/* * SPIKEY.C -- Modeler Plugin Mesh Edit * Make a polygonal object spikey while subdividing * * written by Stuart Ferguson * last revision 12/6/94 */ #include #include #include #include #include /* * Local information packet. This includes the mesh edit context, monitor, * and polygon count. Also holds the spike factor which might be variable. */ typedef struct st_MyData { MeshEditOp *op; Monitor *mon; unsigned int count; double spike; } MyData; /* * Utility to return the distance between two 3D points. */ static double Dist3D ( double v1[3], double v2[3]) { double d, z; int i; d = 0.0; for (i = 0; i < 3; i++) { z = v1[i] - v2[i]; d += z * z; } return sqrt (d); } /* * This is called for all the polygons as a preliminary pass to count the * affected ones. Polygons are only processed if they are faces, they are * selected and they have at least three vertices. */ static EDError CountPols ( MyData *dat, const PolygonInfo *pi) { if ((pi->flags & (PPDF_SELECT | PPDF_CURVE)) == PPDF_SELECT && pi->numPnts >= 3) dat->count ++; return EDERR_NONE; } /* * This is called for all the polygons to delete them and replace them with * triangles around a centeral displaced point. The check for which ones * to process and which to skip is the same as above. */ static EDError Subdivide ( MyData *dat, const PolygonInfo *pi) { MeshEditOp *op = dat->op; EditStateRef s = op->state; PointInfo *vi; double cen[3], norm[3], d; PntID cg; PntID vl[3]; int i; if ((pi->flags & (PPDF_SELECT | PPDF_CURVE)) != PPDF_SELECT || pi->numPnts < 3) return EDERR_NONE; /* * Count this polygon in the aggregate for the monitor. The * step function returns True if the user has requested an abort, * which we can propogate by returning the appropriate code. */ if (dat->mon && (*dat->mon->step) (dat->mon->data, 1)) return EDERR_USERABORT; /* * Compute the CG of the polygon vertices as `cen.' */ cen[0] = cen[1] = cen[2] = 0.0; for (i = 0; i < pi->numPnts; i++) { vi = (*op->pointInfo) (s, pi->points[i]); if (!vi) return EDERR_NOMEMORY; cen[0] += vi->position[0]; cen[1] += vi->position[1]; cen[2] += vi->position[2]; } cen[0] = cen[0] / pi->numPnts; cen[1] = cen[1] / pi->numPnts; cen[2] = cen[2] / pi->numPnts; /* * Compute the average distance from a polygon vertex to * the center point. */ d = 0.0; for (i = 0; i < pi->numPnts; i++) { vi = (*op->pointInfo) (s, pi->points[i]); if (!vi) return EDERR_NOMEMORY; d += Dist3D (vi->position, cen); } d = d / pi->numPnts; /* * Translate the center point out of the polygon's plane by this * average distance times the spikeyness factor. This translation * can only be done if the polygon has a valid normal. */ d *= dat->spike; if (d && (*op->polyNormal) (op->state, pi->pol, norm)) { cen[0] += norm[0] * d; cen[1] += norm[1] * d; cen[2] += norm[2] * d; } /* * Create a new point at the offset center position. */ cg = (*op->addPoint) (s, cen); if (!cg) return EDERR_NOMEMORY; /* * Loop over points in the polygon and create new triangles * from each pair to the center. We use `addPoly' rather than * `addTri' since we want to preserve the original polygon * surface and sidedness. Note the "modulo numPnts" to make * the point index wrap around the end of the point array. */ vl[0] = cg; for (i = 0; i < pi->numPnts; i++) { vl[1] = pi->points[i]; vl[2] = pi->points[(i + 1) % pi->numPnts]; if (!(*op->addPoly) (s, pi->surface, 3, vl)) return EDERR_NOMEMORY; } /* * Delete the orginal and we're done. */ return ((*op->remPoly) (op->state, pi->pol)); } /* * Main entry point for mesh operation. */ XCALL_(int) Activate ( long version, GlobalFunc *global, MeshEditBegin *local, void *serverData) { MeshEditOp *op; DynaMonitorFuncs *mfunc; MyData dat; EDError err; /* * Check interface version. */ XCALL_INIT; if (version != 1) return AFUNC_BADVERSION; /* * Get global data -- monitor functions. */ mfunc = (*global) ("LWM: Dynamic Monitor", GFUSE_TRANSIENT); if (!mfunc) return AFUNC_BADGLOBAL; /* * Attempt to begin edit operation. If the startup fails we still * return OK, but just don't do anything. */ op = (*local) (0, 0, OPSEL_USER); if (!op) return AFUNC_OK; /* * Count the polygons that will be affected by the operation. This * has to be done with an explicit scan and it can fail. The time * for a scan of this type should be small enough to not be very * significant. */ dat.op = op; dat.count = 0; err = (*op->polyScan) (op->state, CountPols, &dat, OPLYR_PRIMARY); if (err) { (*op->done) (op->state, err, 0); return AFUNC_OK; } /* * Start the monitor. If we can create a monitor, initialize it * with the polygon count. */ dat.mon = (*mfunc->create) ("Spikey Subdivide", NULL); if (dat.mon) (*dat.mon->init) (dat.mon->data, dat.count); /* * Process the polygons in a second scan through the polygon * database. The spikiness parameter will just be fixed, * although it could easily be set by a requester. * * We will alter polygons in the primary layer only since we * can only create new data in this layer. */ dat.spike = 2.0; err = (*op->polyScan) (op->state, Subdivide, &dat, OPLYR_PRIMARY); /* * End the monitor whether we completed successfully or not. */ if (dat.mon) { (*dat.mon->done) (dat.mon->data); (*mfunc->destroy) (dat.mon); } /* * Complete the operation by calling `done.' We pass the error * code if there was one, or NONE. We also want to select any * new data if there was data selected to start with. This is * important for maintaining the user's idea that the same stuff * is selected even though we replaced each polygon with several * new ones. */ (*op->done) (op->state, err, EDSELM_SELECTNEW); return AFUNC_OK; } /* * Globals necessary to declare the class and name of this plugin server. */ char ServerClass[] = "MeshDataEdit"; char ServerName[] = "Demo_MakeSpikey";