gls_state_manager_es20_interface.h

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/*! \file
  \brief IGlsStateManager, interface to a state manager that manages the GL Studio
runtime library's use of the OpenGL context, minimizing unnecessary state changes.
 
  \par Copyright Information
 
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*/
 
#ifndef DISTI_GLS_STATE_MANAGER_ES20_INTERFACE_H_INCLUDED
#define DISTI_GLS_STATE_MANAGER_ES20_INTERFACE_H_INCLUDED
 
#include "gls_state_manager_interface.h"
 
#include "gls_es20_effect.h"
#include "gls_es20_effect_params.h"
 
/// The maximum number of lights, matching the fixed function pipeline.
#ifndef LESS_MAX_LIGHTS
#    define MAX_LIGHTS 8
#else
#    define MAX_LIGHTS 6
#endif
 
namespace disti
{
/** \interface IGlsStateManagerES20
  * The interface to a state manager that manages the GL Studio
  * runtime library's use of the OpenGL context, minimizing unnecessary state changes,
  * and has support for managing shaders.
  */
class IGlsStateManagerES20 : virtual public IGlsStateManager
{
public:
    /** Structure used to replicate the Fixed-Function lighting model */
    struct gl_LightSourceParameters
    {
        GLfloat _ambient[ 4 ];  ///< Ambient color RGBA
        GLfloat _diffuse[ 4 ];  ///< Diffuse color RGBA
        GLfloat _specular[ 4 ]; ///< Specular color RGBA
        GLfloat _position[ 4 ]; ///< Position XYZW
 
        GLfloat _spotDirection[ 3 ]; ///< Spotlight direction XYZ vector
 
        float _spotExponent; ///< Spotlight exponent
        float _spotCutoff;   ///< Spotlight cutoff in degrees
 
        float _constantAttenuation;  ///< Constant attenuation
        float _linearAttenuation;    ///< Linear attenuation
        float _quadraticAttenuation; ///< Quadratic attenuation
    };
 
    /// \return A reference to the top of the modelview matrix stack.
    GLS_EXPORT virtual GlsMatrixType& GetTopModelViewMatrix() = 0;
 
    /// \return A reference to the top of the projection matrix stack.
    GLS_EXPORT virtual GlsMatrixType& GetTopProjMatrix() = 0;
 
    ////////////////////////////////////////////////////////////////
    //
    // The following methods manage the various OpenGL state calls
    //
    ////////////////////////////////////////////////////////////////
 
    /// Enable or disable the tangent array vertex attribute.
    /// \param val The new state flag to set.
    GLS_EXPORT virtual void TangentArrayEnabled( bool val ) = 0;
 
    /// Enable or disable the binormal array vertex attribute.
    /// \param val The new state flag to set.
    GLS_EXPORT virtual void BinormalArrayEnabled( bool val ) = 0;
 
    /// Set the vertex attribute pointer (to underlying data) for the tangent array.
    /// \param type Must be GL_FLOAT.
    /// \param stride The stride in bytes between tangent elements in the vertex data.
    /// \param pointer The vertex data.
    GLS_EXPORT virtual void TangentPointer( GLenum type, GLsizei stride, const GLvoid* pointer ) = 0;
 
    /// Set the vertex attribute pointer (to underlying data) for the binormal array.
    /// \param type Must be GL_FLOAT.
    /// \param stride The stride in bytes between binormal elements in the vertex data.
    /// \param pointer The vertex data.
    GLS_EXPORT virtual void BinormalPointer( GLenum type, GLsizei stride, const GLvoid* pointer ) = 0;
 
    /// Set the alpha blend function separately for RGB and A channels.
    /// \param srcColor Function to use for source color.
    /// \param dstColor Function to use for destination color.
    /// \param srcAlpha Function to use for source alpha.
    /// \param dstAlpha Function to use for destination alpha.
    GLS_EXPORT virtual void AlphaBlendFuncSeparate( GLenum srcColor, GLenum dstColor, GLenum srcAlpha, GLenum dstAlpha ) = 0;
 
    /// Set the alpha blend function.
    /// \param src Function to use for source color.
    /// \param dst Function to use for destination color.
    GLS_EXPORT virtual void AlphaBlendFunc( GLenum src, GLenum dst ) = 0;
 
    /// Push the current alpha blend function on the stack.
    GLS_EXPORT virtual void PushAlphaBlendFunc() = 0;
 
    /// Pop the current alpha blend function off the stack.
    GLS_EXPORT virtual void PopAlphaBlendFunc() = 0;
 
    ////////////////////////////////////////////////////////////////
    //
    // The following methods manage the effects
    //
    ////////////////////////////////////////////////////////////////
 
    /// \return The light source paramters for the given light index.
    /// \param index The light index whose parameters are to be returned.
    GLS_EXPORT virtual gl_LightSourceParameters& GetLightSourceParameters( unsigned int index ) = 0;
 
    /** Enable the given custom shader program and push it to the top of the custom shader program stack
      * \param effect custom shader program
      * \param useProgramImmediately GL_TRUE if custom shader program should immediately be set as the active
      *                              shader program else GL_FALSE to allow the state manager to set the program
      *                              active when it is needed
      * \pre number of custom shader programs is < CUSTOM_SHADER_PROGRAM_STACK_DEPTH
      * \post the given custom shader program is at the top of the custom shader program stack and is enabled, it
      *       is set to the current active shader program if useProgramImmediately is GL_TRUE
      */
    GLS_EXPORT virtual void PushCustomShaderProgram( GlsEffect* effect, const GLboolean useProgramImmediately ) = 0;
 
    /** Pop the custom shader program stack enabling the next custom shader program on the stack if there is one
      * \pre number of custom shader programs is > 0
      * \post the custom shader program stack is popped enabling the next custom shader program on the stack if there is one
      */
    GLS_EXPORT virtual void PopCustomShaderProgram() = 0;
 
    /// \return True if there is at least one custom shader on the stack.
    GLS_EXPORT virtual bool HasCustomShader() const = 0;
 
    /** Select the appropriate shader program based on the current settings and update
      * the current shader program if needed
      * \param forceUpdate GL_TRUE to force uniforms to be updated as if shader program changed
      * \pre none
      * \post appropriate shader program based on the current settings is active
      */
    GLS_EXPORT virtual void UpdateShaderProgram( const GLboolean forceUpdate ) = 0;
 
    /** Update the attributes for the current shader as needed
      * \pre none
      * \post Appropriate attributes for the current shader are updated
      */
    GLS_EXPORT virtual void UpdateShaderAttributes() = 0;
 
    /** Update the uniforms for the current shader as needed
      * \pre none
      * \post Appropriate uniforms for the current shader are updated
      */
    GLS_EXPORT virtual void UpdateShaderUniforms() = 0;
 
protected:
    /** empty ctor */
    IGlsStateManagerES20() {}
 
    /** empty dtor */
    ~IGlsStateManagerES20() {}
};
 
} // namespace disti
 
#endif // DISTI_GLS_STATE_MANAGER_ES20_INTERFACE_H_INCLUDED