gllogicop(3g) [suse man page]
GLLOGICOP(3G) GLLOGICOP(3G) NAME
glLogicOp - specify a logical pixel operation for color index rendering C SPECIFICATION
void glLogicOp( GLenum opcode ) PARAMETERS
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. DESCRIPTION
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 location 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 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. NOTES
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). ERRORS
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 execution of glEnd. ASSOCIATED GETS
glGet with argument GL_LOGIC_OP_MODE. glIsEnabled with argument GL_COLOR_LOGIC_OP or GL_INDEX_LOGIC_OP. SEE ALSO
glAlphaFunc(3G), glBlendFunc(3G), glDrawBuffer(3G), glEnable(3G), glStencilOp(3G) GLLOGICOP(3G)
Check Out this Related Man Page
GLDRAWBUFFER(3G) GLDRAWBUFFER(3G) NAME
glDrawBuffer - specify which color buffers are to be drawn into C SPECIFICATION
void glDrawBuffer( GLenum mode ) PARAMETERS
mode Specifies up to four color buffers to be drawn into. Symbolic constants GL_NONE, GL_FRONT_LEFT, GL_FRONT_RIGHT, GL_BACK_LEFT, GL_BACK_RIGHT, GL_FRONT, GL_BACK, GL_LEFT, GL_RIGHT, GL_FRONT_AND_BACK, and GL_AUXi, where i is between 0 and ``GL_AUX_BUFFERS'' -1, are accepted (GL_AUX_BUFFERS is not the upper limit; use glGet to query the number of available aux buffers.) The initial value is GL_FRONT for single-buffered contexts, and GL_BACK for double-buffered contexts. DESCRIPTION
When colors are written to the frame buffer, they are written into the color buffers specified by glDrawBuffer. The specifications are as follows: GL_NONE No color buffers are written. GL_FRONT_LEFT Only the front left color buffer is written. GL_FRONT_RIGHT Only the front right color buffer is written. GL_BACK_LEFT Only the back left color buffer is written. GL_BACK_RIGHT Only the back right color buffer is written. GL_FRONT Only the front left and front right color buffers are written. If there is no front right color buffer, only the front left color buffer is written. GL_BACK Only the back left and back right color buffers are written. If there is no back right color buffer, only the back left color buffer is written. GL_LEFT Only the front left and back left color buffers are written. If there is no back left color buffer, only the front left color buffer is written. GL_RIGHT Only the front right and back right color buffers are written. If there is no back right color buffer, only the front right color buffer is written. GL_FRONT_AND_BACK All the front and back color buffers (front left, front right, back left, back right) are written. If there are no back color buffers, only the front left and front right color buffers are written. If there are no right color buffers, only the front left and back left color buffers are written. If there are no right or back color buf- fers, only the front left color buffer is written. GL_AUXi Only auxiliary color buffer i is written. If more than one color buffer is selected for drawing, then blending or logical operations are computed and applied independently for each color buffer and can produce different results in each buffer. Monoscopic contexts include only left buffers, and stereoscopic contexts include both left and right buffers. Likewise, single-buffered contexts include only front buffers, and double-buffered contexts include both front and back buffers. The context is selected at GL ini- tialization. NOTES
It is always the case that GL_AUXi = GL_AUX0 + i. ERRORS
GL_INVALID_ENUM is generated if mode is not an accepted value. GL_INVALID_OPERATION is generated if none of the buffers indicated by mode exists. GL_INVALID_OPERATION is generated if glDrawBuffer is executed between the execution of glBegin and the corresponding execution of glEnd. ASSOCIATED GETS
glGet with argument GL_DRAW_BUFFER glGet with argument GL_AUX_BUFFERS SEE ALSO
glBlendFunc(3G), glColorMask(3G), glIndexMask(3G), glLogicOp(3G), glReadBuffer(3G) GLDRAWBUFFER(3G)