From 978b548c64f990dec483426ec89405566a993f66 Mon Sep 17 00:00:00 2001
From: Maciej Suminski <maciej.suminski@cern.ch>
Date: Mon, 24 Jun 2013 15:40:31 +0200
Subject: [PATCH] Small improvements to SHADER class.

---
 common/gal/opengl/shader.cpp | 31 ++++++++++---------------------
 include/gal/opengl/shader.h  | 34 +++++++++++++++++++++++++++-------
 2 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/common/gal/opengl/shader.cpp b/common/gal/opengl/shader.cpp
index 6cbd84850d..83eab3d2a7 100644
--- a/common/gal/opengl/shader.cpp
+++ b/common/gal/opengl/shader.cpp
@@ -35,13 +35,14 @@
 
 using namespace KiGfx;
 
-SHADER::SHADER()
+SHADER::SHADER() :
+        isProgramCreated( false ),
+        isShaderLinked( false ),
+        maximumVertices( 4 ),
+        active( false ),
+        geomInputType( GL_LINES ),
+        geomOutputType( GL_LINES )
 {
-    isProgramCreated    = false;
-    isShaderLinked      = false;
-    maximumVertices     = 4;
-    geomInputType       = GL_LINES;
-    geomOutputType      = GL_LINES;
 }
 
 
@@ -108,7 +109,7 @@ std::string SHADER::ReadSource( std::string aShaderSourceName )
 }
 
 
-void SHADER::AddSource( std::string aShaderSourceName, ShaderType aShaderType )
+void SHADER::AddSource( const std::string& aShaderSourceName, ShaderType aShaderType )
 {
     if( isShaderLinked )
     {
@@ -195,19 +196,7 @@ bool SHADER::Link()
 }
 
 
-void SHADER::Use()
-{
-    glUseProgram( programNumber );
-}
-
-
-void SHADER::Deactivate()
-{
-    glUseProgram( 0 );
-}
-
-
-void SHADER::AddParameter( std::string aParameterName )
+void SHADER::AddParameter( const std::string& aParameterName )
 {
     GLint location = glGetUniformLocation( programNumber, aParameterName.c_str() );
 
@@ -224,7 +213,7 @@ void SHADER::SetParameter( int parameterNumber, float value )
 }
 
 
-int SHADER::GetAttribute( std::string aAttributeName )
+int SHADER::GetAttribute( std::string aAttributeName ) const
 {
     return glGetAttribLocation( programNumber, aAttributeName.c_str() );
 }
diff --git a/include/gal/opengl/shader.h b/include/gal/opengl/shader.h
index 71fa03109f..115fa02e49 100644
--- a/include/gal/opengl/shader.h
+++ b/include/gal/opengl/shader.h
@@ -76,23 +76,42 @@ public:
      * @param aShaderSourceName is the shader source file name.
      * @param aShaderType is the type of the shader.
      */
-    void AddSource( std::string aShaderSourceName, ShaderType aShaderType );
+    void AddSource( const std::string& aShaderSourceName, ShaderType aShaderType );
 
     /**
-     * Link the shaders.
+     * @brief Link the shaders.
+     *
      * @return true in case of success, false otherwise.
      */
     bool Link();
 
     /**
-     * Use the shader.
+     * @brief Use the shader.
      */
-    void Use();
+    inline void Use()
+    {
+        glUseProgram( programNumber );
+        active = true;
+    }
 
     /**
      * @brief Deactivate the shader and use the default OpenGL program.
      */
-    void Deactivate();
+    inline void Deactivate()
+    {
+        glUseProgram( 0 );
+        active = false;
+    }
+
+    /**
+     * @brief Returns the current state of the shader.
+     *
+     * @return True if any of shaders is enabled.
+     */
+    inline bool IsActive() const
+    {
+        return active;
+    }
 
     /**
      * @brief Configure the geometry shader - has to be done before linking!
@@ -113,7 +132,7 @@ public:
      *
      * @param aParameterName is the name of the parameter.
      */
-    void AddParameter( std::string aParameterName );
+    void AddParameter( const std::string& aParameterName );
 
     /**
      * @brief Set a parameter of the shader.
@@ -129,7 +148,7 @@ public:
      * @param aAttributeName is the name of the attribute.
      * @return the location.
      */
-    int GetAttribute( std::string aAttributeName );
+    int GetAttribute( std::string aAttributeName ) const;
 
 private:
 
@@ -152,6 +171,7 @@ private:
     GLuint              programNumber;      ///< Shader program number
     bool                isProgramCreated;   ///< Flag for program creation
     bool                isShaderLinked;     ///< Is the shader linked?
+    bool                active;             ///< Is any of shaders used?
     GLuint              maximumVertices;    ///< The maximum of vertices to be generated
     GLuint              geomInputType;      ///< Input type [e.g. GL_LINES, GL_TRIANGLES, GL_QUADS etc.]
     GLuint              geomOutputType;     ///< Output type [e.g. GL_LINES, GL_TRIANGLES, GL_QUADS etc.]