GLLOGICOP(3G) UNIX Programmer's Manual GLLOGICOP(3G)
glLogicOp - specify a logical pixel operation for color
index rendering
void glLogicOp( GLenum opcode )
opcode Specifies a symbolic constant that selects a logical
operation. The following symbols are accepted:
GL_CLEAR, GL_SET, GL_COPY, GL_COPY_INVERTED,
GL_NOOP, GL_INVERT, GL_AND, GL_NAND, GL_OR, GL_NOR,
GL_XOR, GL_EQUIV, GL_AND_REVERSE, GL_AND_INVERTED,
GL_OR_REVERSE, and GL_OR_INVERTED. The initial value
is GL_COPY.
glLogicOp 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 loca-
tion in the frame buffer. To enable or disable the logical
operation, call glEnable and glDisable 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.
______________________________________
Opcode Resulting Operation
______________________________________
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
MirOS BSD #10-current Printed 20.2.2012 1
GLLOGICOP(3G) UNIX Programmer's Manual GLLOGICOP(3G)
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 glDrawBuffer).
GL_INVALID_ENUM is generated if opcode is not an accepted
value.
GL_INVALID_OPERATION is generated if glLogicOp is executed
between the execution of glBegin and the corresponding exe-
cution of glEnd.
glGet with argument GL_LOGIC_OP_MODE.
glIsEnabled with argument GL_COLOR_LOGIC_OP or
GL_INDEX_LOGIC_OP.
glAlphaFunc(3G), glBlendFunc(3G), glDrawBuffer(3G),
glEnable(3G), glStencilOp(3G)
MirOS BSD #10-current Printed 20.2.2012 2
Generated on 2012-02-20 02:47:02 by $MirOS: src/scripts/roff2htm,v 1.70 2011/12/03 18:21:12 tg Exp $
These manual pages and other documentation are copyrighted by their respective writers;
their source is available at our CVSweb,
AnonCVS, and other mirrors. The rest is Copyright © 2002‒2011 The MirOS Project, Germany.
This product includes material
provided by Thorsten Glaser.
This manual page’s HTML representation is supposed to be valid XHTML/1.1; if not, please send a bug report – diffs preferred.