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Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/video/spherical/Projection.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/video/spherical/Projection.java | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/video/spherical/Projection.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/video/spherical/Projection.java new file mode 100644 index 0000000000..e3d614cab3 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/video/spherical/Projection.java @@ -0,0 +1,236 @@ +/* + * 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 org.mozilla.thirdparty.com.google.android.exoplayer2.video.spherical; + +import androidx.annotation.IntDef; +import org.mozilla.thirdparty.com.google.android.exoplayer2.C; +import org.mozilla.thirdparty.com.google.android.exoplayer2.C.StereoMode; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions; +import java.lang.annotation.Documented; +import java.lang.annotation.Retention; +import java.lang.annotation.RetentionPolicy; + +/** The projection mesh used with 360/VR videos. */ +public final class Projection { + + /** Enforces allowed (sub) mesh draw modes. */ + @Documented + @Retention(RetentionPolicy.SOURCE) + @IntDef({DRAW_MODE_TRIANGLES, DRAW_MODE_TRIANGLES_STRIP, DRAW_MODE_TRIANGLES_FAN}) + public @interface DrawMode {} + /** Triangle draw mode. */ + public static final int DRAW_MODE_TRIANGLES = 0; + /** Triangle strip draw mode. */ + public static final int DRAW_MODE_TRIANGLES_STRIP = 1; + /** Triangle fan draw mode. */ + public static final int DRAW_MODE_TRIANGLES_FAN = 2; + + /** Number of position coordinates per vertex. */ + public static final int TEXTURE_COORDS_PER_VERTEX = 2; + /** Number of texture coordinates per vertex. */ + public static final int POSITION_COORDS_PER_VERTEX = 3; + + /** + * Generates a complete sphere equirectangular projection. + * + * @param stereoMode A {@link C.StereoMode} value. + */ + public static Projection createEquirectangular(@C.StereoMode int stereoMode) { + return createEquirectangular( + /* radius= */ 50, // Should be large enough that there are no stereo artifacts. + /* latitudes= */ 36, // Should be large enough to prevent videos looking wavy. + /* longitudes= */ 72, // Should be large enough to prevent videos looking wavy. + /* verticalFovDegrees= */ 180, + /* horizontalFovDegrees= */ 360, + stereoMode); + } + + /** + * Generates an equirectangular projection. + * + * @param radius Size of the sphere. Must be > 0. + * @param latitudes Number of rows that make up the sphere. Must be >= 1. + * @param longitudes Number of columns that make up the sphere. Must be >= 1. + * @param verticalFovDegrees Total latitudinal degrees that are covered by the sphere. Must be in + * (0, 180]. + * @param horizontalFovDegrees Total longitudinal degrees that are covered by the sphere.Must be + * in (0, 360]. + * @param stereoMode A {@link C.StereoMode} value. + * @return an equirectangular projection. + */ + public static Projection createEquirectangular( + float radius, + int latitudes, + int longitudes, + float verticalFovDegrees, + float horizontalFovDegrees, + @C.StereoMode int stereoMode) { + Assertions.checkArgument(radius > 0); + Assertions.checkArgument(latitudes >= 1); + Assertions.checkArgument(longitudes >= 1); + Assertions.checkArgument(verticalFovDegrees > 0 && verticalFovDegrees <= 180); + Assertions.checkArgument(horizontalFovDegrees > 0 && horizontalFovDegrees <= 360); + + // Compute angular size in radians of each UV quad. + float verticalFovRads = (float) Math.toRadians(verticalFovDegrees); + float horizontalFovRads = (float) Math.toRadians(horizontalFovDegrees); + float quadHeightRads = verticalFovRads / latitudes; + float quadWidthRads = horizontalFovRads / longitudes; + + // Each latitude strip has 2 * (longitudes quads + extra edge) vertices + 2 degenerate vertices. + int vertexCount = (2 * (longitudes + 1) + 2) * latitudes; + // Buffer to return. + float[] vertexData = new float[vertexCount * POSITION_COORDS_PER_VERTEX]; + float[] textureData = new float[vertexCount * TEXTURE_COORDS_PER_VERTEX]; + + // Generate the data for the sphere which is a set of triangle strips representing each + // latitude band. + int vOffset = 0; // Offset into the vertexData array. + int tOffset = 0; // Offset into the textureData array. + // (i, j) represents a quad in the equirectangular sphere. + for (int j = 0; j < latitudes; ++j) { // For each horizontal triangle strip. + // Each latitude band lies between the two phi values. Each vertical edge on a band lies on + // a theta value. + float phiLow = quadHeightRads * j - verticalFovRads / 2; + float phiHigh = quadHeightRads * (j + 1) - verticalFovRads / 2; + + for (int i = 0; i < longitudes + 1; ++i) { // For each vertical edge in the band. + for (int k = 0; k < 2; ++k) { // For low and high points on an edge. + // For each point, determine it's position in polar coordinates. + float phi = k == 0 ? phiLow : phiHigh; + float theta = quadWidthRads * i + (float) Math.PI - horizontalFovRads / 2; + + // Set vertex position data as Cartesian coordinates. + vertexData[vOffset++] = -(float) (radius * Math.sin(theta) * Math.cos(phi)); + vertexData[vOffset++] = (float) (radius * Math.sin(phi)); + vertexData[vOffset++] = (float) (radius * Math.cos(theta) * Math.cos(phi)); + + textureData[tOffset++] = i * quadWidthRads / horizontalFovRads; + textureData[tOffset++] = (j + k) * quadHeightRads / verticalFovRads; + + // Break up the triangle strip with degenerate vertices by copying first and last points. + if ((i == 0 && k == 0) || (i == longitudes && k == 1)) { + System.arraycopy( + vertexData, + vOffset - POSITION_COORDS_PER_VERTEX, + vertexData, + vOffset, + POSITION_COORDS_PER_VERTEX); + vOffset += POSITION_COORDS_PER_VERTEX; + System.arraycopy( + textureData, + tOffset - TEXTURE_COORDS_PER_VERTEX, + textureData, + tOffset, + TEXTURE_COORDS_PER_VERTEX); + tOffset += TEXTURE_COORDS_PER_VERTEX; + } + } + // Move on to the next vertical edge in the triangle strip. + } + // Move on to the next triangle strip. + } + SubMesh subMesh = + new SubMesh(SubMesh.VIDEO_TEXTURE_ID, vertexData, textureData, DRAW_MODE_TRIANGLES_STRIP); + return new Projection(new Mesh(subMesh), stereoMode); + } + + /** The Mesh corresponding to the left eye. */ + public final Mesh leftMesh; + /** + * The Mesh corresponding to the right eye. If {@code singleMesh} is true then this mesh is + * identical to {@link #leftMesh}. + */ + public final Mesh rightMesh; + /** The stereo mode. */ + public final @StereoMode int stereoMode; + /** Whether the left and right mesh are identical. */ + public final boolean singleMesh; + + /** + * Creates a Projection with single mesh. + * + * @param mesh the Mesh for both eyes. + * @param stereoMode A {@link StereoMode} value. + */ + public Projection(Mesh mesh, int stereoMode) { + this(mesh, mesh, stereoMode); + } + + /** + * Creates a Projection with dual mesh. Use {@link #Projection(Mesh, int)} if there is single mesh + * for both eyes. + * + * @param leftMesh the Mesh corresponding to the left eye. + * @param rightMesh the Mesh corresponding to the right eye. + * @param stereoMode A {@link C.StereoMode} value. + */ + public Projection(Mesh leftMesh, Mesh rightMesh, int stereoMode) { + this.leftMesh = leftMesh; + this.rightMesh = rightMesh; + this.stereoMode = stereoMode; + this.singleMesh = leftMesh == rightMesh; + } + + /** The sub mesh associated with the {@link Mesh}. */ + public static final class SubMesh { + /** Texture ID for video frames. */ + public static final int VIDEO_TEXTURE_ID = 0; + + /** Texture ID. */ + public final int textureId; + /** The drawing mode. One of {@link DrawMode}. */ + public final @DrawMode int mode; + /** The SubMesh vertices. */ + public final float[] vertices; + /** The SubMesh texture coordinates. */ + public final float[] textureCoords; + + public SubMesh(int textureId, float[] vertices, float[] textureCoords, @DrawMode int mode) { + this.textureId = textureId; + Assertions.checkArgument( + vertices.length * (long) TEXTURE_COORDS_PER_VERTEX + == textureCoords.length * (long) POSITION_COORDS_PER_VERTEX); + this.vertices = vertices; + this.textureCoords = textureCoords; + this.mode = mode; + } + + /** Returns the SubMesh vertex count. */ + public int getVertexCount() { + return vertices.length / POSITION_COORDS_PER_VERTEX; + } + } + + /** A Mesh associated with the projection scene. */ + public static final class Mesh { + private final SubMesh[] subMeshes; + + public Mesh(SubMesh... subMeshes) { + this.subMeshes = subMeshes; + } + + /** Returns the number of sub meshes. */ + public int getSubMeshCount() { + return subMeshes.length; + } + + /** Returns the SubMesh for the given index. */ + public SubMesh getSubMesh(int index) { + return subMeshes[index]; + } + } +} |