Speed up update_PIPE

By making it call rand() once instead of 6 times.

1 files changed, 85 insertions, 78 deletions

diff --git a/src/elements/pipe.c b/src/elements/pipe.c
index 849d2ea..bc7ff00 100644
--- a/src/elements/pipe.c
+++ b/src/elements/pipe.c
@@ -1,8 +1,78 @@
 #include <element.h>
 
+signed char pos_1_rx[] = {-1,-1,-1, 0, 0, 1, 1, 1};
+signed char pos_1_ry[] = {-1, 0, 1,-1, 1,-1, 0, 1};
+
 int update_PIPE(UPDATE_FUNC_ARGS) {
-	int r, rx, ry, np, trade, q, ctype;
-	if (!parts[i].ctype && parts[i].life<=10)
+	int r, rx, ry, np;
+	if (parts[i].ctype>=2 && parts[i].ctype<=4)
+	{
+		if (parts[i].life==3)
+		{
+			// make automatic pipe pattern
+			for (rx=-1; rx<2; rx++)
+				for (ry=-1; ry<2; ry++)
+					if (x+rx>=0 && y+ry>0 && x+rx<XRES && y+ry<YRES && (rx || ry))
+					{
+						r = pmap[y+ry][x+rx];
+						if ((r>>8)>=NPART || !r)
+							continue;
+						if ((r&0xFF)==PT_PIPE&&parts[r>>8].ctype==1)
+						{
+							parts[r>>8].ctype = (((parts[i].ctype)%3)+2);//reverse
+							parts[r>>8].life = 6;
+						}
+					}
+		}
+		else
+		{
+			int rndstore, rnd, q, ctype=(((parts[i].ctype)%3)+2);
+			rndstore = rand();
+			// RAND_MAX is at least 32767 on all platforms i.e. pow(8,5)-1
+			// so can go 5 cycles without regenerating rndstore
+			for (q=0; q<3; q++)
+			{
+				rnd = rndstore&7;
+				rndstore = rndstore>>3;
+				rx = pos_1_rx[rnd];
+				ry = pos_1_ry[rnd];
+				if (x+rx>=0 && y+ry>=0 && x+rx<XRES && y+ry<YRES)
+				{
+					r = pmap[y+ry][x+rx];
+					if ((r>>8)>=NPART)
+						continue;
+					else if (!r&&parts[i].tmp!=0)
+					{
+						np = create_part(-1,x+rx,y+ry,parts[i].tmp);
+						if (np!=-1)
+						{
+							parts[np].temp = parts[i].temp;//pipe saves temp and life now
+							parts[np].life = parts[i].flags;
+						}
+						parts[i].tmp = 0;
+						continue;
+					}
+					else if (!r)
+						continue;
+					else if (parts[i].tmp == 0 && (ptypes[r&0xFF].falldown!= 0 || ptypes[r&0xFF].state == ST_GAS))
+					{
+						parts[i].tmp = parts[r>>8].type;
+						parts[i].temp = parts[r>>8].temp;
+						parts[i].flags = parts[r>>8].life;
+						kill_part(r>>8);
+					}
+					else if ((r&0xFF)==PT_PIPE && parts[r>>8].ctype!=ctype && parts[r>>8].tmp==0&&parts[i].tmp>0)
+					{
+						parts[r>>8].tmp = parts[i].tmp;
+						parts[r>>8].temp = parts[i].temp;
+						parts[r>>8].flags = parts[i].flags;
+						parts[i].tmp = 0;
+					}
+				}
+			}
+		}
+	}
+	else if (!parts[i].ctype && parts[i].life<=10)
 	{
 		if (parts[i].temp<272.15)//manual pipe colors
 		{
@@ -24,13 +94,12 @@ int update_PIPE(UPDATE_FUNC_ARGS) {
 		}
 		else
 		{
+			// make a border
 			for (rx=-2; rx<3; rx++)
 				for (ry=-2; ry<3; ry++)
 					if (x+rx>=0 && y+ry>0 && x+rx<XRES && y+ry<YRES && (rx || ry))
 					{
 						r = pmap[y+ry][x+rx];
