X-Git-Url: http://git.hcoop.net/clinton/guile-figl.git/blobdiff_plain/b002944dd992dc5a273e0067504beb48e1ae3d1c..a6a00658f26c164551287799b194cc2f07eb78be:/upstream-man-pages/man3/xhtml/glBlendFuncSeparate.xml diff --git a/upstream-man-pages/man3/xhtml/glBlendFuncSeparate.xml b/upstream-man-pages/man3/xhtml/glBlendFuncSeparate.xml deleted file mode 100644 index f84cb18..0000000 --- a/upstream-man-pages/man3/xhtml/glBlendFuncSeparate.xml +++ /dev/null @@ -1,1296 +0,0 @@ - - - -glBlendFuncSeparate

Name

glBlendFuncSeparate — specify pixel arithmetic for RGB and alpha components separately

C Specification

void glBlendFuncSeparate(GLenum  srcRGB,
 GLenum  dstRGB,
 GLenum  srcAlpha,
 GLenum  dstAlpha);

Parameters

srcRGB

- Specifies how the red, green, and blue blending factors are computed. - The initial value is GL_ONE. -

dstRGB

- Specifies how the red, green, and blue destination blending factors are - computed. - The initial value is GL_ZERO. -

srcAlpha

- Specified how the alpha source blending factor is computed. - The initial value is GL_ONE. -

dstAlpha

- Specified how the alpha destination blending factor is computed. - The initial value is GL_ZERO. -

Description

- Pixels can be drawn using a function that blends - the incoming (source) RGBA values with the RGBA values - that are already in the frame buffer (the destination values). - Blending is initially disabled. - Use glEnable and glDisable with argument GL_BLEND - to enable and disable blending. -

- glBlendFuncSeparate defines the operation of blending when it is enabled. - srcRGB specifies which method is used to scale the - source RGB-color components. - dstRGB specifies which method is used to scale the - destination RGB-color components. - Likewise, srcAlpha specifies which method is used to scale the source alpha - color component, and dstAlpha specifies which method is used to scale the - destination alpha component. - The possible methods are described in the following table. - Each method defines four scale factors, - one each for red, green, blue, and alpha. -

- In the table and in subsequent equations, first source, second source and destination - color components are referred to as - - - - R - s0 - - G - s0 - - B - s0 - - A - s0 - - - , - - - - R - s1 - - G - s1 - - B - s1 - - A - s1 - - - , - and - - - - R - d - - G - d - - B - d - - A - d - - - , respectively. - The color specified by glBlendColor is referred to as - - - - R - c - - G - c - - B - c - - A - c - - - . - They are understood to have integer values between 0 and - - - - k - R - - k - G - - k - B - - k - A - - - , - where -

-

- - - - k - c - - = - - 2 - - m - c - - - - - - 1 - - - -

-

- and - - - - m - R - - m - G - - m - B - - m - A - - - - is the number of red, - green, - blue, - and alpha bitplanes. -

- Source and destination scale factors are referred to as - - - - s - R - - s - G - - s - B - - s - A - - - - and - - - - d - R - - d - G - - d - B - - d - A - - - . - All scale factors have range - - - - 0 - 1 - - . -

