volray

changeset 0:b050ce167ff1

foo
author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 31 Mar 2012 02:08:42 +0300
parents
children 57072295eb83
files Makefile src/sdr.c src/sdr.h src/volray.c volray.p.glsl volray.v.glsl
diffstat 6 files changed, 817 insertions(+), 0 deletions(-) [+]
line diff
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/Makefile	Sat Mar 31 02:08:42 2012 +0300
     1.3 @@ -0,0 +1,26 @@
     1.4 +src = $(wildcard src/*.c)
     1.5 +obj = $(src:.c=.o)
     1.6 +dep = $(obj:.o=.d)
     1.7 +bin = volray
     1.8 +
     1.9 +CC = gcc
    1.10 +CFLAGS = -pedantic -Wall -g
    1.11 +LDFLAGS = $(libgl) -limago -lvmath -lm
    1.12 +
    1.13 +ifeq ($(shell uname -s), Darwin)
    1.14 +	libgl = -framework OpenGL -framework GLUT
    1.15 +else
    1.16 +	libgl = -lGL -lglut -lGLEW
    1.17 +endif
    1.18 +
    1.19 +$(bin): $(obj)
    1.20 +	$(CC) -o $@ $(obj) $(LDFLAGS)
    1.21 +
    1.22 +-include $(dep)
    1.23 +
    1.24 +%.d: %.c
    1.25 +	@$(CPP) $(CFLAGS) $< -MM -MT $(@:.d=.o) >$@
    1.26 +
    1.27 +.PHONY: clean
    1.28 +clean:
    1.29 +	rm -f $(obj) $(bin)
     2.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     2.2 +++ b/src/sdr.c	Sat Mar 31 02:08:42 2012 +0300
     2.3 @@ -0,0 +1,333 @@
     2.4 +#ifndef NO_SHADERS
     2.5 +
     2.6 +#include <stdio.h>
     2.7 +#include <stdlib.h>
     2.8 +#include <string.h>
     2.9 +#include <errno.h>
    2.10 +#include <assert.h>
    2.11 +#include <GL/glew.h>
    2.12 +
    2.13 +#if defined(unix) || defined(__unix__)
    2.14 +#include <unistd.h>
    2.15 +#include <sys/stat.h>
    2.16 +#endif	/* unix */
    2.17 +
    2.18 +#include "sdr.h"
    2.19 +
    2.20 +unsigned int create_vertex_shader(const char *src)
    2.21 +{
    2.22 +	return create_shader(src, GL_VERTEX_SHADER);
    2.23 +}
    2.24 +
    2.25 +unsigned int create_pixel_shader(const char *src)
    2.26 +{
    2.27 +	return create_shader(src, GL_FRAGMENT_SHADER);
    2.28 +}
    2.29 +
    2.30 +unsigned int create_shader(const char *src, unsigned int sdr_type)
    2.31 +{
    2.32 +	unsigned int sdr;
    2.33 +	int success, info_len;
    2.34 +	char *info_str = 0;
    2.35 +	GLenum err;
    2.36 +
    2.37 +	sdr = glCreateShader(sdr_type);
    2.38 +	assert(glGetError() == GL_NO_ERROR);
    2.39 +	glShaderSource(sdr, 1, &src, 0);
    2.40 +	err = glGetError();
    2.41 +	assert(err == GL_NO_ERROR);
    2.42 +	glCompileShader(sdr);
    2.43 +	assert(glGetError() == GL_NO_ERROR);
    2.44 +
    2.45 +	glGetShaderiv(sdr, GL_COMPILE_STATUS, &success);
    2.46 +	assert(glGetError() == GL_NO_ERROR);
    2.47 +	glGetShaderiv(sdr, GL_INFO_LOG_LENGTH, &info_len);
    2.48 +	assert(glGetError() == GL_NO_ERROR);
    2.49 +
    2.50 +	if(info_len) {
    2.51 +		if((info_str = malloc(info_len + 1))) {
    2.52 +			glGetShaderInfoLog(sdr, info_len, 0, info_str);
    2.53 +			assert(glGetError() == GL_NO_ERROR);
    2.54 +		}
    2.55 +	}
    2.56 +
    2.57 +	if(success) {
    2.58 +		fprintf(stderr, info_str ? "done: %s\n" : "done\n", info_str);
    2.59 +	} else {
    2.60 +		fprintf(stderr, info_str ? "failed: %s\n" : "failed\n", info_str);
    2.61 +		glDeleteShader(sdr);
    2.62 +		sdr = 0;
    2.63 +	}
    2.64 +
    2.65 +	free(info_str);
    2.66 +	return sdr;
    2.67 +}
    2.68 +
