nuclear@0: #include <stdio.h>
nuclear@0: #include <stdlib.h>
nuclear@0: #include <assert.h>
nuclear@0: 
nuclear@0: #include <GL/glew.h>
nuclear@0: #ifndef __APPLE__
nuclear@0: #include <GL/glut.h>
nuclear@0: #else
nuclear@0: #include <GLUT/glut.h>
nuclear@0: #endif
nuclear@0: 
nuclear@0: #include <vmath/vmath.h>
nuclear@0: #include <imago2.h>
nuclear@0: #include "sdr.h"
nuclear@0: 
nuclear@0: struct slice_file {
nuclear@0: 	char *name;
nuclear@0: 	struct slice_file *next;
nuclear@0: };
nuclear@0: 
nuclear@0: int init(void);
nuclear@0: void disp(void);
nuclear@0: void reshape(int x, int y);
nuclear@0: void keyb(unsigned char key, int x, int y);
nuclear@0: void mouse(int bn, int state, int x, int y);
nuclear@0: void motion(int x, int y);
nuclear@0: int parse_args(int argc, char **argv);
nuclear@0: 
nuclear@1: static void create_ray_texture(int xsz, int ysz, float vfov, vec2_t *tex_scale);
nuclear@0: static vec3_t get_primary_ray_dir(int x, int y, int w, int h, float vfov_deg);
nuclear@0: static int round_pow2(int x);
nuclear@0: 
nuclear@0: float cam_theta = 0, cam_phi = 0, cam_dist = 4.0;
nuclear@0: float cam_x, cam_y, cam_z;
nuclear@0: 
nuclear@0: vec2_t tex_scale;
nuclear@0: struct slice_file *flist;
nuclear@0: int nslices;
nuclear@0: unsigned int sdr, vol_tex, ray_tex;
nuclear@0: int win_xsz, win_ysz;
nuclear@1: int raytex_needs_recalc = 1;
nuclear@0: 
nuclear@0: int main(int argc, char **argv)
nuclear@0: {
nuclear@0: 	glutInit(&argc, argv);
nuclear@0: 	glutInitWindowSize(1280, 720);
nuclear@0: 	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
nuclear@0: 
nuclear@0: 	if(parse_args(argc, argv) == -1) {
nuclear@0: 		return 1;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	glutCreateWindow("Volume Raytracer");
nuclear@0: 
nuclear@0: 	glutDisplayFunc(disp);
nuclear@0: 	glutReshapeFunc(reshape);
nuclear@0: 	glutKeyboardFunc(keyb);
nuclear@0: 	glutMouseFunc(mouse);
nuclear@0: 	glutMotionFunc(motion);
nuclear@0: 
nuclear@0: 	glewInit();
nuclear@0: 
nuclear@0: 	if(init() == -1) {
nuclear@0: 		return 1;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	glutMainLoop();
nuclear@0: 	return 0;
nuclear@0: }
nuclear@0: 
nuclear@0: int init(void)
nuclear@0: {
nuclear@0: 	int i, vol_xsz, vol_ysz;
nuclear@0: 
nuclear@0: 	if(!(sdr = create_program_load("volray.v.glsl", "volray.p.glsl"))) {
nuclear@1: 		return -1;
nuclear@0: 	}
nuclear@1: 	set_uniform_int(sdr, "volume", 0);
nuclear@1: 	set_uniform_int(sdr, "ray_tex", 1);
nuclear@0: 
nuclear@0: 	glGenTextures(1, &vol_tex);
nuclear@0: 	glBindTexture(GL_TEXTURE_3D, vol_tex);
nuclear@0: 	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
nuclear@0: 	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
nuclear@1: 	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP);
