glEnableGLBLEND

glEnableGLBLEND is not a standard OpenGL function. The correct function to enable blending in OpenGL is glEnable with the capability GL_BLEND, i.e., glEnable(GL_BLEND). Blending is a per-fragment operation that combines the color of the incoming fragment with the color already stored in the color buffer, according to a blend function and an optional blend equation.

To enable blending in practice, you typically call glEnable(GL_BLEND); followed by a blend function such as glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) to achieve standard alpha blending. This setup makes the source fragment contribute its color scaled by its alpha, and the destination color contribute according to (1 - alpha). The default blend function, when not changed, is (GL_ONE, GL_ZERO), which effectively disables blending even when GL_BLEND is enabled.

The blend equation, set by glBlendEquation, determines how the source and destination terms are combined. The common choice is GL_FUNC_ADD, but other equations like GL_FUNC_SUBTRACT or GL_FUNC_REVERSE_SUBTRACT can be used for special effects. Blending interacts with the color buffer; it does not alter depth testing unless depth writes are adjusted, so correct rendering order is important for translucent objects.

Common use cases include rendering UI overlays, translucent materials, particle systems, and anti-aliased lines. Some advanced workflows use premultiplied alpha and corresponding blend functions to optimize blending and reduce artifacts.

To disable blending, call glDisable(GL_BLEND). If you encounter a function named glEnableGLBLEND in a library, it is likely a wrapper or a non-standard extension; refer to that library’s documentation for specifics.