    2.69 +void free_shader(unsigned int sdr)
    2.70 +{
    2.71 +	glDeleteShader(sdr);
    2.72 +}
    2.73 +
    2.74 +unsigned int load_vertex_shader(const char *fname)
    2.75 +{
    2.76 +	return load_shader(fname, GL_VERTEX_SHADER);
    2.77 +}
    2.78 +
    2.79 +unsigned int load_pixel_shader(const char *fname)
    2.80 +{
    2.81 +	return load_shader(fname, GL_FRAGMENT_SHADER);
    2.82 +}
    2.83 +
    2.84 +unsigned int load_shader(const char *fname, unsigned int sdr_type)
    2.85 +{
    2.86 +#if defined(unix) || defined(__unix__)
    2.87 +	struct stat st;
    2.88 +#endif
    2.89 +	unsigned int sdr;
    2.90 +	size_t filesize;
    2.91 +	FILE *fp;
    2.92 +	char *src;
    2.93 +
    2.94 +	if(!(fp = fopen(fname, "r"))) {
    2.95 +		fprintf(stderr, "failed to open shader %s: %s\n", fname, strerror(errno));
    2.96 +		return 0;
    2.97 +	}
    2.98 +
    2.99 +#if defined(unix) || defined(__unix__)
   2.100 +	fstat(fileno(fp), &st);
   2.101 +	filesize = st.st_size;
   2.102 +#else
   2.103 +	fseek(fp, 0, SEEK_END);
   2.104 +	filesize = ftell(fp);
   2.105 +	fseek(fp, 0, SEEK_SET);
   2.106 +#endif	/* unix */
   2.107 +
   2.108 +	if(!(src = malloc(filesize + 1))) {
   2.109 +		fclose(fp);
   2.110 +		return 0;
   2.111 +	}
   2.112 +	fread(src, 1, filesize, fp);
   2.113 +	src[filesize] = 0;
   2.114 +	fclose(fp);
   2.115 +
   2.116 +	fprintf(stderr, "compiling %s shader: %s... ", (sdr_type == GL_VERTEX_SHADER ? "vertex" : "pixel"), fname);
   2.117 +	sdr = create_shader(src, sdr_type);
   2.118 +
   2.119 +	free(src);
   2.120 +	return sdr;
   2.121 +}
   2.122 +
   2.123 +
   2.124 +unsigned int get_vertex_shader(const char *fname)
   2.125 +{
   2.126 +	return get_shader(fname, GL_VERTEX_SHADER);
   2.127 +}
   2.128 +
   2.129 +unsigned int get_pixel_shader(const char *fname)
   2.130 +{
   2.131 +	return get_shader(fname, GL_FRAGMENT_SHADER);
   2.132 +}
   2.133 +
   2.134 +unsigned int get_shader(const char *fname, unsigned int sdr_type)
   2.135 +{
   2.136 +	unsigned int sdr;
   2.137 +
   2.138 +	if(!(sdr = load_shader(fname, sdr_type))) {
   2.139 +		return 0;
   2.140 +	}
   2.141 +	return sdr;
   2.142 +}
   2.143 +
   2.144 +
   2.145 +/* ---- gpu programs ---- */
   2.146 +
   2.147 +unsigned int create_program(void)
   2.148 +{
   2.149 +	unsigned int prog = glCreateProgram();
   2.150 +	assert(glGetError() == GL_NO_ERROR);
   2.151 +	return prog;
   2.152 +}
   2.153 +
   2.154 +unsigned int create_program_link(unsigned int vs, unsigned int ps)
   2.155 +{
   2.156 +	unsigned int prog;
   2.157 +
   2.158 +	if(!(prog = create_program())) {
   2.159 +		return 0;
   2.160 +	}
   2.161 +
   2.162 +	if(vs) {
   2.163 +		attach_shader(prog, vs);
   2.164 +		assert(glGetError() == GL_NO_ERROR);
   2.165 +	}
   2.166 +	if(ps) {
   2.167 +		attach_shader(prog, ps);
   2.168 +		assert(glGetError() == GL_NO_ERROR);
   2.169 +	}
   2.170 +
   2.171 +	if(link_program(prog) == -1) {
   2.172 +		free_program(prog);
   2.173 +		return 0;
   2.174 +	}
   2.175 +	return prog;
   2.176 +}
   2.177 +
   2.178 +unsigned int create_program_load(const char *vfile, const char *pfile)
   2.179 +{
   2.180 +	unsigned int vs = 0, ps = 0;
   2.181 +
   2.182 +	if(vfile && !(vs = get_vertex_shader(vfile))) {
   2.183 +		return 0;
   2.184 +	}
