+ /* clipping */
+ if(st->opt & G3D_CLIP_FRUSTUM) {
+ for(i=0; i<6; i++) {
+ memcpy(tmpv, v, vnum * sizeof *v);
+
+ if(clip_frustum(v, &vnum, tmpv, vnum, i) < 0) {
+ /* polygon completely outside of view volume. discard */
+ vnum = 0;
+ break;
+ }
+ }
+
+ if(!vnum) continue;
+ }
+
+ for(i=0; i<vnum; i++) {
+ if(v[i].w != 0.0f) {
+ v[i].x /= v[i].w;
+ v[i].y /= v[i].w;
+ /*v[i].z /= v[i].w;*/
+ }
+
+ /* viewport transformation */
+ v[i].x = (v[i].x * 0.5f + 0.5f) * (float)st->vport[2] + st->vport[0];
+ v[i].y = (0.5f - v[i].y * 0.5f) * (float)st->vport[3] + st->vport[1];
+
+ /* convert pos to 24.8 fixed point */
+ pv[i].x = cround64(v[i].x * 256.0f);
+ pv[i].y = cround64(v[i].y * 256.0f);
+ /* convert tex coords to 16.16 fixed point */
+ pv[i].u = cround64(v[i].u * 65536.0f);
+ pv[i].v = cround64(v[i].v * 65536.0f);
+ /* pass the color through as is */
+ pv[i].r = v[i].r;
+ pv[i].g = v[i].g;
+ pv[i].b = v[i].b;
+ pv[i].a = v[i].a;
+ }
+
+ /* backface culling */
+ if(vnum > 2 && st->opt & G3D_CULL_FACE) {
+ int32_t ax = pv[1].x - pv[0].x;
+ int32_t ay = pv[1].y - pv[0].y;
+ int32_t bx = pv[2].x - pv[0].x;
+ int32_t by = pv[2].y - pv[0].y;
+ int32_t cross_z = (ax >> 4) * (by >> 4) - (ay >> 4) * (bx >> 4);
+ int sign = (cross_z >> 31) & 1;
+
+ if(!(sign ^ st->frontface)) {
+ continue; /* back-facing */
+ }
+ }
+
+ switch(vnum) {
+ case 1:
+ if(st->opt & G3D_BLEND) {
+ int r, g, b;
+ int inv_alpha = 255 - pv[0].a;
+ uint16_t *dest = st->pixels + (pv[0].y >> 8) * st->width + (pv[0].x >> 8);
+ r = ((int)pv[0].r * pv[0].a + UNPACK_R16(*dest) * inv_alpha) >> 8;
+ g = ((int)pv[0].g * pv[0].a + UNPACK_G16(*dest) * inv_alpha) >> 8;
+ b = ((int)pv[0].b * pv[0].a + UNPACK_B16(*dest) * inv_alpha) >> 8;
+ *dest++ = PACK_RGB16(r, g, b);
+ } else {
+ uint16_t *dest = st->pixels + (pv[0].y >> 8) * st->width + (pv[0].x >> 8);
+ *dest = PACK_RGB16(pv[0].r, pv[0].g, pv[0].b);
+ }
+ break;
+
+ case 2:
+ /* TODO: draw line */
+ break;
+
+ default:
+ polyfill(st->fill_mode, pv, vnum);
+ }
+ }
+}
+
+void g3d_begin(int prim)
+{
+ st->imm_prim = prim;
+ st->imm_pcount = prim;
+ st->imm_numv = 0;
+}
+
+void g3d_end(void)
+{
+ imm_flush();
+}
+
+static void imm_flush(void)
+{
+ int numv = st->imm_numv;
+ st->imm_numv = 0;
+ g3d_draw_indexed(st->imm_prim, st->imm_vbuf, numv, 0, 0);
+}