1.1 --- a/src/volray.c	Mon Apr 02 14:42:03 2012 +0300
     1.2 +++ b/src/volray.c	Mon Apr 02 17:59:46 2012 +0300
     1.3 @@ -22,8 +22,11 @@
     1.4  
     1.5  int init(void);
     1.6  void disp(void);
     1.7 +void render_volume(void);
     1.8 +void draw_xfer_func(void);
     1.9  void reshape(int x, int y);
    1.10  void keyb(unsigned char key, int x, int y);
    1.11 +void keyb_up(unsigned char key, int x, int y);
    1.12  void mouse(int bn, int state, int x, int y);
    1.13  void motion(int x, int y);
    1.14  int parse_args(int argc, char **argv);
    1.15 @@ -47,6 +50,8 @@
    1.16  float xfer_mean = 0.5, xfer_sdev = 1.0;
    1.17  int xfertex_needs_recalc = 1;
    1.18  
    1.19 +static int uimode_xfer;
    1.20 +
    1.21  int main(int argc, char **argv)
    1.22  {
    1.23  	glutInit(&argc, argv);
    1.24 @@ -62,6 +67,7 @@
    1.25  	glutDisplayFunc(disp);
    1.26  	glutReshapeFunc(reshape);
    1.27  	glutKeyboardFunc(keyb);
    1.28 +	glutKeyboardUpFunc(keyb_up);
    1.29  	glutMouseFunc(mouse);
    1.30  	glutMotionFunc(motion);
    1.31  
    1.32 @@ -90,9 +96,9 @@
    1.33  	glBindTexture(GL_TEXTURE_3D, vol_tex);
    1.34  	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    1.35  	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    1.36 -	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP);
    1.37 -	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP);
    1.38 -	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP);
    1.39 +	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    1.40 +	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    1.41 +	glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
    1.42  
    1.43  	for(i=0; i<nslices; i++) {
    1.44  		int xsz, ysz;
    1.45 @@ -130,14 +136,27 @@
    1.46  
    1.47  void disp(void)
    1.48  {
    1.49 +	/* recalculate primary ray texture if needed */
    1.50  	if(raytex_needs_recalc) {
    1.51  		create_ray_texture(win_xsz, win_ysz, 50.0, &tex_scale);
    1.52  	}
    1.53 +	/* recalculate transfer function texture if needed */
    1.54  	if(xfertex_needs_recalc) {
    1.55  		create_transfer_map(xfer_mean, xfer_sdev);
    1.56  	}
    1.57  
    1.58 +	render_volume();
    1.59 +	draw_xfer_func();
    1.60 +
    1.61 +	glutSwapBuffers();
    1.62 +	assert(glGetError() == GL_NO_ERROR);
    1.63 +}
    1.64 +
    1.65 +void render_volume(void)
    1.66 +{
    1.67 +	/* set the camera transformation */
    1.68  	glMatrixMode(GL_MODELVIEW);
    1.69 +	glPushMatrix();
    1.70  	glLoadIdentity();
    1.71  	glRotatef(-90, 1, 0, 0);
    1.72  	glTranslatef(cam_x, cam_y, -cam_z);
    1.73 @@ -145,18 +164,23 @@
    1.74  	glRotatef(cam_phi, 1, 0, 0);
    1.75  	glTranslatef(0, 0, -cam_dist);
    1.76  
    1.77 +	/* setup the texture matrix to map the useful part of the ray texture to [0,1] */
    1.78  	glMatrixMode(GL_TEXTURE);
    1.79 +	glPushMatrix();
    1.80  	glLoadIdentity();
    1.81  	glScalef(tex_scale.x, tex_scale.y, 1.0);
    1.82  
