#!python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2022/09/11 06:43:37 +0900>
"""
Darw texture

Windows10 x64 21H2 + Python 3.9.13 64bit + PyOpenGL 3.1.6
"""


from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import sys
from PIL import Image


IMGS = [
    "img_rgb.png",
    "img_rgba.png",
    "img_grayscale.png",
    "img_palette.png",
]

IMG_IDX = 0

SCRW, SCRH = 512, 512
FPS = 60
PANGLE = 60.0

window = 0

# Rotation angle for the Quads
rotx = 0.0
roty = 0.0

texture = 0


def load_texture():
    global texture

    # load image by using PIL
    im = Image.open(IMGS[IMG_IDX])
    w, h = im.size
    print("Image: %d x %d, %s" % (w, h, im.mode))

    if im.mode == "RGB":
        # RGB convert to RGBA
        im.putalpha(alpha=255)
    elif im.mode == "L" or im.mode == "P":
        # Grayscale, Index Color convert to RGBA
        im = im.convert("RGBA")

    raw_image = im.tobytes()

    ttype = GL_RGBA
    if im.mode == "RGB":
        ttype = GL_RGB
    elif im.mode == "RGBA":
        ttype = GL_RGBA

    glBindTexture(GL_TEXTURE_2D, glGenTextures(1))

    # glPixelStorei(GL_UNPACK_ALIGNMENT, 1)
    glPixelStorei(GL_UNPACK_ALIGNMENT, 4)

    # set texture
    glTexImage2D(
        GL_TEXTURE_2D,      # target
        0,                  # MIPMAP level
        ttype,              # texture type (RGB, RGBA)
        w,                  # texture image width
        h,                  # texture image height
        0,                  # border width
        ttype,              # texture type (RGB, RGBA)
        GL_UNSIGNED_BYTE,   # data is unsigne char
        raw_image,          # texture data pointer
    )

    glClearColor(0, 0, 0, 0)
    glShadeModel(GL_SMOOTH)

    # set texture repeat
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)

    # set texture filter
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)

    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE)
    # glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL)
    # glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE)
    # glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_BLEND)


def InitGL(width, height):
    glClearColor(0.125, 0.25, 0.5, 0.0)  # background color
    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(PANGLE, float(width) / float(height), 0.1, 100.0)

    glMatrixMode(GL_MODELVIEW)


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

    # Reset The Current Viewport And Perspective Transformation
    glViewport(0, 0, width, height)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluPerspective(PANGLE, float(width) / float(height), 0.1, 100.0)
    glMatrixMode(GL_MODELVIEW)


def DrawGLScene():
    global rotx, roty

    glClearColor(0.125, 0.25, 0.5, 0.0)  # background color
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    glLoadIdentity()  # Reset The View

    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
    glEnable(GL_BLEND)
    glEnable(GL_TEXTURE_2D)

    glPushMatrix()
    glTranslatef(0.0, 0.0, -2.0)  # translate

    # Rotate
    glRotatef(roty, 0.0, 1.0, 0.0)
    glRotatef(rotx, 1.0, 0.0, 0.0)

    glColor4f(1.0, 1.0, 1.0, 1.0)  # color

    # draw quads
    x, y, z = 1.0, 1.0, 0.0
    glBegin(GL_QUADS)

    glTexCoord2f(0.0, 0.0)  # set u, v
    glVertex3f(-x, y, z)  # Top Left

    glTexCoord2f(1.0, 0.0)
    glVertex3f(x, y, z)  # Top Right

    glTexCoord2f(1.0, 1.0)
    glVertex3f(x, -y, z)  # Bottom Right

    glTexCoord2f(0.0, 1.0)
    glVertex3f(-x, -y, z)  # Bottom Left

    glEnd()

    glPopMatrix()
    glDisable(GL_TEXTURE_2D)
    glDisable(GL_BLEND)

    glutSwapBuffers()


def on_timer(value):
    global rotx, roty
    rotx = -10.0
    roty = roty + 1.0
    glutPostRedisplay()
    glutTimerFunc(int(1000 / FPS), on_timer, 0)


def keyPressed(key, x, y):
    # If escape is pressed, kill everything.
    ESCAPE = b"\x1b"
    if key == ESCAPE or key == b'q':
        if glutLeaveMainLoop:
            glutLeaveMainLoop()
        else:
            sys.exit()


def main():
    global window

    glutInit(sys.argv)
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)

    glutInitWindowSize(SCRW, SCRH)
    # glutInitWindowPosition(0, 0)

    window = glutCreateWindow(b"Draw texture")

    glutDisplayFunc(DrawGLScene)
    glutReshapeFunc(ReSizeGLScene)
    # glutFullScreen()

    # glutIdleFunc(DrawGLScene)
    glutTimerFunc(int(1000 / FPS), on_timer, 0)

    glutKeyboardFunc(keyPressed)
    InitGL(SCRW, SCRH)

    load_texture()

    glutMainLoop()


if __name__ == "__main__":
    print("Hit ESC key to quit.")
    main()