1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/metasurf.c	Tue Oct 25 07:34:31 2011 +0300
     1.3 @@ -0,0 +1,362 @@
     1.4 +#include <stdlib.h>
     1.5 +#include "metasurf.h"
     1.6 +#include "mcubes.h"
     1.7 +
     1.8 +#undef USE_MTETRA
     1.9 +#define USE_MCUBES
    1.10 +
    1.11 +#if (defined(USE_MTETRA) && defined(USE_MCUBES)) || (!defined(USE_MTETRA) && !defined(USE_MCUBES))
    1.12 +#error "pick either USE_MTETRA or USE_MCUBES, not both..."
    1.13 +#endif
    1.14 +
    1.15 +typedef float vec3[3];
    1.16 +
    1.17 +struct metasurface {
    1.18 +	vec3 min, max;
    1.19 +	int res[3];
    1.20 +	float thres;
    1.21 +
    1.22 +	msurf_eval_func_t eval;
    1.23 +	msurf_vertex_func_t vertex;
    1.24 +	msurf_normal_func_t normal;
    1.25 +
    1.26 +	vec3 vbuf[3];
    1.27 +	int nverts;
    1.28 +};
    1.29 +
    1.30 +static int msurf_init(struct metasurface *ms);
    1.31 +static void process_cell(struct metasurface *ms, vec3 pos, vec3 sz);
    1.32 +#ifdef USE_MTETRA
    1.33 +static void process_tetra(struct metasurface *ms, int *idx, vec3 *pos, float *val);
    1.34 +#endif
    1.35 +#ifdef USE_MCUBES
    1.36 +static void process_cube(struct metasurface *ms, vec3 *pos, float *val);
    1.37 +#endif
    1.38 +
    1.39 +
    1.40 +struct metasurface *msurf_create(void)
    1.41 +{
    1.42 +	struct metasurface *ms;
    1.43 +
    1.44 +	if(!(ms = malloc(sizeof *ms))) {
    1.45 +		return 0;
    1.46 +	}
    1.47 +	if(msurf_init(ms) == -1) {
    1.48 +		free(ms);
    1.49 +	}
    1.50 +	return ms;
    1.51 +}
    1.52 +
    1.53 +void msurf_free(struct metasurface *ms)
    1.54 +{
    1.55 +	free(ms);
    1.56 +}
    1.57 +
    1.58 +static int msurf_init(struct metasurface *ms)
    1.59 +{
    1.60 +	ms->thres = 0.0;
    1.61 +	ms->eval = 0;
    1.62 +	ms->vertex = 0;
    1.63 +	ms->normal = 0;
    1.64 +	ms->min[0] = ms->min[1] = ms->min[2] = -1.0;
    1.65 +	ms->max[0] = ms->max[1] = ms->max[2] = 1.0;
    1.66 +	ms->res[0] = ms->res[1] = ms->res[2] = 32;
    1.67 +	ms->nverts = 0;
    1.68 +
    1.69 +	return 0;
    1.70 +}
    1.71 +
    1.72 +void msurf_eval_func(struct metasurface *ms, msurf_eval_func_t func)
    1.73 +{
    1.74 +	ms->eval = func;
    1.75 +}
    1.76 +
    1.77 +void msurf_vertex_func(struct metasurface *ms, msurf_vertex_func_t func)
    1.78 +{
    1.79 +	ms->vertex = func;
    1.80 +}
    1.81 +
    1.82 +void msurf_normal_func(struct metasurface *ms, msurf_normal_func_t func)
    1.83 +{
    1.84 +	ms->normal = func;
    1.85 +}
    1.86 +
    1.87 +void msurf_bounds(struct metasurface *ms, float xmin, float ymin, float zmin, float xmax, float ymax, float zmax)