    1.83 +	/* tex unit0: volume data 3D texture */
    1.84  	glActiveTexture(GL_TEXTURE0);
    1.85  	glBindTexture(GL_TEXTURE_3D, vol_tex);
    1.86  	glEnable(GL_TEXTURE_3D);
    1.87  
    1.88 +	/* tex unit1: primary rays in view space */
    1.89  	glActiveTexture(GL_TEXTURE1);
    1.90  	glBindTexture(GL_TEXTURE_2D, ray_tex);
    1.91  	glEnable(GL_TEXTURE_2D);
    1.92  
    1.93 +	/* tex unit2: transfer function (1d) */
    1.94  	glActiveTexture(GL_TEXTURE2);
    1.95  	glBindTexture(GL_TEXTURE_1D, xfer_tex);
    1.96  	glEnable(GL_TEXTURE_1D);
    1.97 @@ -179,15 +203,47 @@
    1.98  	glDisable(GL_TEXTURE_3D);
    1.99  
   1.100  	glMatrixMode(GL_TEXTURE);
   1.101 -	glLoadIdentity();
   1.102 +	glPopMatrix();
   1.103 +	glMatrixMode(GL_MODELVIEW);
   1.104 +	glPopMatrix();
   1.105 +}
   1.106  
   1.107 -	glutSwapBuffers();
   1.108 -	assert(glGetError() == GL_NO_ERROR);
   1.109 +void draw_xfer_func(void)
   1.110 +{
   1.111 +	glMatrixMode(GL_MODELVIEW);
   1.112 +	glPushMatrix();
   1.113 +	glTranslatef(-0.9, -0.9, 0);
   1.114 +	glScalef(0.5, 0.1, 1);
   1.115 +
   1.116 +	glBindTexture(GL_TEXTURE_1D, xfer_tex);
   1.117 +	glEnable(GL_TEXTURE_1D);
   1.118 +
   1.119 +	glBegin(GL_QUADS);
   1.120 +	glColor3f(1, 1, 1);
   1.121 +	glTexCoord1f(1);
   1.122 +	glVertex2f(1, 0);
   1.123 +	glVertex2f(1, 1);
   1.124 +	glTexCoord1f(0);
   1.125 +	glVertex2f(0, 1);
   1.126 +	glVertex2f(0, 0);
   1.127 +	glEnd();
   1.128 +
   1.129 +	glDisable(GL_TEXTURE_1D);
   1.130 +
   1.131 +	glLineWidth(2.0);
   1.132 +	glBegin(GL_LINE_LOOP);
   1.133 +	glColor3f(uimode_xfer ? 1 : 0, 0, uimode_xfer ? 0 : 1);
   1.134 +	glVertex2f(0, 0);
   1.135 +	glVertex2f(1, 0);
   1.136 +	glVertex2f(1, 1);
   1.137 +	glVertex2f(0, 1);
   1.138 +	glEnd();
   1.139 +
   1.140 +	glPopMatrix();
   1.141  }
   1.142  
   1.143  void reshape(int x, int y)
   1.144  {
   1.145 -	printf("reshape: %dx%d\n", x, y);
   1.146  	glViewport(0, 0, x, y);
   1.147  
   1.148  	if(x != win_xsz || y != win_ysz) {
   1.149 @@ -202,6 +258,21 @@
   1.150  	switch(key) {
   1.151  	case 27:
   1.152  		exit(0);
   1.153 +
   1.154 +	case 'x':
   1.155 +		uimode_xfer = 1;
   1.156 +		glutPostRedisplay();
   1.157 +		break;
   1.158 +	}
   1.159 +}
   1.160 +
   1.161 +void keyb_up(unsigned char key, int x, int y)
   1.162 +{
   1.163 +	switch(key) {
   1.164 +	case 'x':
   1.165 +		uimode_xfer = 0;
   1.166 +		glutPostRedisplay();
   1.167 +		break;
   1.168  	}
   1.169  }
   1.170  
   1.171 @@ -219,30 +290,43 @@
   1.172  {
   1.173  	int dx = x - prev_x;
   1.174  	int dy = y - prev_y;
   1.175 -
   1.176  	prev_x = x;
   1.177  	prev_y = y;
   1.178  
   1.179 -	if(bnstate[0]) {
   1.180 -		cam_theta += dx * 0.5;
   1.181 -		cam_phi += dy * 0.5;
   1.182 +	if(uimode_xfer) {
   1.183 +		if(dx || dy) {
   1.184 +			xfer_mean += dx / (float)win_xsz;
   1.185 +			xfer_sdev += 0.5 * dy / (float)win_ysz;
   1.186  
   1.187 -		if(cam_phi <= -90) cam_phi = -89;
   1.188 -		if(cam_phi >= 90) cam_phi = 89;
