Hi , I searched on several sites but there was too much detail and I could not find a subject that describes a simple collision code. That's why I did not understand

how can I hit the boxes with ball and then bounce the ball ?

----------------- This is my code : ----------------------

#include <stdio.h>
#include <allegro5\allegro.h>
#include <allegro5\allegro_font.h>
#include <allegro5\allegro_ttf.h>
#include <allegro5\allegro_native_dialog.h>
#include <allegro5/allegro_primitives.h>
#include<allegro5/allegro_image.h>

const int width = 1024;
const int height = 768;

enum KEYS { LEFT, RIGHT };

struct ball { //KEEPS TRACK OF BALL VARIABLES
float x;
float y;
float vely;
int radius;

};
int main(void) {

int FPS = 60;
int score = 0;
int imagew = width / 2 + 150;
int imageh = 150;

bool done = true;
bool keys[2] = { false,false };

ball myBall; //Make a ball
myBall.x = width / 2;
myBall.y = height / 2;
myBall.vely = 0;
myBall.radius = 15;
//addon init
al_init();
al_init_font_addon();
al_init_ttf_addon();
al_init_primitives_addon();
al_install_keyboard();
al_init_image_addon();
//Allegro variable
ALLEGRO_DISPLAY *display = NULL;
ALLEGRO_EVENT_QUEUE *event_queue = NULL;
ALLEGRO_TIMER *timer = NULL;
ALLEGRO_BITMAP *image;
ALLEGRO_FONT *font = al_load_ttf_font("arial.ttf", 24, 0);

image = al_load_bitmap("image.png");
al_convert_mask_to_alpha(image, al_map_rgb(106, 76, 48));

display = al_create_display(width, height);

event_queue = al_create_event_queue();
timer = al_create_timer(1.0 / FPS);

al_register_event_source(event_queue, al_get_keyboard_event_source());
al_register_event_source(event_queue, al_get_timer_event_source(timer));
al_register_event_source(event_queue, al_get_display_event_source(display));

al_start_timer(timer);
while (done) {
al_draw_textf(font, al_map_rgb(255, 255, 255), 45, 5, ALLEGRO_ALIGN_CENTER, "Score: %d", score);
ALLEGRO_EVENT ev;
al_wait_for_event(event_queue, &ev);

myBall.y += myBall.vely;
myBall.vely += 0.25; //Ball's velocity downward increases (gravity)
printf("%f -- %f \n", myBall.vely, myBall.y + myBall.radius);

if (myBall.y + myBall.radius > 600 && myBall.vely > 0) { //Ball has hit the floor and is moving downward
myBall.y = 600; //Set the ball to just on top of the floor
myBall.vely = -myBall.vely; //Bounce

}

if (ev.type == ALLEGRO_EVENT_KEY_DOWN) {
switch (ev.keyboard.keycode) {
case ALLEGRO_KEY_LEFT:
keys[LEFT] = true; break;
case ALLEGRO_KEY_RIGHT:
keys[RIGHT] = true; break;
}
}
else if (ev.type == ALLEGRO_EVENT_KEY_UP) {
switch (ev.keyboard.keycode) {
case ALLEGRO_KEY_LEFT:
keys[LEFT] = false; break;
case ALLEGRO_KEY_RIGHT:
keys[RIGHT] = false; break;
}
if (ev.keyboard.keycode == ALLEGRO_KEY_ESCAPE)
done = false;
}
else if (ev.type == ALLEGRO_EVENT_DISPLAY_CLOSE) {
done = false;
}
else if (ev.type == ALLEGRO_EVENT_TIMER) { // Smoother movement...
myBall.x -= keys[LEFT] * 15;
myBall.x += keys[RIGHT] * 15;

imageh += 3;

}

al_clear_to_color(al_map_rgb(0, 0, 0));
al_draw_bitmap(image, imagew, imageh, 0);
al_draw_circle(myBall.x, myBall.y, myBall.radius, al_map_rgb(0, 255, 0), 2);
al_flip_display();

}
al_destroy_display(display);
al_destroy_bitmap(image);
}