<graphic fileref="opengl_logo.gif" scale="25"/>Reference Pages

<graphic fileref="opengl_logo.gif" scale="25"/>Reference Pages OpenGL® Reference Pages OpenGL® Architectural Review Board TSG, Khronos Group Inc. BrentInskoE 2.1 11/14/2007 - DRAFT 2007 Khronos Group, Inc. Contents This document contains reference information for the OpenGL® Application Programming Interface. These reference pages (also known as "man pages") include all of the important usage information for each command. This information includes a description of all parameters, return values, error conditions, and related commands. In addition, this document also provides usage information for the OpenGL® Utility Library (GLU) and the OpenGL® extension to the X Window System (GLX). These pages also exist online in the OpenGL® SDK. If you find any inaccuracies or typos in the reference pages, don't hesitate to inform us via the online specification feedback form. Copyrights The following OpenGL reference pages are Copyright © 2007 The Khronos Group Inc. and licensed under the Khronos Free Use License. For details, see http://www.khronos.org/help/legal/KFUL/.

glBlendEquationSeparate, glStencilFuncSeparate, glStencilMaskSeparate, glStencilOpSeparate

The following OpenGL reference pages are Copyright © 2005 Addison-Wesley and may be distributed subject to the terms and conditions set forth in the Open Publication Licesnse, v 1.0, 8, June 1999. For details, see http://openlcontent.org/openpub/.

glBeginQuery, glBindBuffer, glBufferData, glBufferSubData, glDeleteBuffers, glDeleteQueries, glGenBuffers, glGenQueries, glGetBufferParameteriv, glGetBufferPointerv, glGetBufferSubData, glGetQueryiv, glGetQueryObject, glIsBuffer, glIsQuery, glMapBuffer

The following OpenGL reference pages are Copyright © 2003-2005 3Dlabs, Inc. Ltd. And may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8, June 1999. For details, see http://openlcontent.org/openpub/.

glAttachShader, glBindAttribLocation, glCompileShader, glCreateProgram, glCreateShader, glDeleteProgram, glDeleteShader, glDetachShader, glDrawBuffers, glEnableVertexAttribArray, glGetActiveAttrib, glGetActiveUniform, glGetAttachedShaders, glGetAttribLocation, glGetProgram, glGetProgramInfoLog, glGetShader, glGetShaderInfoLog, glGetShaderSource, glGetUniform, glGetUniformLocation, glGetVertexAttrib, glGetVertexAttribPointerv, glIsProgram, glIsShader, glLinkProgram, glShaderSource, glUniform, glUseProgram, glValidateProgram, glVertexAttrib, glVertexAttribPointer

All reference pages referring to the OpenGL Utility Library and the OpenGL extension to the X Window System, and the following core OpenGL reference pages are Copyright © 1991-2006 Silicon Graphics, Inc. and may be distributed subject to the terms and conditions set forth in the Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.