-

- Parameter - - RGB Factor - - Alpha Factor -
- GL_ZERO - - - - - 0 - 0 - 0 - - - - - - 0 - -
- GL_ONE - - - - - 1 - 1 - 1 - - - - - - 1 - -
- GL_SRC_COLOR - - - - - - R - s0 - - k - R - - - - G - s0 - - k - G - - - - B - s0 - - k - B - - - - - - - - - A - s0 - - k - A - - - -
- GL_ONE_MINUS_SRC_COLOR - - - - - - 1 - 1 - 1 - 1 - - - - - - R - s0 - - k - R - - - - G - s0 - - k - G - - - - B - s0 - - k - B - - - - - - - - - - 1 - - - - A - s0 - - k - A - - - - -
- GL_DST_COLOR - - - - - - R - d - - k - R - - - - G - d - - k - G - - - - B - d - - k - B - - - - - - - - - A - d - - k - A - - - -
- GL_ONE_MINUS_DST_COLOR - - - - - - 1 - 1 - 1 - - - - - - R - d - - k - R - - - - G - d - - k - G - - - - B - d - - k - B - - - - - - - - - - 1 - - - - A - d - - k - A - - - - -
- GL_SRC_ALPHA - - - - - - A - s0 - - k - A - - - - A - s0 - - k - A - - - - A - s0 - - k - A - - - - - - - - - A - s0 - - k - A - - - -
- GL_ONE_MINUS_SRC_ALPHA - - - - - - 1 - 1 - 1 - - - - - - A - s0 - - k - A - - - - A - s0 - - k - A - - - - A - s0 - - k - A - - - - - - - - - - 1 - - - - A - s0 - - k - A - - - - -
- GL_DST_ALPHA - - - - - - A - d - - k - A - - - - A - d - - k - A - - - - A - d - - k - A - - - - - - - - - A - d - - k - A - - - -
- GL_ONE_MINUS_DST_ALPHA - - - - - - 1 - 1 - 1 - - - - - - A - d - - k - A - - - - A - d - - k - A - - - - A - d - - k - A - - - - - - - - - - 1 - - - - A - d - - k - A - - - - -
- GL_CONSTANT_COLOR - - - - - R - c - - G - c - - B - c - - - - - - - A - c - - -
- GL_ONE_MINUS_CONSTANT_COLOR - - - - - - 1 - 1 - 1 - - - - - R - c - - G - c - - B - c - - - - - - - - - 1 - - - A - c - - - -
- GL_CONSTANT_ALPHA - - - - - A - c - - A - c - - A - c - - - - - - - A - c - - -
- GL_ONE_MINUS_CONSTANT_ALPHA - - - - - - 1 - 1 - 1 - - - - - A - c - - A - c - - A - c - - - - - - - - - 1 - - - A - c - - - -
- GL_SRC_ALPHA_SATURATE - - - - - i - i - i - - - - - - 1 - -
- GL_SRC1_COLOR - - - - - - R - s1 - - k - R - - - - G - s1 - - k - G - - - - B - s1 - - k - B - - - - - - - - - A - s1 - - k - A - - - -
- GL_ONE_MINUS_SRC_COLOR - - - - - - 1 - 1 - 1 - 1 - - - - - - R - s1 - - k - R - - - - G - s1 - - k - G - - - - B - s1 - - k - B - - - - - - - - - - 1 - - - - A - s1 - - k - A - - - - -
- GL_SRC1_ALPHA - - - - - - A - s1 - - k - A - - - - A - s1 - - k - A - - - - A - s1 - - k - A - - - - - - - - - A - s1 - - k - A - - - -
- GL_ONE_MINUS_SRC_ALPHA - - - - - - 1 - 1 - 1 - - - - - - A - s1 - - k - A - - - - A - s1 - - k - A - - - - A - s1 - - k - A - - - - - - - - - - 1 - - - - A - s1 - - k - A - - - - -

- In the table, -

-

- - - - i - = - - min - ⁡ - - A - s - - - 1 - - - - A - d - - - - - - - -

-

- To determine the blended RGBA values of a pixel, - the system uses the following equations: -

-

- - - - R - d - - = - - min - ⁡ - - k - R - - - R - s - - ⁢ - s - R - - + - R - d - - ⁢ - d - R - - - - - - - - - - G - d - - = - - min - ⁡ - - k - G - - - G - s - - ⁢ - s - G - - + - G - d - - ⁢ - d - G - - - - - - - - - - B - d - - = - - min - ⁡ - - k - B - - - B - s - - ⁢ - s - B - - + - B - d - - ⁢ - d - B - - - - - - - - - - A - d - - = - - min - ⁡ - - k - A - - - A - s - - ⁢ - s - A - - + - A - d - - ⁢ - d - A - - - - - - -

-

- Despite the apparent precision of the above equations, blending arithmetic - is not exactly specified, because blending operates with imprecise integer - color values. However, a blend factor that should be equal to 1 is - guaranteed not to modify its multiplicand, and a blend factor equal to 0 - reduces its multiplicand to 0. For example, when srcRGB is - GL_SRC_ALPHA, dstRGB is GL_ONE_MINUS_SRC_ALPHA, and - - - A - s - - - is - equal to - - - k - A - - , - the equations reduce to simple replacement: -

-

- - - - R - d - - = - R - s - - - - - - - G - d - - = - G - s - - - - - - - B - d - - = - B - s - - - - - - - A - d - - = - A - s - - - -

-

-

Notes

- Incoming (source) alpha is correctly thought of as a material opacity, - ranging from 1.0 - ( - - K - A - - ), - representing complete opacity, - to 0.0 (0), representing complete - transparency. -

- 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 glDrawBuffer.) -

- 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 GL_MAX_DUAL_SOURCE_DRAW_BUFFERS, which may - be lower than GL_MAX_DRAW_BUFFERS. -

Errors

- GL_INVALID_ENUM is generated if either srcRGB or dstRGB is not an - accepted value. -

Associated Gets

- glGet with argument GL_BLEND_SRC_RGB -

- glGet with argument GL_BLEND_SRC_ALPHA -

- glGet with argument GL_BLEND_DST_RGB -

- glGet with argument GL_BLEND_DST_ALPHA -

- glIsEnabled with argument GL_BLEND -

-

See Also

- glBlendColor, - glBlendFunc, - glBlendEquation, - glClear, - glDrawBuffer, - glEnable, - glLogicOp, - glStencilFunc -

Copyright

- 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/. -