# coding: utf-8
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"""This module provides a class to handle shader program compilation."""
__authors__ = ["T. Vincent"]
__license__ = "MIT"
__date__ = "25/07/2016"
import logging
import weakref
import numpy
from . import Context, gl
_logger = logging.getLogger(__name__)
[docs]class Program(object):
"""Wrap OpenGL shader program.
The program is compiled lazily (i.e., at first program :meth:`use`).
When the program is compiled, it stores attributes and uniforms locations.
So, attributes and uniforms must be used after :meth:`use`.
This object supports multiple OpenGL contexts.
:param str vertexShader: The source of the vertex shader.
:param str fragmentShader: The source of the fragment shader.
:param str attrib0:
Attribute's name to bind to position 0 (default: 'position').
On certain platform, this attribute MUST be active and with an
array attached to it in order for the rendering to occur....
"""
def __init__(self, vertexShader, fragmentShader,
attrib0='position'):
self._vertexShader = vertexShader
self._fragmentShader = fragmentShader
self._attrib0 = attrib0
self._programs = weakref.WeakKeyDictionary()
@staticmethod
def _compileGL(vertexShader, fragmentShader, attrib0):
program = gl.glCreateProgram()
gl.glBindAttribLocation(program, 0, attrib0.encode('ascii'))
vertex = gl.glCreateShader(gl.GL_VERTEX_SHADER)
gl.glShaderSource(vertex, vertexShader)
gl.glCompileShader(vertex)
if gl.glGetShaderiv(vertex, gl.GL_COMPILE_STATUS) != gl.GL_TRUE:
raise RuntimeError(gl.glGetShaderInfoLog(vertex))
gl.glAttachShader(program, vertex)
gl.glDeleteShader(vertex)
fragment = gl.glCreateShader(gl.GL_FRAGMENT_SHADER)
gl.glShaderSource(fragment, fragmentShader)
gl.glCompileShader(fragment)
if gl.glGetShaderiv(fragment,
gl.GL_COMPILE_STATUS) != gl.GL_TRUE:
raise RuntimeError(gl.glGetShaderInfoLog(fragment))
gl.glAttachShader(program, fragment)
gl.glDeleteShader(fragment)
gl.glLinkProgram(program)
if gl.glGetProgramiv(program, gl.GL_LINK_STATUS) != gl.GL_TRUE:
raise RuntimeError(gl.glGetProgramInfoLog(program))
attributes = {}
for index in range(gl.glGetProgramiv(program,
gl.GL_ACTIVE_ATTRIBUTES)):
name = gl.glGetActiveAttrib(program, index)[0]
namestr = name.decode('ascii')
attributes[namestr] = gl.glGetAttribLocation(program, name)
uniforms = {}
for index in range(gl.glGetProgramiv(program, gl.GL_ACTIVE_UNIFORMS)):
name = gl.glGetActiveUniform(program, index)[0]
namestr = name.decode('ascii')
uniforms[namestr] = gl.glGetUniformLocation(program, name)
return program, attributes, uniforms
def _getProgramInfo(self):
glcontext = Context.getCurrent()
if glcontext not in self._programs:
raise RuntimeError(
"Program was not compiled for current OpenGL context.")
return self._programs[glcontext]
@property
def attributes(self):
"""Vertex attributes names and locations as a dict of {str: int}.
WARNING:
Read-only usage.
To use only with a valid OpenGL context and after :meth:`use`
has been called for this context.
"""
return self._getProgramInfo()[1]
@property
def uniforms(self):
"""Program uniforms names and locations as a dict of {str: int}.
WARNING:
Read-only usage.
To use only with a valid OpenGL context and after :meth:`use`
has been called for this context.
"""
return self._getProgramInfo()[2]
@property
def program(self):
"""OpenGL id of the program.
WARNING:
To use only with a valid OpenGL context and after :meth:`use`
has been called for this context.
"""
return self._getProgramInfo()[0]
# def discard(self):
# pass # Not implemented yet
[docs] def use(self):
"""Make use of the program, compiling it if necessary"""
glcontext = Context.getCurrent()
if glcontext not in self._programs:
self._programs[glcontext] = self._compileGL(
self._vertexShader,
self._fragmentShader,
self._attrib0)
if _logger.getEffectiveLevel() <= logging.DEBUG:
gl.glValidateProgram(self.program)
if gl.glGetProgramiv(
self.program, gl.GL_VALIDATE_STATUS) != gl.GL_TRUE:
_logger.debug('Cannot validate program: %s',
gl.glGetProgramInfoLog(self.program))
gl.glUseProgram(self.program)
