refcator: opt code (#4)

* refcator: opt code
zhuxudong · Aug 6, 2021 · f4b74a3 · f4b74a3
1 parent 441c885
commit f4b74a3
Showing 2 changed files with 208 additions and 202 deletions.
diff --git a/packages/core/src/lighting/AmbientLight.ts b/packages/core/src/lighting/AmbientLight.ts
@@ -74,7 +74,10 @@ export class AmbientLight {
     const shaderData = this._scene.shaderData;
 
     if (value) {
-      shaderData.setFloatArray(AmbientLight._diffuseSHProperty, value.convertRadianceToIrradiance(this._shArray));
+      shaderData.setFloatArray(
+        AmbientLight._diffuseSHProperty,
+        this._convertRadianceToIrradiance(value, this._shArray)
+      );
     }
   }
 
@@ -131,4 +134,67 @@ export class AmbientLight {
     shaderData.setFloat(AmbientLight._diffuseIntensityProperty, this._diffuseIntensity);
     shaderData.setFloat(AmbientLight._specularIntensityProperty, this._specularIntensity);
   }
+
+  private _convertRadianceToIrradiance(sh: SphericalHarmonics3, out: Float32Array): Float32Array {
+    /**
+     * Basis constants
+     *
+     * 0: 1/2 * Math.sqrt(1 / Math.PI)
+     *
+     * 1: -1/2 * Math.sqrt(3 / Math.PI)
+     * 2: 1/2 * Math.sqrt(3 / Math.PI)
+     * 3: -1/2 * Math.sqrt(3 / Math.PI)
+     *
+     * 4: 1/2 * Math.sqrt(15 / Math.PI)
+     * 5: -1/2 * Math.sqrt(15 / Math.PI)
+     * 6: 1/4 * Math.sqrt(5 / Math.PI)
+     * 7: -1/2 * Math.sqrt(15 / Math.PI)
+     * 8: 1/4 * Math.sqrt(15 / Math.PI)
+     */
+
+    /**
+     * Convolution kernel
+     *
+     * 0: Math.PI
+     * 1: (2 * Math.PI) / 3
+     * 2: Math.PI / 4
+     */
+
+    const src = sh.coefficients;
+
+    // l0
+    out[0] = src[0] * 0.886227; // kernel0 * basis0 = 0.886227
+    out[1] = src[1] * 0.886227;
+    out[2] = src[2] * 0.886227;
+
+    // l1
+    out[3] = src[3] * -1.023327; // kernel1 * basis1 = -1.023327;
+    out[4] = src[4] * -1.023327;
+    out[5] = src[5] * -1.023327;
+    out[6] = src[6] * 1.023327; // kernel1 * basis2 = 1.023327
+    out[7] = src[7] * 1.023327;
+    out[8] = src[8] * 1.023327;
+    out[9] = src[9] * -1.023327; // kernel1 * basis3 = -1.023327
+    out[10] = src[10] * -1.023327;
+    out[11] = src[11] * -1.023327;
+
+    // l2
+    out[12] = src[12] * 0.858086; // kernel2 * basis4 = 0.858086
+    out[13] = src[13] * 0.858086;
+    out[14] = src[14] * 0.858086;
+    out[15] = src[15] * -0.858086; // kernel2 * basis5 = -0.858086
+    out[16] = src[16] * -0.858086;
+    out[17] = src[17] * -0.858086;
+    out[18] = src[18] * 0.247708; // kernel2 * basis6 = 0.247708
+    out[19] = src[19] * 0.247708;
+    out[20] = src[20] * 0.247708;
+    out[21] = src[21] * -0.858086; // kernel2 * basis7 = -0.858086
+    out[22] = src[22] * -0.858086;
+    out[23] = src[23] * -0.858086;
+    out[24] = src[24] * 0.429042; // kernel2 * basis8 = 0.429042
+    out[25] = src[25] * 0.429042;
+    out[26] = src[26] * 0.429042;
+
+    return out;
+  }
 }