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'''OpenGL extension NV.texture_shader
This module customises the behaviour of the
OpenGL.raw.GL.NV.texture_shader to provide a more
Python-friendly API
Overview (from the spec)
Standard OpenGL and the ARB_multitexture extension define a
straightforward direct mechanism for mapping sets of texture
coordinates to filtered colors. This extension provides a more
functional mechanism.
OpenGL's standard texturing mechanism defines a set of texture
targets. Each texture target defines how the texture image
is specified and accessed via a set of texture coordinates.
OpenGL 1.0 defines the 1D and 2D texture targets. OpenGL 1.2
(and/or the EXT_texture3D extension) defines the 3D texture target.
The ARB_texture_cube_map extension defines the cube map texture
target. Each texture unit's texture coordinate set is mapped to a
color using the unit's highest priority enabled texture target.
This extension introduces texture shader stages. A sequence of
texture shader stages provides a more flexible mechanism for mapping
sets of texture coordinates to texture unit RGBA results than standard
OpenGL.
When the texture shader enable is on, the extension replaces the
conventional OpenGL mechanism for mapping sets of texture coordinates
to filtered colors with this extension's sequence of texture shader
stages.
Each texture shader stage runs one of 21 canned texture shader
programs. These programs support conventional OpenGL texture
mapping but also support dependent texture accesses, dot product
texture programs, and special modes. (3D texture mapping
texture shader operations are NOT provided by this extension;
3D texture mapping texture shader operations are added by the
NV_texture_shader2 extension that is layered on this extension.
See the NV_texture_shader2 specification.)
To facilitate the new texture shader programs, this extension
introduces several new texture formats and variations on existing
formats. Existing color texture formats are extended by introducing
new signed variants. Two new types of texture formats (beyond colors)
are also introduced. Texture offset groups encode two signed offsets,
and optionally a magnitude or a magnitude and an intensity. The new
HILO (pronounced high-low) formats provide possibly signed, high
precision (16-bit) two-component textures.
Each program takes as input the stage's interpolated texture
coordinate set (s,t,r,q). Each program generates two results:
a shader stage result that may be used as an input to subsequent
shader stage programs, and a texture unit RGBA result that becomes the
texture color used by the texture unit's texture environment function
or becomes the initial value for the corresponding texture register
for register combiners. The texture unit RGBA result is always
an RGBA color, but the shader stage result may be one of an RGBA
color, a HILO value, a texture offset group, a floating-point value,
or an invalid result. When both results are RGBA colors, the shader
stage result and the texture unit RGBA result are usually identical
(though not in all cases).
Additionally, certain programs have a side-effect such as culling
the fragment or replacing the fragment's depth value.
The twenty-one programs are briefly described:
<none>
1. NONE - Always generates a (0,0,0,0) texture unit RGBA result.
Equivalent to disabling all texture targets in conventional
OpenGL.
<conventional textures>
2. TEXTURE_1D - Accesses a 1D texture via (s/q).
3. TEXTURE_2D - Accesses a 2D texture via (s/q,t/q).
4. TEXTURE_RECTANGLE_NV - Accesses a rectangular texture via (s/q,t/q).
5. TEXTURE_CUBE_MAP_ARB - Accesses a cube map texture via (s,t,r).
<special modes>
6. PASS_THROUGH_NV - Converts a texture coordinate (s,t,r,q)
directly to a [0,1] clamped (r,g,b,a) texture unit RGBA result.
7. CULL_FRAGMENT_NV - Culls the fragment based on the whether each
(s,t,r,q) is "greater than or equal to zero" or "less than zero".
<offset textures>
8. OFFSET_TEXTURE_2D_NV - Transforms the signed (ds,dt) components
of a previous texture unit by a 2x2 floating-point matrix and
then uses the result to offset the stage's texture coordinates
for a 2D non-projective texture.
9. OFFSET_TEXTURE_2D_SCALE_NV - Same as above except the magnitude
component of the previous texture unit result scales the red,
green, and blue components of the unsigned RGBA texture 2D
access.
