y = vox->y + COS(vox->angle) * z - ystep * (vox->fbwidth >> 1);
for(i=0; i<vox->fbwidth; i++) {
hval = vox_height(vox, x, y) - vox->vheight;
y = vox->y + COS(vox->angle) * z - ystep * (vox->fbwidth >> 1);
for(i=0; i<vox->fbwidth; i++) {
hval = vox_height(vox, x, y) - vox->vheight;