// toDraw sets the render data needed for a single draw call.
// The data is copied into a render.Draw instance. One of the key jobs
// of this method is to put each draw request into a particular
// render bucket so that they are drawn in order once sorted.
func (sm *scene) toDraw(d render.Draw, p *pov, cam *camera, m *model, rt uint32) {
d.SetMv(sm.mv.Mult(p.mm, cam.vm)) // model-view
d.SetMvp(sm.mvp.Mult(sm.mv, cam.pm)) // model-view-projection
d.SetPm(cam.pm) // projection only.
d.SetScale(p.Scale())
d.SetTag(p.eid)
// Set the drawing order hints. Overlay trumps transparency since 2D overlay
// objects can't be sorted by distance anyways.
bucket := render.OPAQUE // used to sort the draw data. Lowest first.
switch {
case m.castShadow && rt > 0:
bucket = render.DEPTH_PASS // pre-passes first.
case cam.overlay > 0:
bucket = cam.overlay // OVERLAY draw last.
case m.alpha < 1:
bucket = render.TRANSPARENT // sort and draw after opaque.
}
depth := cam.depth && m.depth // both must be true for depth rendering.
tocam := 0.0
if depth {
tocam = p.toc
}
d.SetHints(bucket, tocam, depth, rt)
// use the shadow map texture for models that show shadows.
if m.hasShadows {
m.UseLayer(sm.shadowMap)
}
}
