# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1333366923 -10800
# Node ID 6f275934717b38154279218f1e52e028947b5053
# Parent  0b73aa7317e199782ed28d8941f1320ea8bc6fb9
foon

diff -r 0b73aa7317e1 -r 6f275934717b Makefile
--- a/Makefile	Mon Apr 02 14:00:28 2012 +0300
+++ b/Makefile	Mon Apr 02 14:42:03 2012 +0300
@@ -4,11 +4,13 @@
 bin = volray
 
 CC = gcc
-CFLAGS = -pedantic -Wall -g
-LDFLAGS = $(libgl) -limago -lvmath -lm
+CFLAGS = -pedantic -Wall -g $(incdir)
+LDFLAGS = $(libdir) $(libgl) -limago -lvmath -lm
 
 ifeq ($(shell uname -s), Darwin)
-	libgl = -framework OpenGL -framework GLUT
+	libgl = -framework OpenGL -framework GLUT -lGLEW
+	incdir = -I/opt/local/include
+	libdir = -L/opt/local/lib
 else
 	libgl = -lGL -lglut -lGLEW
 endif
diff -r 0b73aa7317e1 -r 6f275934717b src/volray.c
--- a/src/volray.c	Mon Apr 02 14:00:28 2012 +0300
+++ b/src/volray.c	Mon Apr 02 14:42:03 2012 +0300
@@ -13,6 +13,8 @@
 #include <imago2.h>
 #include "sdr.h"
 
+#define XFER_MAP_SZ	512
+
 struct slice_file {
 	char *name;
 	struct slice_file *next;
@@ -29,6 +31,7 @@
 static void create_ray_texture(int xsz, int ysz, float vfov, vec2_t *tex_scale);
 static vec3_t get_primary_ray_dir(int x, int y, int w, int h, float vfov_deg);
 static int round_pow2(int x);
+static void create_transfer_map(float mean, float sdev);
 
 float cam_theta = 0, cam_phi = 0, cam_dist = 4.0;
 float cam_x, cam_y, cam_z;
@@ -40,6 +43,10 @@
 int win_xsz, win_ysz;
 int raytex_needs_recalc = 1;
 
+unsigned int xfer_tex;
+float xfer_mean = 0.5, xfer_sdev = 1.0;
+int xfertex_needs_recalc = 1;
+
 int main(int argc, char **argv)
 {
 	glutInit(&argc, argv);
@@ -77,6 +84,7 @@
 	}
 	set_uniform_int(sdr, "volume", 0);
 	set_uniform_int(sdr, "ray_tex", 1);
+	set_uniform_int(sdr, "xfer_tex", 2);
 
 	glGenTextures(1, &vol_tex);
 	glBindTexture(GL_TEXTURE_3D, vol_tex);
@@ -125,6 +133,9 @@
 	if(raytex_needs_recalc) {
 		create_ray_texture(win_xsz, win_ysz, 50.0, &tex_scale);
 	}
+	if(xfertex_needs_recalc) {
+		create_transfer_map(xfer_mean, xfer_sdev);
+	}
 
 	glMatrixMode(GL_MODELVIEW);
 	glLoadIdentity();
@@ -146,6 +157,10 @@
 	glBindTexture(GL_TEXTURE_2D, ray_tex);
 	glEnable(GL_TEXTURE_2D);
 
+	glActiveTexture(GL_TEXTURE2);
+	glBindTexture(GL_TEXTURE_1D, xfer_tex);
+	glEnable(GL_TEXTURE_1D);
+
 	bind_program(sdr);
 	glBegin(GL_QUADS);
 	glColor3f(1, 1, 1);
@@ -156,6 +171,8 @@
 	glEnd();
 	bind_program(0);
 
+	glActiveTexture(GL_TEXTURE2);
+	glDisable(GL_TEXTURE_1D);
 	glActiveTexture(GL_TEXTURE1);
 	glDisable(GL_TEXTURE_2D);
 	glActiveTexture(GL_TEXTURE0);
@@ -234,12 +251,30 @@
 {
 	int i;
 	struct slice_file *tail;
+	char *endp;
 
 	for(i=1; i<argc; i++) {
 		if(argv[i][0] == '-' && argv[i][2] == 0) {
 			switch(argv[i][1]) {
-			case 'r':
+			case 'm':
+				xfer_mean = strtod(argv[++i], &endp);
+				if(endp == argv[i]) {
+					fprintf(stderr, "-m must be followed by the transfer function mean\n");
+					return -1;
+				}
 				break;
+
+			case 'v':
+				xfer_sdev = strtod(argv[++i], &endp);
+				if(endp == argv[i]) {
+					fprintf(stderr, "-v must be followed by the transfer function sdeviance\n");
+					return -1;
+				}
+				break;
+
+			default:
+				fprintf(stderr, "unrecognized option: %s\n", argv[i]);
+				return -1;
 			}
 		} else {
 			struct slice_file *sfile;
@@ -265,7 +300,6 @@
 		fprintf(stderr, "pass the slice filenames\n");
 		return -1;
 	}
-
 	return 0;
 }
 
@@ -346,3 +380,26 @@
 	return x + 1;
 }
 
+static void create_transfer_map(float mean, float sdev)
+{
+	static float map[XFER_MAP_SZ];
+	int i;
+
+	if(!xfer_tex) {
+		glGenTextures(1, &xfer_tex);
+		glBindTexture(GL_TEXTURE_1D, xfer_tex);
+		glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+		glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+		glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE32F_ARB, XFER_MAP_SZ, 0, GL_LUMINANCE, GL_FLOAT, 0);
+	}
+
+	for(i=0; i<XFER_MAP_SZ; i++) {
+		float x = (float)i / (float)XFER_MAP_SZ;
+		map[i] = gaussian(x, mean, sdev);
+	}
+
+	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, XFER_MAP_SZ, 1, GL_LUMINANCE, GL_FLOAT, map);
+	xfertex_needs_recalc = 0;
+}