Blending

Blend :

Mix (a substance) with another substance so that they combine together. or

Mix (a color) with another color so that they combine together.

Blend & GLES:

In this section, we discuss blending pixel colors. Once a fragment passes all of the enabled fragment tests, its color can be combined with the color that’s already present in the fragment’s pixel location. Before the two colors are combined, they’re multiplied by a scaling factor and combined using the specified blending operator. The blending equation is

C_final = sf_source Clr_source opr sf_destination Clr_destination

where sf_source and Clr_source are the incoming fragment’s scaling factor and color, respectively. Likewise, sf_destination and Clr_destination are the pixel’s scaling factor

and color. opr is the mathematical operator for combining the scaled values.

The scaling factors are specified by calling either glBlendFunc or glBlendFuncSeparate.

The possible values for the blending coefficients are

(Rs, Gs, Bs, As) are the color components associated with the incoming fragment color, (Rd, Gd, Bd, Ad) are the components associated with the pixel color already in the color buffer, and (Rc, Gc, Bc, Ac) represent a constant color that you set by calling glBlendColor. In the case of GL_SRC_ALHPA_SATURATE, the minimum value that’s computed is applied to the source color only.

Once the incoming fragment and pixel color have been multiplied by their respective scaling factors, they’re combined using the operator specified by glBlendEquation or glBlendEquationSeparate. By default, blended colors are accumulated using the GL_FUNC_ADD operator. The GL_FUNC_SUBTRACT operator subtracts the scaled color from the framebuffer from the incoming fragment’s value. Likewise, the GL_FUNC_REVERSE_SUBTRACT reverses the blending equation such that the incoming fragment colors are subtracted from the current pixel value.

void glBlendEquation(GLenum mode);

mode specify the blending operator. Valid values are GL_FUNC_ADD,

GL_FUNC_SUBTRACT, or GL_FUNC_REVERSE_SUBTRACT

void glBlendEquationSeparate(GLenum modeRGB, GLenum modeAlpha);

modeRGB specify the blending operator for the red, green, and blue components

modeAlpha specify the alpha component blending operator

Okayyy copy and paste is over, oh god I forgot read what I have copied!