Merge pull request #10087 from CesiumGS/feature-id-changes

Feature ID changes from EXT_mesh_features spec updates
CesiumGS · Feb 11, 2022 · 24f04d7 · 24f04d7
2 parents bcceff1 + 6e61c1a
commit 24f04d7
Show file tree

Hide file tree

Showing 34 changed files with 893 additions and 212 deletions.
diff --git a/Apps/SampleData/models/BoxInstanced/BoxInstanced.gltf b/Apps/SampleData/models/BoxInstanced/BoxInstanced.gltf
@@ -86,20 +86,18 @@
             "TRANSLATION": 3,
             "ROTATION": 4,
             "SCALE": 5,
-            "FEATURE_ID_0": 6
+            "_FEATURE_ID_0": 6
           }
         },
         "EXT_mesh_features": {
-          "propertyTables": [
-            0,
-            1
-          ],
           "featureIds": [
             {
+              "propertyTable": 0,
               "offset": 0,
               "repeat": 1
             },
             {
+              "propertyTable": 1,
               "attribute": 0
             }
           ]

diff --git a/Apps/Sandcastle/gallery/3D Tiles Next Photogrammetry Classification.html b/Apps/Sandcastle/gallery/3D Tiles Next Photogrammetry Classification.html
@@ -101,12 +101,12 @@
           lightingModel: Cesium.LightingModel.UNLIT,
           isTranslucent: true,
           fragmentShaderText: `
-            const float WINDOW = 0.0;
-            const float SKYLIGHT = 4.0;
-            const float TOTAL_FEATURES = 12.0;
+            const int WINDOW = 0;
+            const int SKYLIGHT = 4;
+            const int TOTAL_FEATURES = 12;
             
             void fragmentMain(FragmentInput fsInput, inout czm_modelMaterial material) {
-              float featureId = fsInput.featureIds.featureId_0;
+              int featureId = fsInput.featureIds.featureId_0;
             
               if (featureId == WINDOW || featureId == SKYLIGHT) {
                 material.alpha = 0.4;
@@ -120,21 +120,21 @@
           lightingModel: Cesium.LightingModel.PBR,
           isTranslucent: true,
           fragmentShaderText: `
-            const float WINDOW = 0.0;
-            const float FRAME = 1.0;
-            const float WALL = 2.0;
-            const float ROOF = 3.0;
-            const float SKYLIGHT = 4.0;
-            const float AIR_CONDITIONER_WHITE = 5.0;
-            const float AIR_CONDITIONER_BLACK = 6.0;
-            const float AIR_CONDITIONER_TALL = 7.0;
-            const float CLOCK = 8.0;
-            const float PILLARS = 9.0;
-            const float STREET_LIGHT = 10.0;
-            const float TRAFFIC_LIGHT = 11.0;
+            const int WINDOW = 0;
+            const int FRAME = 1;
+            const int WALL = 2;
+            const int ROOF = 3;
+            const int SKYLIGHT = 4;
+            const int AIR_CONDITIONER_WHITE = 5;
+            const int AIR_CONDITIONER_BLACK = 6;
+            const int AIR_CONDITIONER_TALL = 7;
+            const int CLOCK = 8;
+            const int PILLARS = 9;
+            const int STREET_LIGHT = 10;
+            const int TRAFFIC_LIGHT = 11;
             
             void fragmentMain(FragmentInput fsInput, inout czm_modelMaterial material) {
-              float featureId = fsInput.featureIds.featureId_0;
+              int featureId = fsInput.featureIds.featureId_0;
             
               if (featureId == CLOCK) {
                 // Shiny brass
@@ -172,15 +172,15 @@
         const selectFeatureShader = new Cesium.CustomShader({
           uniforms: {
             u_selectedFeature: {
-              type: Cesium.UniformType.FLOAT,
+              type: Cesium.UniformType.INT,
               value: NOTHING_SELECTED,
             },
           },
           lightingModel: Cesium.LightingModel.PBR,
           fragmentShaderText: `
-            const float NOTHING_SELECTED = 12.0;
+            const int NOTHING_SELECTED = 12;
             void fragmentMain(FragmentInput fsInput, inout czm_modelMaterial material) {
-              float featureId = fsInput.featureIds.featureId_0;
+              int featureId = fsInput.featureIds.featureId_0;
             
