started ropesim tool
[dosdemo] / tools / ropesim / src / cmesh.c
diff --git a/tools/ropesim/src/cmesh.c b/tools/ropesim/src/cmesh.c
new file mode 100644 (file)
index 0000000..64ed2d0
--- /dev/null
@@ -0,0 +1,1619 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <float.h>
+#include <assert.h>
+#include "opengl.h"
+#include "cmesh.h"
+
+
+struct cmesh_vattrib {
+       int nelem;      /* num elements per attribute [1, 4] */
+       float *data;
+       unsigned int count;
+       unsigned int vbo;
+       int vbo_valid, data_valid;
+};
+
+/* istart,icount are valid only when the mesh is indexed, otherwise icount is 0.
+ * vstart,vcount are define the submesh for non-indexed meshes.
+ * For indexed meshes, vstart,vcount denote the range of vertices used by each
+ * submesh.
+ */
+struct submesh {
+       char *name;
+       int nfaces;     /* derived from either icount or vcount */
+       int istart, icount;
+       int vstart, vcount;
+       struct submesh *next;
+};
+
+struct cmesh {
+       char *name;
+       unsigned int nverts, nfaces;
+
+       struct submesh *sublist;
+       int subcount;
+
+       /* current value for each attribute for the immediate mode interface */
+       cgm_vec4 cur_val[CMESH_NUM_ATTR];
+
+       unsigned int buffer_objects[CMESH_NUM_ATTR + 1];
+       struct cmesh_vattrib vattr[CMESH_NUM_ATTR];
+
+       unsigned int *idata;
+       unsigned int icount;
+       unsigned int ibo;
+       int ibo_valid, idata_valid;
+
+       /* index buffer for wireframe rendering (constructed on demand) */
+       unsigned int wire_ibo;
+       int wire_ibo_valid;
+
+       /* axis-aligned bounding box */
+       cgm_vec3 aabb_min, aabb_max;
+       int aabb_valid;
+       /* bounding sphere */
+       cgm_vec3 bsph_center;
+       float bsph_radius;
+       int bsph_valid;
+};
+
+
+static int clone(struct cmesh *cmdest, struct cmesh *cmsrc, struct submesh *sub);
+static int pre_draw(struct cmesh *cm);
+static void post_draw(struct cmesh *cm, int cur_sdr);
+static void update_buffers(struct cmesh *cm);
+static void update_wire_ibo(struct cmesh *cm);
+static void calc_aabb(struct cmesh *cm);
+static void calc_bsph(struct cmesh *cm);
+
+static int def_nelem[CMESH_NUM_ATTR] = {3, 3, 3, 2, 4, 4, 4, 2};
+
+static int sdr_loc[CMESH_NUM_ATTR] = {0, 1, 2, 3, 4, 5, 6, 7};
+static int use_custom_sdr_attr;
+
+
+/* global state */
+void cmesh_set_attrib_sdrloc(int attr, int loc)
+{
+       sdr_loc[attr] = loc;
+}
+
+int cmesh_get_attrib_sdrloc(int attr)
+{
+       return sdr_loc[attr];
+}
+
+void cmesh_clear_attrib_sdrloc(void)
+{
+       int i;
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               sdr_loc[i] = -1;
+       }
+}
+
+/* mesh functions */
+struct cmesh *cmesh_alloc(void)
+{
+       struct cmesh *cm;
+
+       if(!(cm = malloc(sizeof *cm))) {
+               return 0;
+       }
+       if(cmesh_init(cm) == -1) {
+               free(cm);
+               return 0;
+       }
+       return cm;
+}
+
+void cmesh_free(struct cmesh *cm)
+{
+       cmesh_destroy(cm);
+       free(cm);
+}
+
+int cmesh_init(struct cmesh *cm)
+{
+       int i;
+
+       memset(cm, 0, sizeof *cm);
+       cgm_wcons(cm->cur_val + CMESH_ATTR_COLOR, 1, 1, 1, 1);
+
+       glGenBuffers(CMESH_NUM_ATTR + 1, cm->buffer_objects);
+
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               cm->vattr[i].vbo = cm->buffer_objects[i];
+       }
+
+       cm->ibo = cm->buffer_objects[CMESH_NUM_ATTR];
+       return 0;
+}
+
+void cmesh_destroy(struct cmesh *cm)
+{
+       int i;
+
+       free(cm->name);
+
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               free(cm->vattr[i].data);
+       }
+       free(cm->idata);
+
+       cmesh_clear_submeshes(cm);
+
+       glDeleteBuffers(CMESH_NUM_ATTR + 1, cm->buffer_objects);
+       if(cm->wire_ibo) {
+               glDeleteBuffers(1, &cm->wire_ibo);
+       }
+}
+
+void cmesh_clear(struct cmesh *cm)
+{
+       int i;
+
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               cm->vattr[i].nelem = 0;
+               cm->vattr[i].vbo_valid = 0;
+               cm->vattr[i].data_valid = 0;
+               free(cm->vattr[i].data);
+               cm->vattr[i].data = 0;
+               cm->vattr[i].count = 0;
+       }
+       cm->ibo_valid = cm->idata_valid = 0;
+       free(cm->idata);
+       cm->idata = 0;
+       cm->icount = 0;
+
+       cm->wire_ibo_valid = 0;
+       cm->nverts = cm->nfaces = 0;
+
+       cm->bsph_valid = cm->aabb_valid = 0;
+
+       cmesh_clear_submeshes(cm);
+}
+
+int cmesh_clone(struct cmesh *cmdest, struct cmesh *cmsrc)
+{
+       return clone(cmdest, cmsrc, 0);
+}
+
+static int clone(struct cmesh *cmdest, struct cmesh *cmsrc, struct submesh *sub)
+{
+       int i, nelem, vstart, vcount, istart, icount;
+       char *srcname, *name = 0;
+       float *varr[CMESH_NUM_ATTR] = {0};
+       float *vptr;
+       unsigned int *iptr, *iarr = 0;
+
+       /* try do anything that can fail first, before making any changes to cmdest
+        * so we have the option of recovering gracefuly
+        */
+
+       srcname = sub ? sub->name : cmsrc->name;
+       if(srcname) {
+               if(!(name = malloc(strlen(srcname) + 1))) {
+                       return -1;
+               }
+               strcpy(name, srcname);
+       }
+
+       if(sub) {
+               vstart = sub->vstart;
+               vcount = sub->vcount;
+               istart = sub->istart;
+               icount = sub->icount;
+       } else {
+               vstart = istart = 0;
+               vcount = cmsrc->nverts;
+               icount = cmsrc->icount;
+       }
+
+       if(cmesh_indexed(cmsrc)) {
+               if(!(iarr = malloc(icount * sizeof *iarr))) {
+                       free(name);
+                       return -1;
+               }
+       }
+
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               if(cmesh_has_attrib(cmsrc, i)) {
+                       nelem = cmsrc->vattr[i].nelem;
+                       if(!(varr[i] = malloc(vcount * nelem * sizeof(float)))) {
+                               while(--i >= 0) {
+                                       free(varr[i]);
+                               }
+                               free(iarr);
