From a77978e0c9bc91ea3d7b192ce136621e78d4ec5b Mon Sep 17 00:00:00 2001
From: Joshua Grams <josh@qualdan.com>
Date: Mon, 11 Jul 2005 18:21:34 +0000
Subject: [PATCH] fixed 2 more dot collision bugs (last ones?)

---
 main.c  |   16 ++++++++++------
 rocks.c |   16 ++++++++++++----
 shape.c |    4 ++--
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/main.c b/main.c
index 8d131be..b4972a2 100644
--- a/main.c
+++ b/main.c
@@ -193,20 +193,24 @@ draw_bang_dots(SDL_Surface *s)
 	for(i=0; i<MAXBANGDOTS; i++) {
 		if(!bdot[i].active) continue;
 
-		// If the dot has drifted outside the screen, kill it
+		// decrement life and maybe kill
+		bdot[i].life -= bdot[i].decay;
+		if(bdot[i].life<0) { bdot[i].active = 0; continue; }
+
+		// move and clip
+		bdot[i].x += bdot[i].dx*t_frame - xscroll;
+		bdot[i].y += bdot[i].dy*t_frame - yscroll;
 		if(bdot[i].x < 0 || bdot[i].x >= XSIZE || bdot[i].y < 0 || bdot[i].y >= YSIZE) {
 			bdot[i].active = 0;
 			continue;
 		}
+
+		// check collisions
 		if(pixel_hit_rocks(bdot[i].x, bdot[i].y)) { bdot[i].active = 0; continue; }
+
 		pixel = pixels + row_inc*(int)(bdot[i].y) + (int)(bdot[i].x);
 		if(bdot[i].c) c = bdot[i].c; else c = heatcolor[(int)(bdot[i].life)*3];
 		*pixel = c;
-		bdot[i].life -= bdot[i].decay;
-		bdot[i].x += bdot[i].dx*t_frame - xscroll;
-		bdot[i].y += bdot[i].dy*t_frame - yscroll;
-
-		if(bdot[i].life<0) bdot[i].active = 0;
 	}
 }
 
diff --git a/rocks.c b/rocks.c
index a2aa31e..e098fa0 100644
--- a/rocks.c
+++ b/rocks.c
@@ -308,12 +308,9 @@ hit_rocks(float x, float y, struct shape *shape)
 }
 
 int
-pixel_hit_rocks(float x, float y)
+pixel_hit_in_bucket(int b, float x, float y)
 {
-	int b;
 	struct rock_struct *r;
-
-	b = bucket(x, y);
 	for(r=rock_buckets[p][b]; r; r=r->next) {
 		if(x < r->x || y < r->y) continue;
 		if(pixel_collide(x - r->x, y - r->y, r->shape)) return 1;
@@ -321,6 +318,17 @@ pixel_hit_rocks(float x, float y)
 	return 0;
 }
 
+int
+pixel_hit_rocks(float x, float y)
+{
+	int b = bucket(x, y);
+	if(pixel_hit_in_bucket(b, x, y)) return 1;
+	if(pixel_hit_in_bucket(b-1, x, y)) return 1;
+	if(pixel_hit_in_bucket(b-bw, x, y)) return 1;
+	if(pixel_hit_in_bucket(b-bw-1, x, y)) return 1;
+	return 0;
+}
+
 void
 blast_rocks(float x, float y, float radius, int onlyslow)
 {
diff --git a/shape.c b/shape.c
index 5aa7fb7..92729e9 100644
--- a/shape.c
+++ b/shape.c
@@ -116,6 +116,6 @@ pixel_collide(unsigned int xoff, unsigned int yoff, struct shape *r)
 	
 	if(xoff >= r->w || yoff >= r->h) return 0;
 
-	pmask = 1 << (xoff & 31); xoff >>= 5;
-	return r->mask[yoff*r->mw + xoff] & pmask;
+	pmask = 1 << (32 - (xoff&0x1f));
+	return r->mask[(yoff*r->mw) + (xoff>>5)] & pmask;
 }
-- 
1.7.10.4