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@9: #include "volume.h"
nuclear@13: #include "ui.h"
nuclear@18: #include "demo.h"
nuclear@0: 
nuclear@3: #define XFER_MAP_SZ	512
nuclear@3: 
nuclear@11: static void render_volume();
nuclear@11: static void draw_slice();
nuclear@11: static void draw_xfer_func();
nuclear@5: 
nuclear@11: /*
nuclear@0: void keyb(unsigned char key, int x, int y);
nuclear@4: void keyb_up(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@11: */
nuclear@0: 
nuclear@11: static void create_ray_texture(int xsz, int ysz, float vfov, Vector2 *tex_scale);
nuclear@11: static Vector3 get_primary_ray_dir(int x, int y, int w, int h, float vfov_deg);
nuclear@0: static int round_pow2(int x);
nuclear@3: static void create_transfer_map(float mean, float sdev);
nuclear@0: 
nuclear@9: static float cam_theta = 0, cam_phi = 0, cam_dist = 4.0;
nuclear@9: static float cam_x, cam_y, cam_z;
nuclear@0: 
nuclear@13: static Vector2 tex_scale;
nuclear@9: static unsigned int vol_sdr, slice_sdr, ray_tex;
nuclear@9: static int win_xsz, win_ysz;
nuclear@11: static bool raytex_needs_recalc = true;
nuclear@0: 
nuclear@9: static unsigned int xfer_tex;
nuclear@9: static float xfer_mean = 0.7, xfer_sdev = 0.1;
nuclear@11: static bool xfertex_needs_recalc = true;
nuclear@3: 
nuclear@19: static float cur_z = 0.5;
nuclear@23: static bool clip_z;
nuclear@7: static float ray_step = 0.01;
nuclear@4: 
nuclear@18: static Volume *volume;
nuclear@9: 
nuclear@9: 
nuclear@11: bool volray_init()
nuclear@0: {
nuclear@0: 	glewInit();
nuclear@0: 
nuclear@9: 	if(!(vol_sdr = create_program_load("sdr/volray.v.glsl", "sdr/volray.p.glsl"))) {
nuclear@11: 		return false;
nuclear@0: 	}
nuclear@5: 	set_uniform_int(vol_sdr, "volume", 0);
nuclear@5: 	set_uniform_int(vol_sdr, "ray_tex", 1);
nuclear@5: 	set_uniform_int(vol_sdr, "xfer_tex", 2);
nuclear@7: 	set_uniform_float(vol_sdr, "ray_step", ray_step);
nuclear@23: 	set_uniform_float(vol_sdr, "zclip", 0.0);
nuclear@5: 
nuclear@9: 	if(!(slice_sdr = create_program_load(0, "sdr/slice.p.glsl"))) {
nuclear@11: 		return false;
nuclear@5: 	}
nuclear@5: 	set_uniform_int(slice_sdr, "volume", 0);
nuclear@5: 	set_uniform_int(slice_sdr, "xfer_tex", 1);
nuclear@0: 
nuclear@18: 	init_demo();
nuclear@18: 
nuclear@11: 	return true;
nuclear@0: }
nuclear@0: 
nuclear@18: void volray_setvolume(Volume *vol)
nuclear@13: {
nuclear@13: 	volume = vol;
nuclear@13: }
nuclear@13: 
nuclear@18: Volume *volray_getvolume()
nuclear@18: {
nuclear@18: 	return volume;
nuclear@18: }
nuclear@18: 
nuclear@21: void volray_setvalue(int which, float val)
nuclear@21: {
nuclear@21: 	switch(which) {
nuclear@21: 	case VOLRAY_ZCURSOR:
nuclear@21: 		cur_z = val;
nuclear@23: 		if(clip_z) {
nuclear@23: 			set_uniform_float(vol_sdr, "zclip", cur_z);
nuclear@23: 		}
nuclear@21: 		post_redisplay();
