Contents

• Dependencies
• Overview
• New Procedures and Functions
• New Tokens
• Errors
• New State
• New Implementation Dependent State

Dependencies

This extension is written against the OpenGL 1.2.1 Specification.

OpenGL 1.1 and GL_ARB_multitexture are required for this extension.

Overview

New texture environment function COMBINE_ARB allows programmable texture combiner operations, including:

|REPLACE | Arg0 | |:-------------------|:----------| |MODULATE | Arg0 * Arg1 | |ADD | Arg0 + Arg1 | |ADD_SIGNED_ARB | Arg0 + Arg1 - 0.5 | |SUBTRACT_ARB | Arg0 - Arg1 | |INTERPOLATE_ARB | Arg0 * (Arg2) + Arg1 * (1-Arg2) |

where Arg0, Arg1 and Arg2 are derived from

|PRIMARY_COLOR_ARB | primary color of incoming fragment| |:------------------------|:----------------------------------| |TEXTURE | texture color of corresponding texture unit| |CONSTANT_ARB | texture environment constant color| |PREVIOUS_ARB | result of previous texture environment; on texture unit 0, this maps to PRIMARY_COLOR_ARB|

In addition, the result may be scaled by 1.0, 2.0 or 4.0.

New Procedures and Functions

None

New Tokens

Accepted by the

<params>

parameter of TexEnvf, TexEnvi, TexEnvfv, and TexEnviv when the

<pname>

parameter value is TEXTURE_ENV_MODE

|COMBINE_ARB | 0x8570| |:---------------------------|:--------------------------|

Accepted by the

<pname>

parameter of TexEnvf, TexEnvi, TexEnvfv, and TexEnviv when the

<target>

parameter value is TEXTURE_ENV

|COMBINE_RGB_ARB | 0x8571| |:------------------------------|:------------------------| |COMBINE_ALPHA_ARB | 0x8572| |SOURCE0_RGB_ARB | 0x8580| |SOURCE1_RGB_ARB | 0x8581| |SOURCE2_RGB_ARB | 0x8582| |SOURCE0_ALPHA_ARB | 0x8588 | |SOURCE1_ALPHA_ARB | 0x8589 | |SOURCE2_ALPHA_ARB | 0x858A| |OPERAND0_RGB_ARB | 0x8590| |OPERAND1_RGB_ARB | 0x8591 | |OPERAND2_RGB_ARB | 0x8592| |OPERAND0_ALPHA_ARB | 0x8598| |OPERAND1_ALPHA_ARB | 0x8599| |OPERAND2_ALPHA_ARB | 0x859A| |RGB_SCALE_ARB | 0x8573| |ALPHA_SCALE | |

Accepted by the

<params>

parameter of TexEnvf, TexEnvi, TexEnvfv, and TexEnviv when the

<pname>

parameter value is COMBINE_RGB_ARB or COMBINE_ALPHA_ARB

|REPLACE | | |:-------|:| |MODULATE | | |ADD | | |ADD_SIGNED_ARB | 0x8574| |INTERPOLATE_ARB | 0x8575| |SUBTRACT_ARB | 0x84E7|

Accepted by the

<params>

parameter of TexEnvf, TexEnvi, TexEnvfv, and TexEnviv when the

<pname>

parameter value is SOURCE0_RGB_ARB, SOURCE1_RGB_ARB, SOURCE2_RGB_ARB, SOURCE0_ALPHA_ARB, SOURCE1_ALPHA_ARB, or SOURCE2_ALPHA_ARB

