<filename>DemOpenGL/NeHe/lesson16.py
#!/usr/bin/env python3
# -*- coding: utf8 -*-

"""Port of NeHe Lesson 16 by <NAME> <<EMAIL>>"""
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import sys
from PIL import Image

# Some api in the chain is translating the keystrokes to this octal string
# so instead of saying: ESCAPE = 27, we use the following.
ESCAPE = b'\033'

# Number of the glut window.
window = 0

# Rotations for cube.
xrot = yrot = zrot = 0.0

fogColor = (0.5, 0.5, 0.5, 1.0)  # fog color

texture = 0


def LoadTextures():
    #global texture
    image = Image.open("NeHe.bmp")

    ix = image.size[0]
    iy = image.size[1]
    image = image.tobytes('raw', 'RGBX', 0, -1)

    # Create Texture
    # 2d texture (x and y size)
    glBindTexture(GL_TEXTURE_2D, glGenTextures(1))

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1)
    glTexImage2D(GL_TEXTURE_2D, 0, 3, ix, iy, 0,
                 GL_RGBA, GL_UNSIGNED_BYTE, image)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL)

# A general OpenGL initialization function.  Sets all of the initial parameters.


# We call this right after our OpenGL window is created.
def InitGL(Width, Height):
    LoadTextures()
    glEnable(GL_TEXTURE_2D)
    # This Will Clear The Background Color To Black
    glClearColor(0.0, 0.0, 0.0, 0.0)
    glClearDepth(1.0)          # Enables Clearing Of The Depth Buffer
    glDepthFunc(GL_LESS)      # The Type Of Depth Test To Do
    glEnable(GL_DEPTH_TEST)      # Enables Depth Testing
    glShadeModel(GL_SMOOTH)      # Enables Smooth Color Shading

    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()          # Reset The Projection Matrix
    # Calculate The Aspect Ratio Of The Window
    gluPerspective(45.0, float(Width)/float(Height), 0.1, 100.0)

    glMatrixMode(GL_MODELVIEW)

# The function called when our window is resized (which shouldn't happen if you enable fullscreen, below)


def ReSizeGLScene(Width, Height):
    if Height == 0:    # Prevent A Divide By Zero If The Window Is Too Small
        Height = 1

    # Reset The Current Viewport And Perspective Transformation
    glViewport(0, 0, Width, Height)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluPerspective(45.0, float(Width)/float(Height), 0.1, 100.0)
    glMatrixMode(GL_MODELVIEW)

# The main drawing function.


def DrawGLScene():
    global xrot, yrot, zrot, texture

    # Clear The Screen And The Depth Buffer
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    glLoadIdentity()          # Reset The View

    glClearColor(0.5, 0.5, 0.5, 1.0)

    glEnable(GL_FOG)     # Enable fog

    glFogi(GL_FOG_MODE, GL_LINEAR)           # Set fog settings

    glFogfv(GL_FOG_COLOR, fogColor)  # Set fog color

    glFogf(GL_FOG_DENSITY, 0.15)  # Set fog density

    glHint(GL_FOG_HINT, GL_DONT_CARE)  # Set Hint

    glFogf(GL_FOG_START, 1.0)  # Fog start

    glFogf(GL_FOG_END, 5.0)  # Fog end

    glTranslatef(0.0, 0.0, -5.0)  # Move Into The Screen

    glRotatef(xrot, 1.0, 0.0, 0.0)  # Rotate The Cube On It's X Axis
    glRotatef(yrot, 0.0, 1.0, 0.0)  # Rotate The Cube On It's Y Axis
    glRotatef(zrot, 0.0, 0.0, 1.0)  # Rotate The Cube On It's Z Axis

    # Note there does not seem to be support for this call.
    # glBindTexture(GL_TEXTURE_2D,texture)    # Rotate The Pyramid On It's Y Axis

    glBegin(GL_QUADS)      # Start Drawing The Cube

    # Front Face (note that the texture's corners have to match the quad's corners)
    glTexCoord2f(0.0, 0.0)  # Bottom Left Of The Texture and Quad
    glTexCoord2f(1.0, 0.0)  # Bottom Right Of The Texture and Quad
    glTexCoord2f(1.0, 1.0)  # Top Right Of The Texture and Quad
    glTexCoord2f(0.0, 1.0)  # Top Left Of The Texture and Quad