glAccum, glActiveTexture, glAlphaFunc, glAreTexturesResident, glArrayElement, glBegin, glBindTexture, glBitmap, glBlendColor, glBlendEquation, glBlendFunc, glBlendFuncSeparate, glCallList, glCallLists, glClear, glClearAccum, glClearColor, glClearDepth, glClearIndex, gllearStencil, glCLientActiveTexture, glClipPlane, glColor, glColorMask, glColorMaterial, glColorPointer, glColorSubTable, glColorTable, glColorTableParameter, glCompressedTexImage1D, glCompressedTexImage2D, glCompressedTexImage3D, glCompressedTexSubImage1D, glCompressedTexSubImage2D, glCompressedTexSubImage3D, glConvolutionFilter1D, glConvolutionFilter2D, glConvolutionParameter, glCopyColorSubTable, glCopyColorTable, glCopyConvolutionFilter1D, glCopyConvolutionFilter2D, glCopyPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage2D, glCopyTexSubImage3D, glCullFace, glDeleteLists, glDeleteTextures, glDepthFunc, glDepthMask, glDepthRange, glDrawArrays, glDrawBuffer, glDrawElements, glDrawPixels, glDrawRangeElements, glEdgeFlag, glEdgeFlagPointer, glEnable, glEnableClientState, glEvalCoord, glEvalMesh, glEvalPoint, glFeedbackBuffer, glFinish, glFlush, glFog, glFogCoord, glFogCoordPointer, glFrontFace, glFrustum, glGenLists, glGenTextures, glGet, glGetClipPlane, glGetColorTable, glGetColorTableParameter, glGetCompressedTexImage, glGetConvolutionFilter, glGetConvolutionParameter, glGetError, glGetHistogram, glGetHistogramParameter, glGetLight, glGetMap, glGetMaterial, glGetMinmax, glGetMinmaxParameter, glGetPixelMap, glGetPointerv, glGetPolygonStipple, glGetSeparableFilter, glGetString, glGetTexEnv, glGetTexGen, glGetTexImage, glGetTexLevelParameter, glGetTexParameter, glHint, glHistogram, glIndex, glIndexMask, glIndexPointer, glInitNames, glInterleavedArrays, glIsEnabled, glIsList, glIsTexture, glLight, glLightModel, glLineStipple, glLineWidth, glListBase, glLoadIdentity, glLoadMatrix, glLoadName, glLoadTransposeMatrix, glLogicOp, glMap1, glMap2, glMapGrid, glMaterial, glMatrixMode, glMinmax, glMultiDrawArrays, glMultiDrawElements, glMultiTexCoord, glMultMatrix, glMultTransposeMatrix, glNewList, glNormal, glNormalPointer, glOrtho, glPassThrough, glPixelMap, glPixelStore, glPixelTransfer, glPixelZoom, glPointParameter, glPointSize, glPolygonMode, glPolygonOffset, glPolygonStipple, glPrioritizeTextures, glPushAttrib, glPushClientAttrib, glPushMatrix, glPushName, glRasterPos, glReadBuffer, glReadPixels, glRect, glRenderMode, glResetHistogram, glResetMinmax, glRotate, glSampleCoverage, glScale, glScissor, glSecondaryColor, glSecondaryColorPointer, glSelectBuffer, glSeparableFilter2D, glShadeModel, glStencilFunc, glStencilMask, glStencilOp, glTexCoord, glTexCoordPointer, glTexEnv, glTexGen, glTexImage1D, glTexImage2D, glTexImage3D, glTexParameter, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D, glTranslate, glVertex, glVertexPointer, glViewport, glWindowPos

OpenGL<superscript>®</superscript> Commands 1991-2006 Silicon Graphics, Inc. glBlendEquationSeparate 3G glBlendEquationSeparate set the RGB blend equation and the alpha blend equation separately C Specification void glBlendEquationSeparate GLenum modeRGB GLenum modeAlpha Parameters modeRGB specifies the RGB blend equation, how the red, green, and blue components of the source and destination colors are combined. It must be GL_FUNC_ADD, GL_FUNC_SUBTRACT, GL_FUNC_REVERSE_SUBTRACT, GL_MIN, GL_MAX. modeAlpha specifies the alpha blend equation, how the alpha component of the source and destination colors are combined. It must be GL_FUNC_ADD, GL_FUNC_SUBTRACT, GL_FUNC_REVERSE_SUBTRACT, GL_MIN, GL_MAX. Description The blend equations determines how a new pixel (the ''source'' color) is combined with a pixel already in the framebuffer (the ''destination'' color). This function specifies one blend equation for the RGB-color components and one blend equation for the alpha component. The blend 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

(R_{s}, G_{s}, B_{s}, A_{s})

and

(R_{d}, G_{d}, B_{d}, A_{d})

, respectively. The result color is referred to as

(R_{r}, G_{r}, B_{r}, A_{r})

. The source and destination blend factors are denoted

(s_{R}, s_{G}, s_{B}, s_{A})

and

(d_{R}, d_{G}, d_{B}, d_{A})

, respectively. For these equations all color components are understood to have values in the range

[0, 1]

