11 int res[3], newres[3];
19 int varr_size, varr_alloc_size;
20 struct g3d_vertex *varr;
23 static int msurf_init(struct metasurface *ms);
24 static void process_cell(struct metasurface *ms, int xcell, int ycell, int zcell, vec3 pos, vec3 sz);
27 struct metasurface *msurf_create(void)
29 struct metasurface *ms;
31 if(!(ms = malloc(sizeof *ms))) {
34 if(msurf_init(ms) == -1) {
40 void msurf_free(struct metasurface *ms)
49 static int msurf_init(struct metasurface *ms)
53 ms->min[0] = ms->min[1] = ms->min[2] = -1.0;
54 ms->max[0] = ms->max[1] = ms->max[2] = 1.0;
55 ms->res[0] = ms->res[1] = ms->res[2] = 0;
56 ms->newres[0] = ms->newres[1] = ms->newres[2] = 40;
58 ms->varr_alloc_size = ms->varr_size = 0;
61 ms->dx = ms->dy = ms->dz = 0.001;
67 void msurf_enable(struct metasurface *ms, unsigned int opt)
72 void msurf_disable(struct metasurface *ms, unsigned int opt)
77 int msurf_is_enabled(struct metasurface *ms, unsigned int opt)
79 return ms->flags & opt;
82 void msurf_set_inside(struct metasurface *ms, int inside)
86 msurf_enable(ms, MSURF_FLIP);
90 msurf_disable(ms, MSURF_FLIP);
94 fprintf(stderr, "msurf_inside expects MSURF_GREATER or MSURF_LESS\n");
98 int msurf_get_inside(struct metasurface *ms)
100 return msurf_is_enabled(ms, MSURF_FLIP) ? MSURF_LESS : MSURF_GREATER;
103 void msurf_set_bounds(struct metasurface *ms, float xmin, float ymin, float zmin, float xmax, float ymax, float zmax)
113 void msurf_get_bounds(struct metasurface *ms, float *xmin, float *ymin, float *zmin, float *xmax, float *ymax, float *zmax)
123 void msurf_set_resolution(struct metasurface *ms, int xres, int yres, int zres)
125 ms->newres[0] = xres;
126 ms->newres[1] = yres;
127 ms->newres[2] = zres;
130 void msurf_get_resolution(struct metasurface *ms, int *xres, int *yres, int *zres)
137 void msurf_set_threshold(struct metasurface *ms, float thres)
142 float msurf_get_threshold(struct metasurface *ms)
148 float *msurf_voxels(struct metasurface *ms)
150 if(ms->res[0] != ms->newres[0] || ms->res[1] != ms->newres[1] || ms->res[2] != ms->newres[2]) {
152 ms->res[0] = ms->newres[0];
153 ms->res[1] = ms->newres[1];
154 ms->res[2] = ms->newres[2];
155 count = ms->res[0] * ms->res[1] * ms->res[2];
157 if(!(ms->voxels = malloc(count * sizeof *ms->voxels))) {
164 float *msurf_slice(struct metasurface *ms, int idx)
166 float *vox = msurf_voxels(ms);
169 return vox + ms->res[0] * ms->res[1] * idx;
172 int msurf_polygonize(struct metasurface *ms)
177 if(!ms->voxels) return -1;
182 delta[i] = (ms->max[i] - ms->min[i]) / (float)ms->res[i];
185 for(i=0; i<ms->res[0] - 1; i++) {
186 for(j=0; j<ms->res[1] - 1; j++) {
187 for(k=0; k<ms->res[2] - 1; k++) {
189 pos[0] = ms->min[0] + i * delta[0];
190 pos[1] = ms->min[1] + j * delta[1];
191 pos[2] = ms->min[2] + k * delta[2];
193 process_cell(ms, i, j, k, pos, delta);
200 int msurf_vertex_count(struct metasurface *ms)
202 return ms->varr_size;
205 struct g3d_vertex *msurf_vertices(struct metasurface *ms)
