From b37a34219d0d5bd02fa11b7d046616e83c500e49 Mon Sep 17 00:00:00 2001
From: Eduardo Bart <edub4rt@gmail.com>
Date: Wed, 7 Dec 2011 00:09:44 -0200
Subject: [PATCH] fix shaders for OpenGL ES

---
 src/framework/graphics/paintershadersources.h | 15 ++++++---------
 src/framework/graphics/shader.cpp             | 16 +++++++++++++++-
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/src/framework/graphics/paintershadersources.h b/src/framework/graphics/paintershadersources.h
index 667d35ca..1e5d06a7 100644
--- a/src/framework/graphics/paintershadersources.h
+++ b/src/framework/graphics/paintershadersources.h
@@ -30,7 +30,7 @@ static int OPACITY_UNIFORM = 3;
 static int TEXTURE_UNIFORM = 4;
 
 static const std::string glslMainVertexShader = "\n\
-    vec4 calculatePosition();\n\
+    highp vec4 calculatePosition();\n\
     void main() {\n\
         gl_Position = calculatePosition();\n\
     }\n";
@@ -54,26 +54,23 @@ static std::string glslPositionOnlyVertexShader = "\n\
     }\n";
 
 static const std::string glslMainFragmentShader = "\n\
-    precision lowp vec4;\n\
-    precision lowp float;\n\
-    uniform float opacity;\n\
-    vec4 calculatePixel();\n\
+    uniform lowp float opacity;\n\
+    lowp vec4 calculatePixel();\n\
     void main()\n\
     {\n\
         gl_FragColor = calculatePixel() * opacity;\n\
     }\n";
 
 static const std::string glslTextureSrcFragmentShader = "\n\
-    precision mediump vec2;\n\
-    varying vec2 textureCoords;\n\
-    uniform vec4 color;\n\
+    varying mediump vec2 textureCoords;\n\
+    uniform lowp vec4 color;\n\
     uniform sampler2D texture;\n\
     vec4 calculatePixel() {\n\
         return texture2D(texture, textureCoords) * color;\n\
     }\n";
 
 static const std::string glslSolidColorFragmentShader = "\n\
-    uniform vec4 color;\n\
+    uniform lowp vec4 color;\n\
     vec4 calculatePixel() {\n\
         return color;\n\
     }\n";
diff --git a/src/framework/graphics/shader.cpp b/src/framework/graphics/shader.cpp
index 328ae81c..34503202 100644
--- a/src/framework/graphics/shader.cpp
+++ b/src/framework/graphics/shader.cpp
@@ -45,7 +45,21 @@ Shader::~Shader()
 
 bool Shader::compileSourceCode(const std::string& sourceCode)
 {
-    const char *c_source = sourceCode.c_str();
+#ifndef OPENGL_ES2
+    static const char *qualifierDefines =
+        "#define lowp\n"
+        "#define mediump\n"
+        "#define highp\n";
+#else
+    static const char *qualifierDefines =
+        "#ifndef GL_FRAGMENT_PRECISION_HIGH\n"
+        "#define highp mediump\n"
+        "#endif\n";
+#endif
+
+    std::string code = qualifierDefines;
+    code.append(sourceCode);
+    const char *c_source = code.c_str();
     glShaderSource(m_shaderId, 1, &c_source, NULL);
     glCompileShader(m_shaderId);