. Mode RGB Components Alpha Component GL_FUNC_ADD

Rr = R_{s} s_{R} + R_{d} d_{R}

Gr = G_{s} s_{G} + G_{d} d_{G}

Br = B_{s} s_{B} + B_{d} d_{B}

Ar = A_{s} s_{A} + A_{d} d_{A}

GL_FUNC_SUBTRACT

Rr = R_{s} s_{R} - R_{d} d_{R}

Gr = G_{s} s_{G} - G_{d} d_{G}

Br = B_{s} s_{B} - B_{d} d_{B}

Ar = A_{s} s_{A} - A_{d} d_{A}

GL_FUNC_REVERSE_SUBTRACT

Rr = R_{d} d_{R} - R_{s} s_{R}

Gr = G_{d} d_{G} - G_{s} s_{G}

Br = B_{d} d_{B} - B_{s} s_{B}

Ar = A_{d} d_{A} - A_{s} s_{A}

GL_MIN

Rr = \min (R_{s}, R_{d})

Gr = \min (G_{s}, G_{d})

Br = \min (B_{s}, B_{d})

Ar = \min (A_{s}, A_{d})

GL_MAX

Rr = \max (R_{s}, R_{d})

Gr = \max (G_{s}, G_{d})

Br = \max (B_{s}, B_{d})

Ar = \max (A_{s}, A_{d})

The results of these equations are clamped to the range

[0, 1]

. The GL_MIN and GL_MAX equations are useful for applications that analyze image data (image thresholding against a constant color, for example). 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. Notes glBlendEquationSeparate is available only if the GL version is 2.0 or greater. The GL_MIN, and GL_MAX equations do not use the source or destination factors, only the source and destination colors. Errors GL_INVALID_ENUM is generated if either modeRGB or modeAlpha is not one of GL_FUNC_ADD, GL_FUNC_SUBTRACT, GL_FUNC_REVERSE_SUBTRACT, GL_MAX, or GL_MIN. GL_INVALID_OPERATION is generated if glBlendEquationSeparate is executed between the execution of glBegin and the corresponding execution of glEnd. Associated Gets glGet with an argument of GL_BLEND_EQUATION_RGB glGet with an argument of GL_BLEND_EQUATION_ALPHA See Also glGetString, glBlendColor, glBlendFunc, glBlendFuncSeparate 1991-2006 Silicon Graphics, Inc. glStencilFuncSeparate 3G glStencilFuncSeparate set front and/or back function and reference value for stencil testing C Specification void glStencilFuncSeparate GLenum face GLenum func GLint ref GLuint mask Parameters face Specifies whether front and/or back stencil state is updated. Three symbolic constants are valid: GL_FRONT, GL_BACK, and GL_FRONT_AND_BACK. func Specifies the test function. Eight symbolic constants are valid: GL_NEVER, GL_LESS, GL_LEQUAL, GL_GREATER, GL_GEQUAL, GL_EQUAL, GL_NOTEQUAL, and GL_ALWAYS. The initial value is GL_ALWAYS. ref Specifies the reference value for the stencil test. ref is clamped to the range

[0, 2^{n} - 1]

, where

n

is the number of bitplanes in the stencil buffer. The initial value is 0. mask Specifies a mask that is ANDed with both the reference value and the stored stencil value when the test is done. The initial value is all 1's. Description Stenciling, like depth-buffering, enables and disables drawing on a per-pixel basis. You draw into the stencil planes using GL drawing primitives, then render geometry and images, using the stencil planes to mask out portions of the screen. Stenciling is typically used in multipass rendering algorithms to achieve special effects, such as decals, outlining, and constructive solid geometry rendering. The stencil test conditionally eliminates a pixel based on the outcome of a comparison between the reference value and the value in the stencil buffer. To enable and disable the test, call glEnable and glDisable with argument GL_STENCIL_TEST. To specify actions based on the outcome of the stencil test, call glStencilOp or glStencilOpSeparate. There can be two separate sets of func, ref, and mask parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. glStencilFunc sets both front and back stencil state to the same values, as if glStencilFuncSeparate were called with face set to GL_FRONT_AND_BACK. func is a symbolic constant that determines the stencil comparison function. It accepts one of eight values, shown in the following list. ref is an integer reference value that is used in the stencil comparison. It is clamped to the range

[0, 2^{n} - 1]

