opengl_setup.py

"""mcpython - a minecraft clone written in python licenced under MIT-licence
authors: uuk, xkcdjerry

original game by forgleman licenced under MIT-licence
minecraft by Mojang

blocks based on 1.14.4.jar of minecraft, downloaded on 20th of July, 2019"""
from pyglet.gl import *


def setup_fog():
    """ Configure the OpenGL fog properties.

    """
    # Enable fog. Fog "blends a fog color with each rasterized pixel fragment's
    # post-texturing color."
    glEnable(GL_FOG)
    # Set the fog color.
    glFogfv(GL_FOG_COLOR, (GLfloat * 4)(0.5, 0.69, 1.0, 1))
    # Say we have no preference between rendering speed and quality.
    glHint(GL_FOG_HINT, GL_DONT_CARE)
    # Specify the equation used to compute the blending factor.
    glFogi(GL_FOG_MODE, GL_LINEAR)
    # How close and far away fog starts and ends. The closer the start and end,
    # the denser the fog in the fog range.
    glFogf(GL_FOG_START, 20.0)
    glFogf(GL_FOG_END, 60.0)


def setup():
    """ Basic OpenGL configuration.

    """
    # Set the color of "clear", i.e. the sky, in rgba.
    # glClearColor(0.5, 0.69, 1.0, 1)
    # Enable culling (not rendering) of back-facing facets -- facets that aren't
    # visible to you.
    glEnable(GL_CULL_FACE)
    # Set the texture minification/magnification function to GL_NEAREST (nearest
    # in Manhattan distance) to the specified texture coordinates. GL_NEAREST
    # "is generally faster than GL_LINEAR, but it can produce textured images
    # with sharper edges because the transition between texture elements is not
    # as smooth."
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)

    # setup system for alpha drawing

    glEnable(GL_BLEND)
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
    
    setup_fog()