    1.88 +{
    1.89 +	ms->min[0] = xmin;
    1.90 +	ms->min[1] = ymin;
    1.91 +	ms->min[2] = zmin;
    1.92 +	ms->max[0] = xmax;
    1.93 +	ms->max[1] = ymax;
    1.94 +	ms->max[2] = zmax;
    1.95 +}
    1.96 +
    1.97 +void msurf_resolution(struct metasurface *ms, int xres, int yres, int zres)
    1.98 +{
    1.99 +	ms->res[0] = xres;
   1.100 +	ms->res[1] = yres;
   1.101 +	ms->res[2] = zres;
   1.102 +}
   1.103 +
   1.104 +void msurf_threshold(struct metasurface *ms, float thres)
   1.105 +{
   1.106 +	ms->thres = thres;
   1.107 +}
   1.108 +
   1.109 +
   1.110 +void msurf_polygonize(struct metasurface *ms)
   1.111 +{
   1.112 +	int i, j, k;
   1.113 +	vec3 pos, delta;
   1.114 +
   1.115 +	for(i=0; i<3; i++) {
   1.116 +		delta[i] = (ms->max[i] - ms->min[i]) / (float)ms->res[i];
   1.117 +	}
   1.118 +
   1.119 +	pos[0] = ms->min[0];
   1.120 +	for(i=0; i<ms->res[0] - 1; i++) {
   1.121 +
   1.122 +		pos[1] = ms->min[1];
   1.123 +		for(j=0; j<ms->res[1] - 1; j++) {
   1.124 +
   1.125 +			pos[2] = ms->min[2];
   1.126 +			for(k=0; k<ms->res[2] - 1; k++) {
   1.127 +
   1.128 +				process_cell(ms, pos, delta);
   1.129 +
   1.130 +				pos[2] += delta[2];
   1.131 +			}
   1.132 +			pos[1] += delta[1];
   1.133 +		}
   1.134 +		pos[0] += delta[0];
   1.135 +	}
   1.136 +}
   1.137 +
   1.138 +
   1.139 +static void process_cell(struct metasurface *ms, vec3 pos, vec3 sz)
   1.140 +{
   1.141 +	int i;
   1.142 +	vec3 p[8];
   1.143 +	float val[8];
   1.144 +
   1.145 +#ifdef USE_MTETRA
   1.146 +	static int tetra[][4] = {
   1.147 +		{0, 2, 3, 7},
   1.148 +		{0, 2, 6, 7},
   1.149 +		{0, 4, 6, 7},
   1.150 +		{0, 6, 1, 2},
   1.151 +		{0, 6, 1, 4},
   1.152 +		{5, 6, 1, 4}
   1.153 +	};
   1.154 +#endif
   1.155 +
   1.156 +	static const float offs[][3] = {
   1.157 +		{0.0f, 0.0f, 0.0f},
   1.158 +		{1.0f, 0.0f, 0.0f},
   1.159 +		{1.0f, 1.0f, 0.0f},
   1.160 +		{0.0f, 1.0f, 0.0f},
   1.161 +		{0.0f, 0.0f, 1.0f},
   1.162 +		{1.0f, 0.0f, 1.0f},
   1.163 +		{1.0f, 1.0f, 1.0f},
   1.164 +		{0.0f, 1.0f, 1.0f}
   1.165 +	};
   1.166 +
   1.167 +	for(i=0; i<8; i++) {
   1.168 +		p[i][0] = pos[0] + sz[0] * offs[i][2];
   1.169 +		p[i][1] = pos[1] + sz[1] * offs[i][1];
   1.170 +		p[i][2] = pos[2] + sz[2] * offs[i][0];
   1.171 +
   1.172 +		val[i] = ms->eval(p[i][0], p[i][1], p[i][2]);
   1.173 +	}
   1.174 +
   1.175 +#ifdef USE_MTETRA
   1.176 +	for(i=0; i<6; i++) {
   1.177 +		process_tetra(ms, tetra[i], p, val);
   1.178 +	}
   1.179 +#endif
   1.180 +#ifdef USE_MCUBES
   1.181 +	process_cube(ms, p, val);
