From b352ca785c6e7bc2b8e4481dcb2eba07b04efc9e Mon Sep 17 00:00:00 2001
From: Jonathan Westhues <jwesthues@cq.cx>
Date: Fri, 20 Nov 2009 00:43:10 -0800
Subject: [PATCH] My call to glClear (to clear the depth buffer, to place the
 background image behind everything) seems to do bad things for whatever
 reason. So get rid of that, and instead to a glDepthRange to force that at
 the back.

[git-p4: depot-paths = "//depot/solvespace/": change = 2079]
---
 draw.cpp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/draw.cpp b/draw.cpp
index 2ec08a4..0602c99 100644
--- a/draw.cpp
+++ b/draw.cpp
@@ -479,6 +479,8 @@ void GraphicsWindow::Paint(int w, int h) {
         ForceTextWindowShown();
     }
     glClear(GL_COLOR_BUFFER_BIT); 
+    glClearDepth(1.0); 
+    glClear(GL_DEPTH_BUFFER_BIT); 
 
     if(SS.bgImage.fromFile) {
         // If a background image is loaded, then we draw it now as a texture.
@@ -508,6 +510,9 @@ void GraphicsWindow::Paint(int w, int h) {
         origin.z = (offset.ScaledBy(-1)).Dot(n);
         origin = origin.ScaleOutOfCsys(projRight, projUp, n);
 
+        // Place the background at the very back of the Z order, though, by
+        // mucking with the depth range.
+        glDepthRange(1, 1);
         glEnable(GL_TEXTURE_2D);
         glBegin(GL_QUADS);
             glTexCoord2d(0, 0);
@@ -525,11 +530,7 @@ void GraphicsWindow::Paint(int w, int h) {
         glEnd();
         glDisable(GL_TEXTURE_2D);
     }
-
-    // Now clear the depth; so the background color and image are both at
-    // the very back of everything.
-    glClearDepth(1.0); 
-    glClear(GL_DEPTH_BUFFER_BIT); 
+    glxDepthRangeOffset(0);
 
     // Nasty case when we're reloading the imported files; could be that
     // we get an error, so a dialog pops up, and a message loop starts, and