talk/app/webrtc/androidtests/src/org/webrtc/GlRectDrawerTest.java

/*
 * libjingle
 * Copyright 2015 Google Inc.
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 *     this list of conditions and the following disclaimer in the documentation
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 *     derived from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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package org.webrtc;

import android.test.ActivityTestCase;
import android.test.suitebuilder.annotation.SmallTest;

import java.nio.ByteBuffer;
import java.util.Random;

import android.opengl.EGL14;
import android.opengl.Matrix;
import android.opengl.GLES20;

public class GlRectDrawerTest extends ActivityTestCase {
  // Resolution of the test image.
  private static final int WIDTH = 16;
  private static final int HEIGHT = 16;
  // Seed for random pixel creation.
  private static final int SEED = 42;
  // When comparing pixels, allow some slack for float arithmetic and integer rounding.
  final float MAX_DIFF = 1.0f;

  private static float normalizedByte(byte b) {
    return (b & 0xFF) / 255.0f;
  }

  private static float saturatedConvert(float c) {
    return 255.0f * Math.max(0, Math.min(c, 1));
  }

  @SmallTest
  public void testYuvRendering() throws Exception {
    // Create EGL base with a pixel buffer as display output.
    EglBase eglBase = eglBase = new EglBase(EGL14.EGL_NO_CONTEXT, EglBase.ConfigType.PIXEL_BUFFER);
    eglBase.createPbufferSurface(WIDTH, HEIGHT);
    eglBase.makeCurrent();

    // Create YUV byte buffer planes with random content.
    final ByteBuffer[] yuvPlanes = new ByteBuffer[3];
    final Random random = new Random(SEED);
    for (int i = 0; i < 3; ++i) {
      yuvPlanes[i] = ByteBuffer.allocateDirect(WIDTH * HEIGHT);
      random.nextBytes(yuvPlanes[i].array());
    }

    // Generate 3 texture ids for Y/U/V.
    final int yuvTextures[] = new int[3];
    for (int i = 0; i < 3; i++)  {
      yuvTextures[i] = GlUtil.generateTexture(GLES20.GL_TEXTURE_2D);
    }

    // Upload the YUV byte buffer data as textures.
    for (int i = 0; i < 3; ++i) {
      GLES20.glActiveTexture(GLES20.GL_TEXTURE0 + i);
      GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, yuvTextures[i]);
      GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_LUMINANCE, WIDTH,
          HEIGHT, 0, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, yuvPlanes[i]);
    }

    // Draw the YUV frame onto the pixel buffer.
    final GlRectDrawer drawer = new GlRectDrawer();
    final float[] texMatrix = new float[16];
    Matrix.setIdentityM(texMatrix, 0);
    drawer.drawYuv(yuvTextures, texMatrix);

    // Download the pixels in the pixel buffer as RGBA.
    final ByteBuffer data = ByteBuffer.allocateDirect(WIDTH * HEIGHT * 4);
    GLES20.glReadPixels(0, 0, WIDTH, HEIGHT, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, data);

    // Compare the YUV data with the RGBA result.
    for (int y = 0; y < HEIGHT; ++y) {
      for (int x = 0; x < WIDTH; ++x) {
        // YUV color space. Y in [0, 1], UV in [-0.5, 0.5]. The constants are taken from the YUV
        // fragment shader code in GlRectDrawer.
        final float y_luma = normalizedByte(yuvPlanes[0].get());
        final float u_chroma = normalizedByte(yuvPlanes[1].get()) - 0.5f;
        final float v_chroma = normalizedByte(yuvPlanes[2].get()) - 0.5f;
        // Expected color in unrounded RGB [0.0f, 255.0f].
        final float expectedRed = saturatedConvert(y_luma + 1.403f * v_chroma);
        final float expectedGreen =
            saturatedConvert(y_luma - 0.344f * u_chroma - 0.714f * v_chroma);
        final float expectedBlue = saturatedConvert(y_luma + 1.77f * u_chroma);

        // Actual color in RGB8888.
        final int actualRed = data.get() & 0xFF;
        final int actualGreen = data.get() & 0xFF;
        final int actualBlue = data.get() & 0xFF;
        final int actualAlpha = data.get() & 0xFF;

        // Assert rendered image is close to pixel perfect from source YUV.
        assertTrue(Math.abs(actualRed - expectedRed) < MAX_DIFF);
        assertTrue(Math.abs(actualGreen - expectedGreen) < MAX_DIFF);
        assertTrue(Math.abs(actualBlue - expectedBlue) < MAX_DIFF);
        assertEquals(actualAlpha, 255);
      }
    }

    drawer.release();
    GLES20.glDeleteTextures(3, yuvTextures, 0);
    eglBase.release();
  }
}