210 static unsigned int mc_bitcode(float *val, float thres);
212 static void process_cell(struct metasurface *ms, int xcell, int ycell, int zcell, vec3 cellpos, vec3 cellsz)
214 int i, j, slice_size;
216 float dfdx[8], dfdy[8], dfdz[8];
217 vec3 vert[12], norm[12];
222 static const int offs[][3] = {
233 static const int pidx[12][2] = {
234 {0, 1}, {1, 2}, {2, 3}, {3, 0}, {4, 5}, {5, 6},
235 {6, 7}, {7, 4}, {0, 4}, {1, 5}, {2, 6}, {3, 7}
238 slice_size = ms->res[0] * ms->res[1];
239 cellptr = ms->voxels + slice_size * zcell + ms->res[0] * ycell + xcell;
241 #define GRIDOFFS(x, y, z) ((z) * slice_size + (y) * ms->res[0] + (x))
244 val[i] = cellptr[GRIDOFFS(offs[i][0], offs[i][1], offs[i][2])];
247 code = mc_bitcode(val, ms->thres);
248 if(ms->flags & MSURF_FLIP) {
251 if(mc_edge_table[code] == 0) {
255 /* calculate normals at the 8 corners */
257 float *ptr = cellptr + GRIDOFFS(offs[i][0], offs[i][1], offs[i][2]);
259 if(xcell < ms->res[0] - 1) {
260 dfdx[i] = ptr[GRIDOFFS(1, 0, 0)] - *ptr;
262 dfdx[i] = *ptr - ptr[GRIDOFFS(-1, 0, 0)];
264 if(ycell < ms->res[1] - 1) {
265 dfdy[i] = ptr[GRIDOFFS(0, 1, 0)] - *ptr;
267 dfdy[i] = *ptr - ptr[GRIDOFFS(0, -1, 0)];
269 if(zcell < ms->res[2] - 1) {
270 dfdz[i] = ptr[GRIDOFFS(0, 0, 1)] - *ptr;
272 dfdz[i] = *ptr - ptr[GRIDOFFS(0, 0, -1)];
276 /* calculate the world-space position of each corner */
278 pos[i][0] = cellpos[0] + cellsz[0] * offs[i][0];
279 pos[i][1] = cellpos[1] + cellsz[1] * offs[i][1];
280 pos[i][2] = cellpos[2] + cellsz[2] * offs[i][2];
283 /* generate up to a max of 12 vertices per cube. interpolate positions and normals for each one */
284 for(i=0; i<12; i++) {
285 if(mc_edge_table[code] & (1 << i)) {
290 float t = (ms->thres - val[p0]) / (val[p1] - val[p0]);
291 vert[i][0] = pos[p0][0] + (pos[p1][0] - pos[p0][0]) * t;
292 vert[i][1] = pos[p0][1] + (pos[p1][1] - pos[p0][1]) * t;
293 vert[i][2] = pos[p0][2] + (pos[p1][2] - pos[p0][2]) * t;
295 nx = dfdx[p0] + (dfdx[p1] - dfdx[p0]) * t;
296 ny = dfdy[p0] + (dfdy[p1] - dfdy[p0]) * t;
297 nz = dfdz[p0] + (dfdz[p1] - dfdz[p0]) * t;
299 if(ms->flags & MSURF_FLIP) {
305 if(ms->flags & MSURF_NORMALIZE) {
306 float len = sqrt(nx * nx + ny * ny + nz * nz);
308 float s = 1.0f / len;
321 /* for each triangle of the cube add the appropriate vertices to the vertex buffer */
322 for(i=0; mc_tri_table[code][i] != -1; i+=3) {
324 int idx = mc_tri_table[code][i + j];
325 float *v = vert[idx];
326 float *n = norm[idx];
327 struct g3d_vertex *vdest;
329 if(ms->varr_size >= ms->varr_alloc_size) {
330 int newsz = ms->varr_alloc_size ? ms->varr_alloc_size * 2 : 1024;
331 struct g3d_vertex *new_varr;
333 if(!(new_varr = realloc(ms->varr, newsz * sizeof *new_varr))) {
334 fprintf(stderr, "msurf_polygonize: failed to grow vertex buffers to %d elements\n", newsz);
338 ms->varr_alloc_size = newsz;
341 vdest = ms->varr + ms->varr_size++;
353 static unsigned int mc_bitcode(float *val, float thres)
355 unsigned int i, res = 0;