File: vertex_program.py

package info (click to toggle)
pyopengl 3.0.1-1
  • links: PTS, VCS
  • area: main
  • in suites: wheezy
  • size: 6,140 kB
  • sloc: python: 26,428; makefile: 2
file content (142 lines) | stat: -rw-r--r-- 6,038 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
'''OpenGL extension ARB.vertex_program

This module customises the behaviour of the 
OpenGL.raw.GL.ARB.vertex_program to provide a more 
Python-friendly API

Overview (from the spec)
	
	Unextended OpenGL mandates a certain set of configurable per-vertex
	computations defining vertex transformation, texture coordinate generation
	and transformation, and lighting.  Several extensions have added further
	per-vertex computations to OpenGL.  For example, extensions have defined
	new texture coordinate generation modes (ARB_texture_cube_map,
	NV_texgen_reflection, NV_texgen_emboss), new vertex transformation modes
	(ARB_vertex_blend, EXT_vertex_weighting), new lighting modes (OpenGL 1.2's
	separate specular and rescale normal functionality), several modes for fog
	distance generation (NV_fog_distance), and eye-distance point size
	attenuation (EXT/ARB_point_parameters).
	
	Each such extension adds a small set of relatively inflexible
	per-vertex computations.
	
	This inflexibility is in contrast to the typical flexibility provided by
	the underlying programmable floating point engines (whether micro-coded
	vertex engines, DSPs, or CPUs) that are traditionally used to implement
	OpenGL's per-vertex computations.  The purpose of this extension is to
	expose to the OpenGL application writer a significant degree of per-vertex
	programmability for computing vertex parameters.
	
	For the purposes of discussing this extension, a vertex program is a
	sequence of floating-point 4-component vector operations that determines
	how a set of program parameters (defined outside of OpenGL's Begin/End
	pair) and an input set of per-vertex parameters are transformed to a set
	of per-vertex result parameters.
	
	The per-vertex computations for standard OpenGL given a particular set of
	lighting and texture coordinate generation modes (along with any state for
	extensions defining per-vertex computations) is, in essence, a vertex
	program.  However, the sequence of operations is defined implicitly by the
	current OpenGL state settings rather than defined explicitly as a sequence
	of instructions.
	
	This extension provides an explicit mechanism for defining vertex program
	instruction sequences for application-defined vertex programs.  In order
	to define such vertex programs, this extension defines a vertex
	programming model including a floating-point 4-component vector
	instruction set and a relatively large set of floating-point 4-component
	registers.
	
	The extension's vertex programming model is designed for efficient
	hardware implementation and to support a wide variety of vertex programs.
	By design, the entire set of existing vertex programs defined by existing
	OpenGL per-vertex computation extensions can be implemented using the
	extension's vertex programming model.

The official definition of this extension is available here:
http://www.opengl.org/registry/specs/ARB/vertex_program.txt
'''
from OpenGL import platform, constants, constant, arrays
from OpenGL import extensions, wrapper
from OpenGL.GL import glget
import ctypes
from OpenGL.raw.GL.ARB.vertex_program import *
### END AUTOGENERATED SECTION
from OpenGL.lazywrapper import lazy

from OpenGL import converters, error, contextdata
from OpenGL.arrays.arraydatatype import ArrayDatatype
# Note: sizes here are == the only documented sizes I could find,
# may need a lookup table some day...
glGetProgramivARB = wrapper.wrapper(glGetProgramivARB).setOutput(
    'params', (1,),
)
glGetProgramEnvParameterdvARB = wrapper.wrapper(glGetProgramEnvParameterdvARB).setOutput(
    'params',(4,),
)
glGetProgramEnvParameterfvARB = wrapper.wrapper(glGetProgramEnvParameterfvARB).setOutput(
    'params',(4,),
)
glGetProgramLocalParameterdvARB = wrapper.wrapper(glGetProgramLocalParameterdvARB).setOutput(
    'params',(4,),
)
glGetProgramLocalParameterfvARB = wrapper.wrapper(glGetProgramLocalParameterfvARB).setOutput(
    'params',(4,),
)
glGetVertexAttribdvARB = wrapper.wrapper(glGetVertexAttribdvARB).setOutput(
    'params',(1,),
)

##glGetVertexAttribPointervARB = wrapper.wrapper(glGetVertexAttribPointervARB).setOutput(
##	'pointer',(1,),
##)
##
##_base_glGetVertexAttribPointervARB
##def glGetVertexAttribPointervARB( index, pname=GL_VERTEX_ATTRIB_ARRAY_POINTER_ARB ):
##	"""Retrieve named attribute vector
##	
##	XXX Needs logic checking, I don't think I got the number of
##	levels of indirection correct... i.e. I believe it's just going
##	to rewrite the temporary void_p's value, rather than writing
##	into the numpy array.
##	
##	returns 4-element double array...
##	"""
##	output = arrays.GLdoubleArray.zeros( (4,) )
##	pointer = arrays.GLdoubleArray.voidDataPointer( output )
##	_base_glGetVertexAttribPointervARB( index, pname, pointer )
##	return output

@lazy( glVertexAttribPointerARB )
def glVertexAttribPointerARB( 
    baseOperation, index, size, type,
    normalized, stride, pointer,
):
    """Set an attribute pointer for a given shader (index)
    
    index -- the index of the generic vertex to bind, see 
        glGetAttribLocation for retrieval of the value,
        note that index is a global variable, not per-shader
    size -- number of basic elements per record, 1,2,3, or 4
    type -- enum constant for data-type 
    normalized -- whether to perform int to float 
        normalization on integer-type values
    stride -- stride in machine units (bytes) between 
        consecutive records, normally used to create 
        "interleaved" arrays 
    pointer -- data-pointer which provides the data-values,
        normally a vertex-buffer-object or offset into the 
        same.
    
    This implementation stores a copy of the data-pointer 
    in the contextdata structure in order to prevent null-
    reference errors in the renderer.
    """
    array = ArrayDatatype.asArray( pointer )
    key = ('vertex-attrib',index)
    contextdata.setValue( key, array )
    return baseOperation(
        index, size, type,
        normalized, stride, 
        ArrayDatatype.voidDataPointer( array ) 
    )