"""
Terrain generation experiments (1)
Public domain. Based on an academic paper:

Realtime Procedural Terrain Generation
Realtime Synthesis of Eroded Fractal Terrain for Use in Computer Games
Jacob Olsen, xenorg@imada.sdu.dk
Department of Mathematics And Computer Science (IMADA)
University of Southern Denmark
October 31, 2004

This is a quick and dirty implementation of some of the "Voronoi" algorithm
mentioned in the above paper, for terrain generation. This code was done
by Kris Schnee late one night and should not be blamed on the authors.
"""

import pygame
pygame.init()
import random
random.seed("Next My Generation") ## Song title I was listening to
screen = pygame.display.set_mode((512,512))

#### Here's one way of generating some random static.
##t_random = pygame.surface.Surface((256,256))
##t_random.fill((0,0,0))
##for y in range(0,256):
##    for x in range(0,256):
##        c = random.randint(0,128)+random.randint(0,64)+random.randint(0,32)+random.randint(0,16)+random.randint(0,8)
##        t_random.set_at((x,y),(c,c,c))
##
##for r in range(5):
##    for y in range(1,255):
##        for x in range(1,255):
##            n = (t_random.get_at((x,y-1))[0]+t_random.get_at((x,y+1))[0]+
##                 t_random.get_at((x-1,y))[0]+t_random.get_at((x+1,y))[0])/4
##
##            h = t_random.get_at((x,y))[0]
##            if n > h+16:
##                h += 16
##                t_random.set_at((x,y),(h,h,h))
##            elif n < h-16:
##                h -= 16
##                t_random.set_at((x,y),(h,h,h))
##t_random = pygame.transform.scale2x(t_random)
##pygame.image.save(t_random,"smoothed_static.bmp")
## Once you generate this using the above code, just use this line:
##t_random = pygame.image.load("smoothed_static.bmp").convert()


#### This chunk of code doesn't do what it's supposed to,
#### but the effect is cool. A fractal?
##import pygame
##pygame.init()
##import random
##random.seed("Next My Generation")
##screen = pygame.display.set_mode((512,512))
##
##voronoi = pygame.surface.Surface((500,500))
##voronoi.fill((0,0,0))
##for zy in range(0,512,100):
##    for zx in range(0,512,100):
##        f1 = (random.randint(zx,zx+0),random.randint(zy,zy+0))
##        for y in range(zy,zy+99):
##            for x in range(zx,zx+99):
##                dist_approx = pow(zx-x,2) + pow(zy-y,2)
##                h = dist_approx
##                voronoi.set_at((x,y),h) ## Try multiplying h by a power of 2!
##
##screen.blit(voronoi,(0,0))
##pygame.display.update()



#### Another neat glitch effect, kind of like brushed steel.
##t_voronoi = pygame.surface.Surface((512,512))
##t_voronoi.fill((0,0,0))
##for zy in range(0,512,128):
##    for zx in range(0,512,128):
##        f1x,f1y = (random.randint(zx,zx+127),random.randint(zy,zy+127))
##        f2x,f2y = (random.randint(zx,zx+127),random.randint(zy,zy+127))
##        for y in range(zy,zy+128):
##            for x in range(zx,zx+128):
##                dist_approx_1 = pow(f1x-x,2) + pow(f1y-y,2)
##                h1 = int((dist_approx_1 / 32768.0) * 256)
##                dist_approx_2 = pow(f2x-x,2) + pow(f2y-y,2)
##                h2 = 1 / (int((dist_approx_2 / 32768.0) * 256)+1)
##                c = h1-(h2/2)
##                t_voronoi.set_at((x,y),(c,c,c))


t_voronoi = pygame.surface.Surface((513,513))
t_voronoi.fill((0,0,0))
feature_points = []
for zy in range(0,512,128):
    for zx in range(0,512,128):
        f1x,f1y = (random.randint(zx,zx+127),random.randint(zy,zy+127))
        feature_points.append((f1x,f1y))
##        f2x,f2y = (random.randint(zx,zx+127),random.randint(zy,zy+127))

for y in range(0,512):
    for x in range(0,512):
        closest = 99999
        for point in feature_points:
            dist_approx_1 = pow(point[0]-x,2) + pow(point[1]-y,2)
            if dist_approx_1 < closest:
                closest = dist_approx_1
        ## Base the height on the distance to the nearest feature point.
        ## I don't have this part down in an ideal way.

        ## This line version doesn't work.
##        h1 = int((1-(closest/262144.0)) * 256)-1
        ## This version gives little circles.
##        h1 = [0,255][closest < 100]
        ## This version gives dark bubbles on white.
##        h1 = (closest/10000.0)*256
        ## White bubbles on black.
        h1 = (1-(closest/5000.0))*256
        ## Fuzzy; reminds me of some cheese I left in the fridge too long.
##        h1 = (1-(float(closest)/random.randint(3000,40000)))*256

        h1 = max(min(h1,255),0)
        c = h1
        t_voronoi.set_at((x,y),(c,c,c))

## Render the Voronoi terrain.
terrain = t_voronoi
screen.blit(terrain,(0,0))

#### Alternative: Blend it with some random static.
##t_voronoi.set_alpha(200)
##t_random.blit(t_voronoi,(0,0))
##terrain = t_random
##screen.blit(terrain,(0,0))

pygame.display.update()