   2.185 +	if(pfile && !(ps = get_pixel_shader(pfile))) {
   2.186 +		return 0;
   2.187 +	}
   2.188 +	return create_program_link(vs, ps);
   2.189 +}
   2.190 +
   2.191 +void free_program(unsigned int sdr)
   2.192 +{
   2.193 +	glDeleteProgram(sdr);
   2.194 +}
   2.195 +
   2.196 +void attach_shader(unsigned int prog, unsigned int sdr)
   2.197 +{
   2.198 +	glAttachShader(prog, sdr);
   2.199 +	assert(glGetError() == GL_NO_ERROR);
   2.200 +}
   2.201 +
   2.202 +int link_program(unsigned int prog)
   2.203 +{
   2.204 +	int linked, info_len, retval = 0;
   2.205 +	char *info_str = 0;
   2.206 +
   2.207 +	glLinkProgram(prog);
   2.208 +	assert(glGetError() == GL_NO_ERROR);
   2.209 +	glGetProgramiv(prog, GL_LINK_STATUS, &linked);
   2.210 +	assert(glGetError() == GL_NO_ERROR);
   2.211 +	glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &info_len);
   2.212 +	assert(glGetError() == GL_NO_ERROR);
   2.213 +
   2.214 +	if(info_len) {
   2.215 +		if((info_str = malloc(info_len + 1))) {
   2.216 +			glGetProgramInfoLog(prog, info_len, 0, info_str);
   2.217 +			assert(glGetError() == GL_NO_ERROR);
   2.218 +		}
   2.219 +	}
   2.220 +
   2.221 +	if(linked) {
   2.222 +		fprintf(stderr, info_str ? "linking done: %s\n" : "linking done\n", info_str);
   2.223 +	} else {
   2.224 +		fprintf(stderr, info_str ? "linking failed: %s\n" : "linking failed\n", info_str);
   2.225 +		retval = -1;
   2.226 +	}
   2.227 +
   2.228 +	free(info_str);
   2.229 +	return retval;
   2.230 +}
   2.231 +
   2.232 +int bind_program(unsigned int prog)
   2.233 +{
   2.234 +	GLenum err;
   2.235 +
   2.236 +	glUseProgram(prog);
   2.237 +	if(prog && (err = glGetError()) != GL_NO_ERROR) {
   2.238 +		/* maybe the program is not linked, try linking first */
   2.239 +		if(err == GL_INVALID_OPERATION) {
   2.240 +			if(link_program(prog) == -1) {
   2.241 +				return -1;
   2.242 +			}
   2.243 +			glUseProgram(prog);
   2.244 +			return glGetError() == GL_NO_ERROR ? 0 : -1;
   2.245 +		}
   2.246 +		return -1;
   2.247 +	}
   2.248 +	return 0;
   2.249 +}
   2.250 +
   2.251 +/* ugly but I'm not going to write the same bloody code over and over */
   2.252 +#define BEGIN_UNIFORM_CODE \
   2.253 +	int loc, curr_prog; \
   2.254 +	glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog); \
   2.255 +	if(curr_prog != prog && bind_program(prog) == -1) { \
   2.256 +		return -1; \
   2.257 +	} \
   2.258 +	if((loc = glGetUniformLocation(prog, name)) != -1)
   2.259 +
   2.260 +#define END_UNIFORM_CODE \
   2.261 +	if(curr_prog != prog) { \
   2.262 +		bind_program(curr_prog); \
   2.263 +	} \
   2.264 +	return loc == -1 ? -1 : 0
   2.265 +
   2.266 +int set_uniform_int(unsigned int prog, const char *name, int val)
   2.267 +{
   2.268 +	BEGIN_UNIFORM_CODE {
   2.269 +		glUniform1i(loc, val);
   2.270 +	}
   2.271 +	END_UNIFORM_CODE;
   2.272 +}
   2.273 +
   2.274 +int set_uniform_float(unsigned int prog, const char *name, float val)
   2.275 +{
   2.276 +	BEGIN_UNIFORM_CODE {
   2.277 +		glUniform1f(loc, val);
   2.278 +	}
   2.279 +	END_UNIFORM_CODE;
   2.280 +}
   2.281 +
   2.282 +int set_uniform_float3(unsigned int prog, const char *name, float x, float y, float z)
   2.283 +{
   2.284 +	BEGIN_UNIFORM_CODE {
   2.285 +		glUniform3f(loc, x, y, z);
   2.286 +	}
   2.287 +	END_UNIFORM_CODE;
