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Thread: Qt ARGB and RGBA

  1. #1
    Join Date
    Feb 2009
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    Default Qt ARGB and RGBA

    Hello,

    I want to know why Qt uses a ARGB model, and not the RGBA to store images..

    I mean when qt want to send data to openGL they have to use the RGBA model.
    So that is an unnecessary step.

  2. #2
    Join Date
    Jan 2006
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    Default Re: Qt ARGB and RGBA

    QImage can store an arbitrary number of formats and so can OpenGL. Use for example GL_ABGR_EXT to upload a texture in ABGR-mode. OpenGL is one of the many things that Qt can address but Qt was not written with the sole purpose of utilizing OpenGL. There is for sure a reason to do it this way and not the other way around.

    If you use GLuint QGLWidget::bindTexture ( const QImage & image, GLenum target = GL_TEXTURE_2D, GLint format = GL_RGBA ), you give Qt the chance to optimize uploads of textures. Maybe there is no unnecessary step in this case.
    It's nice to be important but it's more important to be nice.

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