nuclear@1: 	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP);
nuclear@1: 	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP);
nuclear@0: 
nuclear@0: 	for(i=0; i<nslices; i++) {
nuclear@0: 		int xsz, ysz;
nuclear@0: 		void *pix;
nuclear@0: 		struct slice_file *sfile = flist;
nuclear@0: 		flist = flist->next;
nuclear@0: 
nuclear@0: 		if(!(pix = img_load_pixels(sfile->name, &xsz, &ysz, IMG_FMT_RGBA32))) {
nuclear@0: 			fprintf(stderr, "failed to load image: %s\n", sfile->name);
nuclear@0: 			return -1;
nuclear@0: 		}
nuclear@0: 
nuclear@0: 		if(i == 0) {
nuclear@0: 			/* allocate storage for the texture */
nuclear@0: 			glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA, xsz, ysz, nslices, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
nuclear@0: 
nuclear@0: 			vol_xsz = xsz;
nuclear@0: 			vol_ysz = ysz;
nuclear@0: 
nuclear@0: 		} else {
nuclear@0: 			if(xsz != vol_xsz || ysz != vol_ysz) {
nuclear@0: 				fprintf(stderr, "%s: inconsistent slice size: %dx%d. expected: %dx%d\n",
nuclear@0: 						sfile->name, xsz, ysz, vol_xsz, vol_ysz);
nuclear@0: 				img_free_pixels(pix);
nuclear@0: 				return -1;
nuclear@0: 			}
nuclear@0: 		}
nuclear@0: 		free(sfile);
nuclear@0: 
nuclear@0: 		glTexSubImage3D(GL_TEXTURE_3D, 0, 0, 0, i, xsz, ysz, 1, GL_RGBA, GL_UNSIGNED_BYTE, pix);
nuclear@0: 		img_free_pixels(pix);
nuclear@0: 	}
nuclear@0: 	return 0;
nuclear@0: }
nuclear@0: 
nuclear@0: void disp(void)
nuclear@0: {
nuclear@1: 	if(raytex_needs_recalc) {
nuclear@1: 		create_ray_texture(win_xsz, win_ysz, 50.0, &tex_scale);
nuclear@1: 	}
nuclear@1: 
nuclear@0: 	glMatrixMode(GL_MODELVIEW);
nuclear@0: 	glLoadIdentity();
nuclear@1: 	glRotatef(-90, 1, 0, 0);
nuclear@0: 	glTranslatef(cam_x, cam_y, -cam_z);
nuclear@0: 	glRotatef(cam_theta, 0, 1, 0);
nuclear@0: 	glRotatef(cam_phi, 1, 0, 0);
nuclear@0: 	glTranslatef(0, 0, -cam_dist);
nuclear@0: 
nuclear@0: 	glMatrixMode(GL_TEXTURE);
nuclear@1: 	glLoadIdentity();
nuclear@0: 	glScalef(tex_scale.x, tex_scale.y, 1.0);
nuclear@0: 
nuclear@0: 	glActiveTexture(GL_TEXTURE0);
nuclear@1: 	glBindTexture(GL_TEXTURE_3D, vol_tex);
nuclear@0: 	glEnable(GL_TEXTURE_3D);
nuclear@0: 
nuclear@0: 	glActiveTexture(GL_TEXTURE1);
nuclear@1: 	glBindTexture(GL_TEXTURE_2D, ray_tex);
nuclear@0: 	glEnable(GL_TEXTURE_2D);
nuclear@0: 
nuclear@0: 	bind_program(sdr);
nuclear@0: 	glBegin(GL_QUADS);
nuclear@0: 	glColor3f(1, 1, 1);
nuclear@1: 	glTexCoord2f(0, 1); glVertex2f(-1, -1);
nuclear@1: 	glTexCoord2f(1, 1); glVertex2f(1, -1);
nuclear@1: 	glTexCoord2f(1, 0); glVertex2f(1, 1);
nuclear@1: 	glTexCoord2f(0, 0); glVertex2f(-1, 1);
nuclear@0: 	glEnd();
nuclear@0: 	bind_program(0);
nuclear@0: 
nuclear@1: 	glActiveTexture(GL_TEXTURE1);
nuclear@0: 	glDisable(GL_TEXTURE_2D);
nuclear@0: 	glActiveTexture(GL_TEXTURE0);
