X-Git-Url: https://jasonwoof.com/gitweb/?p=vor.git;a=blobdiff_plain;f=sprite.c;h=1a35a6a16266a6c3fb4b0db34c86d31063c30988;hp=1609368d324ab653070e6315e90d75b2260ed774;hb=37b3a2e06abc694205e843a573c4bb2eaaabb730;hpb=e06676edd300c8a85d2e6715427e7e22e55c7670

diff --git a/sprite.c b/sprite.c
index 1609368..1a35a6a 100644
--- a/sprite.c
+++ b/sprite.c
@@ -111,7 +111,6 @@ square(int x, int y, int set)
 void
 add_sprite(Sprite *s)
 {
-	if(s->type < 0) s->type = -s->type;
 	insert_sprite(square(s->x, s->y, set), s);
 }
 
@@ -123,18 +122,18 @@ reset_sprites(void)
 	for(i=0; i<gw*gh; i++)
 		while(sprites[set][i]) {
 			Sprite *s = remove_sprite(&sprites[set][i]);
-			if(s->type < 0) s->type = -s->type;
 			insert_sprite(&free_sprites[s->type], s);
-			if(s->type > 0) s->type = -s->type;
+			s->flags = 0;
 		}
 }
 
 void
 move_sprite(Sprite *s)
 {
-	// move it.
-	s->x += (s->dx - screendx)*t_frame;
-	s->y += (s->dy - screendy)*t_frame;
+	if(s->flags & MOVE) {
+		s->x += (s->dx - screendx)*t_frame;
+		s->y += (s->dy - screendy)*t_frame;
+	}
 }
 
 void
@@ -143,9 +142,8 @@ sort_sprite(Sprite *s)
 	// clip it, or sort it into the other set of sprites.
 	if(s->x + s->w < 0 || s->x >= XSIZE
 	   || s->y + s->h < 0 || s->y >= YSIZE) {
-		if(s->type < 0) s->type = -s->type;
 		insert_sprite(&free_sprites[s->type], s);
-		if(s->type > 0) s->type = -s->type;
+		s->flags = 0;
 	} else insert_sprite(square(s->x, s->y, 1-set), s);
 }
 
@@ -214,7 +212,7 @@ collide(Sprite *a, Sprite *b)
 {
 	int dx, dy, xov, yov;
 
-	if(a->type < 0 || b->type < 0) return false;
+	if(!COLLIDES(a) || !COLLIDES(b)) return false;
 
 	if(b->x < a->x) { Sprite *tmp = a; a = b; b = tmp; }
 
@@ -294,6 +292,8 @@ int
 pixel_collide(Sprite *s, int x, int y)
 {
 	uint32_t pmask;
+
+	if(!COLLIDES(s)) return false;
 	
 	if(x < s->x || y < s->y || x >= s->x + s->w || y >= s->y + s->h) return 0;
 
@@ -302,36 +302,37 @@ pixel_collide(Sprite *s, int x, int y)
 	return s->mask[(y*s->mask_w) + (x>>5)] & pmask;
 }
 
-int
+Sprite *
 pixel_hit_in_square(Sprite *r, float x, float y)
 {
 	for(; r; r=r->next) {
-		if(r->type >= 0 && pixel_collide(r, x, y)) return 1;
+		if(COLLIDES(r) && pixel_collide(r, x, y)) return r;
 	}
 	return 0;
 }
 
-int
+Sprite *
 pixel_collides(float x, float y)
 {
 	int l, t;
 	Sprite **sq;
+	Sprite *ret;
 
 	l = (x + grid_size) / grid_size; t = (y + grid_size) / grid_size;
 	sq = &sprites[set][l + t*gw];
-	if(pixel_hit_in_square(*sq, x, y)) return true;
-	if(l > 0 && pixel_hit_in_square(*(sq-1), x, y)) return true;
-	if(t > 0 && pixel_hit_in_square(*(sq-gw), x, y)) return true;
-	if(l > 0 && t > 0 && pixel_hit_in_square(*(sq-1-gw), x, y)) return true;
-	return false;
+	if((ret = pixel_hit_in_square(*sq, x, y))) return ret;
+	if(l > 0 && (ret = pixel_hit_in_square(*(sq-1), x, y))) return ret;
+	if(t > 0 && (ret = pixel_hit_in_square(*(sq-gw), x, y))) return ret;
+	if(l > 0 && t > 0 && (ret = pixel_hit_in_square(*(sq-1-gw), x, y))) return ret;
+	return 0;
 }
 
 
-static float
+float
 sprite_mass(Sprite *s)
 {
 	if(s->type == SHIP) return s->area;
-	else if(s->type == ROCK) return 3*s->area;
+	else if(s->type == ROCK) return 3 * s->area;
 	else return 0;
 }
 
@@ -339,8 +340,8 @@ void
 bounce(Sprite *a, Sprite *b)
 {
 	float x, y, n;
-	float va, vb;
-	float ma, mb, mr;
+	float va, vb, vc;
+	float ma, mb;
 
 	// (x, y) is unit vector pointing from A's center to B's center.
 	x = (b->x + b->w / 2) - (a->x + a->w / 2);
@@ -348,13 +349,13 @@ 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.
-	va = max(x*a->dx + y*a->dy, 0);
-	vb = min(x*b->dx + y*b->dy, 0);
+	va = x*a->dx + y*a->dy;
+	vb = x*b->dx + y*b->dy;
+	if(vb-va > 0) return;
 
-	// mass ratio
 	ma = sprite_mass(a); mb = sprite_mass(b);
-	if(ma && mb) mr = mb/ma; else mr = 1;
+	vc = (va*ma + vb*mb) / (ma+mb);
 
-	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;
+	a->dx += 2*x*(vc-va); a->dy += 2*y*(vc-va);
+	b->dx += 2*x*(vc-vb); b->dy += 2*y*(vc-vb);
 }