+                               free(name);
+                               return -1;
+                       }
+               }
+       }
+
+       /* from this point forward nothing can fail */
+       cmesh_clear(cmdest);
+
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               free(cmdest->vattr[i].data);
+
+               if(cmesh_has_attrib(cmsrc, i)) {
+                       cmesh_attrib(cmsrc, i); /* force validation of the actual data on the source mesh */
+
+                       nelem = cmsrc->vattr[i].nelem;
+                       cmdest->vattr[i].nelem = nelem;
+                       cmdest->vattr[i].data = varr[i];
+                       cmdest->vattr[i].count = vcount;
+                       vptr = cmsrc->vattr[i].data + vstart * nelem;
+                       memcpy(cmdest->vattr[i].data, vptr, vcount * nelem * sizeof(float));
+                       cmdest->vattr[i].data_valid = 1;
+                       cmdest->vattr[i].vbo_valid = 0;
+               } else {
+                       memset(cmdest->vattr + i, 0, sizeof cmdest->vattr[i]);
+               }
+       }
+
+       if(cmesh_indexed(cmsrc)) {
+               cmesh_index(cmsrc);     /* force validation .... */
+
+               cmdest->idata = iarr;
+               cmdest->icount = icount;
+               if(sub) {
+                       /* need to offset all vertex indices by -vstart */
+                       iptr = cmsrc->idata + istart;
+                       for(i=0; i<icount; i++) {
+                               cmdest->idata[i] = *iptr++ - vstart;
+                       }
+               } else {
+                       memcpy(cmdest->idata, cmsrc->idata + istart, icount * sizeof *cmdest->idata);
+               }
+               cmdest->idata_valid = 1;
+       } else {
+               cmdest->idata = 0;
+               cmdest->idata_valid = cmdest->ibo_valid = 0;
+       }
+
+       free(cmdest->name);
+       cmdest->name = name;
+
+       cmdest->nverts = cmsrc->nverts;
+       cmdest->nfaces = sub ? sub->nfaces : cmsrc->nfaces;
+
+       memcpy(cmdest->cur_val, cmsrc->cur_val, sizeof cmdest->cur_val);
+
+       cmdest->aabb_min = cmsrc->aabb_min;
+       cmdest->aabb_max = cmsrc->aabb_max;
+       cmdest->aabb_valid = cmsrc->aabb_valid;
+       cmdest->bsph_center = cmsrc->bsph_center;
+       cmdest->bsph_radius = cmsrc->bsph_radius;
+       cmdest->bsph_valid = cmsrc->bsph_valid;
+
+       /* copy sublist only if we're not cloning a submesh */
+       if(!sub) {
+               struct submesh *sm, *n, *head = 0, *tail = 0;
+
+               sm = cmsrc->sublist;
+               while(sm) {
+                       if(!(n = malloc(sizeof *n)) || !(name = malloc(strlen(sm->name) + 1))) {
+                               free(n);
+                               sm = sm->next;
+                               continue;
+                       }
+                       strcpy(name, sm->name);
+                       *n = *sm;
+                       n->name = name;
+                       n->next = 0;
+
+                       if(head) {
+                               tail->next = n;
+                               tail = n;
+                       } else {
+                               head = tail = n;
+                       }
+
+                       sm = sm->next;
+               }
+
+               cmdest->sublist = head;
+               cmdest->subcount = cmsrc->subcount;
+       }
+
+       return 0;
+}
+
+int cmesh_set_name(struct cmesh *cm, const char *name)
+{
+       int len = strlen(name);
+       char *tmp = malloc(len + 1);
+       if(!tmp) return -1;
+       free(cm->name);
+       cm->name = tmp;
+       memcpy(cm->name, name, len + 1);
+       return 0;
+}
+
+const char *cmesh_name(struct cmesh *cm)
+{
+       return cm->name;
+}
+
+int cmesh_has_attrib(struct cmesh *cm, int attr)
+{
+       if(attr < 0 || attr >= CMESH_NUM_ATTR) {
+               return 0;
+       }
+       return cm->vattr[attr].vbo_valid | cm->vattr[attr].data_valid;
+}
+
+int cmesh_indexed(struct cmesh *cm)
+{
+       return cm->ibo_valid | cm->idata_valid;
+}
+
+/* vdata can be 0, in which case only memory is allocated
+ * returns pointer to the attribute array
+ */
+float *cmesh_set_attrib(struct cmesh *cm, int attr, int nelem, unsigned int num,
+               const float *vdata)
+{
+       float *newarr;
+
+       if(attr < 0 || attr >= CMESH_NUM_ATTR) {
+               return 0;
+       }
+       if(cm->nverts && num != cm->nverts) {
+               return 0;
+       }
+
+       if(!(newarr = malloc(num * nelem * sizeof *newarr))) {
+               return 0;
+       }
+       if(vdata) {
+               memcpy(newarr, vdata, num * nelem * sizeof *newarr);
+       }
+
+       cm->nverts = num;
+
+       free(cm->vattr[attr].data);
+       cm->vattr[attr].data = newarr;
+       cm->vattr[attr].count = num * nelem;
+       cm->vattr[attr].nelem = nelem;
+       cm->vattr[attr].data_valid = 1;
+       cm->vattr[attr].vbo_valid = 0;
+       return newarr;
+}
+
+float *cmesh_attrib(struct cmesh *cm, int attr)
+{
+       if(attr < 0 || attr >= CMESH_NUM_ATTR) {
+               return 0;
+       }
+       cm->vattr[attr].vbo_valid = 0;
+       return (float*)cmesh_attrib_ro(cm, attr);
+}
+
+const float *cmesh_attrib_ro(struct cmesh *cm, int attr)
+{
+       void *tmp;
+       int nelem;
+
+       if(attr < 0 || attr >= CMESH_NUM_ATTR) {
+               return 0;
+       }
+
+       if(!cm->vattr[attr].data_valid) {
+#if GL_ES_VERSION_2_0
+               return 0;
+#else
+               if(!cm->vattr[attr].vbo_valid) {
+                       return 0;
+               }
+
+               /* local data copy unavailable, grab the data from the vbo */
+               nelem = cm->vattr[attr].nelem;
+               if(!(cm->vattr[attr].data = malloc(cm->nverts * nelem * sizeof(float)))) {
+                       return 0;
+               }
+               cm->vattr[attr].count = cm->nverts * nelem;
+
+               glBindBuffer(GL_ARRAY_BUFFER, cm->vattr[attr].vbo);
+               tmp = glMapBuffer(GL_ARRAY_BUFFER, GL_READ_ONLY);
+               memcpy(cm->vattr[attr].data, tmp, cm->nverts * nelem * sizeof(float));
+               glUnmapBuffer(GL_ARRAY_BUFFER);
