在 Android 上的 OpenGL Sphere 上绑定视频纹理

Question

我正在尝试在 Android 上创建一个 360 度视频球体（就像用于纸板的球体）。我通过在 OpenGL ES1.0 中渲染一个球体并在其上附加纹理来完成此操作。之后我可以使用传感器值来旋转球体。

但是，我不知道如何将图片更改为视频。我已经尝试使用 texSubImage2D() 逐帧渲染，但它非常慢。我的视频可能会达到 4k 密度，因为即使只显示了一小部分，我也需要高质量的视频。

我已经阅读了一些关于如何做到这一点的理论资料（即帧缓冲区、外部纹理、同步等），但我找不到任何示例 对于这些事情，所以将非常感谢一些代码...

这是我如何渲染球体、绘制球体并在其上附加纹理（即我的球体类）...

import rapid.decoder.BitmapDecoder;
public class Sphere {


/** Buffer holding the vertices. */
private final List<FloatBuffer> mVertexBuffer = new ArrayList<FloatBuffer>();

/** The vertices for the sphere. */
private final List<float[]> mVertices = new ArrayList<float[]>();

/** Buffer holding the texture coordinates. */
private final List<FloatBuffer> mTextureBuffer = new ArrayList<FloatBuffer>();

/** Mapping texture coordinates for the vertices. */
private final List<float[]> mTexture = new ArrayList<float[]>();

/** The texture pointer. */
private final int[] mTextures = new int[1];

/** Total number of strips for the given depth. */
private final int mTotalNumStrips;

public Sphere(final int depth, final float radius) {

    // Calculate basic values for the sphere.
    this.mTotalNumStrips = Maths.power(2, depth - 1) * 5; //last 5 is related to properties of a icosahedron
    final int numVerticesPerStrip = Maths.power(2, depth) * 3;
    final double altitudeStepAngle = Maths.rad120 / Maths.power(2, depth);
    final double azimuthStepAngle = Maths.rad360 / this.mTotalNumStrips;
    double x, y, z, h, altitude, azimuth;

    Log.e("mTotalNumStrips", ""+mTotalNumStrips);
    Log.e("numVerticesPerStrip", ""+numVerticesPerStrip);

    for (int stripNum = 0; stripNum < this.mTotalNumStrips; stripNum++) {
        // Setup arrays to hold the points for this strip.
        final float[] vertices = new float[numVerticesPerStrip * 3]; // x,y,z
        final float[] texturePoints = new float[numVerticesPerStrip * 2]; // 2d texture
        int vertexPos = 0;
        int texturePos = 0;

        // Calculate position of the first vertex in this strip.
        altitude = Maths.rad90;
        azimuth = stripNum * azimuthStepAngle;

        // Draw the rest of this strip.
        for (int vertexNum = 0; vertexNum < numVerticesPerStrip; vertexNum += 2) {
            // First point - Vertex.
            y = radius * Math.sin(altitude);
            h = radius * Math.cos(altitude);
            z = h * Math.sin(azimuth);
            x = h * Math.cos(azimuth);
            vertices[vertexPos++] = (float) x;
            vertices[vertexPos++] = (float) y;
            vertices[vertexPos++] = (float) z;

            // First point - Texture.
            texturePoints[texturePos++] = (float) (1 + azimuth / Maths.rad360);
            texturePoints[texturePos++] = (float) (1 - (altitude + Maths.rad90) / Maths.rad180);

            // Second point - Vertex.
            altitude -= altitudeStepAngle;
            azimuth -= azimuthStepAngle / 2.0;
            y = radius * Math.sin(altitude);
            h = radius * Math.cos(altitude);
            z = h * Math.sin(azimuth);
            x = h * Math.cos(azimuth);
            vertices[vertexPos++] = (float) x;
            vertices[vertexPos++] = (float) y;
            vertices[vertexPos++] = (float) z;

            // Second point - Texture.
            texturePoints[texturePos++] = (float) (1 + azimuth / Maths.rad360);
            texturePoints[texturePos++] = (float) (1 - (altitude + Maths.rad90) / Maths.rad180);

            azimuth += azimuthStepAngle;
        }

        this.mVertices.add(vertices);
        this.mTexture.add(texturePoints);

        ByteBuffer byteBuffer = ByteBuffer.allocateDirect(numVerticesPerStrip * 3 * Float.SIZE);
        byteBuffer.order(ByteOrder.nativeOrder());
        FloatBuffer fb = byteBuffer.asFloatBuffer();
        fb.put(this.mVertices.get(stripNum));
        fb.position(0);
        this.mVertexBuffer.add(fb);

        // Setup texture.
        byteBuffer = ByteBuffer.allocateDirect(numVerticesPerStrip * 2 * Float.SIZE);
        byteBuffer.order(ByteOrder.nativeOrder());
        fb = byteBuffer.asFloatBuffer();
        fb.put(this.mTexture.get(stripNum));
        fb.position(0);
        this.mTextureBuffer.add(fb);
    }


}


public void loadGLTexture(final GL10 gl, final Context context, final int texture) {
    Bitmap bitmap = BitmapDecoder.from(context.getResources(), texture)
            .scale(4048, 2024)
            .decode();

    // Generate one texture pointer, and bind it to the texture array.
    gl.glGenTextures(1, this.mTextures, 0);
    gl.glBindTexture(GL10.GL_TEXTURE_2D, this.mTextures[0]);

    // Create nearest filtered texture.
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);
    gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);

