X-Git-Url: http://de.git.xonotic.org/?a=blobdiff_plain;f=fractalnoise.c;h=06d00db0eedbc805291b94771b13178d17bbcc42;hb=7c16d23877a1b623d7d7e5ad9f92284896927113;hp=b663027943a24de5409e1c35cec484c00af22230;hpb=8dcce44300385b12c46d494c06aadcfa35a8bc14;p=xonotic%2Fdarkplaces.git

diff --git a/fractalnoise.c b/fractalnoise.c
index b6630279..06d00db0 100644
--- a/fractalnoise.c
+++ b/fractalnoise.c
@@ -1,36 +1,50 @@
 
-#include <stdlib.h>
+#include "quakedef.h"
 
-void fractalnoise(unsigned char *noise, int size)
+void fractalnoise(qbyte *noise, int size, int startgrid)
 {
-	int x, y, g, g2, amplitude, amplitude2, min, max, size1 = size - 1;
+	int x, y, g, g2, amplitude, min, max, size1 = size - 1, sizepower, gridpower;
 	int *noisebuf;
 #define n(x,y) noisebuf[((y)&size1)*size+((x)&size1)]
-	noisebuf = calloc(size*size, sizeof(int));
 
-	amplitude = 32767;
-	g2 = size;
-	n(0,0) = 0;
-	for (;(g = g2 >> 1) >= 1;g2 >>= 1)
+	for (sizepower = 0;(1 << sizepower) < size;sizepower++);
+	if (size != (1 << sizepower))
+		Sys_Error("fractalnoise: size must be power of 2\n");
+
+	for (gridpower = 0;(1 << gridpower) < startgrid;gridpower++);
+	if (startgrid != (1 << gridpower))
+		Sys_Error("fractalnoise: grid must be power of 2\n");
+
+	startgrid = bound(0, startgrid, size);
+
+	amplitude = 0xFFFF; // this gets halved before use
+	noisebuf = Mem_Alloc(tempmempool, size*size*sizeof(int));
+	memset(noisebuf, 0, size*size*sizeof(int));
+
+	for (g2 = startgrid;g2;g2 >>= 1)
 	{
-		// subdivide, diamond-square algorythm (really this has little to do with squares)
-		// diamond
-		for (y = 0;y < size;y += g2)
-			for (x = 0;x < size;x += g2)
-				n(x+g,y+g) = (n(x,y) + n(x+g2,y) + n(x,y+g2) + n(x+g2,y+g2)) >> 2;
-		// square
+		// brownian motion (at every smaller level there is random behavior)
+		amplitude >>= 1;
 		for (y = 0;y < size;y += g2)
 			for (x = 0;x < size;x += g2)
-			{
-				n(x+g,y) = (n(x,y) + n(x+g2,y) + n(x+g,y-g) + n(x+g,y+g)) >> 2;
-				n(x,y+g) = (n(x,y) + n(x,y+g2) + n(x-g,y+g) + n(x+g,y+g)) >> 2;
-			}
-		// brownian motion theory
-		amplitude >>= 1;
-		amplitude2 = amplitude >> 1;
-		for (y = 0;y < size;y += g)
-			for (x = 0;x < size;x += g)
-				n(x,y) += (rand()&amplitude) - amplitude2;
+				n(x,y) += (rand()&amplitude);
+
+		g = g2 >> 1;
+		if (g)
+		{
+			// subdivide, diamond-square algorithm (really this has little to do with squares)
+			// diamond
+			for (y = 0;y < size;y += g2)
+				for (x = 0;x < size;x += g2)
+					n(x+g,y+g) = (n(x,y) + n(x+g2,y) + n(x,y+g2) + n(x+g2,y+g2)) >> 2;
+			// square
+			for (y = 0;y < size;y += g2)
+				for (x = 0;x < size;x += g2)
+				{
+					n(x+g,y) = (n(x,y) + n(x+g2,y) + n(x+g,y-g) + n(x+g,y+g)) >> 2;
+					n(x,y+g) = (n(x,y) + n(x,y+g2) + n(x-g,y+g) + n(x+g,y+g)) >> 2;
+				}
+		}
 	}
 	// find range of noise values
 	min = max = 0;
@@ -41,10 +55,59 @@ void fractalnoise(unsigned char *noise, int size)
 			if (n(x,y) > max) max = n(x,y);
 		}
 	max -= min;
+	max++;
 	// normalize noise and copy to output
 	for (y = 0;y < size;y++)
 		for (x = 0;x < size;x++)
-			*noise++ = (n(x,y) - min) * 255 / max;
-	free(noisebuf);
+			*noise++ = (qbyte) (((n(x,y) - min) * 256) / max);
+	Mem_Free(noisebuf);
+#undef n
+}
+
+// unnormalized, used for explosions mainly, does not allocate/free memory (hence the name quick)
+void fractalnoisequick(qbyte *noise, int size, int startgrid)
+{
+	int x, y, g, g2, amplitude, size1 = size - 1, sizepower, gridpower;
+#define n(x,y) noise[((y)&size1)*size+((x)&size1)]
+
+	for (sizepower = 0;(1 << sizepower) < size;sizepower++);
+	if (size != (1 << sizepower))
+		Sys_Error("fractalnoise: size must be power of 2\n");
+
+	for (gridpower = 0;(1 << gridpower) < startgrid;gridpower++);
+	if (startgrid != (1 << gridpower))
+		Sys_Error("fractalnoise: grid must be power of 2\n");
+
+	startgrid = bound(0, startgrid, size);
+
+	amplitude = 255; // this gets halved before use
+	memset(noise, 0, size*size);
+
+	for (g2 = startgrid;g2;g2 >>= 1)
+	{
+		// brownian motion (at every smaller level there is random behavior)
+		amplitude >>= 1;
+		for (y = 0;y < size;y += g2)
+			for (x = 0;x < size;x += g2)
+				n(x,y) += (rand()&amplitude);
+
+		g = g2 >> 1;
+		if (g)
+		{
+			// subdivide, diamond-square algorithm (really this has little to do with squares)
+			// diamond
+			for (y = 0;y < size;y += g2)
+				for (x = 0;x < size;x += g2)
+					n(x+g,y+g) = (qbyte) (((int) n(x,y) + (int) n(x+g2,y) + (int) n(x,y+g2) + (int) n(x+g2,y+g2)) >> 2);
+			// square
+			for (y = 0;y < size;y += g2)
+				for (x = 0;x < size;x += g2)
+				{
+					n(x+g,y) = (qbyte) (((int) n(x,y) + (int) n(x+g2,y) + (int) n(x+g,y-g) + (int) n(x+g,y+g)) >> 2);
+					n(x,y+g) = (qbyte) (((int) n(x,y) + (int) n(x,y+g2) + (int) n(x-g,y+g) + (int) n(x+g,y+g)) >> 2);
+				}
+		}
+	}
 #undef n
-}
\ No newline at end of file
+}
+