Merge pull request #8727 from CesiumGS/log-depth-frustum-offset

Don't use enormous offset for second log depth frustum near plane.
CesiumGS · Apr 6, 2020 · 0298fa0 · 0298fa0
2 parents ffa1614 + 3ce51fd
commit 0298fa0
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Showing 3 changed files with 4 additions and 3 deletions.
diff --git a/CHANGES.md b/CHANGES.md
@@ -10,6 +10,7 @@ Change Log
 ##### Fixes :wrench:
 
 * Fixed several problems with polylines when the logarithmic depth buffer is enabled, which is the default on most systems. [#8706](https://github.com/CesiumGS/cesium/pull/8706)
+* Fixed a bug with very long view ranges requiring multiple frustums even with the logarithmic depth buffer enabled. Previously, such scenes could resolve depth incorrectly. [#8727](https://github.com/CesiumGS/cesium/pull/8727)
 
 ### 1.68.0 - 2020-04-01
 

diff --git a/Source/Scene/Scene.js b/Source/Scene/Scene.js
@@ -1608,7 +1608,7 @@ import View from './View.js';
          */
         opaqueFrustumNearOffset : {
             get : function() {
-                return this._frameState.useLogDepth ? 0.9 : 0.9999;
+                return 0.9999;
             }
         }
     });

diff --git a/Source/Shaders/Builtin/Functions/vertexLogDepth.glsl b/Source/Shaders/Builtin/Functions/vertexLogDepth.glsl
@@ -36,7 +36,7 @@ vec4 czm_updatePositionDepth(vec4 coords) {
 void czm_vertexLogDepth()
 {
 #ifdef LOG_DEPTH
-    v_depthFromNearPlusOne = 1.0 - czm_currentFrustum.x + gl_Position.w;
+    v_depthFromNearPlusOne = (gl_Position.w - czm_currentFrustum.x) + 1.0;
     gl_Position = czm_updatePositionDepth(gl_Position);
 #endif
 }
@@ -58,7 +58,7 @@ void czm_vertexLogDepth()
 void czm_vertexLogDepth(vec4 clipCoords)
 {
 #ifdef LOG_DEPTH
-    v_depthFromNearPlusOne = 1.0 - czm_currentFrustum.x + clipCoords.w;
+    v_depthFromNearPlusOne = (clipCoords.w - czm_currentFrustum.x) + 1.0;
     czm_updatePositionDepth(clipCoords);
 #endif
 }