Android: Add helper class VideoFrameDrawer that can render VideoFrames

webrtc/sdk/android/api/org/webrtc/VideoFrameDrawer.java

+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+package org.webrtc;
+
+import android.graphics.Matrix;
+import android.graphics.Point;
+
+/**
+ * Helper class to draw VideoFrames. Calls either drawer.drawOes, drawer.drawRgb, or
+ * drawer.drawYuv depending on the type of the buffer. The frame will be rendered with rotation
+ * taken into account. You can supply an additional render matrix for custom transformations.
+ */
+public class VideoFrameDrawer {
+  private static int distance(float x0, float y0, float x1, float y1) {
+    return (int) Math.round(Math.hypot(x1 - x0, y1 - y0));
+  }
+
+  // These points are used to calculate the size of the part of the frame we are rendering.
+  final static float[] srcPoints =
+      new float[] {0f /* x0 */, 0f /* y0 */, 1f /* x1 */, 0f /* y1 */, 0f /* x2 */, 1f /* y2 */};
+  private final float[] dstPoints = new float[6];
+  private final Point renderSize = new Point();
+
+  // Get the frame size after |renderMatrix| is applied.
+  private Point getTransformedSize(int frameWidth, int frameHeight, Matrix renderMatrix) {
+    if (renderMatrix == null) {
+      renderSize.x = frameWidth;
+      renderSize.y = frameHeight;
+      return renderSize;
+    }
+    // Transform the texture coordinates (in the range [0, 1]) according to |renderMatrix|.
+    renderMatrix.mapPoints(dstPoints, srcPoints);
+
+    // Multiply with the width and height to get the positions in terms of pixels.
+    for (int i = 0; i < 3; ++i) {
+      dstPoints[i * 2 + 0] *= frameWidth;
+      dstPoints[i * 2 + 1] *= frameHeight;
+    }
+
+    // Get the length of the sides of the transformed rectangle in terms of pixels.
+    renderSize.x = distance(dstPoints[0], dstPoints[1], dstPoints[2], dstPoints[3]);
+    renderSize.y = distance(dstPoints[0], dstPoints[1], dstPoints[4], dstPoints[5]);
+    return renderSize;
+  }
+
+  private final RendererCommon.YuvUploader yuvUploader = new RendererCommon.YuvUploader();
+  // This variable will only be used for checking reference equality and is used for caching I420
+  // textures.
+  private VideoFrame lastI420Frame;
+  private final Matrix renderMatrix = new Matrix();
+
+  public void drawFrame(VideoFrame frame, RendererCommon.GlDrawer drawer) {
+    drawFrame(frame, drawer, null /* additionalRenderMatrix */);
+  }
+
+  public void drawFrame(
+      VideoFrame frame, RendererCommon.GlDrawer drawer, Matrix additionalRenderMatrix) {
+    drawFrame(frame, drawer, additionalRenderMatrix, 0 /* viewportX */, 0 /* viewportY */,
+        frame.getRotatedWidth(), frame.getRotatedHeight());
+  }
+
+  public void drawFrame(VideoFrame frame, RendererCommon.GlDrawer drawer,
+      Matrix additionalRenderMatrix, int viewportX, int viewportY, int viewportWidth,
+      int viewportHeight) {
+    final int width = frame.getRotatedWidth();
+    final int height = frame.getRotatedHeight();
+
+    final Point renderSize = getTransformedSize(width, height, additionalRenderMatrix);
+
+    final boolean isTextureFrame = frame.getBuffer() instanceof VideoFrame.TextureBuffer;
+    renderMatrix.reset();
+    renderMatrix.preTranslate(0.5f, 0.5f);
+    if (!isTextureFrame) {
+      renderMatrix.preScale(1f, -1f); // I420-frames are upside down
+    }
+    renderMatrix.preRotate(frame.getRotation());
+    renderMatrix.preTranslate(-0.5f, -0.5f);
+    if (additionalRenderMatrix != null) {
+      renderMatrix.preConcat(additionalRenderMatrix);
+    }
+
+    if (isTextureFrame) {
+      lastI420Frame = null;
+      RendererCommon.drawTexture(drawer, (VideoFrame.TextureBuffer) frame.getBuffer(), renderMatrix,

[sakal, 2017/09/11 09:05:58]

Maybe we should move RendererCommon.drawTexture to this class?

[magjed_webrtc, 2017/09/11 12:45:48]

Done, I also moved YuvUploader.

+          renderSize.x, renderSize.y, viewportX, viewportY, viewportWidth, viewportHeight);
+    } else {
+      // Only upload the I420 data to textures once per frame, if we are called multiple times
+      // with the same frame.
+      if (frame != lastI420Frame) {
+        lastI420Frame = frame;
+        final VideoFrame.I420Buffer i420Buffer = frame.getBuffer().toI420();
+        yuvUploader.uploadFromBuffer(i420Buffer);
+        i420Buffer.release();
+      }
+
+      drawer.drawYuv(yuvUploader.getYuvTextures(),
+          RendererCommon.convertMatrixFromAndroidGraphicsMatrix(renderMatrix), renderSize.x,
+          renderSize.y, viewportX, viewportY, viewportWidth, viewportHeight);
+    }
+  }
+
+  public void release() {
+    yuvUploader.release();
+    lastI420Frame = null;
+  }
+}