# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1333148922 -10800
# Node ID b050ce167ff1805a55ba347cfdf80d61b586189d

foo

diff -r 000000000000 -r b050ce167ff1 Makefile
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Makefile	Sat Mar 31 02:08:42 2012 +0300
@@ -0,0 +1,26 @@
+src = $(wildcard src/*.c)
+obj = $(src:.c=.o)
+dep = $(obj:.o=.d)
+bin = volray
+
+CC = gcc
+CFLAGS = -pedantic -Wall -g
+LDFLAGS = $(libgl) -limago -lvmath -lm
+
+ifeq ($(shell uname -s), Darwin)
+	libgl = -framework OpenGL -framework GLUT
+else
+	libgl = -lGL -lglut -lGLEW
+endif
+
+$(bin): $(obj)
+	$(CC) -o $@ $(obj) $(LDFLAGS)
+
+-include $(dep)
+
+%.d: %.c
+	@$(CPP) $(CFLAGS) $< -MM -MT $(@:.d=.o) >$@
+
+.PHONY: clean
+clean:
+	rm -f $(obj) $(bin)
diff -r 000000000000 -r b050ce167ff1 src/sdr.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/sdr.c	Sat Mar 31 02:08:42 2012 +0300
@@ -0,0 +1,333 @@
+#ifndef NO_SHADERS
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <GL/glew.h>
+
+#if defined(unix) || defined(__unix__)
+#include <unistd.h>
+#include <sys/stat.h>
+#endif	/* unix */
+
+#include "sdr.h"
+
+unsigned int create_vertex_shader(const char *src)
+{
+	return create_shader(src, GL_VERTEX_SHADER);
+}
+
+unsigned int create_pixel_shader(const char *src)
+{
+	return create_shader(src, GL_FRAGMENT_SHADER);
+}
+
+unsigned int create_shader(const char *src, unsigned int sdr_type)
+{
+	unsigned int sdr;
+	int success, info_len;
+	char *info_str = 0;
+	GLenum err;
+
+	sdr = glCreateShader(sdr_type);
+	assert(glGetError() == GL_NO_ERROR);
+	glShaderSource(sdr, 1, &src, 0);
+	err = glGetError();
+	assert(err == GL_NO_ERROR);
+	glCompileShader(sdr);
+	assert(glGetError() == GL_NO_ERROR);
+
+	glGetShaderiv(sdr, GL_COMPILE_STATUS, &success);
+	assert(glGetError() == GL_NO_ERROR);
+	glGetShaderiv(sdr, GL_INFO_LOG_LENGTH, &info_len);
+	assert(glGetError() == GL_NO_ERROR);
+
+	if(info_len) {
+		if((info_str = malloc(info_len + 1))) {
+			glGetShaderInfoLog(sdr, info_len, 0, info_str);
+			assert(glGetError() == GL_NO_ERROR);
+		}
+	}
+
+	if(success) {
+		fprintf(stderr, info_str ? "done: %s\n" : "done\n", info_str);
+	} else {
+		fprintf(stderr, info_str ? "failed: %s\n" : "failed\n", info_str);
+		glDeleteShader(sdr);
+		sdr = 0;
+	}
+
+	free(info_str);
+	return sdr;
+}
+
+void free_shader(unsigned int sdr)
+{
+	glDeleteShader(sdr);
+}
+
+unsigned int load_vertex_shader(const char *fname)
+{
+	return load_shader(fname, GL_VERTEX_SHADER);
+}
+
+unsigned int load_pixel_shader(const char *fname)
+{
+	return load_shader(fname, GL_FRAGMENT_SHADER);
+}
+
+unsigned int load_shader(const char *fname, unsigned int sdr_type)
+{
+#if defined(unix) || defined(__unix__)
+	struct stat st;
+#endif
+	unsigned int sdr;
+	size_t filesize;
+	FILE *fp;
+	char *src;
+
+	if(!(fp = fopen(fname, "r"))) {
+		fprintf(stderr, "failed to open shader %s: %s\n", fname, strerror(errno));
+		return 0;
+	}
+
+#if defined(unix) || defined(__unix__)
+	fstat(fileno(fp), &st);
+	filesize = st.st_size;
+#else
+	fseek(fp, 0, SEEK_END);
+	filesize = ftell(fp);
+	fseek(fp, 0, SEEK_SET);
