upgrade to Filament 1.21.0

ios/include/ibl/utilities.h

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef IBL_UTILITIES_H
+#define IBL_UTILITIES_H
+
+#include <math.h>
+
+#include <math/vec2.h>
+#include <math/vec3.h>
+
+namespace filament {
+namespace ibl {
+
+template<typename T>
+static inline constexpr T sq(T x) {
+    return x * x;
+}
+
+template<typename T>
+static inline constexpr T log4(T x) {
+    // log2(x)/log2(4)
+    // log2(x)/2
+    return std::log2(x) * T(0.5);
+}
+
+inline bool isPOT(size_t x) {
+    return !(x & (x - 1));
+}
+
+inline filament::math::float2 hammersley(uint32_t i, float iN) {
+    constexpr float tof = 0.5f / 0x80000000U;
+    uint32_t bits = i;
+    bits = (bits << 16u) | (bits >> 16u);
+    bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u);
+    bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u);
+    bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u);
+    bits = ((bits & 0x00FF00FFu) << 8u) | ((bits & 0xFF00FF00u) >> 8u);
+    return { i * iN, bits * tof };
+}
+
+} // namespace ibl
+} // namespace filament
+#endif /* IBL_UTILITIES_H */