GeometryPipeline.splitLongitudeTriangles() doesn't preserve color attributes

[movestill]

When using custom geometry with color attributes assigned to vertices, the color attributes aren't copied when splitting triangles that cross the -180|180 longitude degree boundary. Specifically, the GeometryPipeline.computeTriangleAttributes() function doesn't take color as an input parameter.

My use case is drawing heat maps on the globe. For heat maps, I want a specific color assigned to each vertex. Below is sandcastle code that will throw a render error due to the color attributes not being copied when the triangle is split.

var viewer = new Cesium.Viewer('cesiumContainer', {
    selectionIndicator: false,
    infoBox: false
});

var p0 = Cesium.Cartesian3.fromDegrees(-179.0, 37.0);
var p1 = Cesium.Cartesian3.fromDegrees(179.0, 32.0);
var p2 = Cesium.Cartesian3.fromDegrees(-179.0, 33.0);

var positions = new Float64Array([
  p0.x, p0.y, p0.z,
  p1.x, p1.y, p1.z,
  p2.x, p2.y, p2.z
]);

var triColors = new Uint8Array([
    255, 0, 0, 128,
    0, 255, 0, 128,
    0, 0, 255, 128
]);

var geometry = new Cesium.Geometry({
  attributes : {
    position : new Cesium.GeometryAttribute({
      componentDatatype : Cesium.ComponentDatatype.DOUBLE,
      componentsPerAttribute : 3,
      values : positions
    }),
    color: new Cesium.GeometryAttribute({
        componentDatatype: Cesium.ComponentDatatype.UNSIGNED_BYTE,
        componentsPerAttribute: 4,
        values: triColors,
        normalize: true
    })
  },
  indices : new Uint16Array([0, 1, 2]),
  primitiveType : Cesium.PrimitiveType.TRIANGLES,
  boundingSphere : Cesium.BoundingSphere.fromVertices(positions)
});

var geometryInstance = new Cesium.GeometryInstance({
    geometry: geometry
});

var prim = new Cesium.Primitive({
    asynchronous: false,
    geometryInstances : geometryInstance,
    appearance: new Cesium.PerInstanceColorAppearance()
});
viewer.scene.primitives.add(prim);

[hpinkos]

Thanks for reporting this @movestill

Related #1894

[likangning93]

@movestill if this is something you're still working on and you don't need Columbus View or 2D, you can also set scene3DOnly to true. You'll also need to indicate Cesium.PerInstanceColorAppearance({flat : true}), since otherwise the appearance expects compressed normals.

var viewer = new Cesium.Viewer('cesiumContainer', {
    selectionIndicator: false,
    infoBox: false,
    scene3DOnly : true
});

var p0 = Cesium.Cartesian3.fromDegrees(-179.0, 37.0);
var p1 = Cesium.Cartesian3.fromDegrees(179.0, 32.0);
var p2 = Cesium.Cartesian3.fromDegrees(-179.0, 33.0);

var positions = new Float64Array([
  p0.x, p0.y, p0.z,
  p1.x, p1.y, p1.z,
  p2.x, p2.y, p2.z
]);

var triColors = new Uint8Array([
    255, 0, 0, 128,
    0, 255, 0, 128,
    0, 0, 255, 128
]);

var geometry = new Cesium.Geometry({
  attributes : {
    position : new Cesium.GeometryAttribute({
      componentDatatype : Cesium.ComponentDatatype.DOUBLE,
      componentsPerAttribute : 3,
      values : positions
    }),
    color: new Cesium.GeometryAttribute({
        componentDatatype: Cesium.ComponentDatatype.UNSIGNED_BYTE,
        componentsPerAttribute: 4,
        values: triColors,
        normalize: true
    })
  },
  indices : new Uint16Array([0, 1, 2]),
  primitiveType : Cesium.PrimitiveType.TRIANGLES,
  boundingSphere : Cesium.BoundingSphere.fromVertices(positions)
});

var geometryInstance = new Cesium.GeometryInstance({
    geometry: geometry
});

var prim = new Cesium.Primitive({
    asynchronous: false,
    geometryInstances : geometryInstance,
    appearance: new Cesium.PerInstanceColorAppearance({
        flat : true
    })
});
viewer.scene.primitives.add(prim);

I'm looking at getting this to work in 2D/CV as well though.

[movestill]

Thanks for the update. We're not currently using Cesium for the project, but we may return to it at some point. Good to know it's getting addressed!