我试图在视频的每一帧上绘制一个位图作为叠加层。我找到了一个关于如何对视频进行解码和编码的示例，并且它正在运行。这个例子有一个带有 drawFrame 函数的 TextureRenderer 类，我需要修改它以添加位图。我是 opengl 的新手，但我了解到我需要使用位图创建纹理并绑定(bind)它。我在下面的代码中尝试过，但它抛出异常。

/*
 * Copyright (C) 2013 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.
 */
// from: https://android.googlesource.com/platform/cts/+/lollipop-release/tests/tests/media/src/android/media/cts/TextureRender.java
// blob: 4125dcfcfed6ed7fddba5b71d657dec0d433da6a
// modified: removed unused method bodies
// modified: use GL_LINEAR for GL_TEXTURE_MIN_FILTER to improve quality.

package com.example.name.videoeditortest;
/**
 * Code for rendering a texture onto a surface using OpenGL ES 2.0.
 */

import android.graphics.Bitmap;
import android.graphics.SurfaceTexture;
import android.opengl.GLES11Ext;
import android.opengl.GLES20;
import android.opengl.GLUtils;
import android.opengl.Matrix;
import android.util.Log;

import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;

/**
 * Code for rendering a texture onto a surface using OpenGL ES 2.0.
 */
class TextureRender {
    private Bitmap bitmap;
    private static final String TAG = "TextureRender";
    private static final int FLOAT_SIZE_BYTES = 4;
    private static final int TRIANGLE_VERTICES_DATA_STRIDE_BYTES = 5 * FLOAT_SIZE_BYTES;
    private static final int TRIANGLE_VERTICES_DATA_POS_OFFSET = 0;
    private static final int TRIANGLE_VERTICES_DATA_UV_OFFSET = 3;
    private final float[] mTriangleVerticesData = {
            // X, Y, Z, U, V
            -1.0f, -1.0f, 0, 0.f, 0.f,
            1.0f, -1.0f, 0, 1.f, 0.f,
            -1.0f,  1.0f, 0, 0.f, 1.f,
            1.0f,  1.0f, 0, 1.f, 1.f,
    };
    private FloatBuffer mTriangleVertices;
    private static final String VERTEX_SHADER =
            "uniform mat4 uMVPMatrix;\n" +
                    "uniform mat4 uSTMatrix;\n" +
                    "attribute vec4 aPosition;\n" +
                    "attribute vec4 aTextureCoord;\n" +
                    "varying vec2 vTextureCoord;\n" +
                    "void main() {\n" +
                    "  gl_Position = uMVPMatrix * aPosition;\n" +
                    "  vTextureCoord = (uSTMatrix * aTextureCoord).xy;\n" +
                    "}\n";
    private static final String FRAGMENT_SHADER =
            "#extension GL_OES_EGL_image_external : require\n" +
                    "precision mediump float;\n" +      // highp here doesn't seem to matter
                    "varying vec2 vTextureCoord;\n" +
                    "uniform samplerExternalOES sTexture;\n" +
                    "void main() {\n" +
                    "  gl_FragColor = texture2D(sTexture, vTextureCoord);\n" +
                    "}\n";
    private float[] mMVPMatrix = new float[16];
    private float[] mSTMatrix = new float[16];
    private int mProgram;
    private int mTextureID = -12345;
    private int mTextureBitmapID = -12345;
    private int muMVPMatrixHandle;
    private int muSTMatrixHandle;
    private int maPositionHandle;
    private int maTextureHandle;
    public TextureRender() {
        mTriangleVertices = ByteBuffer.allocateDirect(
                mTriangleVerticesData.length * FLOAT_SIZE_BYTES)
                .order(ByteOrder.nativeOrder()).asFloatBuffer();
        mTriangleVertices.put(mTriangleVerticesData).position(0);
        Matrix.setIdentityM(mSTMatrix, 0);
    }
    public int getTextureId() {
        return mTextureID;
    }
    public void drawFrame(SurfaceTexture st) {
        checkGlError("onDrawFrame start");
        st.getTransformMatrix(mSTMatrix);
        GLES20.glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
        GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
        GLES20.glUseProgram(mProgram);
        checkGlError("glUseProgram");
        //Bing textrues
        GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID);
        GLES20.glActiveTexture(GLES20.GL_TEXTURE_2D);
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextureBitmapID);

