rendergroup.py

import pyglet

from pyglet.gl import (
    glActiveTexture,
    glEnable,
    glBindTexture,
    glBlendFunc,
    glDisable,
    GL_TEXTURE0,
    GL_BLEND,
    GL_SRC_ALPHA,
    GL_ONE_MINUS_SRC_ALPHA,
)
from pyglet.graphics import Group

#####################################################
# Define a custom `Group` to encapsulate OpenGL state
#####################################################
class RenderGroup(Group):
    """A Group that enables and binds a Texture and ShaderProgram.

    RenderGroups are equal if their Texture and ShaderProgram
    are equal.
    """
    def __init__(self, texture, program, order=0, parent=None):
        """Create a RenderGroup.

        :Parameters:
            `texture` : `~pyglet.image.Texture`
                Texture to bind.
            `program` : `~pyglet.graphics.shader.ShaderProgram`
                ShaderProgram to use.
            `order` : int
                Change the order to render above or below other Groups.
            `parent` : `~pyglet.graphics.Group`
                Parent group.
        """
        super().__init__(order, parent)
        self.texture = texture
        self.program = program

    def set_state(self):
        glActiveTexture(GL_TEXTURE0)
        glBindTexture(self.texture.target, self.texture.id)
        glEnable(GL_BLEND)
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
        self.program.use()

    def unset_state(self):
        glDisable(GL_BLEND)

    def __hash__(self):
        return hash((self.texture.target, self.texture.id, self.order, self.parent, self.program))

    def __eq__(self, other):
        return (self.__class__ is other.__class__ and
                self.texture.target == other.texture.target and
                self.texture.id == other.texture.id and
                self.order == other.order and
                self.program == other.program and
                self.parent == other.parent)