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Name
SGIX_texture_add_env
Name Strings
GL_SGIX_texture_add_env
Version
$Date: 1996/08/27 19:55:58 $ $Revision: 1.6 $
Number
69
Dependencies
None
Overview
New texture environment function ADD is supported with the following
equation:
Cv = Cf + CcCt + Cb
New function may be specified by calling glTexEnv with GL_ADD token.
New parameter Cb (bias) may be specified by calling TexEnv with
TEXTURE_ENV_BIAS_SGIX token.
New Procedures and Functions
None
New Tokens
Accepted by the <params> parameter of TexEnvf, TexEnvi, TexEnvfv, and
TexEnvfi when the <pname> parameter value is GL_TEXTURE_ENV_MODE
ADD
Accepted by the <pname> parameter of GetBooleanv, GetIntegerv, GetFloatv,
and GetDoublev, and by the <pname> parameter of TexEnvfv, and TexEnvfi
TEXTURE_ENV_BIAS_SGIX
Additions to Chapter 2 of the GL Specification (OpenGL Operation)
None
Additions to Chapter 3 of the GL Specification (Rasterization)
Texture Environment
-------------------
Base Texture Format REPLACE MODULATE BLEND DECAL ADD
------------------- ------- -------- ----- ----- ---
ALPHA ... ... ... ... Rv = Rf
... ... ... ... Gv = Gf
... ... ... ... Bv = Bf
... ... ... ... Av = AfAt
LUMINANCE ... ... ... ... Rv = Rf+LtRc+Rb
... ... ... ... Gv = Gf+LtGc+Gb
... ... ... ... Bv = Bf+LtBc+Bb
... ... ... ... Av = Af
LUMINANCE_ALPHA ... ... ... ... Rv = Rf+LtRc+Rb
... ... ... ... Gv = Gf+LtGc+Gb
... ... ... ... Bv = Bf+LtBc+Bb
... ... ... ... Av = AfAt
INTENSITY ... ... ... ... Rv = Rf+ItRc+Rb
... ... ... ... Gv = Gf+ItGc+Gb
... ... ... ... Bv = Bf+ItBc+Bb
... ... ... ... Av = Af+ItAc+Ab
RGB ... ... ... ... Rv = Rf+RtRc+Rb
... ... ... ... Gv = Gf+GtGc+Gb
... ... ... ... Bv = Bf+BtBc+Bb
... ... ... ... Av = Af
RGBA ... ... ... ... Rv = Rf+RtRc+Rb
... ... ... ... Gv = Gf+GtGc+Gb
... ... ... ... Bv = Bf+BtBc+Bb
... ... ... ... Av = AfAt
Table 3.11: Texture functions.
Additions to Chapter 4 of the GL Specification (Per-Fragment Operations
and the Framebuffer)
None
Additions to Chapter 5 of the GL Specification (Special Functions)
None
Additions to Chapter 6 of the GL Specification (State and State Requests)
The value of the texture environment bias is queried by calling
GetBooleanv, GetIntegerv, GetFloatv, and GetDoublev with <pname> set to
TEXTURE_ENV_BIAS_SGIX.
Additions to the GLX Specification
None
GLX Protocol
None
Errors
None
New State
Get Value Get Command Type Initial Value Attribute
--------- ----------- ---- ------------- ---------
TEXTURE_ENV_BIAS_SGIX GetFloatv C (0, 0, 0, 0) texture
New Implementation Dependent State
None