, where

n

is the number of bitplanes in the stencil buffer. mask is bitwise ANDed with both the reference value and the stored stencil value, with the ANDed values participating in the comparison. If stencil represents the value stored in the corresponding stencil buffer location, the following list shows the effect of each comparison function that can be specified by func. Only if the comparison succeeds is the pixel passed through to the next stage in the rasterization process (see glStencilOp). All tests treat stencil values as unsigned integers in the range

[0, 2^{n} - 1]

, where

n

is the number of bitplanes in the stencil buffer. The following values are accepted by func: GL_NEVER Always fails. GL_LESS Passes if ( ref & mask ) < ( stencil & mask ). GL_LEQUAL Passes if ( ref & mask ) <= ( stencil & mask ). GL_GREATER Passes if ( ref & mask ) > ( stencil & mask ). GL_GEQUAL Passes if ( ref & mask ) >= ( stencil & mask ). GL_EQUAL Passes if ( ref & mask ) = ( stencil & mask ). GL_NOTEQUAL Passes if ( ref & mask ) != ( stencil & mask ). GL_ALWAYS Always passes. Notes glStencilFuncSeparate is available only if the GL version is 2.0 or greater. Initially, the stencil test is disabled. If there is no stencil buffer, no stencil modification can occur and it is as if the stencil test always passes. Errors GL_INVALID_ENUM is generated if func is not one of the eight accepted values. GL_INVALID_OPERATION is generated if glStencilFuncSeparate is executed between the execution of glBegin and the corresponding execution of glEnd. Associated Gets glGet with argument GL_STENCIL_FUNC, GL_STENCIL_VALUE_MASK, GL_STENCIL_REF, GL_STENCIL_BACK_FUNC, GL_STENCIL_BACK_VALUE_MASK, GL_STENCIL_BACK_REF, or GL_STENCIL_BITS glIsEnabled with argument GL_STENCIL_TEST See Also glAlphaFunc, glBlendFunc, glDepthFunc, glEnable, glLogicOp, glStencilFunc, glStencilMask, glStencilMaskSeparate, glStencilOp, glStencilOpSeparate 1991-2006 Silicon Graphics, Inc. glStencilMaskSeparate 3G glStencilMaskSeparate control the front and/or back writing of individual bits in the stencil planes C Specification void glStencilMaskSeparate GLenum face GLuint mask Parameters face Specifies whether the front and/or back stencil writemask is updated. Three symbolic constants are valid: GL_FRONT, GL_BACK, and GL_FRONT_AND_BACK. mask Specifies a bit mask to enable and disable writing of individual bits in the stencil planes. Initially, the mask is all 1's. Description glStencilMaskSeparate controls the writing of individual bits in the stencil planes. The least significant

