cleanup and refactoring

raytracer/ray_tracing_gltf/shaders/gltf.glsl

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2019-2021, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-FileCopyrightText: Copyright (c) 2019-2021 NVIDIA CORPORATION
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+
+#include "host_device.h"
+
+vec3 computeDiffuse(GltfShadeMaterial mat, vec3 lightDir, vec3 normal)
+{
+  // Lambertian
+  float dotNL = max(dot(normal, lightDir), 0.0);
+  return mat.pbrBaseColorFactor.xyz * dotNL;
+}
+
+vec3 computeSpecular(GltfShadeMaterial mat, vec3 viewDir, vec3 lightDir, vec3 normal)
+{
+  // Compute specular only if not in shadow
+  const float kPi        = 3.14159265;
+  const float kShininess = 60.0;
+
+  // Specular
+  const float kEnergyConservation = (2.0 + kShininess) / (2.0 * kPi);
+  vec3        V                   = normalize(-viewDir);
+  vec3        R                   = reflect(-lightDir, normal);
+  float       specular            = kEnergyConservation * pow(max(dot(V, R), 0.0), kShininess);
+
+  return vec3(specular);
+}