From fe549d406b589b1c3db83aeea28c911292a5968e Mon Sep 17 00:00:00 2001
From: Joshua Grams <josh@qualdan.com>
Date: Mon, 5 Mar 2007 12:33:24 +0000
Subject: [PATCH] * float.h (fwrap, fclip): new file.

---
 Makefile |    4 ++--
 dust.c   |   12 +++---------
 float.h  |   23 +++++++++++++++++++++++
 main.c   |    5 +++--
 4 files changed, 31 insertions(+), 13 deletions(-)
 create mode 100644 float.h

diff --git a/Makefile b/Makefile
index 3260367..92401ad 100644
--- a/Makefile
+++ b/Makefile
@@ -67,11 +67,11 @@ font.o: font.h
 
 args.o: args.h
 
-dust.o: globals.h dust.h mt.h
+dust.o: globals.h dust.h float.h mt.h
 
 file.o: file.h common.h
 
-main.o: args.h common.h dust.h file.h globals.h mt.h rocks.h score.h sprite.h sound.h
+main.o: args.h common.h dust.h file.h float.h globals.h mt.h rocks.h score.h sprite.h sound.h
 
 mt.o: mt.h
 
diff --git a/dust.c b/dust.c
index 96a5805..4eeeb8b 100644
--- a/dust.c
+++ b/dust.c
@@ -4,6 +4,7 @@
 #include "config.h"
 #include "globals.h"
 #include "dust.h"
+#include "float.h"
 #include "mt.h"
 
 struct dust_mote {
@@ -13,9 +14,6 @@ struct dust_mote {
 
 struct dust_mote motes[N_DUST_MOTES];
 
-// lower bound to ensure that we don't lose precision when wrapping.
-static float zero;
-
 void
 init_dust(void)
 {
@@ -27,8 +25,6 @@ init_dust(void)
 		b = (MAX_DUST_DEPTH - motes[i].z) * 255.0 / MAX_DUST_DEPTH;
 		motes[i].color = SDL_MapRGB(surf_screen->format, b, b, b);
 	}
-
-	zero = pow(-10, ceil(log10(XSIZE)) - FLT_DIG);
 }
 
 void
@@ -40,12 +36,10 @@ move_dust(float ticks)
 	
 	for(i=0; i<N_DUST_MOTES; i++) {
 		motes[i].x -= xscroll / (1.3 + motes[i].z);
-		if(motes[i].x >= XSIZE) motes[i].x -= XSIZE;
-		else if(motes[i].x < zero) motes[i].x += XSIZE;
+		motes[i].x = fwrap(motes[i].x, XSIZE);
 
 		motes[i].y -= yscroll / (1.3 + motes[i].z);
-		if(motes[i].y >= YSIZE) motes[i].y -= YSIZE;
-		else if(motes[i].y < zero) motes[i].y += YSIZE;
+		motes[i].y = fwrap(motes[i].y, YSIZE);
 	}
 }
 
diff --git a/float.h b/float.h
new file mode 100644
index 0000000..58f6616
--- /dev/null
+++ b/float.h
@@ -0,0 +1,23 @@
+#ifndef VOR_FLOAT_H
+#define VOR_FLOAT_H
+
+#include <math.h>
+
+static inline int
+fclip(float f, float max)
+{
+	return f < 0 || (float)f >= (float)max;
+}
+
+static inline float
+fwrap(float f, float max)
+{
+	if((float)f >= (float)max) f = (float)f - (float)max;
+	else if(f < 0) {
+		f += max;
+		if((float)f >= (float)max) f = nextafterf(f, 0);
+	}
+	return f;
+}
+
+#endif // VOR_FLOAT_H
diff --git a/main.c b/main.c
index 72f3cfd..88d207a 100644
--- a/main.c
+++ b/main.c
@@ -34,6 +34,7 @@
 #include "config.h"
 #include "dust.h"
 #include "file.h"
+#include "float.h"
 #include "globals.h"
 #include "mt.h"
 #include "rocks.h"
@@ -192,7 +193,7 @@ move_bang_dots(float ticks)
 		// move and clip
 		bdot[i].x += (bdot[i].dx - screendx)*ticks;
 		bdot[i].y += (bdot[i].dy - screendy)*ticks;
-		if(bdot[i].x < 0 || bdot[i].x >= (XSIZE - 0.000001) || bdot[i].y < 0 || bdot[i].y >= (YSIZE - 0.000001)) {
+		if(fclip(bdot[i].x, XSIZE) || fclip(bdot[i].y, YSIZE)) {
 			bdot[i].active = 0;
 			continue;
 		}
@@ -306,7 +307,7 @@ move_engine_dots(float ticks) {
 		edot[i].x += (edot[i].dx - screendx)*ticks;
 		edot[i].y += (edot[i].dy - screendy)*ticks;
 		edot[i].life -= t_frame*3;
-		if(edot[i].life < 0 || edot[i].x<0 || edot[i].x >= (XSIZE - 0.000001) || edot[i].y < 0 || edot[i].y >= (YSIZE - 0.000001)) {
+		if(edot[i].life < 0 || fclip(edot[i].x, XSIZE) || fclip(edot[i].y, YSIZE)) {
 			edot[i].active = 0;
 			continue;
 		}
-- 
1.7.10.4