n

bits of mask, where

n

is the number of bits in the stencil buffer, specify a mask. Where a 1 appears in the mask, it's possible to write to the corresponding bit in the stencil buffer. Where a 0 appears, the corresponding bit is write-protected. Initially, all bits are enabled for writing. There can be two separate mask writemasks; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. glStencilMask sets both front and back stencil writemasks to the same values, as if glStencilMaskSeparate were called with face set to GL_FRONT_AND_BACK. Notes glStencilMaskSeparate is available only if the GL version is 2.0 or greater. Errors GL_INVALID_OPERATION is generated if glStencilMaskSeparate is executed between the execution of glBegin and the corresponding execution of glEnd. Associated Gets glGet with argument GL_STENCIL_WRITEMASK, GL_STENCIL_BACK_WRITEMASK, or GL_STENCIL_BITS See Also glColorMask, glDepthMask, glIndexMask, glStencilFunc, glStencilFuncSeparate, glStencilMask, glStencilOp, glStencilOpSeparate 1991-2006 Silicon Graphics, Inc. glStencilOpSeparate 3G glStencilOpSeparate set front and/or back stencil test actions C Specification void glStencilOpSeparate GLenum face GLenum sfail GLenum dpfail GLenum dppass Parameters face Specifies whether front and/or back stencil state is updated. Three symbolic constants are valid: GL_FRONT, GL_BACK, and GL_FRONT_AND_BACK. sfail Specifies the action to take when the stencil test fails. Eight symbolic constants are accepted: GL_KEEP, GL_ZERO, GL_REPLACE, GL_INCR, GL_INCR_WRAP, GL_DECR, GL_DECR_WRAP, and GL_INVERT. The initial value is GL_KEEP. dpfail Specifies the stencil action when the stencil test passes, but the depth test fails. dpfail accepts the same symbolic constants as sfail. The initial value is GL_KEEP. dppass Specifies the stencil action when both the stencil test and the depth test pass, or when the stencil test passes and either there is no depth buffer or depth testing is not enabled. dppass accepts the same symbolic constants as sfail. The initial value is GL_KEEP. Description Stenciling, like depth-buffering, enables and disables drawing on a per-pixel basis. You draw into the stencil planes using GL drawing primitives, then render geometry and images, using the stencil planes to mask out portions of the screen. Stenciling is typically used in multipass rendering algorithms to achieve special effects, such as decals, outlining, and constructive solid geometry rendering. The stencil test conditionally eliminates a pixel based on the outcome of a comparison between the value in the stencil buffer and a reference value. To enable and disable the test, call glEnable and glDisable with argument GL_STENCIL_TEST; to control it, call glStencilFunc or glStencilFuncSeparate. There can be two separate sets of sfail, dpfail, and dppass parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. glStencilOp sets both front and back stencil state to the same values, as if glStencilOpSeparate were called with face set to GL_FRONT_AND_BACK. glStencilOpSeparate takes three arguments that indicate what happens to the stored stencil value while stenciling is enabled. If the stencil test fails, no change is made to the pixel's color or depth buffers, and sfail specifies what happens to the stencil buffer contents. The following eight actions are possible. GL_KEEP Keeps the current value. GL_ZERO Sets the stencil buffer value to 0. GL_REPLACE Sets the stencil buffer value to ref, as specified by glStencilFunc. GL_INCR Increments the current stencil buffer value. Clamps to the maximum representable unsigned value. GL_INCR_WRAP Increments the current stencil buffer value. Wraps stencil buffer value to zero when incrementing the maximum representable unsigned value. GL_DECR Decrements the current stencil buffer value. Clamps to 0. GL_DECR_WRAP Decrements the current stencil buffer value. Wraps stencil buffer value to the maximum representable unsigned value when decrementing a stencil buffer value of zero. GL_INVERT Bitwise inverts the current stencil buffer value. Stencil buffer values are treated as unsigned integers. When incremented and decremented, values are clamped to 0 and

2^{n} - 1

, where

n

is the value returned by querying GL_STENCIL_BITS. The other two arguments to glStencilOpSeparate specify stencil buffer actions that depend on whether subsequent depth buffer tests succeed (dppass) or fail (dpfail) (see glDepthFunc). The actions are specified using the same eight symbolic constants as sfail. Note that dpfail is ignored when there is no depth buffer, or when the depth buffer is not enabled. In these cases, sfail and dppass specify stencil action when the stencil test fails and passes, respectively. Notes glStencilOpSeparate is available only if the GL version is 2.0 or greater. Initially the stencil test is disabled. If there is no stencil buffer, no stencil modification can occur and it is as if the stencil test always passes. Errors GL_INVALID_ENUM is generated if face is any value other than GL_FRONT, GL_BACK, or GL_FRONT_AND_BACK. GL_INVALID_ENUM is generated if sfail, dpfail, or dppass is any value other than the eight defined constant values. GL_INVALID_OPERATION is generated if glStencilOpSeparate is executed between the execution of glBegin and the corresponding execution of glEnd. Associated Gets glGet with argument GL_STENCIL_FAIL, GL_STENCIL_PASS_DEPTH_PASS, GL_STENCIL_PASS_DEPTH_FAIL, GL_STENCIL_BACK_FAIL, GL_STENCIL_BACK_PASS_DEPTH_PASS, GL_STENCIL_BACK_PASS_DEPTH_FAIL, or GL_STENCIL_BITS glIsEnabled with argument GL_STENCIL_TEST See Also glAlphaFunc, glBlendFunc, glDepthFunc, glEnable, glLogicOp, glStencilFunc, glStencilFuncSeparate, glStencilMask, glStencilMaskSeparate, glStencilOp