JUCE/modules/juce_opengl/opengl/juce_OpenGLShaderProgram.h

/*
  ==============================================================================

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-11 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE 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 General Public License for more details.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

  ==============================================================================
*/

#ifndef __JUCE_OPENGLSHADERPROGRAM_JUCEHEADER__
#define __JUCE_OPENGLSHADERPROGRAM_JUCEHEADER__

//==============================================================================
/**
    Manages an OpenGL shader program.
*/
class JUCE_API  OpenGLShaderProgram
{
public:
    OpenGLShaderProgram (const OpenGLContext& context) noexcept;
    ~OpenGLShaderProgram() noexcept;

    /** Returns the version of GLSL that the current context supports.
        E.g.
        @code
        if (OpenGLShaderProgram::getLanguageVersion() > 1.199)
        {
            // ..do something that requires GLSL 1.2 or above..
        }
        @endcode
    */
    static double getLanguageVersion();

    /** Compiles and adds a shader to this program.

        After adding all your shaders, remember to call link() to link them into
        a usable program.

        If your app is built in debug mode, this method will assert if the program
        fails to compile correctly.

        The shaderType parameter could be GL_VERTEX_SHADER, GL_FRAGMENT_SHADER, etc.

        @returns  true if the shader compiled successfully. If not, you can call
                  getLastError() to find out what happened.
    */
    bool addShader (const char* const shaderSourceCode, GLenum shaderType);

    /** Links all the compiled shaders into a usable program.
        If your app is built in debug mode, this method will assert if the program
        fails to link correctly.
        @returns  true if the program linked successfully. If not, you can call
                  getLastError() to find out what happened.
    */
    bool link() noexcept;

    /** Get the output for the last shader compilation or link that failed. */
    const String& getLastError() const noexcept            { return errorLog; }

    /** Selects this program into the current context. */
    void use() const noexcept;

    /** Represents an openGL uniform value.
        After a program has been linked, you can create Uniform objects to let you
        set the uniforms that your shaders use.

        Be careful not to call the set() functions unless the appropriate program
        is loaded into the current context.
    */
    struct Uniform
    {
        /** Initialises a uniform.
            The program must have been successfully linked when this
            constructor is called.
        */
        Uniform (const OpenGLShaderProgram& program, const char* uniformName);

        /** Sets a float uniform. */
        void set (GLfloat n1) const noexcept;
        /** Sets an int uniform. */
        void set (GLint n1) const noexcept;
        /** Sets a vec2 uniform. */
        void set (GLfloat n1, GLfloat n2) const noexcept;
        /** Sets a vec3 uniform. */
        void set (GLfloat n1, GLfloat n2, GLfloat n3) const noexcept;
        /** Sets a vec4 uniform. */
        void set (GLfloat n1, GLfloat n2, GLfloat n3, float n4) const noexcept;
        /** Sets an ivec4 uniform. */
        void set (GLint n1, GLint n2, GLint n3, GLint n4) const noexcept;
        /** Sets a vector float uniform. */
        void set (const GLfloat* values, int numValues) const noexcept;

        /** The uniform's ID number.
            If the uniform couldn't be found, this value will be < 0.
        */
        GLint uniformID;

    private:
        const OpenGLContext& context;

        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Uniform);
    };

    /** Represents an openGL vertex attribute value.
        After a program has been linked, you can create Attribute objects to let you
        set the attributes that your vertex shaders use.
    */
    struct Attribute
    {
        /** Initialises an attribute.
            The program must have been successfully linked when this
            constructor is called.
        */
        Attribute (const OpenGLShaderProgram& program, const char* attributeName);

        /** The attribute's ID number.
            If the uniform couldn't be found, this value will be < 0.
        */
        GLint attributeID;
    };

    /** The ID number of the compiled program. */
    GLuint programID;

private:
    const OpenGLContext& context;
    String errorLog;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (OpenGLShaderProgram);
};

#endif   // __JUCE_OPENGLSHADERPROGRAM_JUCEHEADER__