+#endif	/* unix */
+
+	if(!(src = malloc(filesize + 1))) {
+		fclose(fp);
+		return 0;
+	}
+	fread(src, 1, filesize, fp);
+	src[filesize] = 0;
+	fclose(fp);
+
+	fprintf(stderr, "compiling %s shader: %s... ", (sdr_type == GL_VERTEX_SHADER ? "vertex" : "pixel"), fname);
+	sdr = create_shader(src, sdr_type);
+
+	free(src);
+	return sdr;
+}
+
+
+unsigned int get_vertex_shader(const char *fname)
+{
+	return get_shader(fname, GL_VERTEX_SHADER);
+}
+
+unsigned int get_pixel_shader(const char *fname)
+{
+	return get_shader(fname, GL_FRAGMENT_SHADER);
+}
+
+unsigned int get_shader(const char *fname, unsigned int sdr_type)
+{
+	unsigned int sdr;
+
+	if(!(sdr = load_shader(fname, sdr_type))) {
+		return 0;
+	}
+	return sdr;
+}
+
+
+/* ---- gpu programs ---- */
+
+unsigned int create_program(void)
+{
+	unsigned int prog = glCreateProgram();
+	assert(glGetError() == GL_NO_ERROR);
+	return prog;
+}
+
+unsigned int create_program_link(unsigned int vs, unsigned int ps)
+{
+	unsigned int prog;
+
+	if(!(prog = create_program())) {
+		return 0;
+	}
+
+	if(vs) {
+		attach_shader(prog, vs);
+		assert(glGetError() == GL_NO_ERROR);
+	}
+	if(ps) {
+		attach_shader(prog, ps);
+		assert(glGetError() == GL_NO_ERROR);
+	}
+
+	if(link_program(prog) == -1) {
+		free_program(prog);
+		return 0;
+	}
+	return prog;
+}
+
+unsigned int create_program_load(const char *vfile, const char *pfile)
+{
+	unsigned int vs = 0, ps = 0;
+
+	if(vfile && !(vs = get_vertex_shader(vfile))) {
+		return 0;
+	}
+	if(pfile && !(ps = get_pixel_shader(pfile))) {
+		return 0;
+	}
+	return create_program_link(vs, ps);
+}
+
+void free_program(unsigned int sdr)
+{
+	glDeleteProgram(sdr);
+}
+
+void attach_shader(unsigned int prog, unsigned int sdr)
+{
+	glAttachShader(prog, sdr);
+	assert(glGetError() == GL_NO_ERROR);
+}
+
+int link_program(unsigned int prog)
+{
+	int linked, info_len, retval = 0;
+	char *info_str = 0;
+
+	glLinkProgram(prog);
+	assert(glGetError() == GL_NO_ERROR);
+	glGetProgramiv(prog, GL_LINK_STATUS, &linked);
+	assert(glGetError() == GL_NO_ERROR);
+	glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &info_len);
+	assert(glGetError() == GL_NO_ERROR);
+
+	if(info_len) {
+		if((info_str = malloc(info_len + 1))) {
+			glGetProgramInfoLog(prog, info_len, 0, info_str);
+			assert(glGetError() == GL_NO_ERROR);
+		}
+	}
+
+	if(linked) {
+		fprintf(stderr, info_str ? "linking done: %s\n" : "linking done\n", info_str);
+	} else {
+		fprintf(stderr, info_str ? "linking failed: %s\n" : "linking failed\n", info_str);
+		retval = -1;
+	}
+
+	free(info_str);
+	return retval;
+}
+
+int bind_program(unsigned int prog)
+{
+	GLenum err;
+
+	glUseProgram(prog);
+	if(prog && (err = glGetError()) != GL_NO_ERROR) {
+		/* maybe the program is not linked, try linking first */
+		if(err == GL_INVALID_OPERATION) {
+			if(link_program(prog) == -1) {
+				return -1;
+			}
+			glUseProgram(prog);
+			return glGetError() == GL_NO_ERROR ? 0 : -1;
+		}
+		return -1;
+	}
+	return 0;
+}
+
+/* ugly but I'm not going to write the same bloody code over and over */
+#define BEGIN_UNIFORM_CODE \