nuclear@21: 		break;
nuclear@21: 
nuclear@22: 	case VOLRAY_ZCLIP:
nuclear@23: 		clip_z = val > 0.5;
nuclear@23: 		set_uniform_float(vol_sdr, "zclip", clip_z ? cur_z : 0.0);
nuclear@23: 		post_redisplay();
nuclear@23: 		break;
nuclear@22: 
nuclear@21: 	default:
nuclear@21: 		break;
nuclear@21: 	}
nuclear@21: }
nuclear@21: 
nuclear@21: float volray_getvalue(int which)
nuclear@21: {
nuclear@21: 	switch(which) {
nuclear@21: 	case VOLRAY_ZCURSOR:
nuclear@21: 		return cur_z;
nuclear@21: 
nuclear@23: 	case VOLRAY_ZCLIP:
nuclear@23: 		return clip_z > 0.5 ? 1.0 : 0.0;
nuclear@23: 		break;
nuclear@23: 
nuclear@21: 	default:
nuclear@21: 		break;
nuclear@21: 	}
nuclear@21: 	return 0.0;
nuclear@21: }
nuclear@21: 
nuclear@11: void volray_draw(void)
nuclear@0: {
nuclear@4: 	/* recalculate primary ray texture if needed */
nuclear@1: 	if(raytex_needs_recalc) {
nuclear@1: 		create_ray_texture(win_xsz, win_ysz, 50.0, &tex_scale);
nuclear@1: 	}
nuclear@4: 	/* recalculate transfer function texture if needed */
nuclear@3: 	if(xfertex_needs_recalc) {
nuclear@3: 		create_transfer_map(xfer_mean, xfer_sdev);
nuclear@3: 	}
nuclear@1: 
nuclear@18: 	draw_demo();
nuclear@18: 
nuclear@13: 	glClear(GL_COLOR_BUFFER_BIT);
nuclear@13: 
nuclear@13: 	if(volume) {
nuclear@13: 		render_volume();
nuclear@28: 		//draw_slice();
nuclear@13: 		draw_xfer_func();
nuclear@13: 	}
nuclear@4: 
nuclear@4: 	assert(glGetError() == GL_NO_ERROR);
nuclear@4: }
nuclear@4: 
nuclear@11: static void render_volume(void)
nuclear@4: {
nuclear@4: 	/* set the camera transformation */
nuclear@0: 	glMatrixMode(GL_MODELVIEW);
nuclear@4: 	glPushMatrix();
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@4: 	/* setup the texture matrix to map the useful part of the ray texture to [0,1] */
nuclear@0: 	glMatrixMode(GL_TEXTURE);
nuclear@4: 	glPushMatrix();
nuclear@1: 	glLoadIdentity();
nuclear@0: 	glScalef(tex_scale.x, tex_scale.y, 1.0);
nuclear@0: 
nuclear@4: 	/* tex unit0: volume data 3D texture */
nuclear@0: 	glActiveTexture(GL_TEXTURE0);
nuclear@13: 	glBindTexture(GL_TEXTURE_3D, volume->get_texture());
nuclear@0: 	glEnable(GL_TEXTURE_3D);
nuclear@0: 
nuclear@4: 	/* tex unit1: primary rays in view space */
nuclear@0: 	glActiveTexture(GL_TEXTURE1);
nuclear@1: 	glBindTexture(GL_TEXTURE_2D, ray_tex);
nuclear@0: 	glEnable(GL_TEXTURE_2D);
nuclear@0: 
nuclear@4: 	/* tex unit2: transfer function (1d) */
nuclear@3: 	glActiveTexture(GL_TEXTURE2);
nuclear@3: 	glBindTexture(GL_TEXTURE_1D, xfer_tex);
nuclear@3: 	glEnable(GL_TEXTURE_1D);
nuclear@3: 
nuclear@5: 	bind_program(vol_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@3: 	glActiveTexture(GL_TEXTURE2);
nuclear@3: 	glDisable(GL_TEXTURE_1D);
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@4: 	glPopMatrix();
nuclear@4: 	glMatrixMode(GL_MODELVIEW);