+
+               cm->vattr[attr].data_valid = 1;
+#endif
+       }
+       return cm->vattr[attr].data;
+}
+
+float *cmesh_attrib_at(struct cmesh *cm, int attr, int idx)
+{
+       float *vptr = cmesh_attrib(cm, attr);
+       return vptr ? vptr + idx * cm->vattr[attr].nelem : 0;
+}
+
+const float *cmesh_attrib_at_ro(struct cmesh *cm, int attr, int idx)
+{
+       const float *vptr = cmesh_attrib_ro(cm, attr);
+       return vptr ? vptr + idx * cm->vattr[attr].nelem : 0;
+}
+
+int cmesh_attrib_count(struct cmesh *cm, int attr)
+{
+       return cmesh_has_attrib(cm, attr) ? cm->nverts : 0;
+}
+
+int cmesh_push_attrib(struct cmesh *cm, int attr, float *v)
+{
+       float *vptr;
+       int i, cursz, newsz;
+
+       if(!cm->vattr[attr].nelem) {
+               cm->vattr[attr].nelem = def_nelem[attr];
+       }
+
+       cursz = cm->vattr[attr].count;
+       newsz = cursz + cm->vattr[attr].nelem;
+       if(!(vptr = realloc(cm->vattr[attr].data, newsz * sizeof(float)))) {
+               return -1;
+       }
+       cm->vattr[attr].data = vptr;
+       cm->vattr[attr].count = newsz;
+       vptr += cursz;
+
+       for(i=0; i<cm->vattr[attr].nelem; i++) {
+               *vptr++ = *v++;
+       }
+       cm->vattr[attr].data_valid = 1;
+       cm->vattr[attr].vbo_valid = 0;
+
+       if(attr == CMESH_ATTR_VERTEX) {
+               cm->nverts = newsz / cm->vattr[attr].nelem;
+       }
+       return 0;
+}
+
+int cmesh_push_attrib1f(struct cmesh *cm, int attr, float x)
+{
+       float v[4];
+       v[0] = x;
+       v[1] = v[2] = 0.0f;
+       v[3] = 1.0f;
+       return cmesh_push_attrib(cm, attr, v);
+}
+
+int cmesh_push_attrib2f(struct cmesh *cm, int attr, float x, float y)
+{
+       float v[4];
+       v[0] = x;
+       v[1] = y;
+       v[2] = 0.0f;
+       v[3] = 1.0f;
+       return cmesh_push_attrib(cm, attr, v);
+}
+
+int cmesh_push_attrib3f(struct cmesh *cm, int attr, float x, float y, float z)
+{
+       float v[4];
+       v[0] = x;
+       v[1] = y;
+       v[2] = z;
+       v[3] = 1.0f;
+       return cmesh_push_attrib(cm, attr, v);
+}
+
+int cmesh_push_attrib4f(struct cmesh *cm, int attr, float x, float y, float z, float w)
+{
+       float v[4];
+       v[0] = x;
+       v[1] = y;
+       v[2] = z;
+       v[3] = w;
+       return cmesh_push_attrib(cm, attr, v);
+}
+
+/* indices can be 0, in which case only memory is allocated
+ * returns pointer to the index array
+ */
+unsigned int *cmesh_set_index(struct cmesh *cm, int num, const unsigned int *indices)
+{
+       unsigned int *tmp;
+       int nidx = cm->nfaces * 3;
+
+       if(nidx && num != nidx) {
+               return 0;
+       }
+
+       if(!(tmp = malloc(num * sizeof *tmp))) {
+               return 0;
+       }
+       if(indices) {
+               memcpy(tmp, indices, num * sizeof *tmp);
+       }
+
+       free(cm->idata);
+       cm->idata = tmp;
+       cm->icount = num;
+       cm->idata_valid = 1;
+       cm->ibo_valid = 0;
+       return tmp;
+}
+
+unsigned int *cmesh_index(struct cmesh *cm)
+{
+       cm->ibo_valid = 0;
+       return (unsigned int*)cmesh_index_ro(cm);
+}
+
+const unsigned int *cmesh_index_ro(struct cmesh *cm)
+{
+       int nidx;
+       unsigned int *tmp;
+
+       if(!cm->idata_valid) {
+#if GL_ES_VERSION_2_0
+               return 0;
+#else
+               if(!cm->ibo_valid) {
+                       return 0;
+               }
+
+               /* local copy is unavailable, grab the data from the ibo */
+               nidx = cm->nfaces * 3;
+               if(!(tmp = malloc(nidx * sizeof *cm->idata))) {
+                       return 0;
+               }
+               free(cm->idata);
+               cm->idata = tmp;
+               cm->icount = nidx;
+
+               glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, cm->ibo);
+               tmp = glMapBuffer(GL_ELEMENT_ARRAY_BUFFER, GL_READ_ONLY);
+               memcpy(cm->idata, tmp, nidx * sizeof *cm->idata);
+               glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER);
+
+               cm->idata_valid = 1;
+#endif
+       }
+       return cm->idata;
+}
+
+int cmesh_index_count(struct cmesh *cm)
+{
+       return cm->nfaces * 3;
+}
+
+int cmesh_push_index(struct cmesh *cm, unsigned int idx)
+{
+       unsigned int *iptr;
+       unsigned int cur_sz = cm->icount;
+       if(!(iptr = realloc(cm->idata, (cur_sz + 1) * sizeof *iptr))) {
+               return -1;
+       }
+       iptr[cur_sz] = idx;
+       cm->idata = iptr;
+       cm->icount = cur_sz + 1;
+       cm->idata_valid = 1;
+       cm->ibo_valid = 0;
+
+       cm->nfaces = cm->icount / 3;
+       return 0;
+}
+
+int cmesh_poly_count(struct cmesh *cm)
+{
+       if(cm->nfaces) {
+               return cm->nfaces;
+       }
+       if(cm->nverts) {
+               return cm->nverts / 3;
+       }
+       return 0;
+}
+
+/* attr can be -1 to invalidate all attributes */
+void cmesh_invalidate_vbo(struct cmesh *cm, int attr)
+{
+       int i;
+
+       if(attr >= CMESH_NUM_ATTR) {
+               return;
+       }
+
+       if(attr < 0) {
+               for(i=0; i<CMESH_NUM_ATTR; i++) {
+                       cm->vattr[i].vbo_valid = 0;
+               }
+       } else {
+               cm->vattr[attr].vbo_valid = 0;
+       }
+}
+
+void cmesh_invalidate_index(struct cmesh *cm)
+{
+       cm->ibo_valid = 0;
+}
+
+int cmesh_append(struct cmesh *cmdest, struct cmesh *cmsrc)
+{
+       int i, nelem, newsz, origsz, srcsz;
+       float *vptr;
+       unsigned int *iptr;
+       unsigned int idxoffs;
+
+       if(!cmdest->nverts) {
+               return cmesh_clone(cmdest, cmsrc);
+       }
+
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               if(cmesh_has_attrib(cmdest, i) && cmesh_has_attrib(cmsrc, i)) {
+                       /* force validation of the data arrays */
+                       cmesh_attrib(cmdest, i);
+                       cmesh_attrib_ro(cmsrc, i);
+
+                       assert(cmdest->vattr[i].nelem == cmsrc->vattr[i].nelem);
+                       nelem = cmdest->vattr[i].nelem;
+                       origsz = cmdest->nverts * nelem;
+                       newsz = cmdest->nverts + cmsrc->nverts * nelem;
+
+                       if(!(vptr = realloc(cmdest->vattr[i].data, newsz * sizeof *vptr))) {