+	int loc, curr_prog; \
+	glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog); \
+	if(curr_prog != prog && bind_program(prog) == -1) { \
+		return -1; \
+	} \
+	if((loc = glGetUniformLocation(prog, name)) != -1)
+
+#define END_UNIFORM_CODE \
+	if(curr_prog != prog) { \
+		bind_program(curr_prog); \
+	} \
+	return loc == -1 ? -1 : 0
+
+int set_uniform_int(unsigned int prog, const char *name, int val)
+{
+	BEGIN_UNIFORM_CODE {
+		glUniform1i(loc, val);
+	}
+	END_UNIFORM_CODE;
+}
+
+int set_uniform_float(unsigned int prog, const char *name, float val)
+{
+	BEGIN_UNIFORM_CODE {
+		glUniform1f(loc, val);
+	}
+	END_UNIFORM_CODE;
+}
+
+int set_uniform_float3(unsigned int prog, const char *name, float x, float y, float z)
+{
+	BEGIN_UNIFORM_CODE {
+		glUniform3f(loc, x, y, z);
+	}
+	END_UNIFORM_CODE;
+}
+
+int set_uniform_float4(unsigned int prog, const char *name, float x, float y, float z, float w)
+{
+	BEGIN_UNIFORM_CODE {
+		glUniform4f(loc, x, y, z, w);
+	}
+	END_UNIFORM_CODE;
+}
+
+int set_uniform_matrix4(unsigned int prog, const char *name, float *mat)
+{
+	BEGIN_UNIFORM_CODE {
+		glUniformMatrix4fv(loc, 1, GL_FALSE, mat);
+	}
+	END_UNIFORM_CODE;
+}
+
+int set_uniform_matrix4_transposed(unsigned int prog, const char *name, float *mat)
+{
+	BEGIN_UNIFORM_CODE {
+		glUniformMatrix4fv(loc, 1, GL_TRUE, mat);
+	}
+	END_UNIFORM_CODE;
+}
+
+int get_attrib_loc(unsigned int prog, const char *name)
+{
+	int loc, curr_prog;
+
+	glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog);
+	if(curr_prog != prog && bind_program(prog) == -1) {
+		return -1;
+	}
+
+	loc = glGetAttribLocation(prog, (char*)name);
+
+	if(curr_prog != prog) {
+		bind_program(curr_prog);
+	}
+	return loc;
+}
+
+void set_attrib_float3(int attr_loc, float x, float y, float z)
+{
+	glVertexAttrib3f(attr_loc, x, y, z);
+}
+
+#endif	/* !NO_SHADERS */
diff -r 000000000000 -r b050ce167ff1 src/sdr.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/sdr.h	Sat Mar 31 02:08:42 2012 +0300
@@ -0,0 +1,49 @@
+#ifndef SDR_H_
+#define SDR_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif	/* __cplusplus */
+
+/* ---- shaders ---- */
+unsigned int create_vertex_shader(const char *src);
+unsigned int create_pixel_shader(const char *src);
+unsigned int create_shader(const char *src, unsigned int sdr_type);
+void free_shader(unsigned int sdr);
+
+unsigned int load_vertex_shader(const char *fname);
+unsigned int load_pixel_shader(const char *fname);
+unsigned int load_shader(const char *src, unsigned int sdr_type);
+
+unsigned int get_vertex_shader(const char *fname);
+unsigned int get_pixel_shader(const char *fname);
+unsigned int get_shader(const char *fname, unsigned int sdr_type);
+
+int add_shader(const char *fname, unsigned int sdr);
+int remove_shader(const char *fname);
+
+/* ---- gpu programs ---- */
+unsigned int create_program(void);
+unsigned int create_program_link(unsigned int vs, unsigned int ps);
+unsigned int create_program_load(const char *vfile, const char *pfile);
+void free_program(unsigned int sdr);
+
+void attach_shader(unsigned int prog, unsigned int sdr);
