Qt ARGB and RGBA

[zack]

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.

[axeljaeger]

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.