+                               return -1;
+                       }
+                       memcpy(vptr + origsz, cmsrc->vattr[i].data, cmsrc->nverts * nelem * sizeof(float));
+                       cmdest->vattr[i].data = vptr;
+                       cmdest->vattr[i].count = newsz;
+               }
+       }
+
+       if(cmesh_indexed(cmdest)) {
+               assert(cmesh_indexed(cmsrc));
+               /* force validation ... */
+               cmesh_index(cmdest);
+               cmesh_index_ro(cmsrc);
+
+               idxoffs = cmdest->nverts;
+               origsz = cmdest->icount;
+               srcsz = cmsrc->icount;
+               newsz = origsz + srcsz;
+
+               if(!(iptr = realloc(cmdest->idata, newsz * sizeof *iptr))) {
+                       return -1;
+               }
+               cmdest->idata = iptr;
+               cmdest->icount = newsz;
+
+               /* copy and fixup all the new indices */
+               iptr += origsz;
+               for(i=0; i<srcsz; i++) {
+                       *iptr++ = cmsrc->idata[i] + idxoffs;
+               }
+       }
+
+       cmdest->wire_ibo_valid = 0;
+       cmdest->aabb_valid = 0;
+       cmdest->bsph_valid = 0;
+       return 0;
+}
+
+void cmesh_clear_submeshes(struct cmesh *cm)
+{
+       struct submesh *sm;
+
+       while(cm->sublist) {
+               sm = cm->sublist;
+               cm->sublist = cm->sublist->next;
+               free(sm->name);
+               free(sm);
+       }
+       cm->subcount = 0;
+}
+
+int cmesh_submesh(struct cmesh *cm, const char *name, int fstart, int fcount)
+{
+       int i;
+       unsigned int minv = UINT_MAX, maxv = 0;
+       unsigned int *iptr;
+       struct submesh *sm;
+
+       if(fstart < 0 || fcount < 1 || fstart + fcount > cm->nfaces) {
+               return -1;
+       }
+
+       if(!(sm = malloc(sizeof *sm)) || !(sm->name = malloc(strlen(name) + 1))) {
+               free(sm);
+               return -1;
+       }
+       strcpy(sm->name, name);
+       sm->nfaces = fcount;
+
+       if(cmesh_indexed(cm)) {
+               sm->istart = fstart * 3;
+               sm->icount = fcount * 3;
+
+               /* find out which vertices are used by this submesh */
+               iptr = cm->idata + sm->istart;
+               for(i=0; i<sm->icount; i++) {
+                       unsigned int vidx = *iptr++;
+                       if(vidx < minv) minv = vidx;
+                       if(vidx > maxv) maxv = vidx;
+               }
+               sm->vstart = minv;
+               sm->vcount = maxv - minv + 1;
+       } else {
+               sm->istart = sm->icount = 0;
+               sm->vstart = fstart * 3;
+               sm->vcount = fcount * 3;
+       }
+
+       sm->next = cm->sublist;
+       cm->sublist = sm;
+       cm->subcount++;
+       return 0;
+}
+
+int cmesh_remove_submesh(struct cmesh *cm, int idx)
+{
+       struct submesh dummy;
+       struct submesh *prev, *sm;
+
+       if(idx >= cm->subcount) {
+               return -1;
+       }
+
+       dummy.next = cm->sublist;
+       prev = &dummy;
+
+       while(prev->next && idx-- > 0) {
+               prev = prev->next;
+       }
+
+       if(!(sm = prev->next)) return -1;
+
+       prev->next = sm->next;
+       free(sm->name);
+       free(sm);
+
+       cm->subcount--;
+       assert(cm->subcount >= 0);
+
+       cm->sublist = dummy.next;
+       return 0;
+}
+
+int cmesh_find_submesh(struct cmesh *cm, const char *name)
+{
+       int idx = 0;
+       struct submesh *sm = cm->sublist;
+       while(sm) {
+               if(strcmp(sm->name, name) == 0) {
+                       assert(idx <= cm->subcount);
+                       return idx;
+               }
+               idx++;
+               sm = sm->next;
+       }
+       return -1;
+}
+
+int cmesh_submesh_count(struct cmesh *cm)
+{
+       return cm->subcount;
+}
+
+static struct submesh *get_submesh(struct cmesh *m, int idx)
+{
+       struct submesh *sm = m->sublist;
+       while(sm && --idx >= 0) {
+               sm = sm->next;
+       }
+       return sm;
+}
+
+int cmesh_clone_submesh(struct cmesh *cmdest, struct cmesh *cm, int subidx)
+{
+       struct submesh *sub;
+
+       if(!(sub = get_submesh(cm, subidx))) {
+               return -1;
+       }
+       return clone(cmdest, cm, sub);
+}
+
+
+/* assemble a complete vertex by adding all the useful attributes */
+int cmesh_vertex(struct cmesh *cm, float x, float y, float z)
+{
+       int i, j;
+
+       cgm_wcons(cm->cur_val + CMESH_ATTR_VERTEX, x, y, z, 1.0f);
+       cm->vattr[CMESH_ATTR_VERTEX].data_valid = 1;
+       cm->vattr[CMESH_ATTR_VERTEX].nelem = 3;
+
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               if(cm->vattr[i].data_valid) {
+                       int newsz = cm->vattr[i].count + cm->vattr[i].nelem;
+                       float *tmp = realloc(cm->vattr[i].data, newsz * sizeof *tmp);
+                       if(!tmp) return -1;
+                       tmp += cm->vattr[i].count;
+
+                       cm->vattr[i].data = tmp;
+                       cm->vattr[i].count = newsz;
+
+                       for(j=0; j<cm->vattr[i].nelem; j++) {
+                               *tmp++ = *(&cm->cur_val[i].x + j);
+                       }
+               }
+               cm->vattr[i].vbo_valid = 0;
+               cm->vattr[i].data_valid = 1;
+       }
+
+       if(cm->idata_valid) {
+               free(cm->idata);
+               cm->idata = 0;
+               cm->icount = 0;
+       }
+       cm->ibo_valid = cm->idata_valid = 0;
+       return 0;
+}
+
+void cmesh_normal(struct cmesh *cm, float nx, float ny, float nz)
+{
+       cgm_wcons(cm->cur_val + CMESH_ATTR_NORMAL, nx, ny, nz, 1.0f);
+       cm->vattr[CMESH_ATTR_NORMAL].nelem = 3;
+}
+
+void cmesh_tangent(struct cmesh *cm, float tx, float ty, float tz)
+{
+       cgm_wcons(cm->cur_val + CMESH_ATTR_TANGENT, tx, ty, tz, 1.0f);
+       cm->vattr[CMESH_ATTR_TANGENT].nelem = 3;
+}
+
+void cmesh_texcoord(struct cmesh *cm, float u, float v, float w)
+{
+       cgm_wcons(cm->cur_val + CMESH_ATTR_TEXCOORD, u, v, w, 1.0f);
+       cm->vattr[CMESH_ATTR_TEXCOORD].nelem = 3;
+}
+
