altos/pong: Speed up ball as the volley continues

Makes the game a bit more challenging

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/pong/ao_pong.c b/src/pong/ao_pong.c
index 174db29ebcc9fccd00686674a425df1ff77d3524..79b50dd031fb7a3b5915ff49bd289f9f733c64af 100644 (file)
--- a/src/pong/ao_pong.c
+++ b/src/pong/ao_pong.c
@@ -26,8 +26,6 @@
 
 // uint8_t ao_sensor_errors;
 
 
 // uint8_t ao_sensor_errors;
 

-#define BALL_SPEED     3
-

 #define WIN_SCORE      11
 
 #define BALL_WIDTH     5
 #define WIN_SCORE      11
 
 #define BALL_WIDTH     5


@@ -47,6 +45,7 @@ struct rect {
 
 static struct ao_data  ao_data;
 
 
 static struct ao_data  ao_data;
 

+static const int       player_led[2] = { AO_LED_GREEN, AO_LED_BLUE };

 static int             player_value[2];
 static int             player_score[2];
 
 static int             player_value[2];
 static int             player_score[2];
 


@@ -56,10 +55,13 @@ static struct rect  player[2];
 
 static struct rect     ball;
 
 
 static struct rect     ball;
 

+static int     ball_speed;

 static int     ball_e;
 static int     ball_dx, ball_dy;
 static int     ball_step_x, ball_step_y;
 
 static int     ball_e;
 static int     ball_dx, ball_dy;
 static int     ball_step_x, ball_step_y;
 

+static int     volley_count;
+

 static int
 intersect(struct rect *a, struct rect *b)
 {
 static int
 intersect(struct rect *a, struct rect *b)
 {


@@ -73,11 +75,17 @@ ao_ball_step(void)
        int     p;
 
        /* Move the ball */
        int     p;
 
        /* Move the ball */

-       ball_e += ball_dy;
-       ball.x += ball_step_x;
+       ball_e += ball_dy * ball_speed;
+       ball.x += ball_step_x * ball_speed;

        while (ball_e >= ball_dx) {
                ball_e -= ball_dx;
                ball.y += ball_step_y;
        while (ball_e >= ball_dx) {
                ball_e -= ball_dx;
                ball.y += ball_step_y;

+
+               /* bounce off walls */
+               if (ball.y < 0 || ball.y + ball.h > AO_VGA_HEIGHT) {
+                       ball_step_y = -ball_step_y;
+                       ball.y += ball_step_y;
+               }

        }
 
        /* player missed */
        }
 
        /* player missed */


@@ -87,21 +95,20 @@ ao_ball_step(void)
        if (ball.x >= AO_VGA_WIDTH - BALL_WIDTH)
                return -1;
 
        if (ball.x >= AO_VGA_WIDTH - BALL_WIDTH)
                return -1;
 

-       /* bounce off walls */
-       if (ball.y < 0 || ball.y + ball.h > AO_VGA_HEIGHT) {
-               ball_step_y = -ball_step_y;
-               ball.y += ball_step_y;
-       }
-

        /* bounce off paddles */
 
        for (p = 0; p < 2; p++) {
                if (intersect(&ball, &player[p])) {
        /* bounce off paddles */
 
        for (p = 0; p < 2; p++) {
                if (intersect(&ball, &player[p])) {

-                       int     dy = 2 * (ball.y - player[p].y) + ball.h - player[p].h;
+
+                       volley_count++;
+
+                       ball_speed = 3 + volley_count / 4;
+
+                       int     dy = (2 * (ball.y - player[p].y) + ball.h - player[p].h);

                        int     dx = 20;
 
                        ball_step_x = -ball_step_x;
                        int     dx = 20;
 
                        ball_step_x = -ball_step_x;

-                       ball.x += ball_step_x;
+                       ball.x += ball_step_x * ball_speed;

                        ball_step_y = 1;
                        if (dy < 0) {
                                ball_step_y = -1;
                        ball_step_y = 1;
                        if (dy < 0) {
                                ball_step_y = -1;


@@ -148,8 +155,10 @@ ao_pong_start(void)
 
        pong_server = ao_time() & 1;
 
 
        pong_server = ao_time() & 1;
 

-       for (p = 0; p < 2; p++)
+       for (p = 0; p < 2; p++) {
+               ao_led_off(player_led[p]);

                player_score[p] = 0;
                player_score[p] = 0;

+       }

 
        return pong_serve;
 }
 
        return pong_serve;
 }


@@ -165,27 +174,30 @@ ao_pong_serve(void)
 
        ball.y = (AO_VGA_HEIGHT - BALL_HEIGHT) / 2;
 
 
        ball.y = (AO_VGA_HEIGHT - BALL_HEIGHT) / 2;
 

+       ball_speed = 3;
+       volley_count = 0;
+

        if (pong_server) {
                ball.x = player[1].x - BALL_WIDTH;
        if (pong_server) {
                ball.x = player[1].x - BALL_WIDTH;

-               ball_step_x = -BALL_SPEED;
+               ball_step_x = -1;

        } else {
                ball.x = player[0].x + PADDLE_WIDTH;
        } else {
                ball.x = player[0].x + PADDLE_WIDTH;

-               ball_step_x = BALL_SPEED;
+               ball_step_x = 1;

        }
 
        ball.w = BALL_WIDTH;
        ball.h = BALL_HEIGHT;
 
        }
 
        ball.w = BALL_WIDTH;
        ball.h = BALL_HEIGHT;
 

-       ball_dx = 100;
-       ball_dy = (seed & 7) * 10;
+       ball_dx = 20;
+       ball_dy = (seed & 7) * 2;

        ball_e = 0;
 
        seed >>= 3;
 
        if (seed & 1) {
        ball_e = 0;
 
        seed >>= 3;
 
        if (seed & 1) {

-               ball_step_y = BALL_SPEED;
+               ball_step_y = 1;

        } else {
        } else {

-               ball_step_y = -BALL_SPEED;
+               ball_step_y = -1;

        }
 
        return pong_volley;
        }
 
        return pong_volley;


@@ -202,8 +214,10 @@ ao_pong_volley(void)
 
        point = (miss + 1) >> 1;
        player_score[point]++;
 
        point = (miss + 1) >> 1;
        player_score[point]++;

-       if (player_score[point] == WIN_SCORE)
+       if (player_score[point] == WIN_SCORE) {
+               ao_led_on(player_led[point]);

                return pong_endgame;
                return pong_endgame;

+       }

 
        pong_server = point;
        pong_timer = PONG_SERVE_WAIT;
 
        pong_server = point;
        pong_timer = PONG_SERVE_WAIT;