126 lines
4.2 KiB
C
126 lines
4.2 KiB
C
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/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef IBL_CUBEMAPSH_H
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#define IBL_CUBEMAPSH_H
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#include <utils/compiler.h>
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#include <math/mat3.h>
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#include <math/vec3.h>
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#include <memory>
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#include <vector>
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namespace utils {
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class JobSystem;
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} // namespace utils
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namespace filament {
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namespace ibl {
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class Cubemap;
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/**
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* Computes spherical harmonics
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*/
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class CubemapSH {
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public:
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/**
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* Spherical Harmonics decomposition of the given cubemap
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* Optionally calculates irradiance by convolving with truncated cos.
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*/
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static std::unique_ptr<math::float3[]> computeSH(
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utils::JobSystem& js, const Cubemap& cm, size_t numBands, bool irradiance);
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/**
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* Render given spherical harmonics into a cubemap
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*/
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static void renderSH(utils::JobSystem& js, Cubemap& cm,
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const std::unique_ptr<math::float3[]>& sh, size_t numBands);
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static void windowSH(std::unique_ptr<math::float3[]>& sh, size_t numBands, float cutoff);
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/**
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* Compute spherical harmonics of the irradiance of the given cubemap.
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* The SH basis are pre-scaled for easier rendering by the shader. The resulting coefficients
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* are not spherical harmonics (as they're scalled by various factors). In particular they
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* cannot be rendered with renderSH() above. Instead use renderPreScaledSH3Bands() which
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* is exactly the code ran by our shader.
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*/
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static void preprocessSHForShader(std::unique_ptr<math::float3[]>& sh);
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/**
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* Render pre-scaled irrandiance SH
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*/
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static void renderPreScaledSH3Bands(utils::JobSystem& js, Cubemap& cm,
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const std::unique_ptr<math::float3[]>& sh);
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static constexpr size_t getShIndex(ssize_t m, size_t l) {
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return SHindex(m, l);
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}
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private:
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class float5 {
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float v[5];
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public:
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float5() = default;
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constexpr float5(float a, float b, float c, float d, float e) : v{ a, b, c, d, e } {}
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constexpr float operator[](size_t i) const { return v[i]; }
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float& operator[](size_t i) { return v[i]; }
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};
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static inline const float5 multiply(const float5 M[5], float5 x) noexcept {
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return float5{
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M[0][0] * x[0] + M[1][0] * x[1] + M[2][0] * x[2] + M[3][0] * x[3] + M[4][0] * x[4],
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M[0][1] * x[0] + M[1][1] * x[1] + M[2][1] * x[2] + M[3][1] * x[3] + M[4][1] * x[4],
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M[0][2] * x[0] + M[1][2] * x[1] + M[2][2] * x[2] + M[3][2] * x[3] + M[4][2] * x[4],
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M[0][3] * x[0] + M[1][3] * x[1] + M[2][3] * x[2] + M[3][3] * x[3] + M[4][3] * x[4],
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M[0][4] * x[0] + M[1][4] * x[1] + M[2][4] * x[2] + M[3][4] * x[3] + M[4][4] * x[4]
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};
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};
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static inline constexpr size_t SHindex(ssize_t m, size_t l) {
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return l * (l + 1) + m;
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}
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static void computeShBasis(float* SHb, size_t numBands, const math::float3& s);
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static float Kml(ssize_t m, size_t l);
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static std::vector<float> Ki(size_t numBands);
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static constexpr float computeTruncatedCosSh(size_t l);
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static float sincWindow(size_t l, float w);
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static math::float3 rotateShericalHarmonicBand1(math::float3 band1, math::mat3f const& M);
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static float5 rotateShericalHarmonicBand2(float5 const& band2, math::mat3f const& M);
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// debugging only...
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static float Legendre(ssize_t l, ssize_t m, float x);
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static float TSH(int l, int m, const math::float3& d);
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static void printShBase(std::ostream& out, int l, int m);
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};
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} // namespace ibl
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} // namespace filament
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#endif /* IBL_CUBEMAPSH_H */
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