   2.288 +}
   2.289 +
   2.290 +int set_uniform_float4(unsigned int prog, const char *name, float x, float y, float z, float w)
   2.291 +{
   2.292 +	BEGIN_UNIFORM_CODE {
   2.293 +		glUniform4f(loc, x, y, z, w);
   2.294 +	}
   2.295 +	END_UNIFORM_CODE;
   2.296 +}
   2.297 +
   2.298 +int set_uniform_matrix4(unsigned int prog, const char *name, float *mat)
   2.299 +{
   2.300 +	BEGIN_UNIFORM_CODE {
   2.301 +		glUniformMatrix4fv(loc, 1, GL_FALSE, mat);
   2.302 +	}
   2.303 +	END_UNIFORM_CODE;
   2.304 +}
   2.305 +
   2.306 +int set_uniform_matrix4_transposed(unsigned int prog, const char *name, float *mat)
   2.307 +{
   2.308 +	BEGIN_UNIFORM_CODE {
   2.309 +		glUniformMatrix4fv(loc, 1, GL_TRUE, mat);
   2.310 +	}
   2.311 +	END_UNIFORM_CODE;
   2.312 +}
   2.313 +
   2.314 +int get_attrib_loc(unsigned int prog, const char *name)
   2.315 +{
   2.316 +	int loc, curr_prog;
   2.317 +
   2.318 +	glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog);
   2.319 +	if(curr_prog != prog && bind_program(prog) == -1) {
   2.320 +		return -1;
   2.321 +	}
   2.322 +
   2.323 +	loc = glGetAttribLocation(prog, (char*)name);
   2.324 +
   2.325 +	if(curr_prog != prog) {
   2.326 +		bind_program(curr_prog);
   2.327 +	}
   2.328 +	return loc;
   2.329 +}
   2.330 +
   2.331 +void set_attrib_float3(int attr_loc, float x, float y, float z)
   2.332 +{
   2.333 +	glVertexAttrib3f(attr_loc, x, y, z);
   2.334 +}
   2.335 +
   2.336 +#endif	/* !NO_SHADERS */
     3.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     3.2 +++ b/src/sdr.h	Sat Mar 31 02:08:42 2012 +0300
     3.3 @@ -0,0 +1,49 @@
     3.4 +#ifndef SDR_H_
     3.5 +#define SDR_H_
     3.6 +
     3.7 +#ifdef __cplusplus
     3.8 +extern "C" {
     3.9 +#endif	/* __cplusplus */
    3.10 +
    3.11 +/* ---- shaders ---- */
    3.12 +unsigned int create_vertex_shader(const char *src);
    3.13 +unsigned int create_pixel_shader(const char *src);
    3.14 +unsigned int create_shader(const char *src, unsigned int sdr_type);
    3.15 +void free_shader(unsigned int sdr);
    3.16 +
    3.17 +unsigned int load_vertex_shader(const char *fname);
    3.18 +unsigned int load_pixel_shader(const char *fname);
    3.19 +unsigned int load_shader(const char *src, unsigned int sdr_type);
    3.20 +
    3.21 +unsigned int get_vertex_shader(const char *fname);
    3.22 +unsigned int get_pixel_shader(const char *fname);
    3.23 +unsigned int get_shader(const char *fname, unsigned int sdr_type);
    3.24 +
    3.25 +int add_shader(const char *fname, unsigned int sdr);
    3.26 +int remove_shader(const char *fname);
    3.27 +
    3.28 +/* ---- gpu programs ---- */
    3.29 +unsigned int create_program(void);
    3.30 +unsigned int create_program_link(unsigned int vs, unsigned int ps);
    3.31 +unsigned int create_program_load(const char *vfile, const char *pfile);
    3.32 +void free_program(unsigned int sdr);
    3.33 +
    3.34 +void attach_shader(unsigned int prog, unsigned int sdr);
    3.35 +int link_program(unsigned int prog);
    3.36 +int bind_program(unsigned int prog);
    3.37 +
    3.38 +int set_uniform_int(unsigned int prog, const char *name, int val);
    3.39 +int set_uniform_float(unsigned int prog, const char *name, float val);
    3.40 +int set_uniform_float3(unsigned int prog, const char *name, float x, float y, float z);
