Add scene.minimumDisableDepthTestDistance.

Source/Renderer/AutomaticUniforms.js

@@ -1494,11 +1494,19 @@ define([
          * @glslUniform
          */
         czm_geometricToleranceOverMeter : new AutomaticUniform({
-            size: 1,
-            datatype: WebGLConstants.FLOAT,
-            getValue: function(uniformState) {
+            size : 1,
+            datatype : WebGLConstants.FLOAT,
+            getValue : function(uniformState) {
                 return uniformState.geometricToleranceOverMeter;
             }
+        }),
+
+        czm_minimumDisableDepthTestDistance : new AutomaticUniform({
+            size : 1,
+            datatype : WebGLConstants.FLOAT,
+            getValue : function(uniformState) {
+                return uniformState.minimumDisableDepthTestDistance;
+            }
         })
     };
 

Source/Renderer/UniformState.js

@@ -153,6 +153,8 @@ define([
         this._imagerySplitPosition = 0.0;
         this._pixelSizePerMeter = undefined;
         this._geometricToleranceOverMeter = undefined;
+
+        this._minimumDisableDepthTestDistance = undefined;
     }
 
     defineProperties(UniformState.prototype, {
@@ -789,6 +791,12 @@ define([
             get : function() {
                 return this._imagerySplitPosition;
             }
+        },
+
+        minimumDisableDepthTestDistance : {
+            get : function() {
+                return this._minimumDisableDepthTestDistance;
+            }
         }
     });
 
@@ -963,6 +971,11 @@ define([
         }
 
         this._geometricToleranceOverMeter = pixelSizePerMeter * frameState.maximumScreenSpaceError;
+
+        this._minimumDisableDepthTestDistance = frameState.minimumDisableDepthTestDistance;
+        if (this._minimumDisableDepthTestDistance === Number.POSITIVE_INFINITY) {
+            this._minimumDisableDepthTestDistance = -1.0;
+        }
     };
 
     function cleanViewport(uniformState) {

Source/Scene/BillboardCollection.js

@@ -1494,6 +1494,8 @@ define([
             }
         }
 
+        this._shaderDisableDepthDistance = frameState.minimumDisableDepthTestDistance !== 0.0;
+
         if (blendOptionChanged ||
             (this._shaderRotation !== this._compiledShaderRotation) ||
             (this._shaderAlignedAxis !== this._compiledShaderAlignedAxis) ||

Source/Scene/FrameState.js

@@ -249,6 +249,8 @@ define([
          * @default []
          */
         this.frustumSplits = [];
+
+        this.minimumDisableDepthTestDistance = undefined;
     }
 
     /**

Source/Scene/PointPrimitiveCollection.js

@@ -896,6 +896,8 @@ define([
             }
         }
 
+        this._shaderDisableDepthDistance = frameState.minimumDisableDepthTestDistance !== 0.0;
+
         if (blendOptionChanged ||
             (this._shaderScaleByDistance && !this._compiledShaderScaleByDistance) ||
             (this._shaderTranslucencyByDistance && !this._compiledShaderTranslucencyByDistance) ||

Source/Scene/Scene.js

@@ -321,6 +321,8 @@ define([
         this._cameraStartFired = false;
         this._cameraMovedTime = undefined;
 
+        this._minimumDisableDepthTestDistance = 0.0;
+
         /**
          * Exceptions occurring in <code>render</code> are always caught in order to raise the
          * <code>renderError</code> event.  If this property is true, the error is rethrown
@@ -1141,10 +1143,23 @@ define([
             get: function() {
                 return this._frameState.imagerySplitPosition;
             },
-
             set: function(value) {
                 this._frameState.imagerySplitPosition = value;
             }
+        },
+
+        minimumDisableDepthTestDistance : {
+            get : function() {
+                return this._minimumDisableDepthTestDistance;
+            },
+            set : function(value) {
+                //>>includeStart('debug', pragmas.debug);
+                if (!defined(value) || value < 0.0) {
+                    throw new DeveloperError('minimumDisableDepthTestDistance must be greater than or equal to 0.0.');
+                }
+                //>>includeEnd('debug');
+                this._minimumDisableDepthTestDistance = value;
+            }
         }
     });
 
@@ -1257,6 +1272,7 @@ define([
         frameState.cullingVolume = camera.frustum.computeCullingVolume(camera.positionWC, camera.directionWC, camera.upWC);
         frameState.occluder = getOccluder(scene);
         frameState.terrainExaggeration = scene._terrainExaggeration;
+        frameState.minimumDisableDepthTestDistance = scene._minimumDisableDepthTestDistance;
         if (defined(scene.globe)) {
             frameState.maximumScreenSpaceError = scene.globe.maximumScreenSpaceError;
         } else {

Source/Shaders/BillboardCollectionVS.glsl

@@ -260,6 +260,10 @@ void main()
 
 #ifdef DISABLE_DEPTH_DISTANCE
     float disableDepthTestDistance = distanceDisplayConditionAndDisableDepth.z;
+    if (disableDepthTestDistance == 0.0 && czm_minimumDisableDepthTestDistance != 0.0) {
+        disableDepthTestDistance = czm_minimumDisableDepthTestDistance;
+    }
+
     if (disableDepthTestDistance != 0.0) {
         gl_Position.z = min(gl_Position.z, gl_Position.w);
 

Source/Shaders/PointPrimitiveCollectionVS.glsl

@@ -153,6 +153,10 @@ void main()
 
 #ifdef DISABLE_DEPTH_DISTANCE
     float disableDepthTestDistance = distanceDisplayConditionAndDisableDepth.z;
+    if (disableDepthTestDistance == 0.0 && czm_minimumDisableDepthTestDistance != 0.0) {
+        disableDepthTestDistance = czm_minimumDisableDepthTestDistance;
+    }
+
     if (disableDepthTestDistance != 0.0) {
         gl_Position.z = min(gl_Position.z, gl_Position.w);