vec3 lightColor = vec3(1.0, 1.0, 1.0);
-uniform mediump float shininess = 80.0;
+#ifdef EXPLICIT_UNIFORM_LOCATION
+layout(location = 4) uniform vec3 diffuseColor;
+layout(location = 5) uniform vec3 ambientColor = vec3(0.0, 0.0, 0.0);
+layout(location = 6) uniform vec3 specularColor = vec3(1.0, 1.0, 1.0);
+layout(location = 7) uniform vec3 lightColor = vec3(1.0, 1.0, 1.0);
+layout(location = 8) uniform float shininess = 80.0;
+#else
+uniform vec3 diffuseColor;
+uniform vec3 ambientColor = vec3(0.0, 0.0, 0.0);
+uniform vec3 specularColor = vec3(1.0, 1.0, 1.0);
+uniform vec3 lightColor = vec3(1.0, 1.0, 1.0);
+uniform float shininess = 80.0;
+#endif
 #else
+uniform lowp vec3 diffuseColor;
 uniform lowp vec3 ambientColor;
 uniform lowp vec3 specularColor;
 uniform lowp vec3 lightColor;

src/Shaders/PhongShader.h

@@ -123,15 +123,15 @@ class MAGNUM_SHADERS_EXPORT PhongShader: public AbstractShaderProgram {
         }
 
     private:
-        GLint ambientColorUniform,
-            diffuseColorUniform,
-            specularColorUniform,
-            shininessUniform,
-            transformationMatrixUniform,
-            projectionMatrixUniform,
-            normalMatrixUniform,
-            lightUniform,
-            lightColorUniform;
+        GLint transformationMatrixUniform = 0,
+            projectionMatrixUniform = 1,
+            normalMatrixUniform = 2,
+            lightUniform = 3,
+            diffuseColorUniform = 4,
+            ambientColorUniform = 5,
+            specularColorUniform = 6,
+            lightColorUniform = 7,
+            shininessUniform = 8;
 };
 
 }}

src/Shaders/PhongShader.vert

@@ -3,10 +3,17 @@
 #define out varying
 #endif
 
+#ifdef EXPLICIT_UNIFORM_LOCATION
+layout(location = 0) uniform mat4 transformationMatrix;
+layout(location = 1) uniform mat4 projectionMatrix;
+layout(location = 2) uniform mat3 normalMatrix;
+layout(location = 3) uniform vec3 light;
+#else
 uniform highp mat4 transformationMatrix;
 uniform highp mat4 projectionMatrix;
 uniform mediump mat3 normalMatrix;
 uniform highp vec3 light;
+#endif
 
 #ifdef EXPLICIT_ATTRIB_LOCATION
 layout(location = 0) in highp vec4 position;

src/Shaders/VertexColorShader.cpp

@@ -66,7 +66,13 @@ template<std::uint8_t dimensions> VertexColorShader<dimensions>::VertexColorShad
 
     link();
 
-    transformationProjectionMatrixUniform = uniformLocation("transformationProjectionMatrix");
+    #ifndef MAGNUM_TARGET_GLES
+    if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::explicit_uniform_location>()) {
+    #else
+    {
+    #endif
+        transformationProjectionMatrixUniform = uniformLocation("transformationProjectionMatrix");
+    }
 }
 
 template class VertexColorShader<2>;

src/Shaders/VertexColorShader.h

@@ -55,7 +55,7 @@ template<std::uint8_t dimensions> class MAGNUM_SHADERS_EXPORT VertexColorShader:
         }
 
     private:
-        GLint transformationProjectionMatrixUniform;
+        GLint transformationProjectionMatrixUniform = 0;
 };
 
 /** @brief 2D vertex color shader */

src/Shaders/VertexColorShader2D.vert

@@ -3,7 +3,11 @@
 #define out varying
 #endif
 
+#ifdef EXPLICIT_UNIFORM_LOCATION
+layout(location = 0) uniform mat3 transformationProjectionMatrix;
+#else
 uniform highp mat3 transformationProjectionMatrix;
+#endif
 
 #ifdef EXPLICIT_ATTRIB_LOCATION
 layout(location = 0) in highp vec3 position;

src/Shaders/compatibility.glsl

@@ -4,13 +4,22 @@
 
 /* On NVidia and GLSL 1.20 layout qualifiers result in parsing error, even if
    the extension is defined as supported */
-#if !defined(GL_ES) && __VERSION__ >= 120 && defined(GL_ARB_explicit_attrib_location)
-#extension GL_ARB_explicit_attrib_location: enable
-#define EXPLICIT_ATTRIB_LOCATION
+#if !defined(GL_ES) && __VERSION__ >= 120
+
+#ifdef GL_ARB_explicit_attrib_location
+    #extension GL_ARB_explicit_attrib_location: enable
+    #define EXPLICIT_ATTRIB_LOCATION
+#endif
+#ifdef GL_ARB_explicit_uniform_location
+    #extension GL_ARB_explicit_uniform_location: enable
+    #define EXPLICIT_UNIFORM_LOCATION
+#endif
+
 #endif
 
 #if defined(GL_ES) && __VERSION__ >= 300
 #define EXPLICIT_ATTRIB_LOCATION
+/* EXPLICIT_UNIFORM_LOCATION is not available in OpenGL ES */
 #endif
 
 /* Precision qualifiers are not supported in GLSL 1.20 */