nuclear@4: 	glPopMatrix();
nuclear@4: }
nuclear@0: 
nuclear@28: void volray_draw_slice(void)
nuclear@5: {
nuclear@5: 	glActiveTexture(GL_TEXTURE0);
nuclear@13: 	glBindTexture(GL_TEXTURE_3D, volume->get_texture());
nuclear@5: 	glEnable(GL_TEXTURE_3D);
nuclear@5: 
nuclear@5: 	glActiveTexture(GL_TEXTURE1);
nuclear@5: 	glBindTexture(GL_TEXTURE_1D, xfer_tex);
nuclear@5: 	glEnable(GL_TEXTURE_1D);
nuclear@5: 
nuclear@5: 	bind_program(slice_sdr);
nuclear@5: 
nuclear@5: 	glBegin(GL_QUADS);
nuclear@5: 	glColor3f(1, 1, 1);
nuclear@5: 	glTexCoord3f(0, 1, cur_z); glVertex2f(-1, -1);
nuclear@5: 	glTexCoord3f(1, 1, cur_z); glVertex2f(1, -1);
nuclear@5: 	glTexCoord3f(1, 0, cur_z); glVertex2f(1, 1);
nuclear@5: 	glTexCoord3f(0, 0, cur_z); glVertex2f(-1, 1);
nuclear@5: 	glEnd();
nuclear@5: 
nuclear@5: 	bind_program(0);
nuclear@5: 
nuclear@5: 	glActiveTexture(GL_TEXTURE1);
nuclear@5: 	glDisable(GL_TEXTURE_1D);
nuclear@5: 	glActiveTexture(GL_TEXTURE0);
nuclear@5: 	glDisable(GL_TEXTURE_3D);
nuclear@5: }
nuclear@5: 
nuclear@11: static void draw_xfer_func(void)
nuclear@4: {
nuclear@4: 	glMatrixMode(GL_MODELVIEW);
nuclear@4: 	glPushMatrix();
nuclear@4: 	glTranslatef(-0.9, -0.9, 0);
nuclear@4: 	glScalef(0.5, 0.1, 1);
nuclear@4: 
nuclear@4: 	glBindTexture(GL_TEXTURE_1D, xfer_tex);
nuclear@4: 	glEnable(GL_TEXTURE_1D);
nuclear@4: 
nuclear@4: 	glBegin(GL_QUADS);
nuclear@4: 	glColor3f(1, 1, 1);
nuclear@4: 	glTexCoord1f(1);
nuclear@4: 	glVertex2f(1, 0);
nuclear@4: 	glVertex2f(1, 1);
nuclear@4: 	glTexCoord1f(0);
nuclear@4: 	glVertex2f(0, 1);
nuclear@4: 	glVertex2f(0, 0);
nuclear@4: 	glEnd();
nuclear@4: 
nuclear@4: 	glDisable(GL_TEXTURE_1D);
nuclear@4: 
nuclear@4: 	glLineWidth(2.0);
nuclear@4: 	glBegin(GL_LINE_LOOP);
nuclear@13: 	/*if(uimode == UIMODE_XFER) {
nuclear@5: 		glColor3f(1, 0, 0);
nuclear@13: 	} else {*/
nuclear@5: 		glColor3f(0, 0, 1);
nuclear@13: 	//}
nuclear@4: 	glVertex2f(0, 0);
nuclear@4: 	glVertex2f(1, 0);
nuclear@4: 	glVertex2f(1, 1);
nuclear@4: 	glVertex2f(0, 1);
nuclear@4: 	glEnd();
nuclear@4: 
nuclear@4: 	glPopMatrix();
nuclear@0: }
nuclear@0: 
nuclear@11: void volray_resize(int x, int y)
nuclear@0: {
nuclear@0: 	glViewport(0, 0, x, y);
nuclear@0: 
nuclear@0: 	if(x != win_xsz || y != win_ysz) {
nuclear@11: 		raytex_needs_recalc = true;
nuclear@0: 		win_xsz = x;
nuclear@0: 		win_ysz = y;
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@11: #if 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@4: 
nuclear@4: 	case 'x':
nuclear@5: 		uimode = UIMODE_XFER;
nuclear@13: 		post_redisplay();
nuclear@4: 		break;
nuclear@5: 
nuclear@5: 	case 'c':
nuclear@5: 		uimode = UIMODE_CURSOR;
nuclear@13: 		post_redisplay();
nuclear@5: 		break;
nuclear@5: 
nuclear@5: 	default:
nuclear@5: 		break;
nuclear@4: 	}
nuclear@4: }
nuclear@4: 
nuclear@4: void keyb_up(unsigned char key, int x, int y)
