Diff: Bullet/bullet.cpp

Revision:

21:edfeb289b21f

Parent:

20:6a58052b0140

Child:

22:3c68eea5a609

--- a/Bullet/bullet.cpp	Thu Oct 29 02:21:11 2015 +0000
+++ b/Bullet/bullet.cpp	Thu Oct 29 03:56:30 2015 +0000
@@ -21,42 +21,44 @@
     in_flight = true; 
 }
 
-int Bullet::time_step(float dt) {
-    if(!in_flight) {return CONVERT_24_TO_16_BPP(SKY_COLOR);}
+void Bullet::update_position(float dt) {
+    if(!in_flight) { return; }
     time += dt;
-    int new_x = x0 + vx0*time;
-    int new_y = y0 + vy0*time + 0.5*(-9.81)*time*time;
+    x = x0 + vx0*time;
+    y = y0 + vy0*time + 0.5*(-9.81)*time*time;
+}
+
+// return codes:
+//      BULLET_NO_COLLISION: no collision
+//      BULLET_OFF_SCREEN:   off the side of the screen
+//      Otherwise, returns the color you've hit in 16bpp format. 
+
+int Bullet::time_step(float dt) {
+    if(!in_flight) { return BULLET_NO_COLLISION; }
+    int old_x = x;
+    int old_y = y;
     
-    if(new_x == x && new_y == y) {      // Didn't move!
-        return CONVERT_24_TO_16_BPP(SKY_COLOR);
-    }
+    update_position(dt);
     
-    if(new_x < 0 || new_x > 128 || new_y < 0 || new_y > 128) {
-        sync.pixel(x, y, SKY_COLOR);
-        in_flight = false;
-        return CONVERT_24_TO_16_BPP(BLACK);
+    if(x == old_x && y == old_y) {
+        return BULLET_NO_COLLISION;
     }
     
-    int col = sync.read_pixel(new_x, new_y);
-    if(col != CONVERT_24_TO_16_BPP(SKY_COLOR)) {
+    if(x < 0 || x > 128 || y < 0 || y > 128) {
         sync.pixel(x, y, SKY_COLOR);
-        sync.filled_circle(new_x, new_y, 4, SKY_COLOR);
         in_flight = false;
-        
-        if(col == CONVERT_24_TO_16_BPP(TANK_BLUE)) {
-            return col;
-        }
-        
-        if( col == CONVERT_24_TO_16_BPP(TANK_RED)) {
-            return col;
-        }
-        
-        return CONVERT_24_TO_16_BPP(BLACK);
+        return BULLET_OFF_SCREEN;        
     }
-    sync.pixel(x, y, SKY_COLOR);
-            
-    x = new_x;
-    y = new_y;            
+    
+    int col = sync.read_pixel(x, y);
+    if(col != CONVERT_24_TO_16_BPP(SKY_COLOR)) {
+        sync.pixel(old_x, old_y, SKY_COLOR);
+        sync.filled_circle(x, y, 4, SKY_COLOR);
+        in_flight = false;
+        return col;
+    }
+    sync.pixel(old_x, old_y, SKY_COLOR);
     sync.pixel(x, y, BLACK);
-    return CONVERT_24_TO_16_BPP(SKY_COLOR);
-}      
+    return BULLET_NO_COLLISION;
+    
+}
\ No newline at end of file