import pygame
import math
import random
def interpolate(v1, v2, range):
return pygame.math.Vector2(v1.x + (v2.x - v1.x) * range,
v1.y + (v2.y - v1.y) * range)
class Particle(pygame.sprite.Sprite):
def __init__(self, game, image, pos, vel, life, lifetime,
fade_start, dorotate):
pygame.sprite.Sprite.__init__(self)
self.game = game
self.pos = pos
self.vel = vel
self.rot_cache = {}
self.base_image = image
self.dorotate = dorotate
if dorotate:
self.image = pygame.transform.rotate(self.base_image, -self.rot)
else:
self.image = self.base_image.copy()
self.rect = self.image.get_rect()
self.lifetime = lifetime
self.life = life
self.fade_start = fade_start
self.duration = lifetime - fade_start
self.update()
def update(self):
# if self.dorotate:
# old_center = self.rect.center
# if self.rot in self.rot_cache:
# self.image = self.rot_cache[self.rot]
# else:
# self.image = pygame.transform.rotate(self.base_image, -self.rot)
# self.rot_cache[self.rot] = self.image
# self.rect = self.image.get_rect()
# self.rect.center = old_center
self.life += self.game.dt
self.fade()
self.pos += self.vel
self.rect.centerx = self.pos.x #+ self.game.OFFSET.x
self.rect.centery = self.pos.y #+ self.game.OFFSET.y
def blit(self):
return self.game.screen.blit(self.image, self.rect, special_flags=pygame.BLEND_ADD)
def fade(self):
if self.life > self.fade_start:
try:
ratio = (self.life - self.fade_start) / self.duration
except ZeroDivisionError:
ratio = 1.0
if ratio > 1.0:
ratio = 1.0
mask = int(255 * (1 - ratio))
self.image.fill([mask, mask, mask], special_flags=pygame.BLEND_MIN)
def is_dead(self):
if self.life > self.lifetime:
return True
return False
class ParticleEmitter:
def __init__(self, game, parent, offset, vel, image, count, lifetime,
fade_start, size, angle_range, dorotate=False):
self.game = game
self.parent = parent
self.offset = offset
self.particle_vel = vel
self.pos = self.parent.pos + self.game.OFFSET + self.offset.rotate(self.parent.rot)
self.base_image = image
self.size = size
self.angle_range = angle_range
self.image = pygame.transform.scale(self.base_image, (self.size, self.size))
self.count = count
self.lifetime = lifetime
self.fade_start = fade_start
self.particles = []
self.timer = 0
self.prevcurve = [self.pos for x in range(3)]
self.active = True
def print_state(self):
print("c:{}, p:{}".format(self.count, len(self.particles)))
def update(self):
self.pos = self.parent.pos + self.game.OFFSET + self.offset.rotate(-self.parent.rot)
self.rand_angle = random.randint(-self.angle_range, self.angle_range)
# update all particles
for part in self.particles:
part.update()
if part.is_dead():
self.particles.remove(part)
# print("p.kill")
# create a new particle
if self.count != 0 and self.active:
self.timer += self.game.dt
newparticles = self.count * self.timer
if newparticles > 1:
for i in range(int(newparticles)):
t = i / newparticles
time_elapsed = (1.0 - t) * self.game.dt
vel = self.particle_vel.rotate(-self.parent.rot+self.rand_angle)
pos = interpolate(self.prevcurve[0], self.pos, t)
pos += (self.parent.vel + vel) * time_elapsed
# pos += vel * time_elapsed
init_life = time_elapsed
self.timer = 0
# print("new part: pos: {} vel: {}".format(pos, vel))
self.particles.append(Particle(self.game, self.image, pos,
vel, init_life, self.lifetime,
self.fade_start, False))
self.prevcurve[2] = self.prevcurve[1]
self.prevcurve[1] = self.prevcurve[0]
self.prevcurve[0] = self.pos
def draw(self):
rects = []
for part in self.particles:
rects.append(part.blit())
return rects
def kill_all(self):
self.count = 0
self.active = False
self.particles = []