10. OFFSET_TEXTURE_RECTANGLE_NV - Similar to OFFSET_TEXTURE_2D_NV
except that the texture access is into a rectangular
non-projective texture.
11. OFFSET_TEXTURE_RECTANGLE_SCALE_NV - Similar to
OFFSET_TEXTURE_2D_SCALE_NV except that the texture access is
into a rectangular non-projective texture.
<dependent textures>
12. DEPENDENT_AR_TEXTURE_2D_NV - Converts the alpha and red
components of a previous shader result into an (s,t) texture
coordinate set to access a 2D non-projective texture.
13. DEPENDENT_GB_TEXTURE_2D_NV - Converts the green and blue
components of a previous shader result into an (s,t) texture
coordinate set to access a 2D non-projective texture.
<dot product textures>
14. DOT_PRODUCT_NV - Computes the dot product of the texture
shader's texture coordinate set (s,t,r) with some mapping of the
components of a previous texture shader result. The component
mapping depends on the type (RGBA or HILO) and signedness of
the stage's previous texture input. Other dot product texture
programs use the result of this program to compose a texture
coordinate set for a dependent texture access. The color result
is undefined.
15. DOT_PRODUCT_TEXTURE_2D_NV - When preceded by a DOT_PRODUCT_NV
program in the previous texture shader stage, computes a second
similar dot product and composes the two dot products into (s,t)
texture coordinate set to access a 2D non-projective texture.
16. DOT_PRODUCT_TEXTURE_RECTANGLE_NV - Similar to
DOT_PRODUCT_TEXTURE_2D_NV except that the texture acces is into
a rectangular non-projective texture.
17. DOT_PRODUCT_TEXTURE_CUBE_MAP_NV - When preceded by two
DOT_PRODUCT_NV programs in the previous two texture shader
stages, computes a third similar dot product and composes the
three dot products into (s,t,r) texture coordinate set to access
a cube map texture.
18. DOT_PRODUCT_REFLECT_CUBE_MAP_NV - When preceded by two
DOT_PRODUCT_NV programs in the previous two texture shader
stages, computes a third similar dot product and composes the
three dot products into a normal vector (Nx,Ny,Nz). An eye
vector (Ex,Ey,Ez) is composed from the q texture coordinates of
the three stages. A reflection vector (Rx,Ry,Rz) is computed
based on the normal and eye vectors. The reflection vector
forms an (s,t,r) texture coordinate set to access a cube map
texture.
19. DOT_PRODUCT_CONST_EYE_REFLECT_CUBE_MAP_NV - Operates like
DOT_PRODUCT_REFLECT_CUBE_MAP_NV except that the eye vector
(Ex,Ey,Ez) is a user-defined constant rather than composed from
the q coordinates of the three stages.
20. DOT_PRODUCT_DIFFUSE_CUBE_MAP_NV - When used instead of the second
DOT_PRODUCT_NV program preceding
a DOT_PRODUCT_REFLECT_CUBE_MAP_NV or
DOT_PRODUCT_CONST_EYE_REFLECT_CUBE_MAP_NV stage, the normal
vector forms an (s,t,r) texture coordinate set to access a
cube map texture.
<dot product depth replace>
21. DOT_PRODUCT_DEPTH_REPLACE_NV - When preceded by a DOT_PRODUCT_NV
program in the previous texture shader stage, computes a second
similar dot product and replaces the fragment's window-space
depth value with the first dot product results divided by
the second. The texture unit RGBA result is (0,0,0,0).
The official definition of this extension is available here:
http://www.opengl.org/registry/specs/NV/texture_shader.txt
'''
from OpenGL import platform, constants, constant, arrays
from OpenGL import extensions, wrapper
from OpenGL.GL import glget
import ctypes
from OpenGL.raw.GL.NV.texture_shader import *
### END AUTOGENERATED SECTION
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