From 0b18de256368f90628e93045987a045163354a93 Mon Sep 17 00:00:00 2001
From: Aadhavan Srinivasan <aadhavan@twomorecents.org>
Date: Thu, 14 Dec 2023 12:59:27 -0500
Subject: [PATCH] Added ball, and basic ball bouncing physics

---
 pong.c | 37 ++++++++++++++++++++++++++++++-------
 1 file changed, 30 insertions(+), 7 deletions(-)

diff --git a/pong.c b/pong.c
index 787cd70..97c0d90 100644
--- a/pong.c
+++ b/pong.c
@@ -33,21 +33,26 @@ int main(int argc, char** argv) {
 	ALLEGRO_COLOR white = al_map_rgba(255,255,255,255);
 	ALLEGRO_EVENT event;
 	bool running = true;
-	bool key_down_1 = false;
-	bool key_down_2 = false;
 
-	float width = 25;
+	float width = 25;  // Width and height of paddles
 	float height = 150;
-	float start_x_1 = 10;
+	float start_x_1 = 10; // Top-left coordinates of first paddle
 	float start_y_1 = 10;
-	float start_x_2 = WIN_WIDTH - 10 - width;
+	float start_x_2 = WIN_WIDTH - 10 - width; // Top-left coordinates of second paddle
 	float start_y_2 = 10;
-	float velocity_1 = 0;
-	float velocity_2 = 0;
+	float velocity_1 = 0;  // Vertical velocity of first paddle
+	float velocity_2 = 0;  // Vertical velocity of second paddle
+
+	float circ_x = WIN_WIDTH / 2; // Center coordinates of ball
+	float circ_y = WIN_HEIGHT / 2;
+	float circ_rad = 10;  // Radius of ball
+	float circ_vel_x = 5; // Horizontal velocity of ball
+	float circ_vel_y = 0; // Vertical velocity of ball
 
 	al_clear_to_color(black);
 	al_draw_filled_rectangle(start_x_1, start_y_1, start_x_1 + width, start_y_1 + height, white);
 	al_draw_filled_rectangle(start_x_2, start_y_2, start_x_2 + width, start_y_2 + height, white);
+	al_draw_filled_circle(circ_x, circ_y, circ_rad, white);
 	al_flip_display();
 
 	while (running) {
@@ -96,11 +101,29 @@ int main(int argc, char** argv) {
 		}
 
 		al_clear_to_color(black);
+
+		// Update positions
 		((velocity_1 < 0 && start_y_1  > 0) || (velocity_1 > 0 && start_y_1 + height < WIN_HEIGHT)) && (start_y_1 += velocity_1);
 		((velocity_2 < 0 && start_y_2  > 0) || (velocity_2 > 0 && start_y_2 + height < WIN_HEIGHT)) && (start_y_2 += velocity_2);
+		circ_x += circ_vel_x;
+		circ_y += circ_vel_y;
+		
+		//Redraw shapes
 		al_draw_filled_rectangle(start_x_1, start_y_1, start_x_1 + width, start_y_1 + height + velocity_1, white);		
 		al_draw_filled_rectangle(start_x_2, start_y_2, start_x_2 + width, start_y_2 + height + velocity_2, white);		
+		al_draw_filled_circle(circ_x, circ_y, circ_rad, white);
 		al_flip_display();
+
+		if (circ_x + circ_rad >= WIN_WIDTH - 10 - width) { // FOR PADDLE 2: If the circle has reached the point where the paddle would be...
+			if (circ_y > start_y_2 && circ_y < start_y_2 + height) { // If the circle is touching the paddle...
+				circ_vel_x = -circ_vel_x;
+			}
+		} else if (circ_x - circ_rad <= 10 + width) { // FOR PADDLE 1
+			if (circ_y > start_y_1 && circ_y < start_y_1 + height) {
+				circ_vel_x =- circ_vel_x;
+			}
+		}
+
 	}
 
 //	Clean up