nuclear@0: 	glDisable(GL_TEXTURE_3D);
nuclear@0: 
nuclear@0: 	glMatrixMode(GL_TEXTURE);
nuclear@1: 	glLoadIdentity();
nuclear@0: 
nuclear@0: 	glutSwapBuffers();
nuclear@0: 	assert(glGetError() == GL_NO_ERROR);
nuclear@0: }
nuclear@0: 
nuclear@0: void reshape(int x, int y)
nuclear@0: {
nuclear@1: 	printf("reshape: %dx%d\n", x, y);
nuclear@0: 	glViewport(0, 0, x, y);
nuclear@0: 
nuclear@0: 	if(x != win_xsz || y != win_ysz) {
nuclear@1: 		raytex_needs_recalc = 1;
nuclear@0: 		win_xsz = x;
nuclear@0: 		win_ysz = y;
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: void keyb(unsigned char key, int x, int y)
nuclear@0: {
nuclear@0: 	switch(key) {
nuclear@0: 	case 27:
nuclear@0: 		exit(0);
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: static int bnstate[32];
nuclear@0: static int prev_x, prev_y;
nuclear@0: 
nuclear@0: void mouse(int bn, int state, int x, int y)
nuclear@0: {
nuclear@0: 	bnstate[bn - GLUT_LEFT_BUTTON] = state == GLUT_DOWN;
nuclear@0: 	prev_x = x;
nuclear@0: 	prev_y = y;
nuclear@0: }
nuclear@0: 
nuclear@0: void motion(int x, int y)
nuclear@0: {
nuclear@0: 	int dx = x - prev_x;
nuclear@0: 	int dy = y - prev_y;
nuclear@0: 
nuclear@0: 	prev_x = x;
nuclear@0: 	prev_y = y;
nuclear@0: 
nuclear@0: 	if(bnstate[0]) {
nuclear@0: 		cam_theta += dx * 0.5;
nuclear@0: 		cam_phi += dy * 0.5;
nuclear@0: 
nuclear@1: 		if(cam_phi <= -90) cam_phi = -89;
nuclear@1: 		if(cam_phi >= 90) cam_phi = 89;
nuclear@0: 
nuclear@0: 		glutPostRedisplay();
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	if(bnstate[1]) {
nuclear@1: 		cam_x += dx * 0.025;
nuclear@1: 		cam_y += dy * 0.025;
nuclear@0: 		glutPostRedisplay();
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	if(bnstate[2]) {
nuclear@1: 		cam_dist += dy * 0.025;
nuclear@0: 		if(cam_dist < 0.0) cam_dist = 0.0;
nuclear@0: 		glutPostRedisplay();
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: 
nuclear@0: int parse_args(int argc, char **argv)
nuclear@0: {
nuclear@0: 	int i;
nuclear@0: 	struct slice_file *tail;
nuclear@0: 
nuclear@0: 	for(i=1; i<argc; i++) {
nuclear@0: 		struct slice_file *sfile;
nuclear@0: 
nuclear@0: 		if(!(sfile = malloc(sizeof *sfile))) {
nuclear@0: 			perror("failed to allocate memory");
nuclear@0: 			return -1;
nuclear@0: 		}
nuclear@0: 		sfile->name = argv[i];
nuclear@0: 		sfile->next = 0;
nuclear@0: 
nuclear@0: 		if(!flist) {
nuclear@0: 			flist = tail = sfile;
nuclear@0: 		} else {
nuclear@0: 			tail->next = sfile;
nuclear@0: 			tail = sfile;
nuclear@0: 		}
nuclear@0: 		nslices++;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	if(!nslices) {
nuclear@0: 		fprintf(stderr, "pass the slice filenames\n");
nuclear@0: 		return -1;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	return 0;
nuclear@0: }
nuclear@0: 
nuclear@0: 