+int link_program(unsigned int prog);
+int bind_program(unsigned int prog);
+
+int set_uniform_int(unsigned int prog, const char *name, int val);
+int set_uniform_float(unsigned int prog, const char *name, float val);
+int set_uniform_float3(unsigned int prog, const char *name, float x, float y, float z);
+int set_uniform_float4(unsigned int prog, const char *name, float x, float y, float z, float w);
+int set_uniform_matrix4(unsigned int prog, const char *name, float *mat);
+int set_uniform_matrix4_transposed(unsigned int prog, const char *name, float *mat);
+
+int get_attrib_loc(unsigned int prog, const char *name);
+void set_attrib_float3(int attr_loc, float x, float y, float z);
+
+#ifdef __cplusplus
+}
+#endif	/* __cplusplus */
+
+#endif	/* SDR_H_ */
diff -r 000000000000 -r b050ce167ff1 src/volray.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/volray.c	Sat Mar 31 02:08:42 2012 +0300
@@ -0,0 +1,332 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include <GL/glew.h>
+#ifndef __APPLE__
+#include <GL/glut.h>
+#else
+#include <GLUT/glut.h>
+#endif
+
+#include <vmath/vmath.h>
+#include <imago2.h>
+#include "sdr.h"
+
+struct slice_file {
+	char *name;
+	struct slice_file *next;
+};
+
+int init(void);
+void disp(void);
+void reshape(int x, int y);
+void keyb(unsigned char key, int x, int y);
+void mouse(int bn, int state, int x, int y);
+void motion(int x, int y);
+int parse_args(int argc, char **argv);
+
+unsigned int 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);
+
+float cam_theta = 0, cam_phi = 0, cam_dist = 4.0;
+float cam_x, cam_y, cam_z;
+
+vec2_t tex_scale;
+struct slice_file *flist;
+int nslices;
+unsigned int sdr, vol_tex, ray_tex;
+int win_xsz, win_ysz;
+
+int main(int argc, char **argv)
+{
+	glutInit(&argc, argv);
+	glutInitWindowSize(1280, 720);
+	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
+
+	if(parse_args(argc, argv) == -1) {
+		return 1;
+	}
+
+	glutCreateWindow("Volume Raytracer");
+
+	glutDisplayFunc(disp);
+	glutReshapeFunc(reshape);
+	glutKeyboardFunc(keyb);
+	glutMouseFunc(mouse);
+	glutMotionFunc(motion);
+
+	glewInit();
+
+	if(init() == -1) {
+		return 1;
+	}
+
+	glutMainLoop();
+	return 0;
+}
+
+int init(void)
+{
+	int i, vol_xsz, vol_ysz;
+
+	if(!(sdr = create_program_load("volray.v.glsl", "volray.p.glsl"))) {
+		return 1;
+	}
+
+	glGenTextures(1, &vol_tex);
+	glBindTexture(GL_TEXTURE_3D, vol_tex);
+	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
+
+	for(i=0; i<nslices; i++) {
+		int xsz, ysz;
+		void *pix;
+		struct slice_file *sfile = flist;
+		flist = flist->next;
+
+		if(!(pix = img_load_pixels(sfile->name, &xsz, &ysz, IMG_FMT_RGBA32))) {
+			fprintf(stderr, "failed to load image: %s\n", sfile->name);
+			return -1;
+		}
+
+		if(i == 0) {
+			/* allocate storage for the texture */
+			glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA, xsz, ysz, nslices, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
+
+			vol_xsz = xsz;
+			vol_ysz = ysz;
+
+		} else {
+			if(xsz != vol_xsz || ysz != vol_ysz) {
+				fprintf(stderr, "%s: inconsistent slice size: %dx%d. expected: %dx%d\n",
