Render: Add depth-only pass (temporary until pass system is rewritten).

src/graphics/render.nim

@@ -495,6 +495,13 @@ proc draw_viewport*(self: RenderManager, viewport: Viewport, rect: (int32,int32,
     #             self.draw_mesh(ob, ob.world_matrix, cd, 0)
     #     glClear(GL_DEPTH_BUFFER_BIT)
 
+    if scene.depth_pass.len != 0:
+        glColorMask(false, false, false, false)
+        for ob in scene.depth_pass:
+            if ob.visible == true:
+                self.draw_mesh(ob, ob.world_matrix, cd, 0)
+        glColorMask(true, true, true, true)
+
     # PASS 0   (opaque)
     if passes.find(0) >= 0 and scene.mesh_passes[0].len != 0:
         # Sort by distence to camera

src/types.nim

@@ -353,6 +353,7 @@ type
         children*: seq[GameObject]
         auto_updated_children*: seq[GameObject]
         mesh_passes*: seq[seq[Mesh]]
+        depth_pass*: seq[Mesh]
         bg_pass*: seq[Mesh]
         fg_pass*: seq[Mesh]
         lights*: seq[Light]