Fix picking bug in fragment shader. Since we're not doing a camera-relative

depth sort, we can't do 1-bit alpha correctly. Revert to using discard in the
picking shader until we do a global camera-space z sort (if ever).

Aggregate [PointAccessor, PointAccessor, PointAccessor] as a new type,
PointAccessors3D.
Change: 137823236

tensorflow/tensorboard/components/vz_projector/data.ts

@@ -23,6 +23,7 @@ import {SpriteMetadata} from './data-provider';
 
 export type DistanceFunction = (a: number[], b: number[]) => number;
 export type PointAccessor = (index: number) => number;
+export type PointAccessors3D = [PointAccessor, PointAccessor, PointAccessor];
 
 export interface PointMetadata {
   [key: string]: number | string;

tensorflow/tensorboard/components/vz_projector/scatterPlot.ts

@@ -13,7 +13,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 ==============================================================================*/
 
-import {PointAccessor, DataSet} from './data';
+import {DataSet, PointAccessors3D} from './data';
 import {HoverContext} from './hoverContext';
 import {LabelRenderParams, RenderContext} from './renderContext';
 import {ScatterPlotVisualizer} from './scatterPlotVisualizer';
@@ -103,7 +103,7 @@ export class ScatterPlot {
   private onCameraMoveListeners: OnCameraMoveListener[] = [];
 
   // Accessors for rendering and labeling the points.
-  private pointAccessors: [PointAccessor, PointAccessor, PointAccessor];
+  private pointAccessors: PointAccessors3D;
 
   // Scaling functions for each axis.
   private xScale: d3.scale.Linear<number, number>;
@@ -718,8 +718,7 @@ export class ScatterPlot {
     this.renderer.render(this.scene, this.camera);
   }
 
-  setPointAccessors(pointAccessors:
-                        [PointAccessor, PointAccessor, PointAccessor]) {
+  setPointAccessors(pointAccessors: PointAccessors3D) {
     this.pointAccessors = pointAccessors;
   }
 

tensorflow/tensorboard/components/vz_projector/scatterPlotVisualizerSprites.ts

@@ -122,8 +122,11 @@ const FRAGMENT_SHADER_PICKING = `
     if (isImage) {
       gl_FragColor = vec4(vColor, 1);
     } else {
-      float a = float(point_in_unit_circle(gl_PointCoord));
-      gl_FragColor = vec4(vColor, a);
+      bool inside = point_in_unit_circle(gl_PointCoord);
+      if (!inside) {
+        discard;
+      }
+      gl_FragColor = vec4(vColor, 1);
     }
   }`;