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Blending and Fog
Blending and fog are two OpenGL capabilities that allow you to produce
interesting lighting and coloring affects. When a pixel is to be drawn
on the screen, it normally overwrites any existing pixel color. When
blending is enabled (by calling glEnable(GL_BLEND)) then the
new (source) pixel is blended with the existing (destination) pixel
in the frame buffer.
- glBlendFunc(GLenum sfactor, GLenum dfactor):
-
Determines how new pixel values are blended with existing
values. The arguments indicate what factors are multiplied by
the source and destination RGBA values, respectively, before
they are added together. See the reference manuals for complete
information.
Fog produces an effect whereby more distant objects are blended
increasingly with a fog color, typically some shade of gray. It
is enabled by calling glEnable(GL_FOG).
- glFogf(GLenum pname, GLfloat param):
-
-
Specifies the parameters that define how fog is computed.
The first version is for defining scalar parameters, and the
second is for vector parameters. See the reference manual
for complete details.
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Dave Mount
Last updated: Sat, Feb 8, 2003.