               if (u_selectedFeature < NOTHING_SELECTED && featureId == u_selectedFeature) {
                 material.specular = vec3(1.00, 0.85, 0.57);
@@ -199,16 +199,16 @@
           },
           lightingModel: Cesium.LightingModel.UNLIT,
           fragmentShaderText: `
-            const float IDS0_WINDOW = 0.0;
-            const float IDS1_FACADE = 2.0;
-            const float IDS1_ROOF = 3.0;
+            const int IDS0_WINDOW = 0;
+            const int IDS1_FACADE = 2;
+            const int IDS1_ROOF = 3;
             const vec3 PURPLE = vec3(0.5, 0.0, 1.0);
             const vec3 YELLOW = vec3(1.0, 1.0, 0.0);
             const vec3 NO_TINT = vec3(1.0);
             
             void fragmentMain(FragmentInput fsInput, inout czm_modelMaterial material) {
-              float featureId0 = fsInput.featureIds.featureId_0; // fine features
-              float featureId1 = fsInput.featureIds.featureId_1; // coarse features
+              int featureId0 = fsInput.featureIds.featureId_0; // fine features
+              int featureId1 = fsInput.featureIds.featureId_1; // coarse features
             
               // use both feature ID sets to determine where the features are
               float isWindow = float(featureId0 == IDS0_WINDOW);

diff --git a/Apps/Sandcastle/gallery/3D Tiles Next S2 Globe.html b/Apps/Sandcastle/gallery/3D Tiles Next S2 Globe.html
@@ -104,10 +104,10 @@
           fragmentShaderText: `
             void fragmentMain(FragmentInput fsInput, inout czm_modelMaterial material)
             {
-              float featureId = fsInput.featureIds.featureId_0;
+              int featureId = fsInput.featureIds.featureId_0;
               // Use cartesian coordinates but scale to be roughly [-1, 1]
               vec3 positionWC = fsInput.attributes.positionWC / 6.3e6;
-              if (featureId == 60.0)
+              if (featureId == 60)
               {
                 // Something like FM synthesis to make irregularly spaced waves
                 float wave = sin(14.0 * positionWC.z - u_time);

diff --git a/CHANGES.md b/CHANGES.md
@@ -11,6 +11,7 @@
 - Added support for shadows in `ModelExperimental`. [#10077](https://github.com/CesiumGS/cesium/pull/10077)
 - Added the ability to load implicit tiling subtree files from JSON. [#10086](https://github.com/CesiumGS/cesium/pull/10086)
 - Added support for subtree metadata in tilesets with implicit tiling. [#10093](https://github.com/CesiumGS/cesium/pull/10093)
+- Updated Feature ID parsing to match changes to the EXT_mesh_features specification. [#10087](https://github.com/CesiumGS/cesium/pull/10087)
 
 ##### Fixes :wrench:
 

diff --git a/Documentation/CustomShaderGuide/README.md b/Documentation/CustomShaderGuide/README.md
@@ -265,6 +265,13 @@ This struct is dynamically generated to gather all the various feature IDs into
 a single collection, regardless of whether the value came from an attribute,
 texture or varying.
 
+Feature IDs are represented as a GLSL `int`, though in WebGL 1 this has a couple
+limitations:
+
+- Above `2^24`, values may have a loss of precision since WebGL 1 implements
+  `highp int` as a floating point value.
+- Ideally the type would be `uint` but this is not available until WebGL 2
+
 ### 3D Tiles 1.0 Batch IDs
 
