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

filterNearest = True

squareSize = 5
deltaSquareSize = 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)
    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 drawSquare():
    glBegin(GL_QUADS)
    glTexCoord2f(0,0)
    glVertex2f(-squareSize, -squareSize)
    glTexCoord2f(1,0)
    glVertex2f(squareSize, -squareSize)
    glTexCoord2f(1,1)
    glVertex2f(squareSize, squareSize)
    glTexCoord2f(0,1)
    glVertex2f(-squareSize, squareSize)
    glEnd()

def draw():
    glClearColor(1, 1, 1, 0)
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluOrtho2D(-10, 10, -10, 10)
    glMatrixMode(GL_MODELVIEW)

    glLoadIdentity()

    glEnable(GL_TEXTURE_2D)
    glBindTexture(GL_TEXTURE_2D, textureID)
    if filterNearest:
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
    else:
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)

    glColor3f(1, 1, 1)
    drawSquare()

    glDisable(GL_TEXTURE_2D)

    if filterNearest:
        drawLabel("GL_NEAREST")
    else:
        drawLabel("GL_LINEAR")

    glutSwapBuffers()

    
def drawLabel(label):
    glDisable(GL_DEPTH_TEST)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    gluOrtho2D(0.0, 1.0, 0.0, 1.0)
    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity()
    glColor3f(0, 0, 0)
    glRasterPos2f(0.25, 0.05)
    for c in label:
        glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24, ord(c))
    glEnable(GL_DEPTH_TEST)




def keyboard(key, x, y):
    global filterNearest
    if key == chr(27):
        sys.exit(0)
    elif key == ' ':
        filterNearest = not filterNearest

def specialkey(key,x,y):
    global deltaSquareSize
    if key == GLUT_KEY_UP:
        deltaSquareSize = 2
    elif key == GLUT_KEY_DOWN:
        deltaSquareSize = -2

def specialkeyUp(key,x,y):
    global deltaSquareSize
    if key == GLUT_KEY_UP:
        deltaSquareSize = 0
    elif key == GLUT_KEY_DOWN:
        deltaSquareSize = 0

def update():
    global squareSize, deltaSquareSize
    global prevTime
    t = time.time()
    dt = t - prevTime
    prevTime = t
    squareSize += deltaSquareSize * dt
    glutPostRedisplay()

glutInit([])
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH)
glutInitWindowSize(600,600)
glutCreateWindow(sys.argv[0])
glutDisplayFunc(draw)
glutKeyboardFunc(keyboard)
glutSpecialFunc(specialkey)
glutSpecialUpFunc(specialkeyUp)
glutIgnoreKeyRepeat(1)
glutIdleFunc(update)
glEnable(GL_DEPTH_TEST)
if len(sys.argv) > 1:
    initTexture(sys.argv[1])
else:
    initTexture("texture.tiff")
glutMainLoop()