overhaul to the collision system... should have maybe made more commits.
This commit is contained in:
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218
main.py
218
main.py
@@ -1,176 +1,90 @@
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import pygame as pg
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from abc import ABC, abstractmethod
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from dataclasses import dataclass
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from itertools import combinations
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from collections import namedtuple
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from random import random
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from math import pi
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from rigidbody import *
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from collider import LineCollider, CircleCollider
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GLOBAL_GRAVITY=250
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DIMENSIONS = namedtuple("Dimensions", ["WIDTH", "HEIGHT"])(500,500)
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@dataclass
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class ColliderContact:
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__slots__ = ["point", "normal", "penetration"]
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point: pg.Vector2
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normal: pg.Vector2
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penetration: float
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class Ball:
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@dataclass
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class RigidBody:
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position: pg.Vector2
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collider: "BaseCollider"
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velocity: pg.Vector2
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mass: float = 1.0
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restitution: float = 0.5
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@property
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def inv_mass(self):
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return 0.0 if self.mass == 0 else 1.0 / self.mass
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class BaseCollider(ABC):
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def collide(self, other: "BaseCollider", this_position: pg.Vector2, other_position: pg.Vector2) -> ColliderContact | None:
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if isinstance(other, CircleCollider):
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return self.collide_circle(other, this_position, other_position)
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@abstractmethod
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def collide_circle(self, other: "CircleCollider", this_position: pg.Vector2, other_position: pg.Vector2) -> ColliderContact | None:
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pass
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class CircleCollider(BaseCollider):
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def __init__(self, radius: float):
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def __init__(self, transform: Transform, radius: float):
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self.transform = transform
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self.radius = radius
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def collide_circle(self, other: "CircleCollider", this_position: pg.Vector2, other_position: pg.Vector2) -> ColliderContact | None:
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delta = this_position - other_position
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dist = delta.length()
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radii = self.radius + other.radius
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if dist >= radii or dist == 0:
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return None
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normal = delta.normalize()
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return ColliderContact(
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point=other_position + normal * other.radius,
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normal=normal,
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penetration=radii - dist,
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)
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class PhysicsSystem:
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def __init__(self):
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self.bodies: list[RigidBody] = []
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self.gravity = pg.Vector2(0,GLOBAL_GRAVITY)
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def add_body(self, body: RigidBody) -> None:
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self.bodies.append(body)
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def update(self, dt: float):
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g = self.gravity * dt
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for body in self.bodies:
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body.velocity += g
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body.position += dt * body.velocity
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self.resolve_bounds(body)
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for a, b in combinations(self.bodies, 2):
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if collision := a.collider.collide(b.collider, a.position, b.position):
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self.resolve_collision(a, b, collision)
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def resolve_collision(self, a: RigidBody, b: RigidBody, collision: ColliderContact) -> None:
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SLACK=0.4
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correction = collision.penetration / (a.inv_mass + b.inv_mass) * SLACK * collision.normal
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a.position += correction
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b.position -= correction
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v_rel = a.velocity - b.velocity
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restitution = a.restitution * b.restitution
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impulse = (-(1 + restitution) * (collision.normal.dot(v_rel))) / (a.inv_mass + b.inv_mass)
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a.velocity += collision.normal*impulse*a.inv_mass
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b.velocity -= collision.normal*impulse*b.inv_mass
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def resolve_bounds(self, body: RigidBody) -> None:
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r = body.collider.radius
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if body.position.x - r < 0:
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body.position.x = r
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body.velocity.x = abs(body.velocity.x) * body.restitution
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elif body.position.x + r > DIMENSIONS.WIDTH:
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body.position.x = DIMENSIONS.WIDTH - r
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body.velocity.x = -abs(body.velocity.x) * body.restitution
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if body.position.y - r < 0:
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body.position.y = r
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body.velocity.y = abs(body.velocity.y) * body.restitution
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elif body.position.y + r > DIMENSIONS.HEIGHT:
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body.position.y = DIMENSIONS.HEIGHT - r
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body.velocity.y = -abs(body.velocity.y) * body.restitution
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class Circle:
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def __init__(self, radius: float, body: RigidBody, sprite: pg.Surface):
