pygame2-o1.py

# ...existing code...
import pygame
import math
import sys

# Constants
WIDTH, HEIGHT = 800, 600
GRAVITY = 0.5  # gravitational acceleration
FPS = 60

class PhysicsObject:
    """Represents a 2D object with position, velocity, mass, and radius."""
    def __init__(self, x, y, vx, vy, mass, radius, color):
        self.x = x
        self.y = y
        self.vx = vx
        self.vy = vy
        self.mass = mass
        self.radius = radius
        self.color = color

    def update(self):
        """Update velocity with gravity and move."""
        self.vy += GRAVITY
        self.x += self.vx
        self.y += self.vy

    def check_boundary_collision(self):
        """Bounce off screen boundaries."""
        if self.x - self.radius < 0:
            self.x = self.radius
            self.vx *= -1
        if self.x + self.radius > WIDTH:
            self.x = WIDTH - self.radius
            self.vx *= -1
        if self.y - self.radius < 0:
            self.y = self.radius
            self.vy *= -1
        if self.y + self.radius > HEIGHT:
            self.y = HEIGHT - self.radius
            self.vy *= -1

def detect_and_handle_collisions(objects):
    """Detect circle collisions and handle elastic collision response."""
    for i in range(len(objects)):
        for j in range(i + 1, len(objects)):
            obj1 = objects[i]
            obj2 = objects[j]
            dx = obj2.x - obj1.x
            dy = obj2.y - obj1.y
            distance = math.hypot(dx, dy)
            if distance < obj1.radius + obj2.radius:
                # Simple elastic collision response
                nx, ny = dx / distance, dy / distance
                p = 2 * (obj1.vx * nx + obj1.vy * ny - obj2.vx * nx - obj2.vy * ny) / (obj1.mass + obj2.mass)
                obj1.vx -= p * obj2.mass * nx
                obj1.vy -= p * obj2.mass * ny
                obj2.vx += p * obj1.mass * nx
                obj2.vy += p * obj1.mass * ny

def main():
    """Initialize Pygame and run the simulation loop."""
    pygame.init()
    screen = pygame.display.set_mode((WIDTH, HEIGHT))
    clock = pygame.time.Clock()

    # Create multiple objects
    objects = [
        PhysicsObject(100, 100, 3, 2, 1, 20, (255, 0, 0)),
        PhysicsObject(300, 150, -2, 2, 1, 30, (0, 255, 0)),
        PhysicsObject(500, 200, 2, -3, 1, 25, (0, 0, 255))
    ]

    running = True
    while running:
        clock.tick(FPS)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                running = False

        # Update physics
        for obj in objects:
            obj.update()
            obj.check_boundary_collision()
        detect_and_handle_collisions(objects)

        # Render
        screen.fill((255, 255, 255))
        for obj in objects:
            pygame.draw.circle(screen, obj.color, (int(obj.x), int(obj.y)), obj.radius)
        pygame.display.flip()

    pygame.quit()
    sys.exit()

if __name__ == "__main__":
    main()
# ...existing code...