renamed *_SPRITE to *, made rocks bounce off each other.

[vor.git] / sprite.c

diff --git a/sprite.c b/sprite.c
index ec9fb01..1905510 100644 (file)
--- a/sprite.c
+++ b/sprite.c
@@ -198,6 +198,8 @@ collide(Sprite *a, Sprite *b)
 {
        int dx, dy, xov, yov;
 
+       if(a->type < 0 || b->type < 0) return false;
+
        if(b->x < a->x) { Sprite *tmp = a; a = b; b = tmp; }
 
        dx = b->x - a->x;
@@ -212,6 +214,17 @@ collide(Sprite *a, Sprite *b)
        else return mask_collide(xov, yov, a, b);
 }
 
+void
+collisions(void)
+{
+       int i;
+       Sprite *a, *b;
+       for(i=0; i<gw*gh; i++)
+               for(a=sprites[set][i]; a; a=a->next)
+                       for(b=a->next; b; b=b->next)
+                               if(collide(a, b)) do_collision(a, b);
+}
+
 Sprite *
 hit_in_square(Sprite *r, Sprite *s)
 {
@@ -287,11 +300,11 @@ pixel_collides(float x, float y)
 }
 
 
-float
+static float
 sprite_mass(Sprite *s)
 {
-       if(s->type == SHIP_SPRITE) return s->area;
-       else if(s->type == ROCK_SPRITE) return 3*s->area;
+       if(s->type == SHIP) return s->area;
+       else if(s->type == ROCK) return 3*s->area;
        else return 0;
 }
 
@@ -299,7 +312,7 @@ void
 bounce(Sprite *a, Sprite *b)
 {
        float x, y, n;
-       float da, db;
+       float va, vb;
        float ma, mb, mr;
 
        // (x, y) is unit vector pointing from A's center to B's center.
@@ -308,13 +321,13 @@ bounce(Sprite *a, Sprite *b)
        n = sqrt(x*x + y*y); x /= n; y /= n;
 
        // velocities along (x, y), or 0 if already moving away.
-       da = max(x*a->dx + y*a->dy, 0);
-       db = min(x*b->dx + y*b->dy, 0);
+       va = max(x*a->dx + y*a->dy, 0);
+       vb = min(x*b->dx + y*b->dy, 0);
 
        // mass ratio
        ma = sprite_mass(a); mb = sprite_mass(b);
        if(ma && mb) mr = mb/ma; else mr = 1;
 
-       a->dx += x*(db*mr - da); a->dy += y*(db*mr - da);
-       b->dx += x*(da/mr - db); b->dy += y*(da/mr - db);
+       a->dx += x*(mb*vb - ma*va)/ma; a->dy += y*(mb*vb - ma*va)/ma;
+       b->dx += x*(ma*va - mb*vb)/mb; b->dy += y*(ma*va - mb*vb)/mb;
 }