+void cmesh_boneweights(struct cmesh *cm, float w1, float w2, float w3, float w4)
+{
+       cgm_wcons(cm->cur_val + CMESH_ATTR_BONEWEIGHTS, w1, w2, w3, w4);
+       cm->vattr[CMESH_ATTR_BONEWEIGHTS].nelem = 4;
+}
+
+void cmesh_boneidx(struct cmesh *cm, int idx1, int idx2, int idx3, int idx4)
+{
+       cgm_wcons(cm->cur_val + CMESH_ATTR_BONEIDX, idx1, idx2, idx3, idx4);
+       cm->vattr[CMESH_ATTR_BONEIDX].nelem = 4;
+}
+
+static float *get_vec4(struct cmesh *cm, int attr, int idx, cgm_vec4 *res)
+{
+       int i;
+       float *sptr, *dptr;
+       cgm_wcons(res, 0, 0, 0, 1);
+       if(!(sptr = cmesh_attrib_at(cm, attr, idx))) {
+               return 0;
+       }
+       dptr = &res->x;
+
+       for(i=0; i<cm->vattr[attr].nelem; i++) {
+               *dptr++ = sptr[i];
+       }
+       return sptr;
+}
+
+static float *get_vec3(struct cmesh *cm, int attr, int idx, cgm_vec3 *res)
+{
+       int i;
+       float *sptr, *dptr;
+       cgm_vcons(res, 0, 0, 0);
+       if(!(sptr = cmesh_attrib_at(cm, attr, idx))) {
+               return 0;
+       }
+       dptr = &res->x;
+
+       for(i=0; i<cm->vattr[attr].nelem; i++) {
+               *dptr++ = sptr[i];
+       }
+       return sptr;
+}
+
+/* dir_xform can be null, in which case it's calculated from xform */
+void cmesh_apply_xform(struct cmesh *cm, float *xform, float *dir_xform)
+{
+       unsigned int i;
+       int j;
+       cgm_vec4 v;
+       cgm_vec3 n, t;
+       float *vptr;
+
+       for(i=0; i<cm->nverts; i++) {
+               if(!(vptr = get_vec4(cm, CMESH_ATTR_VERTEX, i, &v))) {
+                       return;
+               }
+               cgm_wmul_m4v4(&v, xform);
+               for(j=0; j<cm->vattr[CMESH_ATTR_VERTEX].nelem; j++) {
+                       *vptr++ = (&v.x)[j];
+               }
+
+               if(cmesh_has_attrib(cm, CMESH_ATTR_NORMAL)) {
+                       if((vptr = get_vec3(cm, CMESH_ATTR_NORMAL, i, &n))) {
+                               cgm_vmul_m3v3(&n, dir_xform);
+                               for(j=0; j<cm->vattr[CMESH_ATTR_NORMAL].nelem; j++) {
+                                       *vptr++ = (&n.x)[j];
+                               }
+                       }
+               }
+               if(cmesh_has_attrib(cm, CMESH_ATTR_TANGENT)) {
+                       if((vptr = get_vec3(cm, CMESH_ATTR_TANGENT, i, &t))) {
+                               cgm_vmul_m3v3(&t, dir_xform);
+                               for(j=0; j<cm->vattr[CMESH_ATTR_TANGENT].nelem; j++) {
+                                       *vptr++ = (&t.x)[j];
+                               }
+                       }
+               }
+       }
+}
+
+void cmesh_flip(struct cmesh *cm)
+{
+       cmesh_flip_faces(cm);
+       cmesh_flip_normals(cm);
+}
+
+void cmesh_flip_faces(struct cmesh *cm)
+{
+       int i, j, idxnum, vnum, nelem;
+       unsigned int *indices;
+       float *verts, *vptr;
+
+       if(cmesh_indexed(cm)) {
+               if(!(indices = cmesh_index(cm))) {
+                       return;
+               }
+               idxnum = cmesh_index_count(cm);
+               for(i=0; i<idxnum; i+=3) {
+                       unsigned int tmp = indices[i + 2];
+                       indices[i + 2] = indices[i + 1];
+                       indices[i + 1] = tmp;
+               }
+       } else {
+               if(!(verts = cmesh_attrib(cm, CMESH_ATTR_VERTEX))) {
+                       return;
+               }
+               vnum = cmesh_attrib_count(cm, CMESH_ATTR_VERTEX);
+               nelem = cm->vattr[CMESH_ATTR_VERTEX].nelem;
+               for(i=0; i<vnum; i+=3) {
+                       for(j=0; j<nelem; j++) {
+                               vptr = verts + (i + 1) * nelem + j;
+                               float tmp = vptr[nelem];
+                               vptr[nelem] = vptr[0];
+                               vptr[0] = tmp;
+                       }
+               }
+       }
+}
+void cmesh_flip_normals(struct cmesh *cm)
+{
+       int i, num;
+       float *nptr = cmesh_attrib(cm, CMESH_ATTR_NORMAL);
+       if(!nptr) return;
+
+       num = cm->nverts * cm->vattr[CMESH_ATTR_NORMAL].nelem;
+       for(i=0; i<num; i++) {
+               *nptr = -*nptr;
+               nptr++;
+       }
+}
+
+int cmesh_explode(struct cmesh *cm)
+{
+       int i, j, k, idxnum, nnverts;
+       unsigned int *indices;
+
+       if(!cmesh_indexed(cm)) return 0;
+
+       indices = cmesh_index(cm);
+       assert(indices);
+
+       idxnum = cmesh_index_count(cm);
+       nnverts = idxnum;
+
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               const float *srcbuf;
+               float *tmpbuf, *dstptr;
+
+               if(!cmesh_has_attrib(cm, i)) continue;
+
+               srcbuf = cmesh_attrib(cm, i);
+               if(!(tmpbuf = malloc(nnverts * cm->vattr[i].nelem * sizeof(float)))) {
+                       return -1;
+               }
+               dstptr = tmpbuf;
+
+               for(j=0; j<idxnum; j++) {
+                       unsigned int idx = indices[j];
+                       const float *srcptr = srcbuf + idx * cm->vattr[i].nelem;
+
+                       for(k=0; k<cm->vattr[i].nelem; k++) {
+                               *dstptr++ = *srcptr++;
+                       }
+               }
+
+               free(cm->vattr[i].data);
+               cm->vattr[i].data = tmpbuf;
+               cm->vattr[i].count = nnverts * cm->vattr[i].nelem;
+               cm->vattr[i].data_valid = 1;
+       }
+
+       cm->ibo_valid = 0;
+       cm->idata_valid = 0;
+       free(cm->idata);
+       cm->idata = 0;
+       cm->icount = 0;
+
+       cm->nverts = nnverts;
+       cm->nfaces = idxnum / 3;
+       return 0;
+}
+
+void cmesh_calc_face_normals(struct cmesh *cm)
+{
+       /* TODO */
+}
+
+static int pre_draw(struct cmesh *cm)
+{
+       int i, loc, cur_sdr;
+
+       glGetIntegerv(GL_CURRENT_PROGRAM, &cur_sdr);
+
+       update_buffers(cm);
+
+       if(!cm->vattr[CMESH_ATTR_VERTEX].vbo_valid) {
+               return -1;
+       }
+
+       if(cur_sdr && use_custom_sdr_attr) {
+               if(sdr_loc[CMESH_ATTR_VERTEX] == -1) {
+                       return -1;
+               }
+
+               for(i=0; i<CMESH_NUM_ATTR; i++) {