    # Back Face
    glTexCoord2f(1.0, 0.0)  # Bottom Right Of The Texture and Quad
    glTexCoord2f(1.0, 1.0)  # Top Right Of The Texture and Quad
    glTexCoord2f(0.0, 1.0)  # Top Left Of The Texture and Quad
    glTexCoord2f(0.0, 0.0)  # Bottom Left Of The Texture and Quad

    # Top Face
    glTexCoord2f(0.0, 1.0)  # Top Left Of The Texture and Quad
    glTexCoord2f(0.0, 0.0)  # Bottom Left Of The Texture and Quad
    glTexCoord2f(1.0, 0.0)  # Bottom Right Of The Texture and Quad
    glTexCoord2f(1.0, 1.0)  # Top Right Of The Texture and Quad

    # Bottom Face
    glTexCoord2f(1.0, 1.0)  # Top Right Of The Texture and Quad
    glTexCoord2f(0.0, 1.0)  # Top Left Of The Texture and Quad
    glTexCoord2f(0.0, 0.0)  # Bottom Left Of The Texture and Quad
    glTexCoord2f(1.0, 0.0)  # Bottom Right Of The Texture and Quad

    # Right face
    glTexCoord2f(1.0, 0.0)  # Bottom Right Of The Texture and Quad
    glTexCoord2f(1.0, 1.0)  # Top Right Of The Texture and Quad
    glTexCoord2f(0.0, 1.0)  # Top Left Of The Texture and Quad
    glTexCoord2f(0.0, 0.0)  # Bottom Left Of The Texture and Quad

    # Left Face
    glTexCoord2f(0.0, 0.0)  # Bottom Left Of The Texture and Quad
    glTexCoord2f(1.0, 0.0)  # Bottom Right Of The Texture and Quad
    glTexCoord2f(1.0, 1.0)  # Top Right Of The Texture and Quad
    glTexCoord2f(0.0, 1.0)  # Top Left Of The Texture and Quad

    glEnd()  # Done Drawing The Cube

    xrot = xrot + 0.2      # X rotation
    yrot = yrot + 0.2       # Y rotation
    zrot = zrot + 0.2       # Z rotation

    #  since this is double buffered, swap the buffers to display what just got drawn.
    glutSwapBuffers()

# The function called whenever a key is pressed. Note the use of Python tuples to pass in: (key, x, y)


def keyPressed(*args):
    # If escape is pressed, kill everything.
    if args[0] == ESCAPE:
        glutDestroyWindow(window)


def main():
    global window
    glutInit(sys.argv)

    # Select type of Display mode:
    #  Double buffer
    #  RGBA color
    # Alpha components supported
    # Depth buffer
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)

    # get a 640 x 480 window
    glutInitWindowSize(640, 480)

    # the window starts at the upper left corner of the screen
    glutInitWindowPosition(0, 0)

    # Okay, like the C version we retain the window id to use when closing, but for those of you new
    # to Python (like myself), remember this assignment would make the variable local and not global
    # if it weren't for the global declaration at the start of main.
    window = glutCreateWindow('Fog by RISC')

    # Register the drawing function with glut, BUT in Python land, at least using PyOpenGL, we need to
    # set the function pointer and invoke a function to actually register the callback, otherwise it
    # would be very much like the C version of the code.
    glutDisplayFunc(DrawGLScene)

    # Uncomment this line to get full screen.
    # glutFullScreen()

    # When we are doing nothing, redraw the scene.
    glutIdleFunc(DrawGLScene)

    # Register the function called when our window is resized.
    glutReshapeFunc(ReSizeGLScene)

    # Register the function called when the keyboard is pressed.
    glutKeyboardFunc(keyPressed)

    # Print message to console, and kick off the main to get it rolling.
    print('Hit ESC key to quit.')

    # Initialize our window.
    InitGL(640, 480)

    # Start Event Processing Engine
    glutMainLoop()


if __name__ == "__main__":
    main()
