From 335bf720607baaa1511d7b1523f96b6ef92792d4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20Sumi=C5=84ski?= <maciej.suminski@cern.ch>
Date: Sun, 30 Jun 2013 15:37:46 +0200
Subject: [PATCH] More debug information in case of failure compilation of
 shaders.

---
 common/gal/opengl/opengl_gal.cpp | 12 +++++++++--
 common/gal/opengl/shader.cpp     | 36 +++++++++++++++++++++++++++++++-
 include/gal/opengl/shader.h      |  9 +++++++-
 3 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/common/gal/opengl/opengl_gal.cpp b/common/gal/opengl/opengl_gal.cpp
index 919e1c1282..b984655e13 100644
--- a/common/gal/opengl/opengl_gal.cpp
+++ b/common/gal/opengl/opengl_gal.cpp
@@ -359,8 +359,16 @@ void OPENGL_GAL::BeginDrawing()
     // Compile the shaders
     if( !isShaderInitialized && isUseShader )
     {
-        shader.AddSource( shaderPath + std::string( "/shader.vert" ), SHADER_TYPE_VERTEX );
-        shader.AddSource( shaderPath + std::string( "/shader.frag" ), SHADER_TYPE_FRAGMENT );
+        if( !shader.AddSource( shaderPath + std::string( "/shader.vert" ), SHADER_TYPE_VERTEX ) )
+        {
+        	wxLogFatalError( wxT( "Cannot compile vertex shader!" ) );
+        }
+
+        if( !shader.AddSource( shaderPath + std::string( "/shader.frag" ), SHADER_TYPE_FRAGMENT ) )
+        {
+        	wxLogFatalError( wxT( "Cannot compile fragment shader!" ) );
+        }
+
         if( !shader.Link() )
         {
             wxLogFatalError( wxT( "Cannot link the shaders!" ) );
diff --git a/common/gal/opengl/shader.cpp b/common/gal/opengl/shader.cpp
index 83eab3d2a7..8baf9f68c1 100644
--- a/common/gal/opengl/shader.cpp
+++ b/common/gal/opengl/shader.cpp
@@ -83,6 +83,27 @@ void SHADER::ProgramInfo( GLuint aProgram )
 }
 
 
+void SHADER::ShaderInfo( GLuint aShader )
+{
+    GLint glInfoLogLength = 0;
+    GLint writtenChars    = 0;
+
+    // Get the length of the info string
+    glGetShaderiv( aShader, GL_INFO_LOG_LENGTH, &glInfoLogLength );
+
+    // Print the information
+    if( glInfoLogLength > 2 )
+    {
+        GLchar* glInfoLog = new GLchar[glInfoLogLength];
+        glGetShaderInfoLog( aShader, glInfoLogLength, &writtenChars, glInfoLog );
+
+        wxLogInfo( wxString::FromUTF8( (char*) glInfoLog ) );
+
+        delete glInfoLog;
+    }
+}
+
+
 std::string SHADER::ReadSource( std::string aShaderSourceName )
 {
     // Open the shader source for reading
@@ -109,7 +130,7 @@ std::string SHADER::ReadSource( std::string aShaderSourceName )
 }
 
 
-void SHADER::AddSource( const std::string& aShaderSourceName, ShaderType aShaderType )
+bool SHADER::AddSource( const std::string& aShaderSourceName, ShaderType aShaderType )
 {
     if( isShaderLinked )
     {
@@ -144,6 +165,17 @@ void SHADER::AddSource( const std::string& aShaderSourceName, ShaderType aShader
 
     // Compile and attach shader to the program
     glCompileShader( shaderNumber );
+    GLint status;
+    glGetShaderiv( shaderNumber, GL_COMPILE_STATUS, &status );
+    if( status != GL_TRUE )
+    {
+    	wxLogError( wxT( "Shader compilation error" ) );
+
+    	ShaderInfo( shaderNumber );
+
+    	return false;
+    }
+
     glAttachShader( programNumber, shaderNumber );
     ProgramInfo( programNumber );
 
@@ -157,6 +189,8 @@ void SHADER::AddSource( const std::string& aShaderSourceName, ShaderType aShader
 
     // Delete the allocated char array
     delete[] source;
+
+    return true;
 }
 
 
diff --git a/include/gal/opengl/shader.h b/include/gal/opengl/shader.h
index 115fa02e49..f4804c3b66 100644
--- a/include/gal/opengl/shader.h
+++ b/include/gal/opengl/shader.h
@@ -76,7 +76,7 @@ public:
      * @param aShaderSourceName is the shader source file name.
      * @param aShaderType is the type of the shader.
      */
-    void AddSource( const std::string& aShaderSourceName, ShaderType aShaderType );
+    bool AddSource( const std::string& aShaderSourceName, ShaderType aShaderType );
 
     /**
      * @brief Link the shaders.
@@ -159,6 +159,13 @@ private:
      */
     void ProgramInfo( GLuint aProgram );
 
+    /**
+	 * @brief Get the shader information.
+	 *
+	 * @param aShader is the shader number.
+	 */
+	void ShaderInfo( GLuint aShader );
+
     /**
      * @brief Read the shader source file
      *