Renderer|Refactor: Added tangentspace.glsl; moved lighting functions

Doomsday will now define the symbols DENG_VERTEX_SHADER or
DENG_FRAGMENT_SHADER when it compiles vertex and fragment shaders.
This allows the included GLSL files to adapt their behavior accordingly.

doomsday/apps/client/net.dengine.client.pack/renderer.pack/shaders/include/lighting.glsl

@@ -23,10 +23,28 @@ uniform highp float uEmission; // factor for emissive light
 uniform highp vec4 uAmbientLight;
 uniform highp vec4 uLightIntensities[4];        
 uniform highp vec3 uLightDirs[4];
+uniform highp vec3 uEyePos;
 
 varying highp vec3 vLightDirs[4]; // tangent space
 varying highp vec3 vEyeDir;       // tangent space
 
+#ifdef DENG_VERTEX_SHADER
+
+void calculateSurfaceLighting(highp mat3 surface)
+{
+    vLightDirs[0] = uLightDirs[0] * surface;
+    vLightDirs[1] = uLightDirs[1] * surface;
+    vLightDirs[2] = uLightDirs[2] * surface;
+    vLightDirs[3] = uLightDirs[3] * surface;
+}
+
+void calculateEyeDirection(highp vec4 vertex, highp mat3 surface)
+{
+    vEyeDir = (uEyePos - vertex.xyz/vertex.w) * surface;    
+}
+
+#endif // DENG_VERTEX_SHADER
+
 highp vec4 diffuseLightContrib(int index, highp vec3 normal) 
 {
     if(uLightIntensities[index].a <= 0.001) 

doomsday/apps/client/net.dengine.client.pack/renderer.pack/shaders/include/tangentspace.glsl

@@ -0,0 +1,36 @@
+/*
+ * The Doomsday Engine Project
+ * Common OpenGL Shaders: Tangent space
+ *
+ * Copyright (c) 2015 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * LGPL: http://www.gnu.org/licenses/lgpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+ * General Public License for more details. You should have received a copy of
+ * the GNU Lesser General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small>
+ */
+
+attribute highp vec3 aNormal;
+attribute highp vec3 aTangent;
+attribute highp vec3 aBitangent;
+
+highp vec3 transformVector(highp vec3 dir, highp mat4 matrix) 
+{
+    return (matrix * vec4(dir, 0.0)).xyz;
+}
+
+highp mat3 tangentSpace(highp mat4 modelSpace)
+{
+    highp vec3 normal    = transformVector(aNormal, modelSpace);
+    highp vec3 tangent   = transformVector(aTangent, modelSpace);
+    highp vec3 bitangent = transformVector(aBitangent, modelSpace);
+    return mat3(tangent, bitangent, normal);    
+}

doomsday/apps/client/net.dengine.client.pack/renderer.pack/shaders/model.dei

@@ -1,24 +1,21 @@
-model {
+model.skeletal {
     # Shader for skeletal animation and generic per-pixel lighting:
     # diffuse color, normal map, emission map, specular intensity.
-    shader skeletal.normal_specular_emission {
+    shader normal_specular_emission {
         variable uAlpha      { value = 1 }
         variable uAlphaLimit { value = 0 }
         variable uEmission   { value = 0 }
 
         # Mapping when used with ModelDrawable.
         textureMapping <diffuse, normals, specular, emission>
 
-        include.vertex <include/skeletal.glsl,
+        include.vertex <include/tangentspace.glsl,
+                        include/skeletal.glsl,
                         include/lighting.glsl>
         vertex = "
             uniform highp mat4 uMvpMatrix;
-            uniform highp vec3 uEyePos;
 
             attribute highp vec4 aVertex;
-            attribute highp vec3 aNormal;
-            attribute highp vec3 aTangent;
-            attribute highp vec3 aBitangent;
             attribute highp vec2 aUV;
             attribute highp vec4 aBounds;   // diffuse map
             attribute highp vec4 aBounds2;  // normal map
@@ -28,33 +25,18 @@ model {
             varying highp vec2 vUV;
             varying highp vec4 vUVBounds[4];
 
-            highp vec3 transformVector(highp vec3 dir, highp mat4 matrix) 
-            {
-                return (matrix * vec4(dir, 0.0)).xyz;
-            }
-
             void main(void) 
             {
                 highp mat4 bone = vertexBoneTransform();
+                highp mat3 surface = tangentSpace(bone);
+                calculateSurfaceLighting(surface);
 
                 // Vertex position.
                 highp vec4 modelPos = bone * aVertex;
                 gl_Position = uMvpMatrix * modelPos;
-
-                // Tangent space.
-                highp vec3 normal       = transformVector(aNormal, bone);
-                highp vec3 tangent      = transformVector(aTangent, bone);
-                highp vec3 bitangent    = transformVector(aBitangent, bone);
-                highp mat3 tangentSpace = mat3(tangent, bitangent, normal);
-
-                // Light direction in tangent space.
-                vLightDirs[0] = uLightDirs[0] * tangentSpace;
-                vLightDirs[1] = uLightDirs[1] * tangentSpace;
-                vLightDirs[2] = uLightDirs[2] * tangentSpace;
-                vLightDirs[3] = uLightDirs[3] * tangentSpace;
-
+
                 // Eye direction in tangent space.
-                vEyeDir = (uEyePos - modelPos.xyz/modelPos.w) * tangentSpace;
+                calculateEyeDirection(modelPos, surface);
 
                 vUV = aUV;
                 vUVBounds[0] = aBounds;

doomsday/sdk/libgui/src/graphics/glshader.cpp

@@ -13,7 +13,7 @@
  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
  * General Public License for more details. You should have received a copy of
  * the GNU Lesser General Public License along with this program; if not, see:
- * http://www.gnu.org/licenses</small> 
+ * http://www.gnu.org/licenses</small>
  */
 
 #include "de/GLShader"
@@ -141,9 +141,20 @@ void GLShader::compile(Type shaderType, IByteArray const &source)
     d->type = shaderType;
     d->alloc();
 
+    // Additional predefined symbols for the shader.
+    QByteArray predefs;
+    if(shaderType == Vertex)
+    {
+        predefs = QByteArray("#define DENG_VERTEX_SHADER\n");
+    }
+    else
+    {
+        predefs = QByteArray("#define DENG_FRAGMENT_SHADER\n");
+    }
+
     // Prepare the shader source. This would be the time to substitute any
     // remaining symbols in the shader source.
-    Block src = prefixToSource(source, prefix);
+    Block src = prefixToSource(source, prefix + predefs);
 
     char const *srcPtr = src.constData();
     glShaderSource(d->name, 1, &srcPtr, 0);