   1.182 +#endif
   1.183 +}
   1.184 +
   1.185 +
   1.186 +/* ---- marching cubes implementation ---- */
   1.187 +#ifdef USE_MCUBES
   1.188 +
   1.189 +static unsigned int mc_bitcode(float *val, float thres);
   1.190 +
   1.191 +static void process_cube(struct metasurface *ms, vec3 *pos, float *val)
   1.192 +{
   1.193 +	static const int pidx[12][2] = {
   1.194 +		{0, 1}, {1, 2}, {2, 3}, {3, 0}, {4, 5}, {5, 6},
   1.195 +		{6, 7},	{7, 4}, {0, 4}, {1, 5}, {2, 6}, {3, 7}
   1.196 +	};
   1.197 +	int i, j;
   1.198 +	vec3 vert[12];
   1.199 +	unsigned int code = mc_bitcode(val, ms->thres);
   1.200 +
   1.201 +	if(mc_edge_table[code] == 0) {
   1.202 +		return;
   1.203 +	}
   1.204 +
   1.205 +	for(i=0; i<12; i++) {
   1.206 +		if(mc_edge_table[code] & (1 << i)) {
   1.207 +			int p0 = pidx[i][0];
   1.208 +			int p1 = pidx[i][1];
   1.209 +
   1.210 +			float t = (ms->thres - val[p0]) / (val[p1] - val[p0]);
   1.211 +			vert[i][0] = pos[p0][0] + (pos[p1][0] - pos[p0][0]) * t;
   1.212 +			vert[i][1] = pos[p0][1] + (pos[p1][1] - pos[p0][1]) * t;
   1.213 +			vert[i][2] = pos[p0][2] + (pos[p1][2] - pos[p0][2]) * t;
   1.214 +		}
   1.215 +	}
   1.216 +
   1.217 +	for(i=0; mc_tri_table[code][i] != -1; i+=3) {
   1.218 +		for(j=0; j<3; j++) {
   1.219 +			float *v = vert[mc_tri_table[code][i + j]];
   1.220 +			ms->vertex(v[0], v[1], v[2]);
   1.221 +		}
   1.222 +	}
   1.223 +}
   1.224 +
   1.225 +static unsigned int mc_bitcode(float *val, float thres)
   1.226 +{
   1.227 +	unsigned int i, res = 0;
   1.228 +
   1.229 +	for(i=0; i<8; i++) {
   1.230 +		if(val[i] > thres) {
   1.231 +			res |= 1 << i;
   1.232 +		}
   1.233 +	}
   1.234 +	return res;
   1.235 +}
   1.236 +#endif	/* USE_MCUBES */
   1.237 +
   1.238 +
   1.239 +/* ---- marching tetrahedra implementation (incomplete) ---- */
   1.240 +#ifdef USE_MTETRA
   1.241 +
   1.242 +static unsigned int mt_bitcode(float v0, float v1, float v2, float v3, float thres);
   1.243 +static void emmit(struct metasurface *ms, float v0, float v1, vec3 p0, vec3 p1, int rev)
   1.244 +
   1.245 +
   1.246 +#define REVBIT(x)	((x) & 8)
   1.247 +#define INV(x)		(~(x) & 0xf)
   1.248 +#define EDGE(a, b)	emmit(ms, val[idx[a]], val[idx[b]], pos[idx[a]], pos[idx[b]], REVBIT(code))
   1.249 +static void process_tetra(struct metasurface *ms, int *idx, vec3 *pos, float *val)
   1.250 +{
   1.251 +	unsigned int code = mt_bitcode(val[idx[0]], val[idx[1]], val[idx[2]], val[idx[3]], ms->thres);
   1.252 +
   1.253 +	switch(code) {
   1.254 +	/*case 1:
   1.255 +	case INV(1):*/
   1.256 +	case 0x0e:
   1.257 +	case 0x01:
   1.258 +		EDGE(0, 1);
