From 6ef32c6dac1c7ce76e5b03fdfa1854c388f6f4aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fernando=20Garc=C3=ADa=20Li=C3=B1=C3=A1n?=
 <fernandogarcialinan@gmail.com>
Date: Mon, 30 Mar 2020 18:43:25 +0200
Subject: [PATCH] Compositor: Use depth partitioning in the low spec pipeline.

---
 Compositor/low-spec.xml | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/Compositor/low-spec.xml b/Compositor/low-spec.xml
index a4bfe5be9..8a22a859b 100644
--- a/Compositor/low-spec.xml
+++ b/Compositor/low-spec.xml
@@ -1,9 +1,27 @@
 <?xml version="1.0" encoding="utf-8"?>
 
+<!--
+    This Compositor pipeline imitates the classic forward pipeline used before
+    multi-pass rendering was introduced. It doesn't involve any FBOs and all the
+    rendering happens in two passes rendering directly to the screen.
+
+    The precision of the Z-buffer deteriorates with huge near-far spreads, so
+    two passes with different depth ranges are used to avoid Z-fighting and
+    other unpleasantness.
+-->
 <PropertyList>
   <name>low-spec</name>
-  <pass>
-    <name>display</name>
+  <pass n="0">
+    <name>far</name>
     <type>scene</type>
+    <z-near>100.0</z-near>
+  </pass>
+  <pass n="1">
+    <name>near</name>
+    <type>scene</type>
+    <cull-mask>0xfff7ff</cull-mask> <!-- Cull the sky (bit 11 off) -->
+    <!-- Only clear the depth buffer so color information isn't overwritten -->
+    <clear-mask>depth</clear-mask>
+    <z-far>100.0</z-far>
   </pass>
 </PropertyList>