+                       loc = sdr_loc[i];
+                       if(loc >= 0 && cm->vattr[i].vbo_valid) {
+                               glBindBuffer(GL_ARRAY_BUFFER, cm->vattr[i].vbo);
+                               glVertexAttribPointer(loc, cm->vattr[i].nelem, GL_FLOAT, GL_FALSE, 0, 0);
+                               glEnableVertexAttribArray(loc);
+                       }
+               }
+       } else {
+#ifndef GL_ES_VERSION_2_0
+               glBindBuffer(GL_ARRAY_BUFFER, cm->vattr[CMESH_ATTR_VERTEX].vbo);
+               glVertexPointer(cm->vattr[CMESH_ATTR_VERTEX].nelem, GL_FLOAT, 0, 0);
+               glEnableClientState(GL_VERTEX_ARRAY);
+
+               if(cm->vattr[CMESH_ATTR_NORMAL].vbo_valid) {
+                       glBindBuffer(GL_ARRAY_BUFFER, cm->vattr[CMESH_ATTR_NORMAL].vbo);
+                       glNormalPointer(GL_FLOAT, 0, 0);
+                       glEnableClientState(GL_NORMAL_ARRAY);
+               }
+               if(cm->vattr[CMESH_ATTR_TEXCOORD].vbo_valid) {
+                       glBindBuffer(GL_ARRAY_BUFFER, cm->vattr[CMESH_ATTR_TEXCOORD].vbo);
+                       glTexCoordPointer(cm->vattr[CMESH_ATTR_TEXCOORD].nelem, GL_FLOAT, 0, 0);
+                       glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+               }
+               if(cm->vattr[CMESH_ATTR_COLOR].vbo_valid) {
+                       glBindBuffer(GL_ARRAY_BUFFER, cm->vattr[CMESH_ATTR_COLOR].vbo);
+                       glColorPointer(cm->vattr[CMESH_ATTR_COLOR].nelem, GL_FLOAT, 0, 0);
+                       glEnableClientState(GL_COLOR_ARRAY);
+               }
+               if(cm->vattr[CMESH_ATTR_TEXCOORD2].vbo_valid) {
+                       glClientActiveTexture(GL_TEXTURE1);
+                       glBindBuffer(GL_ARRAY_BUFFER, cm->vattr[CMESH_ATTR_TEXCOORD2].vbo);
+                       glTexCoordPointer(cm->vattr[CMESH_ATTR_TEXCOORD2].nelem, GL_FLOAT, 0, 0);
+                       glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+                       glClientActiveTexture(GL_TEXTURE0);
+               }
+#endif /* GL_ES_VERSION_2_0 */
+       }
+       glBindBuffer(GL_ARRAY_BUFFER, 0);
+       return cur_sdr;
+}
+
+void cmesh_draw(struct cmesh *cm)
+{
+       if(cm->ibo_valid) {
+               cmesh_draw_range(cm, 0, cm->nfaces * 3);
+       } else {
+               cmesh_draw_range(cm, 0, cm->nverts);
+       }
+}
+
+void cmesh_draw_range(struct cmesh *cm, int start, int count)
+{
+       int cur_sdr;
+
+       if((cur_sdr = pre_draw(cm)) == -1) {
+               return;
+       }
+
+       if(cm->ibo_valid) {
+               glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, cm->ibo);
+               glDrawElements(GL_TRIANGLES, count, GL_UNSIGNED_INT, (void*)(start * 4));
+               glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+       } else {
+               glDrawArrays(GL_TRIANGLES, start, count);
+       }
+
+       post_draw(cm, cur_sdr);
+}
+
+void cmesh_draw_submesh(struct cmesh *cm, int subidx)
+{
+       struct submesh *sm = cm->sublist;
+
+       while(sm && subidx-- > 0) {
+               sm = sm->next;
+       }
+       if(!sm) return;
+
+       if(sm->icount) {
+               cmesh_draw_range(cm, sm->istart, sm->icount);
+       } else {
+               cmesh_draw_range(cm, sm->vstart, sm->vcount);
+       }
+}
+
+static void post_draw(struct cmesh *cm, int cur_sdr)
+{
+       int i;
+
+       if(cur_sdr && use_custom_sdr_attr) {
+               for(i=0; i<CMESH_NUM_ATTR; i++) {
+                       int loc = sdr_loc[i];
+                       if(loc >= 0 && cm->vattr[i].vbo_valid) {
+                               glDisableVertexAttribArray(loc);
+                       }
+               }
+       } else {
+#ifndef GL_ES_VERSION_2_0
+               glDisableClientState(GL_VERTEX_ARRAY);
+               if(cm->vattr[CMESH_ATTR_NORMAL].vbo_valid) {
+                       glDisableClientState(GL_NORMAL_ARRAY);
+               }
+               if(cm->vattr[CMESH_ATTR_TEXCOORD].vbo_valid) {
+                       glDisableClientState(GL_TEXTURE_COORD_ARRAY);
+               }
+               if(cm->vattr[CMESH_ATTR_COLOR].vbo_valid) {
+                       glDisableClientState(GL_COLOR_ARRAY);
+               }
+               if(cm->vattr[CMESH_ATTR_TEXCOORD2].vbo_valid) {
+                       glClientActiveTexture(GL_TEXTURE1);
+                       glDisableClientState(GL_TEXTURE_COORD_ARRAY);
+                       glClientActiveTexture(GL_TEXTURE0);
+               }
+#endif /* GL_ES_VERSION_2_0 */
+       }
+}
+
+void cmesh_draw_wire(struct cmesh *cm, float linesz)
+{
+       int cur_sdr, nfaces;
+
+       if((cur_sdr = pre_draw(cm)) == -1) {
+               return;
+       }
+       update_wire_ibo(cm);
+
+       nfaces = cmesh_poly_count(cm);
+       glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, cm->wire_ibo);
+       glDrawElements(GL_LINES, nfaces * 6, GL_UNSIGNED_INT, 0);
+       glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+
+       post_draw(cm, cur_sdr);
+}
+
+void cmesh_draw_vertices(struct cmesh *cm, float ptsz)
+{
+       int cur_sdr;
+       if((cur_sdr = pre_draw(cm)) == -1) {
+               return;
+       }
+
+       glPushAttrib(GL_POINT_BIT);
+       glPointSize(ptsz);
+       glDrawArrays(GL_POINTS, 0, cm->nverts);
+       glPopAttrib();
+
+       post_draw(cm, cur_sdr);
+}
+
+void cmesh_draw_normals(struct cmesh *cm, float len)
+{
+#ifndef GL_ES_VERSION_2_0
+       int i, cur_sdr, vert_nelem, norm_nelem;
+       int loc = -1;
+       const float *varr, *norm;
+
+       varr = cmesh_attrib_ro(cm, CMESH_ATTR_VERTEX);
+       norm = cmesh_attrib_ro(cm, CMESH_ATTR_NORMAL);
+       if(!varr || !norm) return;
+
+       vert_nelem = cm->vattr[CMESH_ATTR_VERTEX].nelem;
+       norm_nelem = cm->vattr[CMESH_ATTR_NORMAL].nelem;
+
+       glGetIntegerv(GL_CURRENT_PROGRAM, &cur_sdr);
+       if(cur_sdr && use_custom_sdr_attr) {
+               if((loc = sdr_loc[CMESH_ATTR_VERTEX]) < 0) {
+                       return;
+               }
+       }
+
+       glBegin(GL_LINES);
+       for(i=0; i<cm->nverts; i++) {
+               float x, y, z, endx, endy, endz;
+
+               x = varr[i * vert_nelem];