nuclear@4: {
nuclear@4: 	switch(key) {
nuclear@4: 	case 'x':
nuclear@5: 		if(uimode == UIMODE_XFER) {
nuclear@5: 			uimode = UIMODE_DEFAULT;
nuclear@13: 			post_redisplay();
nuclear@5: 		}
nuclear@5: 		break;
nuclear@5: 
nuclear@5: 	case 'c':
nuclear@5: 		if(uimode == UIMODE_CURSOR) {
nuclear@5: 			uimode = UIMODE_DEFAULT;
nuclear@13: 			post_redisplay();
nuclear@5: 		}
nuclear@5: 		break;
nuclear@5: 
nuclear@5: 	default:
nuclear@4: 		break;
nuclear@0: 	}
nuclear@0: }
nuclear@13: #endif
nuclear@0: 
nuclear@0: static int bnstate[32];
nuclear@0: static int prev_x, prev_y;
nuclear@0: 
nuclear@13: void volray_mouse(int bn, int state, int x, int y)
nuclear@0: {
nuclear@13: 	bnstate[bn] = state;
nuclear@0: 	prev_x = x;
nuclear@0: 	prev_y = y;
nuclear@0: }
nuclear@0: 
nuclear@13: void volray_motion(int x, int y)
nuclear@0: {
nuclear@0: 	int dx = x - prev_x;
nuclear@0: 	int dy = y - prev_y;
nuclear@0: 	prev_x = x;
nuclear@0: 	prev_y = y;
nuclear@0: 
nuclear@13: 	/*switch(uimode) {
nuclear@5: 	case UIMODE_XFER:
nuclear@4: 		if(dx || dy) {
nuclear@4: 			xfer_mean += dx / (float)win_xsz;
nuclear@4: 			xfer_sdev += 0.5 * dy / (float)win_ysz;
nuclear@0: 
nuclear@4: 			xfer_mean = xfer_mean < 0.0 ? 0.0 : (xfer_mean > 1.0 ? 1.0 : xfer_mean);
nuclear@4: 			xfer_sdev = xfer_sdev < 0.0 ? 0.0 : (xfer_sdev > 1.0 ? 1.0 : xfer_sdev);
nuclear@0: 
nuclear@11: 			xfertex_needs_recalc = true;
nuclear@13: 			post_redisplay();
nuclear@4: 		}
nuclear@5: 		break;
nuclear@0: 
nuclear@5: 	case UIMODE_CURSOR:
nuclear@5: 		cur_z += 0.5 * dy / (float)win_ysz;
nuclear@5: 
nuclear@5: 		if(cur_z < 0.0)
nuclear@5: 			cur_z = 0.0;
nuclear@5: 		if(cur_z > 1.0)
nuclear@5: 			cur_z = 1.0;
nuclear@7: 
nuclear@7: 		set_uniform_float(vol_sdr, "zclip", cur_z);
nuclear@13: 		post_redisplay();
nuclear@5: 		break;
nuclear@5: 
nuclear@13: 	default:*/
nuclear@5: 		/* view control */
nuclear@4: 		if(bnstate[0]) {
nuclear@4: 			cam_theta += dx * 0.5;
nuclear@4: 			cam_phi += dy * 0.5;
nuclear@0: 
nuclear@4: 			if(cam_phi <= -90) cam_phi = -89;
nuclear@4: 			if(cam_phi >= 90) cam_phi = 89;
nuclear@13: 			post_redisplay();
nuclear@4: 		}
nuclear@4: 
nuclear@4: 		if(bnstate[1]) {
nuclear@4: 			cam_x += dx * 0.025;
nuclear@4: 			cam_y += dy * 0.025;
nuclear@13: 			post_redisplay();
nuclear@4: 		}
nuclear@4: 
nuclear@4: 		if(bnstate[2]) {
nuclear@4: 			cam_dist += dy * 0.025;
nuclear@4: 			if(cam_dist < 0.0) cam_dist = 0.0;
nuclear@13: 			post_redisplay();
nuclear@4: 		}
nuclear@13: 	//}
nuclear@0: }
nuclear@0: 
nuclear@13: #if 0
nuclear@0: int parse_args(int argc, char **argv)
nuclear@0: {
nuclear@0: 	int i;
nuclear@3: 	char *endp;
nuclear@0: 
nuclear@0: 	for(i=1; i<argc; i++) {
nuclear@2: 		if(argv[i][0] == '-' && argv[i][2] == 0) {
nuclear@2: 			switch(argv[i][1]) {
nuclear@3: 			case 'm':
