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| {{infobox feature
| | #REDIRECT [[GLAPI/glBlendFuncSeparate]] |
| | name = glBlendFunc
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| | core = 1.0
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| }}
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| '''glBlendFunc:''' specify pixel arithmetic
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| == Function Definition ==
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| void '''glBlendFunc'''(GLenum {{param|sfactor}}, GLenum {{param|dfactor}});
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| void '''glBlendFunci'''(GLuint {{param|buf}}, GLenum {{param|sfactor}}, GLenum {{param|dfactor}});
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| ; buf
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| : For '''glBlendFunci''', specifies the index of the draw buffer for which to set the blend function.
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| ; sfactor
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| : Specifies how the red, green, blue, and alpha source blending factors are computed. The initial value is {{enum|GL_ONE}}.
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| ; dfactor
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| : Specifies how the red, green, blue, and alpha destination blending factors are computed. The following symbolic constants are accepted: {{enum|GL_ZERO}}, {{enum|GL_ONE}}, {{enum|GL_SRC_COLOR}}, {{enum|GL_ONE_MINUS_SRC_COLOR}}, {{enum|GL_DST_COLOR}}, {{enum|GL_ONE_MINUS_DST_COLOR}}, {{enum|GL_SRC_ALPHA}}, {{enum|GL_ONE_MINUS_SRC_ALPHA}}, {{enum|GL_DST_ALPHA}}, {{enum|GL_ONE_MINUS_DST_ALPHA}}. {{enum|GL_CONSTANT_COLOR}}, {{enum|GL_ONE_MINUS_CONSTANT_COLOR}}, {{enum|GL_CONSTANT_ALPHA}}, and {{enum|GL_ONE_MINUS_CONSTANT_ALPHA}}. The initial value is {{enum|GL_ZERO}}.
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| == Description ==
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| These functions operate as their more specific counterparts. '''glBlendFunc''' is equivalent to:
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| {{apifunc|glBlendFuncSeparate}}({{param|sfactor}}, {{param|dfactor}}, {{param|sfactor}}, {{param|dfactor}});
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| ''glBlendFunci'' is equivalent to:
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| {{apifunc|glBlendFuncSeparate|i}}({{param|buf}}, {{param|sfactor}}, {{param|dfactor}}, {{param|sfactor}}, {{param|dfactor}});
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| == Notes ==
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| Incoming (source) alpha is correctly thought of as a material opacity, ranging from 1.0 (<math>k_A</math>), representing complete opacity, to 0.0 (0), representing complete transparency.
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| When more than one color buffer is enabled for drawing, the GL performs blending separately for each enabled buffer, using the contents of that buffer for destination color. (See {{apifunc|glDrawBuffer}}.)
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| When dual source blending is enabled (i.e., one of the blend factors requiring the second color input is used), the maximum number of enabled draw buffers is given by {{enum|GL_MAX_DUAL_SOURCE_DRAW_BUFFERS}}, which may be lower than {{enum|GL_MAX_DRAW_BUFFERS}}.
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| == Errors ==
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| {{enum|GL_INVALID_ENUM}} is generated if either {{param|sfactor}} or {{param|dfactor}} is not an accepted value.
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| {{enum|GL_INVALID_VALUE}} is generated by '''glBlendFunci''' if {{param|buf}} is greater than or equal to the value of {{enum|GL_MAX_DRAW_BUFFERS}}.
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| == Associated Gets ==
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| {{apifunc|glGet}} with argument {{enum|GL_BLEND_SRC}}
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| {{apifunc|glGet}} with argument {{enum|GL_BLEND_DST}}
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| {{apifunc|glIsEnabled}} with argument {{enum|GL_BLEND}}
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| == See Also ==
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| {{apifunc|glBlendColor}}, {{apifunc|glBlendEquation}}, {{apifunc|glBlendFuncSeparate}}, {{apifunc|glClear}}, {{apifunc|glDrawBuffer}}, {{apifunc|glEnable}}, {{apifunc|glLogicOp}}, {{apifunc|glStencilFunc}}
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| == Copyright ==
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| Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see [http://oss.sgi.com/projects/FreeB/ http://oss.sgi.com/projects/FreeB/].
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| [[Category:Core API Ref Post Fragment Shader Operations|BlendFunc]] | | [[Category:Core API Ref Post Fragment Shader Operations|BlendFunc]] |
| [[Category:Core API Reference|BlendFunc]] | | [[Category:Core API Reference|BlendFunc]] |