import sys, time, math, os
import Image
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *

startDir = os.getcwd()

useTexture = False
modulateTexture = False

viewDistance = 15.0
viewRotY = 0.0
viewRotX = 0.0
cameraVelX = 0.0
cameraVelY = 0.0
prevTime = time.time()

textureID = 0


def initTexture(filename):
    img = Image.open(filename)
    img = img.transpose(Image.FLIP_TOP_BOTTOM)
    global textureID
    textureID = glGenTextures(1)
    glBindTexture(GL_TEXTURE_2D, textureID)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img.size[0], img.size[1],
                 0, GL_RGB, GL_UNSIGNED_BYTE, img.tostring())
    glBindTexture(GL_TEXTURE_2D, 0)


def draw():
    glClearColor(0, 0.3, 0.5, 0)
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluPerspective(50.0, 1.0, 1.0, 100.0)
    glMatrixMode(GL_MODELVIEW)

    glLoadIdentity()
    glTranslatef(0.0, 0.0, -viewDistance)
    glRotatef(viewRotX, 1.0, 0.0, 0.0)
    glRotatef(viewRotY, 0.0, 1.0, 0.0)
    
    if useTexture:
        glEnable(GL_TEXTURE_2D)
        glBindTexture(GL_TEXTURE_2D, textureID)
    else:
        glDisable(GL_TEXTURE_2D)

    if modulateTexture:
        glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE)
    else:
        glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE)

    glColor3f(1, 1, 1)
    glTranslatef(-3, 0, 0)
    gluSphere(quadric, 2, 32, 24)

    glColor3f(0.9, 0.5, 0.2)
    glTranslatef(6, 0, 0)
    gluSphere(quadric, 2, 32, 24)

    glDisable(GL_TEXTURE_2D)
    
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()   
    gluOrtho2D(0.0, 1.0, 0.0, 1.0)
    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity()
    glColor3f(1, 1, 1)
    glRasterPos2f(0.25, 0.05)
    if not useTexture:
        drawBitmapString("No texture")
    elif modulateTexture:
        drawBitmapString("GL_MODULATE")
    else:
        drawBitmapString("GL_REPLACE")

    glutSwapBuffers()


def drawBitmapString(text, font=GLUT_BITMAP_TIMES_ROMAN_24):
    for c in text:
        glutBitmapCharacter(font, ord(c))


def keyboard(key, x, y):
    global viewDistance, modulateTexture, useTexture
    if key == chr(27):
        sys.exit(0)
    elif key == '.':
        viewDistance -= 1
    elif key == ',':
        viewDistance += 1
    elif key == ' ':
        modulateTexture = not modulateTexture
    elif key == 't':
        useTexture = not useTexture

def specialkey(key,x,y):
    global cameraVelX, cameraVelY
    if key == GLUT_KEY_LEFT:
        cameraVelY += 90
    elif key == GLUT_KEY_RIGHT:
        cameraVelY -= 90
    elif key == GLUT_KEY_UP:
        cameraVelX += 90
    elif key == GLUT_KEY_DOWN:
        cameraVelX -= 90

def specialkeyUp(key,x,y):
    global cameraVelX, cameraVelY
    if key == GLUT_KEY_LEFT:
        cameraVelY -= 90
    elif key == GLUT_KEY_RIGHT:
        cameraVelY += 90
    elif key == GLUT_KEY_UP:
        cameraVelX -= 90
    elif key == GLUT_KEY_DOWN:
        cameraVelX += 90

def update():
    global viewRotX, viewRotY, cameraVelX, cameraVelY
    global prevTime
    t = time.time()
    dt = t - prevTime
    prevTime = t
    viewRotX += cameraVelX * dt
    viewRotY += cameraVelY * dt
    glutPostRedisplay()

glutInit([])
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH)
glutInitWindowSize(400,400)
glutCreateWindow(sys.argv[0])
glutDisplayFunc(draw)
glutKeyboardFunc(keyboard)
glutSpecialFunc(specialkey)
glutSpecialUpFunc(specialkeyUp)
glutIgnoreKeyRepeat(1)
glutIdleFunc(update)
glEnable(GL_DEPTH_TEST)
os.chdir(startDir)
if len(sys.argv) > 1:
    initTexture(sys.argv[1])
else:
    initTexture("texture.tiff")
quadric = gluNewQuadric()
gluQuadricTexture(quadric, GL_TRUE)
print """Hit 't' to enable/disable texturing
Hit space to switch between GL_REPLACE and GL_MODULATE"""
glutMainLoop()