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Validating Spherical Projection Calculations in SmartTube

This test suite validates the Projection class functionality in ExoPlayer’s spherical video rendering system, focusing on equirectangular projection and mesh generation for 360-degree video playback.

Test Coverage Overview

The test suite provides comprehensive coverage of the Projection class’s core functionality, particularly for spherical mesh generation and argument validation.

Tests spherical mesh generation with specific radius and grid parameters
Validates vertex calculations and mesh geometry
Covers argument validation for all projection parameters
Tests boundary conditions and invalid input handling

Implementation Analysis

The testing approach employs JUnit with AndroidJUnit4 runner for Android-specific testing context. The implementation uses precise floating-point comparisons with defined epsilon values for geometric calculations.

Uses Truth assertion library for enhanced verification
Implements systematic parameter validation testing
Employs mathematical validation of 3D mesh properties

Technical Details

JUnit test framework with AndroidJUnit4 runner
Google Truth assertion library
Custom epsilon-based floating point comparison
Constant test parameters for 360-degree sphere projection
Structured test methods for mesh validation and argument checking

Best Practices Demonstrated

The test suite exemplifies robust testing practices for 3D graphics computations and parameter validation.

Clear separation of test cases for mesh generation and parameter validation
Precise floating-point comparison methodology
Comprehensive boundary testing
Well-structured test constants and helper methods
Proper exception testing patterns

yuliskov/smarttube

exoplayer-amzn-2.10.6/library/core/src/test/java/com/google/android/exoplayer2/video/spherical/ProjectionTest.java

            
/*
 * Copyright (C) 2018 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.
 */
package com.google.android.exoplayer2.video.spherical;

import static com.google.common.truth.Truth.assertThat;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;

import androidx.test.ext.junit.runners.AndroidJUnit4;
import com.google.android.exoplayer2.C;
import org.junit.Test;
import org.junit.runner.RunWith;

/** Tests for {@link Projection}. */
@RunWith(AndroidJUnit4.class)
public class ProjectionTest {
  private static final float EPSILON = .00001f;

  // Default 360 sphere.
  private static final float RADIUS = 1;
  private static final int LATITUDES = 12;
  private static final int LONGITUDES = 24;
  private static final float VERTICAL_FOV_DEGREES = 180;
  private static final float HORIZONTAL_FOV_DEGREES = 360;

  @Test
  public void testSphericalMesh() throws Exception {
    // Only the first param is important in this test.
    Projection projection =
        Projection.createEquirectangular(
            RADIUS,
            LATITUDES,
            LONGITUDES,
            VERTICAL_FOV_DEGREES,
            HORIZONTAL_FOV_DEGREES,
            C.STEREO_MODE_MONO);

    Projection.SubMesh subMesh = projection.leftMesh.getSubMesh(0);
    assertThat(subMesh.getVertexCount()).isGreaterThan(LATITUDES * LONGITUDES);

    float[] data = subMesh.vertices;
    for (int i = 0; i < data.length; ) {
      float x = data[i++];
      float y = data[i++];
      float z = data[i++];
      assertEquals(RADIUS, Math.sqrt(x * x + y * y + z * z), EPSILON);
    }
  }

  @Test
  public void testArgumentValidation() {
    checkIllegalArgumentException(0, 1, 1, 1, 1);
    checkIllegalArgumentException(1, 0, 1, 1, 1);
    checkIllegalArgumentException(1, 1, 0, 1, 1);
    checkIllegalArgumentException(1, 1, 1, 0, 1);
    checkIllegalArgumentException(1, 1, 1, 181, 1);
    checkIllegalArgumentException(1, 1, 1, 1, 0);
    checkIllegalArgumentException(1, 1, 1, 1, 361);
  }

  private void checkIllegalArgumentException(
      float radius,
      int latitudes,
      int longitudes,
      float verticalFovDegrees,
      float horizontalFovDegrees) {
    try {
      Projection.createEquirectangular(
          radius,
          latitudes,
          longitudes,
          verticalFovDegrees,
          horizontalFovDegrees,
          C.STEREO_MODE_MONO);
      fail();
    } catch (IllegalArgumentException e) {
      // Do nothing. Expected.
    }
  }
}