+               y = varr[i * vert_nelem + 1];
+               z = varr[i * vert_nelem + 2];
+               endx = x + norm[i * norm_nelem] * len;
+               endy = y + norm[i * norm_nelem + 1] * len;
+               endz = z + norm[i * norm_nelem + 2] * len;
+
+               if(loc == -1) {
+                       glVertex3f(x, y, z);
+                       glVertex3f(endx, endy, endz);
+               } else {
+                       glVertexAttrib3f(loc, x, y, z);
+                       glVertexAttrib3f(loc, endx, endy, endz);
+               }
+       }
+       glEnd();
+#endif /* GL_ES_VERSION_2_0 */
+}
+
+void cmesh_draw_tangents(struct cmesh *cm, float len)
+{
+#ifndef GL_ES_VERSION_2_0
+       int i, cur_sdr, vert_nelem, tang_nelem;
+       int loc = -1;
+       const float *varr, *tang;
+
+       varr = cmesh_attrib_ro(cm, CMESH_ATTR_VERTEX);
+       tang = cmesh_attrib_ro(cm, CMESH_ATTR_TANGENT);
+       if(!varr || !tang) return;
+
+       vert_nelem = cm->vattr[CMESH_ATTR_VERTEX].nelem;
+       tang_nelem = cm->vattr[CMESH_ATTR_TANGENT].nelem;
+
+       glGetIntegerv(GL_CURRENT_PROGRAM, &cur_sdr);
+       if(cur_sdr && use_custom_sdr_attr) {
+               if((loc = sdr_loc[CMESH_ATTR_VERTEX]) < 0) {
+                       return;
+               }
+       }
+
+       glBegin(GL_LINES);
+       for(i=0; i<cm->nverts; i++) {
+               float x, y, z, endx, endy, endz;
+
+               x = varr[i * vert_nelem];
+               y = varr[i * vert_nelem + 1];
+               z = varr[i * vert_nelem + 2];
+               endx = x + tang[i * tang_nelem] * len;
+               endy = y + tang[i * tang_nelem + 1] * len;
+               endz = z + tang[i * tang_nelem + 2] * len;
+
+               if(loc == -1) {
+                       glVertex3f(x, y, z);
+                       glVertex3f(endx, endy, endz);
+               } else {
+                       glVertexAttrib3f(loc, x, y, z);
+                       glVertexAttrib3f(loc, endx, endy, endz);
+               }
+       }
+       glEnd();
+#endif /* GL_ES_VERSION_2_0 */
+}
+
+static void update_buffers(struct cmesh *cm)
+{
+       int i;
+
+       for(i=0; i<CMESH_NUM_ATTR; i++) {
+               if(cmesh_has_attrib(cm, i) && !cm->vattr[i].vbo_valid) {
+                       glBindBuffer(GL_ARRAY_BUFFER, cm->vattr[i].vbo);
+                       glBufferData(GL_ARRAY_BUFFER, cm->nverts * cm->vattr[i].nelem * sizeof(float),
+                                       cm->vattr[i].data, GL_STATIC_DRAW);
+                       cm->vattr[i].vbo_valid = 1;
+               }
+       }
+       glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+       if(cm->idata_valid && !cm->ibo_valid) {
+               glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, cm->ibo);
+               glBufferData(GL_ELEMENT_ARRAY_BUFFER, cm->nfaces * 3 * sizeof(unsigned int),
+                               cm->idata, GL_STATIC_DRAW);
+               cm->ibo_valid = 1;
+               glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+       }
+}
+
+static void update_wire_ibo(struct cmesh *cm)
+{
+       int i, num_faces;
+       unsigned int *wire_idxarr, *dest;
+
+       update_buffers(cm);
+
+       if(cm->wire_ibo_valid) return;
+
+       if(!cm->wire_ibo) {
+               glGenBuffers(1, &cm->wire_ibo);
+       }
+       num_faces = cmesh_poly_count(cm);
+
+       if(!(wire_idxarr = malloc(num_faces * 6 * sizeof *wire_idxarr))) {
+               return;
+       }
+       dest = wire_idxarr;
+
+       if(cm->ibo_valid) {
+               /* we're dealing with an indexed mesh */
+               const unsigned int *idxarr = cmesh_index_ro(cm);
+
+               for(i=0; i<num_faces; i++) {
+                       *dest++ = idxarr[0];
+                       *dest++ = idxarr[1];
+                       *dest++ = idxarr[1];
+                       *dest++ = idxarr[2];
+                       *dest++ = idxarr[2];
+                       *dest++ = idxarr[0];
+                       idxarr += 3;
+               }
+       } else {
+               /* not an indexed mesh */
+               for(i=0; i<num_faces; i++) {
+                       int vidx = i * 3;
+                       *dest++ = vidx;
+                       *dest++ = vidx + 1;
+                       *dest++ = vidx + 1;
+                       *dest++ = vidx + 2;
+                       *dest++ = vidx + 2;
+                       *dest++ = vidx;
+               }
+       }
+
+       glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, cm->wire_ibo);
+       glBufferData(GL_ELEMENT_ARRAY_BUFFER, num_faces * 6 * sizeof(unsigned int),
+                       wire_idxarr, GL_STATIC_DRAW);
+       free(wire_idxarr);
+       cm->wire_ibo_valid = 1;
+       glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+}
+
+static void calc_aabb(struct cmesh *cm)
+{
+       int i, j;
+
+       if(!cmesh_attrib_ro(cm, CMESH_ATTR_VERTEX)) {
+               return;
+       }
+
+       cgm_vcons(&cm->aabb_min, FLT_MAX, FLT_MAX, FLT_MAX);
+       cgm_vcons(&cm->aabb_max, -FLT_MAX, -FLT_MAX, -FLT_MAX);
+
+       for(i=0; i<cm->nverts; i++) {
+               const float *v = cmesh_attrib_at_ro(cm, CMESH_ATTR_VERTEX, i);
+               for(j=0; j<3; j++) {
+                       if(v[j] < (&cm->aabb_min.x)[j]) {
+                               (&cm->aabb_min.x)[j] = v[j];
+                       }
+                       if(v[j] > (&cm->aabb_max.x)[j]) {
+                               (&cm->aabb_max.x)[j] = v[j];
+                       }
+               }
+       }
+       cm->aabb_valid = 1;
+}
+
+void cmesh_aabbox(struct cmesh *cm, cgm_vec3 *vmin, cgm_vec3 *vmax)
+{
+       if(!cm->aabb_valid) {
+               calc_aabb(cm);
+       }
+       *vmin = cm->aabb_min;
+       *vmax = cm->aabb_max;
+}
+
+static void calc_bsph(struct cmesh *cm)
+{
+       int i;
+       float s, dist_sq;
+
+       if(!cmesh_attrib_ro(cm, CMESH_ATTR_VERTEX)) {
+               return;
+       }
+
+       cgm_vcons(&cm->bsph_center, 0, 0, 0);
+
+       /* first find the center */
+       for(i=0; i<cm->nverts; i++) {
+               const float *v = cmesh_attrib_at_ro(cm, CMESH_ATTR_VERTEX, i);
+               cm->bsph_center.x += v[0];
+               cm->bsph_center.y += v[1];
