JUCE/modules/juce_opengl/opengl/juce_OpenGLHelpers.h

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

   This file is part of the JUCE library.
   Copyright (c) 2013 - Raw Material Software Ltd.

   Permission is granted to use this software under the terms of either:
   a) the GPL v2 (or any later version)
   b) the Affero GPL v3

   Details of these licenses can be found 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.juce.com for more information.

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

#ifndef JUCE_OPENGLHELPERS_H_INCLUDED
#define JUCE_OPENGLHELPERS_H_INCLUDED

class OpenGLTexture;
class OpenGLFrameBuffer;


//==============================================================================
/**
    A set of miscellaneous openGL helper functions.
*/
class JUCE_API  OpenGLHelpers
{
public:
    /** Clears the GL error state. */
    static void resetErrorState();

    /** Returns true if the current thread has an active OpenGL context. */
    static bool isContextActive();

    /** Clears the current context using the given colour. */
    static void clear (Colour colour);

    static void enableScissorTest (const Rectangle<int>& clip);

    /** Checks whether the current context supports the specified extension. */
    static bool isExtensionSupported (const char* extensionName);

    /** Returns the address of a named GL extension function */
    static void* getExtensionFunction (const char* functionName);

   #if JUCE_USE_OPENGL_FIXED_FUNCTION
    /** Sets the current colour using a JUCE colour. */
    static void setColour (Colour colour);

    /** Gives the current context an orthoganal rendering mode for 2D drawing into the given size. */
    static void prepareFor2D (int width, int height);

    /** This does the same job as gluPerspective(). */
    static void setPerspective (double fovy, double aspect, double zNear, double zFar);

    static void applyTransform (const AffineTransform& t);

    static void applyMatrix (const float matrixValues[16]);
   #if ! JUCE_OPENGL_ES
    static void applyMatrix (const double matrixValues[16]);
   #endif

    /** Draws a 2D quad with the specified corner points. */
    static void drawQuad2D (float x1, float y1,
                            float x2, float y2,
                            float x3, float y3,
                            float x4, float y4,
                            Colour colour);

    /** Draws a 3D quad with the specified corner points. */
    static void drawQuad3D (float x1, float y1, float z1,
                            float x2, float y2, float z2,
                            float x3, float y3, float z3,
                            float x4, float y4, float z4,
                            Colour colour);
    static void drawTriangleStrip (const GLfloat* const vertices, const GLfloat* const textureCoords, const int numVertices) noexcept;

    static void drawTriangleStrip (const GLfloat* const vertices, const GLfloat* const textureCoords,
                                   const int numVertices, const GLuint textureID) noexcept;

    static void drawTextureQuad (GLuint textureID, const Rectangle<int>& rect);

    static void fillRectWithTexture (const Rectangle<int>& rect, GLuint textureID, const float alpha);

    /** Fills a rectangle with the specified colour. */
    static void fillRectWithColour (const Rectangle<int>& rect,
                                    Colour colour);

    static void fillRect (const Rectangle<int>& rect);
   #endif
};

//==============================================================================
/**
    Used as a local object while rendering, this will create a temporary texture ID
    from an image in the quickest way possible.

    If the image is backed by an OpenGL framebuffer, it will use that directly; otherwise,
    this object will create a temporary texture or framebuffer and copy the image.
*/
class JUCE_API  OpenGLTextureFromImage
{
public:
    OpenGLTextureFromImage (const Image& image);
    ~OpenGLTextureFromImage();

    GLuint textureID;
    const int imageWidth, imageHeight;
    float fullWidthProportion, fullHeightProportion;

private:
    ScopedPointer<OpenGLTexture> texture;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (OpenGLTextureFromImage)
};


#endif   // JUCE_OPENGLHELPERS_H_INCLUDED