+						sfile->name, xsz, ysz, vol_xsz, vol_ysz);
+				img_free_pixels(pix);
+				return -1;
+			}
+		}
+		free(sfile);
+
+		glTexSubImage3D(GL_TEXTURE_3D, 0, 0, 0, i, xsz, ysz, 1, GL_RGBA, GL_UNSIGNED_BYTE, pix);
+		img_free_pixels(pix);
+	}
+
+	return 0;
+}
+
+void disp(void)
+{
+	glMatrixMode(GL_MODELVIEW);
+	glLoadIdentity();
+	glTranslatef(cam_x, cam_y, -cam_z);
+	glRotatef(cam_theta, 0, 1, 0);
+	glRotatef(cam_phi, 1, 0, 0);
+	glTranslatef(0, 0, -cam_dist);
+
+	glMatrixMode(GL_TEXTURE);
+	glPushMatrix();
+	glScalef(tex_scale.x, tex_scale.y, 1.0);
+
+	glActiveTexture(GL_TEXTURE0);
+	glEnable(GL_TEXTURE_3D);
+	glBindTexture(GL_TEXTURE_3D, vol_tex);
+
+	glActiveTexture(GL_TEXTURE1);
+	glEnable(GL_TEXTURE_2D);
+	glBindTexture(GL_TEXTURE_2D, ray_tex);
+
+	bind_program(sdr);
+	glBegin(GL_QUADS);
+	glColor3f(1, 1, 1);
+	glTexCoord2f(0, 1);
+	glVertex2f(-1, -1);
+	glTexCoord2f(1, 1);
+	glVertex2f(1, -1);
+	glTexCoord2f(1, 0);
+	glVertex2f(1, 1);
+	glTexCoord2f(0, 0);
+	glVertex2f(-1, 1);
+	glEnd();
+	bind_program(0);
+
+	glDisable(GL_TEXTURE_2D);
+	glActiveTexture(GL_TEXTURE0);
+	glDisable(GL_TEXTURE_3D);
+
+	glMatrixMode(GL_TEXTURE);
+	glPopMatrix();
+
+	glutSwapBuffers();
+	assert(glGetError() == GL_NO_ERROR);
+}
+
+void reshape(int x, int y)
+{
+	glViewport(0, 0, x, y);
+
+	if(x != win_xsz || y != win_ysz) {
+		ray_tex = create_ray_texture(x, y, 50.0, &tex_scale);
+		win_xsz = x;
+		win_ysz = y;
+	}
+}
+
+void keyb(unsigned char key, int x, int y)
+{
+	switch(key) {
+	case 27:
+		exit(0);
+	}
+}
+
+static int bnstate[32];
+static int prev_x, prev_y;
+
+void mouse(int bn, int state, int x, int y)
+{
+	bnstate[bn - GLUT_LEFT_BUTTON] = state == GLUT_DOWN;
+	prev_x = x;
+	prev_y = y;
+}
+
+void motion(int x, int y)
+{
+	int dx = x - prev_x;
+	int dy = y - prev_y;
+
+	prev_x = x;
+	prev_y = y;
+
+	if(bnstate[0]) {
+		cam_theta += dx * 0.5;
+		cam_phi += dy * 0.5;
+
+		if(cam_phi < -90) cam_phi = -90;
+		if(cam_phi > 90) cam_phi = 90;
+
+		glutPostRedisplay();
+	}
+
+	if(bnstate[1]) {
+		cam_y += dy * 0.1;
+		glutPostRedisplay();
+	}
+
+	if(bnstate[2]) {
+		cam_dist += dy * 0.1;
+		if(cam_dist < 0.0) cam_dist = 0.0;
+		glutPostRedisplay();
+	}
+}
+
+
+int parse_args(int argc, char **argv)
+{
+	int i;
+	struct slice_file *tail;
+
+	for(i=1; i<argc; i++) {
+		struct slice_file *sfile;
+
+		if(!(sfile = malloc(sizeof *sfile))) {
+			perror("failed to allocate memory");
+			return -1;
+		}
+		sfile->name = argv[i];
+		sfile->next = 0;
+
+		if(!flist) {
+			flist = tail = sfile;
+		} else {
+			tail->next = sfile;
+			tail = sfile;
+		}
+		nslices++;
+	}
+
+	if(!nslices) {
+		fprintf(stderr, "pass the slice filenames\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+
+unsigned int create_ray_texture(int xsz, int ysz, float vfov, vec2_t *tex_scale)
+{
+	int i, j;
+	unsigned int tex;
+	int tex_xsz = round_pow2(xsz);
+	int tex_ysz = round_pow2(ysz);
+	float *teximg, *dir;
+
+	if(!(teximg = malloc(3 * tex_xsz * tex_ysz * sizeof *teximg))) {
+		return 0;
+	}
+	dir = teximg;
+
+	for(i=0; i<tex_ysz; i++) {
