static void
subdivide(glb_data *d,
const GLfloat * v1, GLuint vi1,
const GLfloat * v2, GLuint vi2,
const GLfloat * v3, GLuint vi3,
int depth)
{
int i;
if (depth == 0) {
save_triangle(d, vi1, vi2, vi3);
} else {
GLuint vi12, vi23, vi31;
GLfloat v12[3], v23[3], v31[3];
for (i = 0; i < 3; ++i) {
v12[i] = v1[i] + v2[i];
v23[i] = v2[i] + v3[i];
v31[i] = v3[i] + v1[i];
}
normalize(v12);
vi12 = save_vertex(d, v12);
normalize(v23);
vi23 = save_vertex(d, v23);
normalize(v31);
vi31 = save_vertex(d, v31);
subdivide(d, v1, vi1, v12, vi12, v31, vi31, depth - 1);
subdivide(d, v2, vi2, v23, vi23, v12, vi12, depth - 1);
subdivide(d, v3, vi3, v31, vi31, v23, vi23, depth - 1);
subdivide(d, v12, vi12, v23, vi23, v31, vi31, depth - 1);
}
}
/* Public interface: Create the sphere. */
glb_data *
glb_sphere_init(void)
{
glb_data *d = (glb_data *) calloc (1, sizeof (*d));
int i;
for (i = 0; i < 20; ++i) {
subdivide(d, vdata[tindices[i][0]], save_vertex(d, vdata[tindices[i][0]]),
vdata[tindices[i][1]], save_vertex(d, vdata[tindices[i][1]]),
vdata[tindices[i][2]], save_vertex(d, vdata[tindices[i][2]]),
glb_config.subdivision_depth);
}
return d;
}
static void
render_tri(struct draw_stage *stage, struct prim_header *prim)
{
struct render_stage *rs = render_stage(stage);
struct cell_context *cell = rs->cell;
struct cell_prim_buffer *buf = &cell->prim_buffer;
uint i;
if (buf->num_verts + 3 > CELL_MAX_VERTS) {
cell_flush_prim_buffer(cell);
}
i = buf->num_verts;
assert(i+2 <= CELL_MAX_VERTS);
save_vertex(buf, i+0, prim->v[0]);
save_vertex(buf, i+1, prim->v[1]);
save_vertex(buf, i+2, prim->v[2]);
buf->num_verts += 3;
}