    3.41 +int set_uniform_float4(unsigned int prog, const char *name, float x, float y, float z, float w);
    3.42 +int set_uniform_matrix4(unsigned int prog, const char *name, float *mat);
    3.43 +int set_uniform_matrix4_transposed(unsigned int prog, const char *name, float *mat);
    3.44 +
    3.45 +int get_attrib_loc(unsigned int prog, const char *name);
    3.46 +void set_attrib_float3(int attr_loc, float x, float y, float z);
    3.47 +
    3.48 +#ifdef __cplusplus
    3.49 +}
    3.50 +#endif	/* __cplusplus */
    3.51 +
    3.52 +#endif	/* SDR_H_ */
     4.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     4.2 +++ b/src/volray.c	Sat Mar 31 02:08:42 2012 +0300
     4.3 @@ -0,0 +1,332 @@
     4.4 +#include <stdio.h>
     4.5 +#include <stdlib.h>
     4.6 +#include <assert.h>
     4.7 +
     4.8 +#include <GL/glew.h>
     4.9 +#ifndef __APPLE__
    4.10 +#include <GL/glut.h>
    4.11 +#else
    4.12 +#include <GLUT/glut.h>
    4.13 +#endif
    4.14 +
    4.15 +#include <vmath/vmath.h>
    4.16 +#include <imago2.h>
    4.17 +#include "sdr.h"
    4.18 +
    4.19 +struct slice_file {
    4.20 +	char *name;
    4.21 +	struct slice_file *next;
    4.22 +};
    4.23 +
    4.24 +int init(void);
    4.25 +void disp(void);
    4.26 +void reshape(int x, int y);
    4.27 +void keyb(unsigned char key, int x, int y);
    4.28 +void mouse(int bn, int state, int x, int y);
    4.29 +void motion(int x, int y);
    4.30 +int parse_args(int argc, char **argv);
    4.31 +
    4.32 +unsigned int create_ray_texture(int xsz, int ysz, float vfov, vec2_t *tex_scale);
    4.33 +static vec3_t get_primary_ray_dir(int x, int y, int w, int h, float vfov_deg);
    4.34 +static int round_pow2(int x);
    4.35 +
    4.36 +float cam_theta = 0, cam_phi = 0, cam_dist = 4.0;
    4.37 +float cam_x, cam_y, cam_z;
    4.38 +
    4.39 +vec2_t tex_scale;
    4.40 +struct slice_file *flist;
    4.41 +int nslices;
    4.42 +unsigned int sdr, vol_tex, ray_tex;
    4.43 +int win_xsz, win_ysz;
    4.44 +
    4.45 +int main(int argc, char **argv)
    4.46 +{
    4.47 +	glutInit(&argc, argv);
    4.48 +	glutInitWindowSize(1280, 720);
    4.49 +	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
    4.50 +
    4.51 +	if(parse_args(argc, argv) == -1) {
    4.52 +		return 1;
    4.53 +	}
    4.54 +
    4.55 +	glutCreateWindow("Volume Raytracer");
    4.56 +
    4.57 +	glutDisplayFunc(disp);
    4.58 +	glutReshapeFunc(reshape);
    4.59 +	glutKeyboardFunc(keyb);
    4.60 +	glutMouseFunc(mouse);
    4.61 +	glutMotionFunc(motion);
    4.62 +
    4.63 +	glewInit();
    4.64 +
    4.65 +	if(init() == -1) {
    4.66 +		return 1;
    4.67 +	}
    4.68 +
    4.69 +	glutMainLoop();
    4.70 +	return 0;
    4.71 +}
    4.72 +
    4.73 +int init(void)
    4.74 +{
    4.75 +	int i, vol_xsz, vol_ysz;
    4.76 +
    4.77 +	if(!(sdr = create_program_load("volray.v.glsl", "volray.p.glsl"))) {
    4.78 +		return 1;
    4.79 +	}
    4.80 +
    4.81 +	glGenTextures(1, &vol_tex);
    4.82 +	glBindTexture(GL_TEXTURE_3D, vol_tex);
    4.83 +	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    4.84 +	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    4.85 +	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    4.86 +	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    4.87 +	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
