Problem is: objects fall into a 2D tank, leaving 1D ripples.
I have implemented techniques similar to the technique best described here: http://freespace.virgin.net/hugo.elias/graphics/x_water.htm. Unfortunately, these quickly result in high frequency noise because of the initial discontinuity of perturbing a single particle. However, though the particles are oscillating, I can make out slow-moving waves. It's these slow-moving waves that I want!
Basically, I'm looking for a hackish algorithm that can generate plausible-looking waves on the surface of a 1D grid, using any detail level of grid.
I present the following Python code as a demonstration of the algorithm's faults, and as a testbed for new algorithms:[source lang="python"]import pygame
from pygame.locals import *
import sys, os, traceback
if sys.platform == 'win32' or sys.platform == 'win64':
os.environ['SDL_VIDEO_CENTERED'] = '1'
pygame.display.init()
pygame.font.init()
screen_size = [1200,200]
icon = pygame.Surface((1,1)); icon.set_alpha(0); pygame.display.set_icon(icon)
pygame.display.set_caption("1D Surface Test - Ian Mallett - v.1 - 2012")
surface = pygame.display.set_mode(screen_size)
num = 300
#====================================METHOD 1====================================
###My feeble algorithm
##class particle:
## def __init__(self):
## self.height = 0
## self.speed = 0
## self.force = 0
## def apply(self,force):
## self.force += 10*force
##def update():
## particles[0].force += -0.1*(particles[0].height-0.0)
## for i in xrange(1,num,1):
## particles.force += -0.1*(particles.height-particles[i-1].height)
##
## for i in xrange(0,num-1,1):
## particles.force += -0.1*(particles.height-particles[i+1].height)
## particles[-1].force += -0.1*(particles[-1].height-0.0)
##
## for i in xrange(0,num,1):
## particles.force += -0.1*(particles.height-0.0)
##
## for i in xrange(0,num,1):
## particles.speed += particles.force
## particles.speed *= 0.9999
## particles.height += particles.speed
## particles.force = 0
#====================================METHOD 2====================================
#Method after http://freespace.virgin.net/hugo.elias/graphics/x_water.htm
class particle:
def __init__(self):
self.buffer1 = 0.0
self.buffer2 = 0.0
self.height = 0.0
def apply(self,force):
self.buffer1 += 10*force
def update():
## kernel = 1
for i in xrange(1,num-1,1):
particles.buffer2 = (
particles[i-1].buffer1+
particles[i+1].buffer1
)/2.0 - particles.buffer2
## last = particles.buffer2
## particles.buffer2 = 0.0
## max_sum = 0.0
## for x in xrange(-kernel,kernel+1,1):
## index = i + x
## if index < 0: continue
## if index >= num: continue
## particles.buffer2 += particles[index].buffer1
## max_sum += 1.0
## particles.buffer2 /= max_sum
## particles.buffer2 -= last
particles.buffer2 *= 0.99999
particles.height = particles.buffer2
for i in xrange(0,num,1):
temp = particles.buffer2
particles.buffer2 = particles.buffer1
particles.buffer1 = temp
#====================================END METHODS====================================
def setup():
global particles, paused
particles = [particle() for x in xrange(num)]
paused = False
def get_input():
global paused
key = pygame.key.get_pressed()
for event in pygame.event.get():
if event.type == QUIT: return False
elif event.type == KEYDOWN:
if event.key == K_ESCAPE: return False
elif event.key == K_UP: particles[150].apply(10)
elif event.key == K_DOWN: particles[150].apply(-10)
elif event.key == K_p: paused = not paused
elif event.key == K_LEFT: update()
elif event.key == K_r: setup()
return True
def draw():
surface.fill((0,0,0))
points = []
x = 0
for particle in particles:
x += 4
points.append((x,particle.height+100))
pygame.draw.aalines(surface,(50,50,50),False,points)
i = 0
for point in points:
color = [(255,0,0),(0,255,0)][i%10==0]
pygame.draw.circle(surface,color,point,2,0)
i += 1
pygame.display.flip()
def main():
setup()
clock = pygame.time.Clock()
while True:
if not get_input(): break
if not paused: update()
draw()
clock.tick(60)
pygame.quit(); sys.exit()
if __name__ == '__main__':
try:
main()
except Exception, e:
tb = sys.exc_info()[2]
traceback.print_exception(e.__class__, e, tb)
pygame.quit()
raw_input()
sys.exit()[/source]After a few waves hit the tank, you get:
So, can anyone suggest an algorithm? Or maybe some gaping flaw in my implementation?
Thanks!
Ian