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self.radius = radius
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self.body = body
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self.sprite = sprite
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self.surface = pg.Surface((2*self.radius, 2*self.radius), pg.SRCALPHA)
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self.surface.fill((255,255,255,0))
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pg.draw.circle(
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self.surface,
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color=(0,255,0,255),
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center=(self.radius,self.radius),
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radius=self.radius
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)
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def draw(self, screen: pg.Surface):
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screen.blit(
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self.sprite,
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(
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self.body.position.x - self.radius,
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self.body.position.y - self.radius
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)
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)
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class World:
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def __init__(self, screen: pg.Surface):
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self.physics = PhysicsSystem()
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self.screen = screen
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self.entities = []
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def update(self, dt) -> None:
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self.physics.update(dt)
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def draw(self) -> None:
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for entity in self.entities:
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entity.draw(self.screen)
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surface = pg.transform.rotate(self.surface, self.transform.global_degrees)
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screen.blit(surface, self.transform.global_position - pg.Vector2(self.radius, self.radius))
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def spawn_circle(self, radius: float, position: pg.Vector2, velocity: pg.Vector2 | None = None, restitution:float = 0.5, mass: float = 1.0) -> None:
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if velocity is None:
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velocity = pg.Vector2(0,0)
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collider = CircleCollider(radius)
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body = RigidBody(position=position, collider=collider, velocity=velocity, restitution=restitution,mass=mass)
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self.physics.add_body(body)
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sprite = pg.Surface((2*radius, 2*radius),pg.SRCALPHA)
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sprite.fill((255,255,255,0))
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pg.draw.circle(
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sprite,
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color=(0,255,0,255),
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center=(radius, radius),
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radius=radius
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class Square:
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def __init__(self, transform: Transform, side: float, color=(255,0,0,255)):
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self.transform = transform
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self.side = side
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self.surface = pg.Surface((side, side), pg.SRCALPHA)
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self.surface.fill((255,255,255,0))
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pg.draw.rect(
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self.surface,
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color=color,
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rect=pg.Rect(0, 0, self.side, self.side)
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)
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self.entities.append(Circle(radius,body,sprite))
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def draw(self, screen: pg.Surface):
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surface = pg.transform.rotate(self.surface, self.transform.global_degrees)
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screen.blit(surface, self.transform.global_position - pg.Vector2(self.side / 2.0, self.side / 2.0))
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def main():
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running=True
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pg.init()
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clock=pg.time.Clock()
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screen = pg.display.set_mode(size=DIMENSIONS)
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world=World(screen)
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screen = pg.display.set_mode((500,500))
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physics = PhysicsSystem()
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ball_transform = Transform(position=pg.Vector2(250,250), rotation=pi/8.0)
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square_transform = Transform(position=pg.Vector2(250, 100))
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ball = Square(ball_transform, 20)
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ball2 = Square(square_transform, 20, color=(0,255,0,255))
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physics.add_body(
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RigidBody(
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ball_transform,
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RectCollider((20,20)),
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velocity=pg.Vector2(0,-400),
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restitution=1.0,
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)
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)
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physics.add_body(
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RigidBody(
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square_transform,
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RectCollider((20,20)),
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pg.Vector2(0,0),
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restitution=1.0
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)
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)
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while running:
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dt = clock.tick(144) / 1000
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screen.fill((0,0,0,0))
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world.update(dt)
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world.draw()
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physics.update(dt)
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ball.draw(screen)
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ball2.draw(screen)
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pg.display.flip()
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for event in pg.event.get():
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if event.type == pg.MOUSEBUTTONDOWN:
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world.spawn_circle(
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10,
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pg.Vector2(pg.mouse.get_pos()),
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restitution=random()
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)
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if event.type == pg.QUIT:
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running = False
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