nuclear@3: 				xfer_mean = strtod(argv[++i], &endp);
nuclear@3: 				if(endp == argv[i]) {
nuclear@3: 					fprintf(stderr, "-m must be followed by the transfer function mean\n");
nuclear@3: 					return -1;
nuclear@3: 				}
nuclear@2: 				break;
nuclear@3: 
nuclear@4: 			case 'd':
nuclear@3: 				xfer_sdev = strtod(argv[++i], &endp);
nuclear@3: 				if(endp == argv[i]) {
nuclear@4: 					fprintf(stderr, "-d must be followed by the transfer function std.deviation\n");
nuclear@3: 					return -1;
nuclear@3: 				}
nuclear@3: 				break;
nuclear@3: 
nuclear@3: 			default:
nuclear@3: 				fprintf(stderr, "unrecognized option: %s\n", argv[i]);
nuclear@3: 				return -1;
nuclear@2: 			}
nuclear@2: 		} else {
nuclear@9: 			if(fname) {
nuclear@9: 				fprintf(stderr, "unexpected argument: %s\n", argv[i]);
nuclear@2: 				return -1;
nuclear@2: 			}
nuclear@9: 			fname = argv[i];
nuclear@0: 		}
nuclear@0: 	}
nuclear@0: 
nuclear@9: 	if(!fname) {
nuclear@9: 		fprintf(stderr, "pass the volume descriptor filename\n");
nuclear@0: 		return -1;
nuclear@0: 	}
nuclear@0: 	return 0;
nuclear@0: }
nuclear@11: #endif
nuclear@0: 
nuclear@0: 
nuclear@11: static void create_ray_texture(int xsz, int ysz, float vfov, Vector2 *tex_scale)
nuclear@0: {
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@11: 	teximg = new float[3 * xsz * ysz];
nuclear@0: 	dir = teximg;
nuclear@0: 
nuclear@11: 	for(int i=0; i<ysz; i++) {
nuclear@11: 		for(int j=0; j<xsz; j++) {
nuclear@11: 			Vector3 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@11: 	delete [] 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@11: 	raytex_needs_recalc = false;
nuclear@0: }
nuclear@0: 
nuclear@11: static Vector3 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@11: 	return Vector3(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: 
nuclear@3: static void create_transfer_map(float mean, float sdev)
nuclear@3: {
nuclear@3: 	static float map[XFER_MAP_SZ];
nuclear@3: 
nuclear@3: 	if(!xfer_tex) {
nuclear@3: 		glGenTextures(1, &xfer_tex);
nuclear@3: 		glBindTexture(GL_TEXTURE_1D, xfer_tex);
nuclear@3: 		glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
nuclear@3: 		glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
nuclear@3: 		glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
nuclear@3: 		glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
nuclear@3: 		glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE32F_ARB, XFER_MAP_SZ, 0, GL_LUMINANCE, GL_FLOAT, 0);
nuclear@3: 	}
nuclear@3: 
nuclear@11: 	for(int i=0; i<XFER_MAP_SZ; i++) {
nuclear@4: 		float x = (float)i / (float)(XFER_MAP_SZ - 1);
nuclear@4: 		map[i] = gaussian(x, mean, sdev) - 1.0;
nuclear@3: 	}
nuclear@3: 
nuclear@4: 	glTexSubImage1D(GL_TEXTURE_1D, 0, 0, XFER_MAP_SZ, GL_LUMINANCE, GL_FLOAT, map);
nuclear@11: 	xfertex_needs_recalc = false;
nuclear@3: }