Fixing rect clipline and demo

[hankxu1212]

Resolving
Issue #3999.

Brief
On top of PR #4065, fixed syntax issues and SDL rectangle definitions.

Demo
Also attached here a demo on top of the work done in #4065.
Specifically we only ever draw the raycast once (what butlerch did earlier raises the problem of drawing x lines for each ray., where x is the number of rectangles. This was also why there were line overlaps..

Results
Shown here a results from the demo, with multiple overlapping line issues fixed.

# CLIPLINE BUG DEMO
import pygame
import numpy as np
import math
from pygame.locals import *

# Init settings
window = 800  # window size (square)
dist = 2000  # raycast max distance
angle = 2  # angle between each ray
origin = (window / 2, window / 2)  # origin of raycasts (centre of screen)
r_radii = 160  # rectangle origin radius from raycast origin
r_width = 50  # rect width
r_height = 50  # rect height
r_angle = 45  # angle of rectangles
speed = 0.02  # Speed of rectangles rotation
c = 0  # starting offset angle of rectangles

screen = pygame.display.set_mode((window, window))  # resolution
screen.fill((150, 150, 150))  # grey bg
pygame.init()  # init


# Main loop
while True:
    screen.fill((150, 150, 150))  # grey bg
    c += speed
    rects = [
        pygame.Rect(  # Init rectangle (x,y,w,h)
            np.cos(np.radians(t + c)) * r_radii + origin[0] - r_width / 2,  # x
            np.sin(np.radians(t + c)) * r_radii + origin[1] - r_height / 2,  # y
            r_width,
            r_height,
        )
        for t in range(0, 360, r_angle)
    ]  # angle iterator

    # Draw rectangles
    for r in rects:
        pygame.draw.rect(screen, "white", r)

    # Raycasts
    for theta in range(0, 360, angle):
        rad = np.radians(theta)
        point = (
            np.cos(rad) * dist + origin[0],  # x
            np.sin(rad) * dist + origin[1],  # y
        )

        # Check raycast collision
        collision = False
        res = None

        for r in rects:
            res = r.clipline(origin, point)
            if res != ():
                collision = True
                break
            
        if collision:  # check
            collision_origin, collision_dest = res
            # draws blue line from origin to collision point
            pygame.draw.line(
                screen, "blue", origin, collision_origin, 3
            )
            # draws red for the region inside the rectangle
            pygame.draw.line(
                screen, "red", collision_origin, collision_dest, 4
            )
        else:
            pygame.draw.line(
                screen, "green", origin, point, 3
            )  # draw green otherwise

    # Query quit
    pygame.display.flip()
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()

[hankxu1212]

@illume Request for review