Change mouse input to use mouse speed

Instead of directly setting the object accordingly to the mouse's cursor
orientation, use a 'speed' trick to move the object.

X and Y coordinates are now incremented according to the speed instead
of hard setting them to the current x*y hardware coordinates.

Use al_set_mouse_xy() to always reset the real mouse position (not the
object). This will avoid the mouse position to hit one of the limits
preventing the object to be moved further.

Signed-off-by: Carlos Maiolino <[email protected]>

2 files changed, 35 insertions, 13 deletions

diff --git a/src/include/rb.h b/src/include/rb.h
index aba3488..abbeb0e 100644
--- a/src/include/rb.h
+++ b/src/include/rb.h
@@ -3,8 +3,8 @@
 
 #include <allegro5/allegro5.h>
 
-#define RB_WIDTH 2240
-#define RB_HEIGHT 1400
+#define RB_WIDTH 640
+#define RB_HEIGHT 480
 #define RB_FPS	(1.0 / 80.0) /* 1 sec divided by 30 frames */
 
 struct rb {
diff --git a/src/rb.c b/src/rb.c
index 83a7f28..0307d57 100644
--- a/src/rb.c
+++ b/src/rb.c
@@ -108,6 +108,7 @@ register_events(struct rb *rb)
 	al_register_event_source(rb->event_queue,
 				 al_get_mouse_event_source());
 	al_hide_mouse_cursor(rb->display);
+	al_grab_mouse(rb->display);
 }
 
 void
@@ -119,11 +120,14 @@ start_game(struct rb *rb)
 	bool done	= false;
 	bool redraw	= true;
 	float x, y;
+	float dx, dy; /* mouse velocity  - change in coordinate since prev event*/
 	ALLEGRO_EVENT	event;
 	unsigned char key[ALLEGRO_KEY_MAX];
 	memset(key, 0, sizeof(key));
 
 
+	dx = 0;
+	dy = 0;
 	x = 100;
 	y = 100;
 	al_start_timer(rb->timer);
@@ -133,18 +137,35 @@ start_game(struct rb *rb)
 
 		switch(event.type) {
 		case ALLEGRO_EVENT_TIMER:
-			if (key[ALLEGRO_KEY_UP])
-				y--;
-			if (key[ALLEGRO_KEY_DOWN])
-				y++;
-			if (key[ALLEGRO_KEY_LEFT])
-				x--;
-			if (key[ALLEGRO_KEY_RIGHT])
-				x++;
+			x += dx;
+			y += dy;
+
+			if (x < 0) {
+				x *= -1;
+				dx *= -1;
+			}
+
+			if (x > rb->width) {
+				x -= (x - rb->width) * 2;
+				dx *= -1;
+			}
+
+			if (y < 0) {
+				y *= -1;
+				dy *= -1;
+			}
+
+			if (y > rb->height) {
+				y -= (y - rb->height) * 2;
+				dy *= -1;
+			}
 
 			if (key[ALLEGRO_KEY_ESCAPE])
 				done = true;
 
+			dx *= 0.9;
+			dy *= 0.9;
+
 			for (int i = 0; i < ALLEGRO_KEY_MAX; i++)
 				key[i] &= ~KEY_SEEN;
 
@@ -152,8 +173,9 @@ start_game(struct rb *rb)
 			break;
 
 		case ALLEGRO_EVENT_MOUSE_AXES:
-			x = event.mouse.x;
-			y = event.mouse.y;
+			dx += event.mouse.dx * 0.1;
+			dy += event.mouse.dy * 0.1;
+			al_set_mouse_xy(rb->display, 320, 240);
 			break;
 
 		case ALLEGRO_EVENT_KEY_DOWN:
@@ -190,7 +212,7 @@ start_game(struct rb *rb)
 			al_clear_to_color(al_map_rgb(0, 0, 0));
 			al_draw_textf(rb->font, al_map_rgb(255, 255, 255),
 				      0, 0, 0,
-				      "X: %.1f Y: %.1f", x, y);
+				      "X: %.1f Y: %.1f DX: %f DY: %f", x, y, dx, dy);
 			al_draw_filled_rectangle(x, y, x+40, y+120,
 						 al_map_rgb(255, 0, 0));
 			al_flip_display();