[pygame] Code: Center of Triangle

[Kamilche <kamilche@xxxxxxxxxxxx>]

Worked this up today for myself, thought I'd post it in case someone 
else found it useful.

import pygame

def CenterOfTriangle(A, B, C):
    return  (A[0] + B[0] + C[0])/3.0, (A[1] + B[1] + C[1])/3.0, (A[2] + 
B[2] + C[2])/3.0

def CalculateDistance(a, b):
    x, y, z = b[0] - a[0], b[1] - a[1], b[2] - a[2]
    dist = x*x + y*y + z*z
    return dist * dist

def NearestVert(triangle, pos):
    distance = 99999999999999999999
    v = -1
    for i in range(len(triangle)):
        temp = CalculateDistance(triangle[i], [pos[0], pos[1], 0])
        if temp < distance:
            distance = temp
            v = i
    assert(v >= 0)
    return v

def main():
    pygame.init()
    screen = pygame.display.set_mode([640, 480], 0, 32)
    quit = 0

    triangle = [[132, 319, 0], [282, 120, 0], [434, 319, 0]]
    center = CenterOfTriangle(*triangle)

    v = -1
    font = pygame.font.Font(None, 18)
    pic = font.render('Center: %d, %d, %d Triangle: %s' % 
(int(center[0]), int(center[1]), int(center[2]), triangle), 1, (0, 0, 0))

    while not quit:
        screen.fill((255, 255, 255))
        pygame.draw.polygon(screen, (0, 0, 0), [triangle[0][:2], 
triangle[1][:2], triangle[2][:2]], 1)
        x, y, z = int(center[0]), int(center[1]), int(center[2])
        screen.fill((255, 0, 0), [x-2, y-2, 4, 4])
        screen.blit(pic, [0, 450])
        pygame.display.flip()
        pygame.event.pump()
        for e in pygame.event.get():
            if e.type == pygame.QUIT:
                quit = 1
                break
            elif e.type == pygame.MOUSEBUTTONDOWN:
                v = NearestVert(triangle, e.pos)
            elif e.type == pygame.MOUSEMOTION:
                if v > -1:
                    triangle[v] = [e.pos[0], e.pos[1], 0]
                    center = CenterOfTriangle(*triangle)
                    pic = font.render('Center: %d, %d, %d Triangle: %s' 
% (int(center[0]), int(center[1]), int(center[2]), triangle), 1, (0, 0, 0))
            elif e.type == pygame.MOUSEBUTTONUP:
                v = -1

    pygame.quit()

main()