X-Git-Url: https://jasonwoof.com/gitweb/?p=vor.git;a=blobdiff_plain;f=dust.c;h=7b6286732228e755ee2fae7880cb33def25ec3c8;hp=691649d412b821b42f83766a3af059a361b6a4c3;hb=88a9e026caed5568363cefb7d49308b875dc5e4a;hpb=841f94c4182f8dff0253db9bae4922c3c9039a5f

diff --git a/dust.c b/dust.c
index 691649d..7b62867 100644
--- a/dust.c
+++ b/dust.c
@@ -27,16 +27,39 @@ init_dust(void)
 }
 
 void
-move_dust(void)
+move_dust(float ticks)
 {
 	int i;
+	float xscroll = screendx * ticks;
+	float yscroll = screendy * ticks;
+
+	// Originally this code was much simpler, but it would crash sometimes
+	// because the floating point numbers wouldn't always round the same
+	// direction, and we'd ocanially try to draw off the screen.
+	
 	for(i=0; i<N_DUST_MOTES; i++) {
 		motes[i].x -= xscroll / (1.3 + motes[i].z);
 		motes[i].y -= yscroll / (1.3 + motes[i].z);
-		if(motes[i].y >= XSIZE) motes[i].x -= XSIZE;
-		else if(motes[i].x < 0) motes[i].x += XSIZE;
-		if(motes[i].y > YSIZE) motes[i].y -= YSIZE;
-		else if(motes[i].y < 0) motes[i].y += YSIZE;
+
+		if(motes[i].x < 0) {
+			motes[i].x += XSIZE;
+		}
+		if(motes[i].x > (XSIZE - 0.000001)) {
+			motes[i].x -= XSIZE;
+			if(motes[i].x < 0) {
+				motes[i].x = 0;
+			}
+		}
+
+		if(motes[i].y < 0) {
+			motes[i].y += YSIZE;
+		}
+		if(motes[i].y > (YSIZE - 0.000001)) {
+			motes[i].y -= YSIZE;
+			if(motes[i].y < 0) {
+				motes[i].y = 0;
+			}
+		}
 	}
 }