   1.259 +		EDGE(0, 2);
   1.260 +		EDGE(0, 3);
   1.261 +		break;
   1.262 +
   1.263 +	/*case 2:
   1.264 +	case INV(2):*/
   1.265 +	case 0x0d:
   1.266 +	case 0x02:
   1.267 +		EDGE(1, 0);
   1.268 +		EDGE(1, 3);
   1.269 +		EDGE(1, 2);
   1.270 +		break;
   1.271 +
   1.272 +	/*case 3:
   1.273 +	case INV(3):*/
   1.274 +	case 0x0c:
   1.275 +	case 0x03:
   1.276 +		EDGE(0, 3);
   1.277 +		EDGE(0, 2);
   1.278 +		EDGE(1, 3);
   1.279 +
   1.280 +		EDGE(1, 3);
   1.281 +		EDGE(1, 2);
   1.282 +		EDGE(0, 2);
   1.283 +		break;
   1.284 +
   1.285 +	/*case 4:
   1.286 +	case INV(4):*/
   1.287 +	case 0x0b:
   1.288 +	case 0x04:
   1.289 +		EDGE(2, 0);
   1.290 +		EDGE(2, 1);
   1.291 +		EDGE(2, 3);
   1.292 +		break;
   1.293 +
   1.294 +	/*case 5:
   1.295 +	case INV(5):*/
   1.296 +	case 0x0a:
   1.297 +	case 0x05:
   1.298 +		EDGE(0, 1);
   1.299 +		EDGE(2, 3);
   1.300 +		EDGE(0, 3);
   1.301 +
   1.302 +		EDGE(0, 1);
   1.303 +		EDGE(1, 2);
   1.304 +		EDGE(2, 3);
   1.305 +		break;
   1.306 +
   1.307 +	/*case 6:
   1.308 +	case INV(6):*/
   1.309 +	case 0x09:
   1.310 +	case 0x06:
   1.311 +		EDGE(0, 1);
   1.312 +		EDGE(1, 3);
   1.313 +		EDGE(2, 3);
   1.314 +
   1.315 +		EDGE(0, 1);
   1.316 +		EDGE(0, 2);
   1.317 +		EDGE(2, 3);
   1.318 +		break;
   1.319 +
   1.320 +	/*case 7:
   1.321 +	case INV(7):*/
   1.322 +	case 0x07:
   1.323 +	case 0x08:
   1.324 +		EDGE(3, 0);
   1.325 +		EDGE(3, 2);
   1.326 +		EDGE(3, 1);
   1.327 +		break;
   1.328 +
   1.329 +	default:
   1.330 +		break;	/* cases 0 and 15 */
   1.331 +	}
   1.332 +}
   1.333 +
   1.334 +#define BIT(i)	((v##i > thres) ? (1 << i) : 0)
   1.335 +static unsigned int mt_bitcode(float v0, float v1, float v2, float v3, float thres)
   1.336 +{
   1.337 +	return BIT(0) | BIT(1) | BIT(2) | BIT(3);
   1.338 +}
   1.339 +
   1.340 +static void emmit(struct metasurface *ms, float v0, float v1, vec3 p0, vec3 p1, int rev)
   1.341 +{
   1.342 +	int i;
   1.343 +	float t = (ms->thres - v0) / (v1 - v0);
   1.344 +
   1.345 +	vec3 p;
   1.346 +	for(i=0; i<3; i++) {
   1.347 +		p[i] = p0[i] + (p1[i] - p0[i]) * t;
   1.348 +	}
   1.349 +	ms->vertex(p[0], p[1], p[2]);
   1.350 +
   1.351 +	/*for(i=0; i<3; i++) {
   1.352 +		ms->vbuf[ms->nverts][i] = p0[i] + (p1[i] - p0[i]) * t;
   1.353 +	}
   1.354 +
   1.355 +	if(++ms->nverts >= 3) {
   1.356 +		ms->nverts = 0;
   1.357 +
   1.358 +		for(i=0; i<3; i++) {
   1.359 +			int idx = rev ? (2 - i) : i;
   1.360 +			ms->vertex(ms->vbuf[idx][0], ms->vbuf[idx][1], ms->vbuf[idx][2]);
   1.361 +		}
   1.362 +	}*/
   1.363 +}
   1.364 +
   1.365 +#endif	/* USE_MTETRA */