JUCE/modules/juce_opengl/opengl/juce_OpenGLTexture.h

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

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
   27th April 2017).

   End User License Agreement: www.juce.com/juce-5-licence
   Privacy Policy: www.juce.com/juce-5-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

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

namespace juce
{

//==============================================================================
/**
    Creates an openGL texture from an Image.

    @tags{OpenGL}
*/
class JUCE_API  OpenGLTexture
{
public:
    OpenGLTexture();
    ~OpenGLTexture();

    /** Creates a texture from the given image.

        Note that if the image's dimensions aren't a power-of-two, the texture may
        be created with a larger size.

        The image will be arranged so that its top-left corner is at texture
        coordinate (0, 1).
    */
    void loadImage (const Image& image);

    /** Creates a texture from a raw array of pixels.
        If width and height are not powers-of-two, the texture will be created with a
        larger size, and only the subsection (0, 0, width, height) will be initialised.
        The data is sent directly to the OpenGL driver without being flipped vertically,
        so the first pixel will be mapped onto texture coordinate (0, 0).
    */
    void loadARGB (const PixelARGB* pixels, int width, int height);

    /** Creates a texture from a raw array of pixels.
        This is like loadARGB, but will vertically flip the data so that the first
        pixel ends up at texture coordinate (0, 1), and if the width and height are
        not powers-of-two, it will compensate by using a larger texture size.
    */
    void loadARGBFlipped (const PixelARGB* pixels, int width, int height);

    /** Creates an alpha-channel texture from an array of alpha values.
        If width and height are not powers-of-two, the texture will be created with a
        larger size, and only the subsection (0, 0, width, height) will be initialised.
        The data is sent directly to the OpenGL driver without being flipped vertically,
        so the first pixel will be mapped onto texture coordinate (0, 0).
    */
    void loadAlpha (const uint8* pixels, int width, int height);

    /** Frees the texture, if there is one. */
    void release();

    /** Binds the texture to the currently active openGL context. */
    void bind() const;

    /** Unbinds the texture to the currently active openGL context. */
    void unbind() const;

    /** Returns the GL texture ID number. */
    GLuint getTextureID() const noexcept        { return textureID; }

    int getWidth() const noexcept               { return width; }
    int getHeight() const noexcept              { return height; }

    /** Returns true if a texture can be created with the given size.
        Some systems may require that the sizes are powers-of-two.
    */
    static bool isValidSize (int width, int height);

private:
    GLuint textureID;
    int width, height;
    OpenGLContext* ownerContext;

    void create (int w, int h, const void*, GLenum, bool topLeft);

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (OpenGLTexture)
};

} // namespace juce