Parameters

Description

The blend equations determine how a new pixel (the ''source'' color) is combined with a pixel already in the framebuffer (the ''destination'' color). This function sets both the RGB blend equation and the alpha blend equation to a single equation.

These equations use the source and destination blend factors specified by either glBlendFunc or glBlendFuncSeparate. See glBlendFunc or glBlendFuncSeparate for a description of the various blend factors.

In the equations that follow, source and destination color components are referred to as $\left({\mathit{R}}_{\mathit{s}},{\mathit{G}}_{\mathit{s}},{\mathit{B}}_{\mathit{s}},{\mathit{A}}_{\mathit{s}}\right)$ and $\left({\mathit{R}}_{\mathit{d}},{\mathit{G}}_{\mathit{d}},{\mathit{B}}_{\mathit{d}},{\mathit{A}}_{\mathit{d}}\right)$, respectively. The result color is referred to as $\left({\mathit{R}}_{\mathit{r}},{\mathit{G}}_{\mathit{r}},{\mathit{B}}_{\mathit{r}},{\mathit{A}}_{\mathit{r}}\right)$. The source and destination blend factors are denoted $\left({\mathit{s}}_{\mathit{R}},{\mathit{s}}_{\mathit{G}},{\mathit{s}}_{\mathit{B}},{\mathit{s}}_{\mathit{A}}\right)$ and $\left({\mathit{d}}_{\mathit{R}},{\mathit{d}}_{\mathit{G}},{\mathit{d}}_{\mathit{B}},{\mathit{d}}_{\mathit{A}}\right)$, respectively. For these equations all color components are understood to have values in the range $\left[0,1\right]$.

The results of these equations are clamped to the range $\left[0,1\right]$.

The GL_FUNC_ADD equation is useful for antialiasing and transparency, among other things.

Initially, both the RGB blend equation and the alpha blend equation are set to GL_FUNC_ADD.

Errors

GL_INVALID_ENUM is generated if mode is not one of GL_FUNC_ADD, GL_FUNC_SUBTRACT, or GL_FUNC_REVERSE_SUBTRACT.

Associated Gets

glGet with an argument of GL_BLEND_EQUATION_RGB

glGet with an argument of GL_BLEND_EQUATION_ALPHA

See Also

glGetString, glBlendColor, glBlendEquationSeparate, glBlendFunc glBlendFuncSeparate