Fixed issues with merging buffers that weren't a multiple of 4. Also …

…fixed generate face normals to not crash on degenerate triangles.
CesiumGS · Jul 6, 2017 · d445114 · d445114
1 parent cb7af37
commit d445114
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Showing 3 changed files with 35 additions and 8 deletions.
diff --git a/lib/generateNormals.js b/lib/generateNormals.js
@@ -5,6 +5,7 @@ var clone = require('clone');
 var Cartesian3 = Cesium.Cartesian3;
 var GeometryPipeline = Cesium.GeometryPipeline;
 var WebGLConstants = Cesium.WebGLConstants;
+var CesiumMath = Cesium.Math;
 var defaultValue = Cesium.defaultValue;
 var defined = Cesium.defined;
 
@@ -127,8 +128,23 @@ function generateFaceNormals(gltf, primitive, positionSemantic) {
                     Cartesian3.subtract(positionTwo, positionOne, scratchNormalOne);
                     Cartesian3.subtract(positionThree, positionOne, scratchNormalTwo);
                     var normal = new Cartesian3();
-                    Cartesian3.cross(scratchNormalOne, scratchNormalTwo, normal);
-                    Cartesian3.normalize(normal, normal);
+
+                    // Check for degenerate triangles
+                    if (scratchNormalOne.equals(Cartesian3.ZERO) || scratchNormalTwo.equals(Cartesian3.ZERO)) {
+                        Cartesian3.clone(Cartesian3.UNIT_X, normal);
+                    } else {
+                        Cartesian3.normalize(scratchNormalOne, scratchNormalOne);
+                        Cartesian3.normalize(scratchNormalTwo, scratchNormalTwo);
+
+                        // Make sure normals aren't parallel
+                        var dot = Math.abs(Cartesian3.dot(scratchNormalOne, scratchNormalTwo));
+                        if (CesiumMath.equalsEpsilon(dot, 1.0, CesiumMath.EPSILON15)) {
+                            Cartesian3.clone(Cartesian3.UNIT_X, normal);
+                        } else {
+                            Cartesian3.cross(scratchNormalOne, scratchNormalTwo, normal);
+                            Cartesian3.normalize(normal, normal);
+                        }
+                    }
                     generatedNormals.push(normal);
                     generatedNormals.push(normal);
                     generatedNormals.push(normal);

diff --git a/lib/mergeBuffers.js b/lib/mergeBuffers.js
@@ -41,8 +41,19 @@ function mergeBuffers(gltf, bufferId) {
                         bufferView.buffer = bufferId;
                     }
                 }
-                buffersToMerge.push(buffer.extras._pipeline.source);
-                lengthSoFar += buffer.extras._pipeline.source.length;
+
+                var sourceBuffer = buffer.extras._pipeline.source;
+                var currentBufferLength = sourceBuffer.length;
+                if (currentBufferLength % 4)
+                {
+                    currentBufferLength += 4 - (currentBufferLength % 4);
+                    var newBuffer = Buffer.alloc(currentBufferLength);
+                    sourceBuffer.copy(newBuffer);
+                    sourceBuffer = buffer.extras._pipeline.source = newBuffer;
+                }
+
+                buffersToMerge.push(sourceBuffer);
+                lengthSoFar += currentBufferLength;
             }
         }
 
@@ -85,4 +96,4 @@ function getBufferViewsForBuffers(gltf) {
         }
     }
     return bufferViewsForBuffers;
-}
+}
diff --git a/specs/lib/mergeBuffersSpec.js b/specs/lib/mergeBuffersSpec.js
@@ -6,7 +6,7 @@ describe('mergeBuffers', function() {
     it('merges buffers', function() {
         var buffer0 = Buffer.from([1, 2]);
         var buffer1 = Buffer.from([3, 4, 5]);
-        var bufferMerged = Buffer.from([1, 2, 3, 4, 5]);
+        var bufferMerged = Buffer.from([1, 2, 0, 0, 3, 4, 5, 0]);
         var gltf = {
             "bufferViews": {
                 "bufferView_0": {
@@ -58,12 +58,12 @@ describe('mergeBuffers', function() {
                 "bufferView_1": {
                     "buffer": "mergedBuffers",
                     "byteLength": 3,
-                    "byteOffset": 2
+                    "byteOffset": 4
                 }
             },
             "buffers": {
                 "mergedBuffers": {
-                    "byteLength": 5,
+                    "byteLength": 8,
                     "type": "arraybuffer",
                     "uri": "data:,",
                     "extras": {