    4.88 +
    4.89 +	for(i=0; i<nslices; i++) {
    4.90 +		int xsz, ysz;
    4.91 +		void *pix;
    4.92 +		struct slice_file *sfile = flist;
    4.93 +		flist = flist->next;
    4.94 +
    4.95 +		if(!(pix = img_load_pixels(sfile->name, &xsz, &ysz, IMG_FMT_RGBA32))) {
    4.96 +			fprintf(stderr, "failed to load image: %s\n", sfile->name);
    4.97 +			return -1;
    4.98 +		}
    4.99 +
   4.100 +		if(i == 0) {
   4.101 +			/* allocate storage for the texture */
   4.102 +			glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA, xsz, ysz, nslices, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
   4.103 +
   4.104 +			vol_xsz = xsz;
   4.105 +			vol_ysz = ysz;
   4.106 +
   4.107 +		} else {
   4.108 +			if(xsz != vol_xsz || ysz != vol_ysz) {
   4.109 +				fprintf(stderr, "%s: inconsistent slice size: %dx%d. expected: %dx%d\n",
   4.110 +						sfile->name, xsz, ysz, vol_xsz, vol_ysz);
   4.111 +				img_free_pixels(pix);
   4.112 +				return -1;
   4.113 +			}
   4.114 +		}
   4.115 +		free(sfile);
   4.116 +
   4.117 +		glTexSubImage3D(GL_TEXTURE_3D, 0, 0, 0, i, xsz, ysz, 1, GL_RGBA, GL_UNSIGNED_BYTE, pix);
   4.118 +		img_free_pixels(pix);
   4.119 +	}
   4.120 +
   4.121 +	return 0;
   4.122 +}
   4.123 +
   4.124 +void disp(void)
   4.125 +{
   4.126 +	glMatrixMode(GL_MODELVIEW);
   4.127 +	glLoadIdentity();
   4.128 +	glTranslatef(cam_x, cam_y, -cam_z);
   4.129 +	glRotatef(cam_theta, 0, 1, 0);
   4.130 +	glRotatef(cam_phi, 1, 0, 0);
   4.131 +	glTranslatef(0, 0, -cam_dist);
   4.132 +
   4.133 +	glMatrixMode(GL_TEXTURE);
   4.134 +	glPushMatrix();
   4.135 +	glScalef(tex_scale.x, tex_scale.y, 1.0);
   4.136 +
   4.137 +	glActiveTexture(GL_TEXTURE0);
   4.138 +	glEnable(GL_TEXTURE_3D);
   4.139 +	glBindTexture(GL_TEXTURE_3D, vol_tex);
   4.140 +
   4.141 +	glActiveTexture(GL_TEXTURE1);
   4.142 +	glEnable(GL_TEXTURE_2D);
   4.143 +	glBindTexture(GL_TEXTURE_2D, ray_tex);
   4.144 +
   4.145 +	bind_program(sdr);
   4.146 +	glBegin(GL_QUADS);
   4.147 +	glColor3f(1, 1, 1);
   4.148 +	glTexCoord2f(0, 1);
   4.149 +	glVertex2f(-1, -1);
   4.150 +	glTexCoord2f(1, 1);
   4.151 +	glVertex2f(1, -1);
   4.152 +	glTexCoord2f(1, 0);
   4.153 +	glVertex2f(1, 1);
   4.154 +	glTexCoord2f(0, 0);
   4.155 +	glVertex2f(-1, 1);
   4.156 +	glEnd();
   4.157 +	bind_program(0);
   4.158 +
   4.159 +	glDisable(GL_TEXTURE_2D);
   4.160 +	glActiveTexture(GL_TEXTURE0);
   4.161 +	glDisable(GL_TEXTURE_3D);
   4.162 +
   4.163 +	glMatrixMode(GL_TEXTURE);
   4.164 +	glPopMatrix();
   4.165 +
   4.166 +	glutSwapBuffers();
   4.167 +	assert(glGetError() == GL_NO_ERROR);
   4.168 +}
   4.169 +
   4.170 +void reshape(int x, int y)
   4.171 +{
   4.172 +	glViewport(0, 0, x, y);
   4.173 +
   4.174 +	if(x != win_xsz || y != win_ysz) {
   4.175 +		ray_tex = create_ray_texture(x, y, 50.0, &tex_scale);
   4.176 +		win_xsz = x;
   4.177 +		win_ysz = y;
   4.178 +	}
   4.179 +}
   4.180 +
   4.181 +void keyb(unsigned char key, int x, int y)
   4.182 +{
   4.183 +	switch(key) {
   4.184 +	case 27:
   4.185 +		exit(0);
   4.186 +	}
   4.187 +}
   4.188 +
   4.189 +static int bnstate[32];
   4.190 +static int prev_x, prev_y;
   4.191 +
   4.192 +void mouse(int bn, int state, int x, int y)
   4.193 +{