|TEXTURE| | |:------|:| |CONSTANT_ARB | 0x8576| |PRIMARY_COLOR_ARB | 0x8577| |PREVIOUS_ARB | 0x8578|

Accepted by the

<params>

parameter of TexEnvf, TexEnvi, TexEnvfv, and TexEnviv when the

<pname>

parameter value is OPERAND0_RGB_ARB, OPERAND1_RGB_ARB, or OPERAND2_RGB_ARB

|SRC_COLOR| |:---------| |ONE_MINUS_SRC_COLOR| |SRC_ALPHA| |ONE_MINUS_SRC_ALPHA|

Accepted by the

<params>

parameter of TexEnvf, TexEnvi, TexEnvfv, and TexEnviv when the

<pname>

parameter value is OPERAND0_ALPHA_ARB, OPERAND1_ALPHA_ARB, or OPERAND2_ALPHA_ARB

|SRC_ALPHA| |:---------| |ONE_MINUS_SRC_ALPHA|

Accepted by the

<params>

parameter of TexEnvf, TexEnvi, TexEnvfv, and TexEnviv when the

<pname>

parameter value is RGB_SCALE_ARB or ALPHA_SCALE

|1.0| |:--| |2.0| |4.0|

Errors

INVALID_ENUM is generated if

<params>

value for COMBINE_RGB_ARB or COMBINE_ALPHA_ARB is not one of REPLACE, MODULATE, ADD, ADD_SIGNED_ARB, INTERPOLATE_ARB, or SUBTRACT_ARB

INVALID_ENUM is generated if

<params>

value for SOURCE0_RGB_ARB, SOURCE1_RGB_ARB, SOURCE2_RGB_ARB, SOURCE0_ALPHA_ARB, SOURCE1_ALPHA_ARB or SOURCE2_ALPHA_ARB is not one of TEXTURE, CONSTANT_ARB, PRIMARY_COLOR_ARB, or PREVIOUS_ARB.

INVALID_ENUM is generated if

<params>

value for OPERAND0_RGB_ARB, OPERAND1_RGB_ARB, or OPERAND2_RGB_ARB is not one of SRC_COLOR, ONE_MINUS_SRC_COLOR, SRC_ALPHA or ONE_MINUS_SRC_ALPHA.

INVALID_ENUM is generated if

<params>

value for OPERAND0_ALPHA_ARB, OPERAND1_ALPHA_ARB, or OPERAND2_ALPHA_ARB is not one of SRC_ALPHA or ONE_MINUS_SRC_ALPHA.

INVALID_VALUE is generated if

<params>

value for RGB_SCALE_ARB or ALPHA_SCALE is not one of 1.0, 2.0, or 4.0.

New State

| Get Value | Get Command | Type | Initial Value | |:--------------|:----------------|:---------|:------------------| |COMBINE_RGB_ARB | GetTexEnviv | n x Z4 | MODULATE | |COMBINE_ALPHA_ARB | GetTexEnviv | n x Z4 | MODULATE | |SOURCE0_RGB_ARB | GetTexEnviv | n x Z3 | TEXTURE | |SOURCE1_RGB_ARB | GetTexEnviv | n x Z3 | PREVIOUS_ARB | |SOURCE2_RGB_ARB | GetTexEnviv | n x Z3 | CONSTANT_ARB | |SOURCE0_ALPHA_ARB | GetTexEnviv | n x Z3 | TEXTURE | |SOURCE1_ALPHA_ARB | GetTexEnviv | n x Z3 | PREVIOUS_ARB | |SOURCE2_ALPHA_ARB | GetTexEnviv | n x Z3 | CONSTANT_ARB | |OPERAND0_RGB_ARB | GetTexEnviv | n x Z6 | SRC_COLOR | |OPERAND1_RGB_ARB | GetTexEnviv | n x Z6 | SRC_COLOR | |OPERAND2_RGB_ARB | GetTexEnviv | n x Z1 | SRC_ALPHA | |OPERAND0_ALPHA_ARB | GetTexEnviv | n x Z4 | SRC_ALPHA | |OPERAND1_ALPHA_ARB | GetTexEnviv | n x Z4 | SRC_ALPHA | |OPERAND2_ALPHA_ARB | GetTexEnviv | n x Z1 | SRC_ALPHA | |RGB_SCALE_ARB | GetTexEnvfv | n x R3 | 1.0 | |ALPHA_SCALE | GetTexEnvfv | n x R3 | 1.0 |

New Implementation Dependent State

None