   1.189 +			xfer_mean = xfer_mean < 0.0 ? 0.0 : (xfer_mean > 1.0 ? 1.0 : xfer_mean);
   1.190 +			xfer_sdev = xfer_sdev < 0.0 ? 0.0 : (xfer_sdev > 1.0 ? 1.0 : xfer_sdev);
   1.191  
   1.192 -		glutPostRedisplay();
   1.193 -	}
   1.194 +			xfertex_needs_recalc = 1;
   1.195 +			glutPostRedisplay();
   1.196 +		}
   1.197 +	} else {
   1.198  
   1.199 -	if(bnstate[1]) {
   1.200 -		cam_x += dx * 0.025;
   1.201 -		cam_y += dy * 0.025;
   1.202 -		glutPostRedisplay();
   1.203 -	}
   1.204 +		if(bnstate[0]) {
   1.205 +			cam_theta += dx * 0.5;
   1.206 +			cam_phi += dy * 0.5;
   1.207  
   1.208 -	if(bnstate[2]) {
   1.209 -		cam_dist += dy * 0.025;
   1.210 -		if(cam_dist < 0.0) cam_dist = 0.0;
   1.211 -		glutPostRedisplay();
   1.212 +			if(cam_phi <= -90) cam_phi = -89;
   1.213 +			if(cam_phi >= 90) cam_phi = 89;
   1.214 +
   1.215 +			glutPostRedisplay();
   1.216 +		}
   1.217 +
   1.218 +		if(bnstate[1]) {
   1.219 +			cam_x += dx * 0.025;
   1.220 +			cam_y += dy * 0.025;
   1.221 +			glutPostRedisplay();
   1.222 +		}
   1.223 +
   1.224 +		if(bnstate[2]) {
   1.225 +			cam_dist += dy * 0.025;
   1.226 +			if(cam_dist < 0.0) cam_dist = 0.0;
   1.227 +			glutPostRedisplay();
   1.228 +		}
   1.229  	}
   1.230  }
   1.231  
   1.232 @@ -264,10 +348,10 @@
   1.233  				}
   1.234  				break;
   1.235  
   1.236 -			case 'v':
   1.237 +			case 'd':
   1.238  				xfer_sdev = strtod(argv[++i], &endp);
   1.239  				if(endp == argv[i]) {
   1.240 -					fprintf(stderr, "-v must be followed by the transfer function sdeviance\n");
   1.241 +					fprintf(stderr, "-d must be followed by the transfer function std.deviation\n");
   1.242  					return -1;
   1.243  				}
   1.244  				break;
   1.245 @@ -396,10 +480,11 @@
   1.246  	}
   1.247  
   1.248  	for(i=0; i<XFER_MAP_SZ; i++) {
   1.249 -		float x = (float)i / (float)XFER_MAP_SZ;
   1.250 -		map[i] = gaussian(x, mean, sdev);
   1.251 +		float x = (float)i / (float)(XFER_MAP_SZ - 1);
   1.252 +		map[i] = gaussian(x, mean, sdev) - 1.0;
   1.253  	}
   1.254 +	putchar('\n');
   1.255  
   1.256 -	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, XFER_MAP_SZ, 1, GL_LUMINANCE, GL_FLOAT, map);
   1.257 +	glTexSubImage1D(GL_TEXTURE_1D, 0, 0, XFER_MAP_SZ, GL_LUMINANCE, GL_FLOAT, map);
   1.258  	xfertex_needs_recalc = 0;
   1.259  }

     2.1 --- a/volray.p.glsl	Mon Apr 02 14:42:03 2012 +0300
     2.2 +++ b/volray.p.glsl	Mon Apr 02 17:59:46 2012 +0300
     2.3 @@ -1,10 +1,15 @@
     2.4  uniform sampler3D volume;
     2.5  uniform sampler2D ray_tex;
     2.6 +uniform sampler1D xfer_tex;
     2.7  
     2.8  struct Ray {
     2.9  	vec3 origin, dir;
    2.10  };
    2.11  
    2.12 +struct AABBox {
    2.13 +	vec3 min, max;
    2.14 +};
    2.15 +
    2.16  struct ISect {
    2.17  	bool hit;
    2.18  	float t;
    2.19 @@ -16,13 +21,22 @@
    2.20  vec3 ray_march(Ray ray);
    2.21  vec3 shade(Ray ray, ISect isect);
    2.22  Ray get_primary_ray();
    2.23 +bool intersect_aabb(Ray ray, AABBox aabb, out float t);