   4.194 +	bnstate[bn - GLUT_LEFT_BUTTON] = state == GLUT_DOWN;
   4.195 +	prev_x = x;
   4.196 +	prev_y = y;
   4.197 +}
   4.198 +
   4.199 +void motion(int x, int y)
   4.200 +{
   4.201 +	int dx = x - prev_x;
   4.202 +	int dy = y - prev_y;
   4.203 +
   4.204 +	prev_x = x;
   4.205 +	prev_y = y;
   4.206 +
   4.207 +	if(bnstate[0]) {
   4.208 +		cam_theta += dx * 0.5;
   4.209 +		cam_phi += dy * 0.5;
   4.210 +
   4.211 +		if(cam_phi < -90) cam_phi = -90;
   4.212 +		if(cam_phi > 90) cam_phi = 90;
   4.213 +
   4.214 +		glutPostRedisplay();
   4.215 +	}
   4.216 +
   4.217 +	if(bnstate[1]) {
   4.218 +		cam_y += dy * 0.1;
   4.219 +		glutPostRedisplay();
   4.220 +	}
   4.221 +
   4.222 +	if(bnstate[2]) {
   4.223 +		cam_dist += dy * 0.1;
   4.224 +		if(cam_dist < 0.0) cam_dist = 0.0;
   4.225 +		glutPostRedisplay();
   4.226 +	}
   4.227 +}
   4.228 +
   4.229 +
   4.230 +int parse_args(int argc, char **argv)
   4.231 +{
   4.232 +	int i;
   4.233 +	struct slice_file *tail;
   4.234 +
   4.235 +	for(i=1; i<argc; i++) {
   4.236 +		struct slice_file *sfile;
   4.237 +
   4.238 +		if(!(sfile = malloc(sizeof *sfile))) {
   4.239 +			perror("failed to allocate memory");
   4.240 +			return -1;
   4.241 +		}
   4.242 +		sfile->name = argv[i];
   4.243 +		sfile->next = 0;
   4.244 +
   4.245 +		if(!flist) {
   4.246 +			flist = tail = sfile;
   4.247 +		} else {
   4.248 +			tail->next = sfile;
   4.249 +			tail = sfile;
   4.250 +		}
   4.251 +		nslices++;
   4.252 +	}
   4.253 +
   4.254 +	if(!nslices) {
   4.255 +		fprintf(stderr, "pass the slice filenames\n");
   4.256 +		return -1;
   4.257 +	}
   4.258 +
   4.259 +	return 0;
   4.260 +}
   4.261 +
   4.262 +
   4.263 +unsigned int create_ray_texture(int xsz, int ysz, float vfov, vec2_t *tex_scale)
   4.264 +{
   4.265 +	int i, j;
   4.266 +	unsigned int tex;
   4.267 +	int tex_xsz = round_pow2(xsz);
   4.268 +	int tex_ysz = round_pow2(ysz);
   4.269 +	float *teximg, *dir;
   4.270 +
   4.271 +	if(!(teximg = malloc(3 * tex_xsz * tex_ysz * sizeof *teximg))) {
   4.272 +		return 0;
   4.273 +	}
   4.274 +	dir = teximg;
   4.275 +
   4.276 +	for(i=0; i<tex_ysz; i++) {
   4.277 +		for(j=0; j<tex_xsz; j++) {
   4.278 +			if(j < xsz && i < ysz) {
   4.279 +				vec3_t rdir = get_primary_ray_dir(j, i, xsz, ysz, vfov);
   4.280 +				dir[0] = rdir.x;
   4.281 +				dir[1] = rdir.y;
   4.282 +				dir[2] = rdir.z;
   4.283 +			} else {
   4.284 +				dir[0] = dir[1] = 0.0f;
   4.285 +				dir[2] = 1.0f;
   4.286 +			}
   4.287 +
   4.288 +			dir += 3;
   4.289 +		}
   4.290 +	}
   4.291 +
   4.292 +	glGenTextures(1, &tex);
   4.293 +	glBindTexture(GL_TEXTURE_2D, tex);
   4.294 +	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   4.295 +	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   4.296 +	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
   4.297 +	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
   4.298 +	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F_ARB, tex_xsz, tex_ysz, 0, GL_RGB, GL_FLOAT, teximg);
   4.299 +	free(teximg);
   4.300 +
   4.301 +	if(tex_scale) {
   4.302 +		tex_scale->x = (float)xsz / (float)tex_xsz;
   4.303 +		tex_scale->y = (float)ysz / (float)tex_ysz;
   4.304 +	}
   4.305 +	return tex;
   4.306 +}
   4.307 +
   4.308 +static vec3_t get_primary_ray_dir(int x, int y, int w, int h, float vfov_deg)