-						if ((r>>8)>=NPART )
-							continue;
 						if (!r)
 							create_part(-1,x+rx,y+ry,PT_BRCK);//BRCK border, people didn't like DMND
 					}
@@ -38,85 +107,23 @@ int update_PIPE(UPDATE_FUNC_ARGS) {
 				parts[i].ctype = 1;
 		}
 	}
-	if (parts[i].ctype==1)//waiting for empty space
+	else if (parts[i].ctype==1)//wait for empty space before starting to generate automatic pipe pattern
 	{
-		for (rx=-1; rx<2; rx++)
-			for (ry=-1; ry<2; ry++)
-				if (x+rx>=0 && y+ry>0 && x+rx<XRES && y+ry<YRES && (rx || ry))
-				{
-					r = pmap[y+ry][x+rx];
-					if ((r>>8)>=NPART)
-						continue;
-					if (!r&&!parts[i].life)
-						parts[i].life=50;
-				}
-		if (parts[i].life==2)
+		if (!parts[i].life)
+		{
+			for (rx=-1; rx<2; rx++)
+				for (ry=-1; ry<2; ry++)
+					if (x+rx>=0 && y+ry>0 && x+rx<XRES && y+ry<YRES && (rx || ry))
+					{
+						if (!pmap[y+ry][x+rx])
+							parts[i].life=50;
+					}
+		}
+		else if (parts[i].life==2)
 		{
 			parts[i].ctype = 2;
 			parts[i].life = 6;
 		}
 	}
-	if (parts[i].ctype>1)
-		for ( q = 0; q<3; q++)
-			for ( ctype = 2; ctype<5; ctype++)
-			{
-				if (parts[i].ctype==ctype)
-				{
-					if (parts[i].life==3)
-					{
-						for (rx=-1; rx<2; rx++)
-							for (ry=-1; ry<2; ry++)
-								if (x+rx>=0 && y+ry>0 && x+rx<XRES && y+ry<YRES && (rx || ry))
-								{
-									r = pmap[y+ry][x+rx];
-									if ((r>>8)>=NPART || !r)
-										continue;
-									if ((r&0xFF)==PT_PIPE&&parts[r>>8].ctype==1)
-									{
-										parts[r>>8].ctype = (((ctype)%3)+2);//reverse
-										parts[r>>8].life = 6;
-									}
-								}
-					}
-					else
-					{
-						rx = rand()%3-1;
-						ry = rand()%3-1;
-						if (x+rx>=0 && y+ry>0 && x+rx<XRES && y+ry<YRES && (rx || ry))
-						{
-							r = pmap[y+ry][x+rx];
-							if ((r>>8)>=NPART)
-								continue;
-							else if (!r&&parts[i].tmp!=0)
-							{
-								np = create_part(-1,x+rx,y+ry,parts[i].tmp);
-								if (np!=-1)
-								{
-									parts[np].temp = parts[i].temp;//pipe saves temp and life now
-									parts[np].life = parts[i].flags;
-								}
-								parts[i].tmp = 0;
-								continue;
-							}
-							else if (!r)
-								continue;
-							else if (parts[i].tmp == 0 && (ptypes[r&0xFF].falldown!= 0 || ptypes[r&0xFF].state == ST_GAS))
-							{
-								parts[i].tmp = parts[r>>8].type;
-								parts[i].temp = parts[r>>8].temp;
-								parts[i].flags = parts[r>>8].life;
-								kill_part(r>>8);
-							}
-							else if ((r&0xFF)==PT_PIPE && parts[r>>8].ctype!=(((ctype)%3)+2) && parts[r>>8].tmp==0&&parts[i].tmp>0)
-							{
-								parts[r>>8].tmp = parts[i].tmp;
-								parts[r>>8].temp = parts[i].temp;
-								parts[r>>8].flags = parts[i].flags;
-								parts[i].tmp = 0;
-							}
-						}
-					}
-				}
-			}
 	return 0;
 }