+		for(j=0; j<tex_xsz; j++) {
+			if(j < xsz && i < ysz) {
+				vec3_t rdir = get_primary_ray_dir(j, i, xsz, ysz, vfov);
+				dir[0] = rdir.x;
+				dir[1] = rdir.y;
+				dir[2] = rdir.z;
+			} else {
+				dir[0] = dir[1] = 0.0f;
+				dir[2] = 1.0f;
+			}
+
+			dir += 3;
+		}
+	}
+
+	glGenTextures(1, &tex);
+	glBindTexture(GL_TEXTURE_2D, tex);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F_ARB, tex_xsz, tex_ysz, 0, GL_RGB, GL_FLOAT, teximg);
+	free(teximg);
+
+	if(tex_scale) {
+		tex_scale->x = (float)xsz / (float)tex_xsz;
+		tex_scale->y = (float)ysz / (float)tex_ysz;
+	}
+	return tex;
+}
+
+static vec3_t get_primary_ray_dir(int x, int y, int w, int h, float vfov_deg)
+{
+	float vfov = M_PI * vfov_deg / 180.0;
+	float aspect = (float)w / (float)h;
+
+	float ysz = 2.0;
+	float xsz = aspect * ysz;
+
+	float px = ((float)x / (float)w) * xsz - xsz / 2.0;
+	float py = 1.0 - ((float)y / (float)h) * ysz;
+	float pz = 1.0 / tan(0.5 * vfov);
+
+	float mag = sqrt(px * px + py * py + pz * pz);
+
+	return v3_cons(px / mag, py / mag, pz / mag);
+}
+
+static int round_pow2(int x)
+{
+	x--;
+	x = (x >> 1) | x;
+	x = (x >> 2) | x;
+	x = (x >> 4) | x;
+	x = (x >> 8) | x;
+	x = (x >> 16) | x;
+	return x + 1;
+}
+
diff -r 000000000000 -r b050ce167ff1 volray.p.glsl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/volray.p.glsl	Sat Mar 31 02:08:42 2012 +0300
@@ -0,0 +1,72 @@
+uniform sampler3D volume;
+uniform sampler2D ray_tex;
+
+struct Ray {
+	vec3 origin, dir;
+};
+
+struct ISect {
+	bool hit;
+	float t;
+	vec3 pos;
+	vec3 normal;
+};
+
+vec3 ray_march(Ray ray);
+vec3 shade(Ray ray, ISect isect);
+Ray get_primary_ray();
+
+void main()
+{
+	Ray ray = get_primary_ray();
+
+	gl_FragColor = vec4(ray_march(ray), 1.0);
+}
+
+/*vec3 sky(Ray ray)
+{
+	vec3 col1 = vec3(0.75, 0.78, 0.8);
+	vec3 col2 = vec3(0.56, 0.7, 1.0);
+
+	float t = max(ray.dir.y, -0.5);
+	return mix(col1, col2, t);
+}*/
+
+vec3 ray_march(Ray ray)
+{
+	const float ray_step = 0.05;
+	float energy = 1.0;
+	vec3 pos = ray.origin;
+
+	// assuming view space
+	while(pos.z < 1.0) {
+		energy -= texture3D(volume, pos).x;
+		pos += ray.dir * ray_step;
+	}
+
+	return vec3(energy, energy, energy);
+}
+
+vec3 shade(Ray ray, ISect isect)
+{
+	vec3 ldir = normalize(vec3(10.0, 10.0, -10.0) - isect.pos);
+	vec3 vdir = -ray.dir;
+	vec3 hdir = normalize(ldir + vdir);
+
+	float ndotl = dot(ldir, isect.normal);
+	float ndoth = dot(hdir, isect.normal);
+
+	vec3 dcol = vec3(1.0, 1.0, 1.0) * max(ndotl, 0.0);
+	vec3 scol = vec3(0.6, 0.6, 0.6) * pow(max(ndoth, 0.0), 50.0);
+
+	return vec3(0.01, 0.01, 0.01) + dcol + scol;
+}
+
+Ray get_primary_ray()
+{
+	Ray ray;
+	vec2 tc = gl_TexCoord[0].xy;
+	ray.dir = gl_NormalMatrix * normalize(texture2D(ray_tex, tc).xyz);
+	ray.origin = (gl_ModelViewMatrix * vec4(0.0, 0.0, 0.0, 1.0)).xyz;
+	return ray;
+}
diff -r 000000000000 -r b050ce167ff1 volray.v.glsl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/volray.v.glsl	Sat Mar 31 02:08:42 2012 +0300
@@ -0,0 +1,5 @@
+void main()
+{
+	gl_Position = gl_Vertex;
+	gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
+}