   4.309 +{
   4.310 +	float vfov = M_PI * vfov_deg / 180.0;
   4.311 +	float aspect = (float)w / (float)h;
   4.312 +
   4.313 +	float ysz = 2.0;
   4.314 +	float xsz = aspect * ysz;
   4.315 +
   4.316 +	float px = ((float)x / (float)w) * xsz - xsz / 2.0;
   4.317 +	float py = 1.0 - ((float)y / (float)h) * ysz;
   4.318 +	float pz = 1.0 / tan(0.5 * vfov);
   4.319 +
   4.320 +	float mag = sqrt(px * px + py * py + pz * pz);
   4.321 +
   4.322 +	return v3_cons(px / mag, py / mag, pz / mag);
   4.323 +}
   4.324 +
   4.325 +static int round_pow2(int x)
   4.326 +{
   4.327 +	x--;
   4.328 +	x = (x >> 1) | x;
   4.329 +	x = (x >> 2) | x;
   4.330 +	x = (x >> 4) | x;
   4.331 +	x = (x >> 8) | x;
   4.332 +	x = (x >> 16) | x;
   4.333 +	return x + 1;
   4.334 +}
   4.335 +
     5.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     5.2 +++ b/volray.p.glsl	Sat Mar 31 02:08:42 2012 +0300
     5.3 @@ -0,0 +1,72 @@
     5.4 +uniform sampler3D volume;
     5.5 +uniform sampler2D ray_tex;
     5.6 +
     5.7 +struct Ray {
     5.8 +	vec3 origin, dir;
     5.9 +};
    5.10 +
    5.11 +struct ISect {
    5.12 +	bool hit;
    5.13 +	float t;
    5.14 +	vec3 pos;
    5.15 +	vec3 normal;
    5.16 +};
    5.17 +
    5.18 +vec3 ray_march(Ray ray);
    5.19 +vec3 shade(Ray ray, ISect isect);
    5.20 +Ray get_primary_ray();
    5.21 +
    5.22 +void main()
    5.23 +{
    5.24 +	Ray ray = get_primary_ray();
    5.25 +
    5.26 +	gl_FragColor = vec4(ray_march(ray), 1.0);
    5.27 +}
    5.28 +
    5.29 +/*vec3 sky(Ray ray)
    5.30 +{
    5.31 +	vec3 col1 = vec3(0.75, 0.78, 0.8);
    5.32 +	vec3 col2 = vec3(0.56, 0.7, 1.0);
    5.33 +
    5.34 +	float t = max(ray.dir.y, -0.5);
    5.35 +	return mix(col1, col2, t);
    5.36 +}*/
    5.37 +
    5.38 +vec3 ray_march(Ray ray)
    5.39 +{
    5.40 +	const float ray_step = 0.05;
    5.41 +	float energy = 1.0;
    5.42 +	vec3 pos = ray.origin;
    5.43 +
    5.44 +	// assuming view space
    5.45 +	while(pos.z < 1.0) {
    5.46 +		energy -= texture3D(volume, pos).x;
    5.47 +		pos += ray.dir * ray_step;
    5.48 +	}
    5.49 +
    5.50 +	return vec3(energy, energy, energy);
    5.51 +}
    5.52 +
    5.53 +vec3 shade(Ray ray, ISect isect)
    5.54 +{
    5.55 +	vec3 ldir = normalize(vec3(10.0, 10.0, -10.0) - isect.pos);
    5.56 +	vec3 vdir = -ray.dir;
    5.57 +	vec3 hdir = normalize(ldir + vdir);
    5.58 +
    5.59 +	float ndotl = dot(ldir, isect.normal);
    5.60 +	float ndoth = dot(hdir, isect.normal);
    5.61 +
    5.62 +	vec3 dcol = vec3(1.0, 1.0, 1.0) * max(ndotl, 0.0);
    5.63 +	vec3 scol = vec3(0.6, 0.6, 0.6) * pow(max(ndoth, 0.0), 50.0);
    5.64 +
    5.65 +	return vec3(0.01, 0.01, 0.01) + dcol + scol;
    5.66 +}
    5.67 +
    5.68 +Ray get_primary_ray()
    5.69 +{
    5.70 +	Ray ray;
    5.71 +	vec2 tc = gl_TexCoord[0].xy;
    5.72 +	ray.dir = gl_NormalMatrix * normalize(texture2D(ray_tex, tc).xyz);
    5.73 +	ray.origin = (gl_ModelViewMatrix * vec4(0.0, 0.0, 0.0, 1.0)).xyz;
    5.74 +	return ray;
    5.75 +}
     6.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     6.2 +++ b/volray.v.glsl	Sat Mar 31 02:08:42 2012 +0300
     6.3 @@ -0,0 +1,5 @@
     6.4 +void main()
     6.5 +{
     6.6 +	gl_Position = gl_Vertex;
     6.7 +	gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
     6.8 +}