+               cm->bsph_center.z += v[2];
+       }
+       s = 1.0f / (float)cm->nverts;
+       cm->bsph_center.x *= s;
+       cm->bsph_center.y *= s;
+       cm->bsph_center.z *= s;
+
+       cm->bsph_radius = 0.0f;
+       for(i=0; i<cm->nverts; i++) {
+               const cgm_vec3 *v = (const cgm_vec3*)cmesh_attrib_at_ro(cm, CMESH_ATTR_VERTEX, i);
+               if((dist_sq = cgm_vdist_sq(v, &cm->bsph_center)) > cm->bsph_radius) {
+                       cm->bsph_radius = dist_sq;
+               }
+       }
+       cm->bsph_radius = sqrt(cm->bsph_radius);
+       cm->bsph_valid = 1;
+}
+
+float cmesh_bsphere(struct cmesh *cm, cgm_vec3 *center, float *rad)
+{
+       if(!cm->bsph_valid) {
+               calc_bsph(cm);
+       }
+       *center = cm->bsph_center;
+       *rad = cm->bsph_radius;
+       return cm->bsph_radius;
+}
+
+/* TODO */
+void cmesh_texcoord_apply_xform(struct cmesh *cm, float *xform);
+void cmesh_texcoord_gen_plane(struct cmesh *cm, cgm_vec3 *norm, cgm_vec3 *tang);
+void cmesh_texcoord_gen_box(struct cmesh *cm);
+void cmesh_texcoord_gen_cylinder(struct cmesh *cm);
+
+int cmesh_dump(struct cmesh *cm, const char *fname)
+{
+       FILE *fp = fopen(fname, "wb");
+       if(fp) {
+               int res = cmesh_dump_file(cm, fp);
+               fclose(fp);
+               return res;
+       }
+       return -1;
+}
+
+int cmesh_dump_file(struct cmesh *cm, FILE *fp)
+{
+       static const char *label[] = { "pos", "nor", "tan", "tex", "col", "bw", "bid", "tex2" };
+       static const char *elemfmt[] = { 0, " %s(%g)", " %s(%g, %g)", " %s(%g, %g, %g)", " %s(%g, %g, %g, %g)", 0 };
+       int i, j;
+
+       if(!cmesh_has_attrib(cm, CMESH_ATTR_VERTEX)) {
+               return -1;
+       }
+
+       fprintf(fp, "VERTEX ATTRIBUTES\n");
+
+       for(i=0; i<cm->nverts; i++) {
+               fprintf(fp, "%5u:", i);
+               for(j=0; j<CMESH_NUM_ATTR; j++) {
+                       if(cmesh_has_attrib(cm, j)) {
+                               const float *v = cmesh_attrib_at_ro(cm, j, i);
+                               int nelem = cm->vattr[j].nelem;
+                               fprintf(fp, elemfmt[nelem], label[j], v[0], nelem > 1 ? v[1] : 0.0f,
+                                               nelem > 2 ? v[2] : 0.0f, nelem > 3 ? v[3] : 0.0f);
+                       }
+               }
+               fputc('\n', fp);
+       }
+
+       if(cmesh_indexed(cm)) {
+               const unsigned int *idx = cmesh_index_ro(cm);
+               int numidx = cmesh_index_count(cm);
+               int numtri = numidx / 3;
+               assert(numidx % 3 == 0);
+
+               fprintf(fp, "FACES\n");
+
+               for(i=0; i<numtri; i++) {
+                       fprintf(fp, "%5d: %d %d %d\n", i, idx[0], idx[1], idx[2]);
+                       idx += 3;
+               }
+       }
+       return 0;
+}
+
+int cmesh_dump_obj(struct cmesh *cm, const char *fname)
+{
+       FILE *fp = fopen(fname, "wb");
+       if(fp) {
+               int res = cmesh_dump_obj_file(cm, fp, 0);
+               fclose(fp);
+               return res;
+       }
+       return -1;
+}
+
+#define HAS_VN 1
+#define HAS_VT 2
+
+int cmesh_dump_obj_file(struct cmesh *cm, FILE *fp, int voffs)
+{
+       static const char *fmtstr[] = {" %u", " %u//%u", " %u/%u", " %u/%u/%u"};
+       int i, j, num, nelem;
+       unsigned int aflags = 0;
+
+       if(!cmesh_has_attrib(cm, CMESH_ATTR_VERTEX)) {
+               return -1;
+       }
+
+
+       nelem = cm->vattr[CMESH_ATTR_VERTEX].nelem;
+       if((num = cm->vattr[CMESH_ATTR_VERTEX].count) != cm->nverts * nelem) {
+               fprintf(stderr, "vertex array size (%d) != nverts (%d)\n", num, cm->nverts);
+       }
+       for(i=0; i<cm->nverts; i++) {
+               const float *v = cmesh_attrib_at_ro(cm, CMESH_ATTR_VERTEX, i);
+               fprintf(fp, "v %f %f %f\n", v[0], nelem > 1 ? v[1] : 0.0f, nelem > 2 ? v[2] : 0.0f);
+       }
+
+       if(cmesh_has_attrib(cm, CMESH_ATTR_NORMAL)) {
+               aflags |= HAS_VN;
+               nelem = cm->vattr[CMESH_ATTR_NORMAL].nelem;
+               if((num = cm->vattr[CMESH_ATTR_NORMAL].count) != cm->nverts * nelem) {
+                       fprintf(stderr, "normal array size (%d) != nverts (%d)\n", num, cm->nverts);
+               }
+               for(i=0; i<cm->nverts; i++) {
+                       const float *v = cmesh_attrib_at_ro(cm, CMESH_ATTR_NORMAL, i);
+                       fprintf(fp, "vn %f %f %f\n", v[0], nelem > 1 ? v[1] : 0.0f, nelem > 2 ? v[2] : 0.0f);
+               }
+       }
+
+       if(cmesh_has_attrib(cm, CMESH_ATTR_TEXCOORD)) {
+               aflags |= HAS_VT;
+               nelem = cm->vattr[CMESH_ATTR_TEXCOORD].nelem;
+               if((num = cm->vattr[CMESH_ATTR_TEXCOORD].count) != cm->nverts * nelem) {
+                       fprintf(stderr, "texcoord array size (%d) != nverts (%d)\n", num, cm->nverts);
+               }
+               for(i=0; i<cm->nverts; i++) {
+                       const float *v = cmesh_attrib_at_ro(cm, CMESH_ATTR_TEXCOORD, i);
+                       fprintf(fp, "vt %f %f\n", v[0], nelem > 1 ? v[1] : 0.0f);
+               }
+       }
+
+       if(cmesh_indexed(cm)) {
+               const unsigned int *idxptr = cmesh_index_ro(cm);
+               int numidx = cmesh_index_count(cm);
+               int numtri = numidx / 3;
+               assert(numidx % 3 == 0);
+
+               for(i=0; i<numtri; i++) {
+                       fputc('f', fp);
+                       for(j=0; j<3; j++) {
+                               unsigned int idx = *idxptr++ + 1 + voffs;
+                               fprintf(fp, fmtstr[aflags], idx, idx, idx);
+                       }
+                       fputc('\n', fp);
+               }
+       } else {
+               int numtri = cm->nverts / 3;
+               unsigned int idx = 1 + voffs;
+               for(i=0; i<numtri; i++) {
+                       fputc('f', fp);
+                       for(j=0; j<3; j++) {
+                               fprintf(fp, fmtstr[aflags], idx, idx, idx);
+                               ++idx;
+                       }
+                       fputc('\n', fp);
+               }
+       }
+       return 0;
+}