Prevent negative eigen value

Author: mkkellogg

src/SplatMesh.js

@@ -123,7 +123,7 @@ export class SplatMesh extends THREE.Mesh {
                 float traceOver2 = 0.5 * trace;
                 float term2 = sqrt(trace * trace / 4.0 - D);
                 float eigenValue1 = traceOver2 + term2;
-                float eigenValue2 = max(traceOver2 - term2, 0.01);
+                float eigenValue2 = max(traceOver2 - term2, 0.00); // prevent negative eigen value
 
                 const float maxSplatSize = 1024.0;
                 vec2 eigenVector1 = normalize(vec2(b, eigenValue1 - a));