nuclear@1: static void create_ray_texture(int xsz, int ysz, float vfov, vec2_t *tex_scale)
nuclear@0: {
nuclear@0: 	int i, j;
nuclear@1: 	int cur_tex_xsz, cur_tex_ysz;
nuclear@0: 	int tex_xsz = round_pow2(xsz);
nuclear@0: 	int tex_ysz = round_pow2(ysz);
nuclear@0: 	float *teximg, *dir;
nuclear@0: 
nuclear@1: 	if(!(teximg = malloc(3 * xsz * ysz * sizeof *teximg))) {
nuclear@1: 		return;
nuclear@0: 	}
nuclear@0: 	dir = teximg;
nuclear@0: 
nuclear@1: 	for(i=0; i<ysz; i++) {
nuclear@1: 		for(j=0; j<xsz; j++) {
nuclear@1: 			vec3_t rdir = get_primary_ray_dir(j, i, xsz, ysz, vfov);
nuclear@1: 			*dir++ = rdir.x;
nuclear@1: 			*dir++ = rdir.y;
nuclear@1: 			*dir++ = rdir.z;
nuclear@0: 		}
nuclear@0: 	}
nuclear@0: 
nuclear@1: 	if(!ray_tex) {
nuclear@1: 		glGenTextures(1, &ray_tex);
nuclear@1: 	}
nuclear@1: 
nuclear@1: 	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &cur_tex_xsz);
nuclear@1: 	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &cur_tex_ysz);
nuclear@1: 
nuclear@1: 	if(tex_xsz > cur_tex_xsz || tex_ysz > cur_tex_ysz) {
nuclear@1: 		glBindTexture(GL_TEXTURE_2D, ray_tex);
nuclear@1: 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
nuclear@1: 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
nuclear@1: 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
nuclear@1: 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
nuclear@1: 		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F_ARB, tex_xsz, tex_ysz, 0, GL_RGB, GL_FLOAT, 0);
nuclear@1: 	}
nuclear@1: 
nuclear@1: 	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, xsz, ysz, GL_RGB, GL_FLOAT, teximg);
nuclear@0: 	free(teximg);
nuclear@0: 
nuclear@0: 	if(tex_scale) {
nuclear@0: 		tex_scale->x = (float)xsz / (float)tex_xsz;
nuclear@0: 		tex_scale->y = (float)ysz / (float)tex_ysz;
nuclear@0: 	}
nuclear@1: 	raytex_needs_recalc = 0;
nuclear@0: }
nuclear@0: 
nuclear@0: static vec3_t get_primary_ray_dir(int x, int y, int w, int h, float vfov_deg)
nuclear@0: {
nuclear@0: 	float vfov = M_PI * vfov_deg / 180.0;
nuclear@0: 	float aspect = (float)w / (float)h;
nuclear@0: 
nuclear@0: 	float ysz = 2.0;
nuclear@0: 	float xsz = aspect * ysz;
nuclear@0: 
nuclear@0: 	float px = ((float)x / (float)w) * xsz - xsz / 2.0;
nuclear@0: 	float py = 1.0 - ((float)y / (float)h) * ysz;
nuclear@0: 	float pz = 1.0 / tan(0.5 * vfov);
nuclear@0: 
nuclear@0: 	float mag = sqrt(px * px + py * py + pz * pz);
nuclear@0: 
nuclear@0: 	return v3_cons(px / mag, py / mag, pz / mag);
nuclear@0: }
nuclear@0: 
nuclear@0: static int round_pow2(int x)
nuclear@0: {
nuclear@0: 	x--;
nuclear@0: 	x = (x >> 1) | x;
nuclear@0: 	x = (x >> 2) | x;
nuclear@0: 	x = (x >> 4) | x;
nuclear@0: 	x = (x >> 8) | x;
nuclear@0: 	x = (x >> 16) | x;
nuclear@0: 	return x + 1;
nuclear@0: }
nuclear@0: