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/*
Copyright 2018 Google Inc. 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.
*/
#include "geometrical_acoustics/acoustic_source.h"
#include <cmath>
#include <random>
#include <vector>
#include "third_party/googletest/googletest/include/gtest/gtest.h"
#include "base/constants_and_types.h"
#include "geometrical_acoustics/test_util.h"
namespace vraudio {
namespace {
TEST(AcousticSource, GeneratedRayNonDirectionalDataTest) {
std::default_random_engine engine(0);
std::uniform_real_distribution<float> distribution(0.0f, 1.0f);
const std::array<float, kNumReverbOctaveBands> energies{
{1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f}};
AcousticSource source({0.1f, 0.2f, 0.3f}, energies, [&engine, &distribution] {
return distribution(engine);
});
AcousticRay ray = source.GenerateRay();
EXPECT_EQ(ray.type(), AcousticRay::RayType::kSpecular);
for (size_t i = 0; i < kNumReverbOctaveBands; ++i) {
EXPECT_FLOAT_EQ(ray.energies().at(i), energies.at(i));
}
EXPECT_FLOAT_EQ(ray.t_near(), 0.0f);
const float expected_origin[3] = {0.1f, 0.2f, 0.3f};
ExpectFloat3Close(ray.origin(), expected_origin);
}
TEST(AcousticSource, GeneratedRayDirectionDistributionTest) {
std::default_random_engine engine(0);
std::uniform_real_distribution<float> distribution(0.0f, 1.0f);
const std::array<float, kNumReverbOctaveBands> energies{
{1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f}};
AcousticSource source({0.0f, 0.0f, 0.0f}, energies, [&engine, &distribution] {
return distribution(engine);
});
// Check that the direction vectors on generated rays are all normalized,
// i.e., of unit lengths.
for (size_t i = 0; i < 1000; ++i) {
AcousticRay ray = source.GenerateRay();
const float direction_squared_norm =
ray.direction()[0] * ray.direction()[0] +
ray.direction()[1] * ray.direction()[1] +
ray.direction()[2] * ray.direction()[2];
EXPECT_FLOAT_EQ(direction_squared_norm, 1.0f);
}
// For a ray whose direction is uniformly distributed over a sphere:
// - The PDF of theta is sin(theta), and the CDF is (1 - cos(theta)) / 2.
// - The PDF of phi is 1 / 2 pi, and the CDF is 0.5 + phi / 2 pi.
ValidateDistribution(100000, 100, [&source]() {
AcousticRay ray = source.GenerateRay();
const float cos_theta = ray.direction()[2];
return 0.5f * (1.0f - cos_theta);
});
ValidateDistribution(100000, 100, [&source]() {
AcousticRay ray = source.GenerateRay();
const float* direction = ray.direction();
const float phi = std::atan2(direction[1], direction[0]);
return 0.5f + phi / 2.0f / static_cast<float>(M_PI);
});
}
// Similar to GeneratedRayDirectionDistributionTest, but tests on the whole
// set of rays generated by AcousticSource::GenerateStratifiedRays() that they
// are uniformly distributed.
TEST(AcousticSource, GeneratedStratifiedRaysDirectionDistributionTest) {
std::default_random_engine engine(0);
std::uniform_real_distribution<float> distribution(0.0f, 1.0f);
const std::array<float, kNumReverbOctaveBands> energies{
{1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f}};
AcousticSource source({0.0f, 0.0f, 0.0f}, energies, [&engine, &distribution] {
return distribution(engine);
});
// Check that the direction vectors on generated rays are all normalized,
// i.e., of unit lengths.
const size_t num_rays = 10000;
const size_t sqrt_num_rays = 100;
std::vector<AcousticRay> rays =
source.GenerateStratifiedRays(num_rays, sqrt_num_rays);
for (const AcousticRay& ray : rays) {
const float direction_squared_norm =
ray.direction()[0] * ray.direction()[0] +
ray.direction()[1] * ray.direction()[1] +
ray.direction()[2] * ray.direction()[2];
EXPECT_FLOAT_EQ(direction_squared_norm, 1.0f);
}
// For a ray whose direction is uniformly distributed over a sphere:
// - The PDF of theta is sin(theta), and the CDF is (1 - cos(theta)) / 2.
// - The PDF of phi is 1 / 2 pi, and the CDF is 0.5 + phi / 2 pi.
size_t ray_index = 0;
ValidateDistribution(num_rays, 100, [&rays, &ray_index]() {
const AcousticRay& ray = rays[ray_index];
++ray_index;
const float cos_theta = ray.direction()[2];
return 0.5f * (1.0f - cos_theta);
});
ray_index = 0;
ValidateDistribution(num_rays, 100, [&rays, &ray_index]() {
const AcousticRay& ray = rays[ray_index];
++ray_index;
const float* direction = ray.direction();
const float phi = std::atan2(direction[1], direction[0]);
return 0.5f + phi / kTwoPi;
});
}
} // namespace
} // namespace vraudio
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