    // Use Android GLUtils to specify a two-dimensional texture image from our bitmap.
    GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);

    // Tide up.
    bitmap.recycle();
}

/**
 * The draw method for the square with the GL context.
 *
 * @param gl Graphics handle.
 */
public void draw(final GL10 gl) {
    // bind the previously generated texture.
    gl.glBindTexture(GL10.GL_TEXTURE_2D, this.mTextures[0]);

    // Point to our buffers.
    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

    // Set the face rotation, clockwise in this case.
    gl.glFrontFace(GL10.GL_CW);

    // Point to our vertex buffer.
    for (int i = 0; i < this.mTotalNumStrips; i++) {
        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, this.mVertexBuffer.get(i));
        gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, this.mTextureBuffer.get(i));

        // Draw the vertices as triangle strip.
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, this.mVertices.get(i).length / 3);
    }

    // Disable the client state before leaving.
    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
}

}

这是我的渲染器...

@Override
public void onDrawFrame(final GL10 gl) {

    zvector = new float[] {0,0,1,0};
    resultvector = new float[] {0,0,1,0};
    gl.glMatrixMode(GL10.GL_MODELVIEW);
    gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
    gl.glLoadIdentity();

    float radiansX = (float) Math.toRadians(gyro_angle[1]);
    float radiansY = (float) Math.toRadians(-gyro_angle[0]);
    float radiansZ = (float) Math.toRadians(-gyro_angle[2]);

    // Finds the Sin and Cosin for the half angle.
    float sinX =(float) Math.sin(radiansX * 0.5);
    float cosX =(float) Math.cos(radiansX * 0.5);
    float sinY =(float) Math.sin(radiansY * 0.5);
    float cosY =(float) Math.cos(radiansY * 0.5);
    float sinZ =(float) Math.sin(radiansZ * 0.5);
    float cosZ =(float) Math.cos(radiansZ * 0.5);

    // Formula to construct a new Quaternion based on direction and angle.
    quatX[0] = cosX;
    quatX[1] = 1 * sinX;
    quatX[2] = 0 * sinX;
    quatX[3] = 0 * sinX;
    quatY[0] = cosY;
    quatY[1] = 0 * sinY;
    quatY[2] = 1 * sinY;
    quatY[3] = 0 * sinY;
    quatZ[0] = cosZ;
    quatZ[1] = 0 * sinZ;
    quatZ[2] = 0 * sinZ;
    quatZ[3] = 1 * sinZ;


    quat1 = multiplyQuat(quatX, quatY);
    quat2 = multiplyQuat(quat1, quatZ);

    mMatrix = getMatrixfromQuat(quat1);
    gl.glLoadMatrixf(mMatrix, 0);
    this.mSphere.draw(gl);
}
@Override
public void onSurfaceChanged(final GL10 gl, final int width, final int height) {
    final float aspectRatio = (float) width / (float) (height == 0 ? 1 : height);

    gl.glViewport(0, 0, width, height);
    gl.glMatrixMode(GL10.GL_PROJECTION);
    gl.glLoadIdentity();
    GLU.gluPerspective(gl, 45.0f, aspectRatio, 0.1f, 100.0f);
    gl.glMatrixMode(GL10.GL_MODELVIEW);
    gl.glLoadIdentity();
}
@Override
public void onSurfaceCreated(final GL10 gl, final EGLConfig config) {
    this.mSphere.loadGLTexture(gl, this.mContext, R.drawable.pic360);
    gl.glEnable(GL10.GL_TEXTURE_2D);
    gl.glShadeModel(GL10.GL_SMOOTH);
    gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
    gl.glClearDepthf(1.0f);
    gl.glEnable(GL10.GL_DEPTH_TEST);
    gl.glDepthFunc(GL10.GL_LEQUAL);
    gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);
}

//CONSTRUCTER
public GlRenderer(final Context context) {
    this.mContext = context;
    this.mSphere = new Sphere(5, 2);
    sensorManager = (SensorManager) this.mContext.getSystemService(this.mContext.SENSOR_SERVICE);
    sensorGyroscope = sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
    sensorAccelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    sensorMagneticField = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
    valuesAccelerometer = new float[3];
    valuesMagneticField = new float[3];
    matrixR = new float[9];
    matrixI = new float[9];
    matrixValues = new float[3];

    sensorManager.registerListener(this, sensorGyroscope, SensorManager.SENSOR_DELAY_FASTEST);
    sensorManager.registerListener(this, sensorAccelerometer, SensorManager.SENSOR_DELAY_FASTEST);
    sensorManager.registerListener(this, sensorMagneticField, SensorManager.SENSOR_DELAY_FASTEST);
}
//HERE GOES SOME CURRENTLY IRRELEVANT STUFF ABOUT THE SENSORS AND QUATERNIONS

Answer 1

我遇到了一些此类视频纹理问题。我第一次使用 ffmpeg 进行视频解码，但性能很差（就像你一样 - 逐帧提取）。为了提高性能，我使用了 android 默认媒体播放器。您可以使用表面纹理创建一个 opengl 表面（球体、圆柱体、立方体等），然后在媒体播放器中设置表面

Surface surface = new Surface(mSurface);//mSurface is your surface texture
mMediaPlayer.setSurface(surface);
mMediaPlayer.setScreenOnWhilePlaying(true);

这只是一种技巧。我是为一些商业封闭项目做的，所以我不能分享代码。我希望我能尽快在 github 上发布免费代码。