    2.24  
    2.25  void main()
    2.26  {
    2.27 +	const AABBox aabb = AABBox(vec3(0.0, 0.0, 0.0), vec3(1.0, 1.0, 1.0));
    2.28  	Ray ray = get_primary_ray();
    2.29  
    2.30 -	gl_FragColor = vec4(ray_march(ray), 1.0);
    2.31 -	//gl_FragColor = vec4(sky(ray), 1.0);
    2.32 +	vec3 color = vec3(0.0, 0.0, 0.0);
    2.33 +
    2.34 +	float start_t;
    2.35 +	if(intersect_aabb(ray, aabb, start_t)) {
    2.36 +		ray.origin += ray.dir * start_t;
    2.37 +		color = vec3(1.0, 0.0, 0.0);//ray_march(ray);
    2.38 +	}
    2.39 +
    2.40 +	gl_FragColor = vec4(color, 1.0);
    2.41  }
    2.42  
    2.43  vec3 sky(Ray ray)
    2.44 @@ -34,6 +48,11 @@
    2.45  	return mix(col1, col2, t);
    2.46  }
    2.47  
    2.48 +float eval(vec3 pos)
    2.49 +{
    2.50 +	return texture1D(xfer_tex, texture3D(volume, pos).x).x;
    2.51 +}
    2.52 +
    2.53  vec3 ray_march(Ray ray)
    2.54  {
    2.55  	const float ray_step = 0.1;
    2.56 @@ -42,8 +61,7 @@
    2.57  	float col = 0.0;
    2.58  
    2.59  	for(int i=0; i<40; i++) {
    2.60 -		float val = texture3D(volume, pos).x;
    2.61 -		val *= energy;
    2.62 +		float val = eval(pos) * energy;
    2.63  		col += val;
    2.64  		energy -= val;
    2.65  		if(energy < 0.001) {
    2.66 @@ -78,3 +96,45 @@
    2.67  	ray.origin = (gl_ModelViewMatrix * vec4(0.0, 0.0, 0.0, 1.0)).xyz;
    2.68  	return ray;
    2.69  }
    2.70 +
    2.71 +bool intersect_aabb(Ray ray, AABBox aabb, out float t)
    2.72 +{
    2.73 +	if(ray.origin.x >= aabb.min.x && ray.origin.y >= aabb.min.y && ray.origin.z >= aabb.min.z &&
    2.74 +			ray.origin.x < aabb.max.x && ray.origin.y < aabb.max.y && ray.origin.z < aabb.max.z) {
    2.75 +		return true;
    2.76 +	}
    2.77 +
    2.78 +	vec4 bbox[2];
    2.79 +	bbox[0] = vec4(aabb.min.x, aabb.min.y, aabb.min.z, 0);
    2.80 +	bbox[1] = vec4(aabb.max.x, aabb.max.y, aabb.max.z, 0);
    2.81 +
    2.82 +	int xsign = int(ray.dir.x < 0.0);
    2.83 +	float invdirx = 1.0 / ray.dir.x;
    2.84 +	float tmin = (bbox[xsign].x - ray.origin.x) * invdirx;
    2.85 +	float tmax = (bbox[1 - xsign].x - ray.origin.x) * invdirx;
    2.86 +
    2.87 +	int ysign = int(ray.dir.y < 0.0);
    2.88 +	float invdiry = 1.0 / ray.dir.y;
    2.89 +	float tymin = (bbox[ysign].y - ray.origin.y) * invdiry;
    2.90 +	float tymax = (bbox[1 - ysign].y - ray.origin.y) * invdiry;
    2.91 +
    2.92 +	if(tmin > tymax || tymin > tmax) {
    2.93 +		return false;
    2.94 +	}
    2.95 +
    2.96 +	if(tymin > tmin) tmin = tymin;
    2.97 +	if(tymax < tmax) tmax = tymax;
    2.98 +
    2.99 +	int zsign = int(ray.dir.z < 0.0);
   2.100 +	float invdirz = 1.0 / ray.dir.z;
   2.101 +	float tzmin = (bbox[zsign].z - ray.origin.z) * invdirz;
   2.102 +	float tzmax = (bbox[1 - zsign].z - ray.origin.z) * invdirz;
   2.103 +
   2.104 +	if(tmin > tzmax || tzmin > tmax) {
   2.105 +		return false;
   2.106 +	}
   2.107 +
   2.108 +	t = tmin;
   2.109 +	return tmin < 1.0 && tmax > 0.0;
   2.110 +}
   2.111 +