 In 3D Tiles 1.0, the same concept of identifying features within a primitive
@@ -303,28 +310,29 @@ For example, suppose we had a glTF primitive with the following feature IDs:
       "EXT_mesh_gpu_instancing": {
         "attributes": {
           "TRANSLATION": 3,
-          "FEATURE_ID_0": 4
+          "_FEATURE_ID_0": 4
         }
       },
       "EXT_mesh_features": {
-        "propertyTables": [0, 1],
         "featureIds": [
           {
             // Feature ID attribute from implicit range
             //
             // Vertex Shader: vsInput.featureIds.instanceFeatureId_0
             // Fragment Shader: fsInput.featureIds.instanceFeatureId_0
+            "propertyTable": 0,
             "offset": 0,
             "repeat": 1
           },
           {
-            // Feature ID attribute. This corresponds to FEATURE_ID_0 from the
+            // Feature ID attribute. This corresponds to _FEATURE_ID_0 from the
             // instancing extension above. Note that this is
             // labeled as instanceFeatureId_1 since it is the second feature ID
             // set in the featureIds array
             //
             // Vertex Shader: vsInput.featureIds.instanceFeatureId_1
             // Fragment Shader: fsInput.featureIds.instanceFeatureId_1
+            "propertyTable": 1,
             "attribute": 0
           }
         ]
@@ -338,18 +346,18 @@ For example, suppose we had a glTF primitive with the following feature IDs:
       {
         "attributes": {
           "POSITION": 0,
-          "FEATURE_ID_0": 1,
-          "FEATURE_ID_1": 2
+          "_FEATURE_ID_0": 1,
+          "_FEATURE_ID_1": 2
         },
         "extensions": {
           "EXT_mesh_features": {
-            "propertyTables": [2, 3, 4, 5],
             "featureIds": [
               {
                 // Feature ID Texture
                 //
                 // Vertex Shader: (Not supported)
                 // Fragment Shader: fsInput.featureIds.featureId_0
+                "propertyTable": 2,
                 "index": 0,
                 "texCoord": 0,
                 "channel": 0
@@ -359,25 +367,28 @@ For example, suppose we had a glTF primitive with the following feature IDs:
                 //
                 // Vertex Shader: vsInput.featureIds.featureId_1
                 // Fragment Shader: fsInput.featureIds.featureId_1
+                "propertyTable": 3,
                 "offset": 0,
                 "repeat": 3
               },
               {
-                // Feature ID Attribute (FEATURE_ID_0). Note that this
+                // Feature ID Attribute (_FEATURE_ID_0). Note that this
                 // is labeled featureId_2 for its index in the featureIds
                 // array
                 //
                 // Vertex Shader: vsInput.featureIds.featureId_2
                 // Fragment Shader: fsInput.featureIds.featureId_2
+                "propertyTable": 4,
                 "attribute": 0
               },
               {
-                // Feature ID Attribute (FEATURE_ID_1). Note that this
+                // Feature ID Attribute (_FEATURE_ID_1). Note that this
                 // is labeled featureId_3 for its index in the featureIds
                 // array
                 //
                 // Vertex Shader: vsInput.featureIds.featureId_3
                 // Fragment Shader: fsInput.featureIds.featureId_3
+                "propertyTable": 5,
                 "attribute": 1
               }
             ]
@@ -434,7 +445,7 @@ to the `EXT_feature_metadata` extension:
                 }
               },
               {
-                // Feature ID attribute. This corresponds to FEATURE_ID_0 from the
+                // Feature ID attribute. This corresponds to _FEATURE_ID_0 from the
                 // instancing extension above. Note that this is
                 // labeled as instanceFeatureId_1 since it is the second feature ID
                 // set in the featureIds array
@@ -477,7 +488,7 @@ to the `EXT_feature_metadata` extension:
                 }
               },
               {
-                // Feature ID Attribute (FEATURE_ID_0). Note that this
+                // Feature ID Attribute (_FEATURE_ID_0). Note that this
                 // is labeled featureId_1 for its index in the featureIds
                 // array
                 //
@@ -489,7 +500,7 @@ to the `EXT_feature_metadata` extension:
                 }
               },
               {
-                // Feature ID Attribute (FEATURE_ID_1). Note that this
+                // Feature ID Attribute (_FEATURE_ID_1). Note that this
                 // is labeled featureId_2 for its index in the featureIds
                 // array
                 //

diff --git a/Source/Renderer/ShaderSource.js b/Source/Renderer/ShaderSource.js
@@ -242,8 +242,10 @@ function combineShader(shaderSource, isFragmentShader, context) {
       "\
 #ifdef GL_FRAGMENT_PRECISION_HIGH\n\
     precision highp float;\n\
+    precision highp int;\n\
 #else\n\
     precision mediump float;\n\
+    precision mediump int;\n\
     #define highp mediump\n\
 #endif\n\n";
   }