Name
gl.LogicOp -- specify a logical pixel operation for color index rendering
Synopsis
gl.LogicOp(opcode)
Function
gl.LogicOp() specifies a logical operation that, when enabled, is applied between the incoming color index or RGBA color and the color index or RGBA color at the corresponding location in the frame buffer. To enable or disable the logical operation, call gl.Enable() and gl.Disable() using the symbolic constant #GL_COLOR_LOGIC_OP for RGBA mode or #GL_INDEX_LOGIC_OP for color index mode. The initial value is disabled for both operations.

#GL_CLEAR
0
#GL_SET
1
#GL_COPY
s
#GL_COPY_INVERTED
~s
#GL_NOOP
d
#GL_INVERT
~d
#GL_AND
s & d
#GL_NAND
~(s & d)
#GL_OR
s | d
#GL_NOR
~(s | d)
#GL_XOR
s ^ d
#GL_EQUIV
~(s ^ d)
#GL_AND_REVERSE
s & ~d
#GL_AND_INVERTED
~s & d
#GL_OR_REVERSE
s | ~d
#GL_OR_INVERTED
~s | d

opcode is a symbolic constant chosen from the list above. In the explanation of the logical operations, s represents the incoming color index and d represents the index in the frame buffer. Standard C-language operators are used. As these bitwise operators suggest, the logical operation is applied independently to each bit pair of the source and destination indices or colors.

Color index logical operations are always supported. RGBA logical operations are supported only if the GL version is 1.1 or greater.

When more than one RGBA color or index buffer is enabled for drawing, logical operations are performed separately for each enabled buffer, using for the destination value the contents of that buffer (See gl.DrawBuffer for details.).

Please consult an OpenGL reference manual for more information.

Inputs
opcode
specifies a symbolic constant that selects a logical operation (see above for supported constants)
Errors
#GL_INVALID_ENUM is generated if opcode is not an accepted value.

#GL_INVALID_OPERATION is generated if gl.LogicOp() is executed between the execution of gl.Begin() and the corresponding execution of gl.End().

Associated gets
gl.Get() with argument #GL_LOGIC_OP_MODE.

gl.IsEnabled() with argument #GL_COLOR_LOGIC_OP or #GL_INDEX_LOGIC_OP.

Show TOC