        mTriangleVertices.position(TRIANGLE_VERTICES_DATA_POS_OFFSET);
        GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false,
                TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
        checkGlError("glVertexAttribPointer maPosition");
        GLES20.glEnableVertexAttribArray(maPositionHandle);
        checkGlError("glEnableVertexAttribArray maPositionHandle");
        mTriangleVertices.position(TRIANGLE_VERTICES_DATA_UV_OFFSET);
        GLES20.glVertexAttribPointer(maTextureHandle, 2, GLES20.GL_FLOAT, false,
                TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
        checkGlError("glVertexAttribPointer maTextureHandle");
        GLES20.glEnableVertexAttribArray(maTextureHandle);
        checkGlError("glEnableVertexAttribArray maTextureHandle");
        Matrix.setIdentityM(mMVPMatrix, 0);
        GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0);
        GLES20.glUniformMatrix4fv(muSTMatrixHandle, 1, false, mSTMatrix, 0);
        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
        checkGlError("glDrawArrays");
        GLES20.glFinish();
    }
    /**
     * Initializes GL state.  Call this after the EGL surface has been created and made current.
     */
    public void surfaceCreated() {
        mProgram = createProgram(VERTEX_SHADER, FRAGMENT_SHADER);
        if (mProgram == 0) {
            throw new RuntimeException("failed creating program");
        }
        maPositionHandle = GLES20.glGetAttribLocation(mProgram, "aPosition");
        checkGlError("glGetAttribLocation aPosition");
        if (maPositionHandle == -1) {
            throw new RuntimeException("Could not get attrib location for aPosition");
        }
        maTextureHandle = GLES20.glGetAttribLocation(mProgram, "aTextureCoord");
        checkGlError("glGetAttribLocation aTextureCoord");
        if (maTextureHandle == -1) {
            throw new RuntimeException("Could not get attrib location for aTextureCoord");
        }
        muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
        checkGlError("glGetUniformLocation uMVPMatrix");
        if (muMVPMatrixHandle == -1) {
            throw new RuntimeException("Could not get attrib location for uMVPMatrix");
        }
        muSTMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uSTMatrix");
        checkGlError("glGetUniformLocation uSTMatrix");
        if (muSTMatrixHandle == -1) {
            throw new RuntimeException("Could not get attrib location for uSTMatrix");
        }
        int[] textures = new int[1];
        GLES20.glGenTextures(1, textures, 0);
        mTextureID = textures[0];
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID);
        checkGlError("glBindTexture mTextureID");
        GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER,
                GLES20.GL_NEAREST);
        GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER,
                GLES20.GL_LINEAR);
        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S,
                GLES20.GL_CLAMP_TO_EDGE);
        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T,
                GLES20.GL_CLAMP_TO_EDGE);
        checkGlError("glTexParameter");

        mTextureBitmapID = loadBitmapTexture();
    }


    private int loadBitmapTexture()
    {
        final int[] textureHandle = new int[1];

        GLES20.glGenTextures(1, textureHandle, 0);

        if (textureHandle[0] != 0)
        {
            // Bind to the texture in OpenGL
            GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle[0]);

            // Set filtering
            GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST);
            GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST);

            // Load the bitmap into the bound texture.
            GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);
        }

        if (textureHandle[0] == 0)
        {
            throw new RuntimeException("Error loading texture.");
        }

        return textureHandle[0];
    }

    /**
     * Replaces the fragment shader.
     */
    public void changeFragmentShader(String fragmentShader) {
        GLES20.glDeleteProgram(mProgram);
        mProgram = createProgram(VERTEX_SHADER, fragmentShader);
        if (mProgram == 0) {
            throw new RuntimeException("failed creating program");
        }
    }
    private int loadShader(int shaderType, String source) {
        int shader = GLES20.glCreateShader(shaderType);
        checkGlError("glCreateShader type=" + shaderType);
        GLES20.glShaderSource(shader, source);
        GLES20.glCompileShader(shader);
        int[] compiled = new int[1];
        GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compiled, 0);
        if (compiled[0] == 0) {
            Log.e(TAG, "Could not compile shader " + shaderType + ":");
            Log.e(TAG, " " + GLES20.glGetShaderInfoLog(shader));
            GLES20.glDeleteShader(shader);
            shader = 0;
        }
        return shader;
    }
    private int createProgram(String vertexSource, String fragmentSource) {
        int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexSource);
        if (vertexShader == 0) {
            return 0;
        }
        int pixelShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentSource);
        if (pixelShader == 0) {
            return 0;
        }
        int program = GLES20.glCreateProgram();
        checkGlError("glCreateProgram");
        if (program == 0) {
            Log.e(TAG, "Could not create program");
        }
        GLES20.glAttachShader(program, vertexShader);
        checkGlError("glAttachShader");
        GLES20.glAttachShader(program, pixelShader);
        checkGlError("glAttachShader");
        GLES20.glLinkProgram(program);
        int[] linkStatus = new int[1];
        GLES20.glGetProgramiv(program, GLES20.GL_LINK_STATUS, linkStatus, 0);
        if (linkStatus[0] != GLES20.GL_TRUE) {
            Log.e(TAG, "Could not link program: ");
            Log.e(TAG, GLES20.glGetProgramInfoLog(program));
            GLES20.glDeleteProgram(program);
            program = 0;
        }
        return program;
    }
    public void checkGlError(String op) {
        int error;
        while ((error = GLES20.glGetError()) != GLES20.GL_NO_ERROR) {
            Log.e(TAG, op + ": glError " + error);
            throw new RuntimeException(op + ": glError " + error);
        }
    }

    public void setBitmap(Bitmap bitmap){
        this.bitmap = bitmap;

    }
    /**
     * Saves the current frame to disk as a PNG image.  Frame starts from (0,0).
     * <p>
     * Useful for debugging.
     */
    public static void saveFrame(String filename, int width, int height) {
        // glReadPixels gives us a ByteBuffer filled with what is essentially big-endian RGBA
        // data (i.e. a byte of red, followed by a byte of green...).  We need an int[] filled
        // with native-order ARGB data to feed to Bitmap.
        //
        // If we implement this as a series of buf.get() calls, we can spend 2.5 seconds just
        // copying data around for a 720p frame.  It's better to do a bulk get() and then
        // rearrange the data in memory.  (For comparison, the PNG compress takes about 500ms
        // for a trivial frame.)
        //
        // So... we set the ByteBuffer to little-endian, which should turn the bulk IntBuffer
        // get() into a straight memcpy on most Android devices.  Our ints will hold ABGR data.
        // Swapping B and R gives us ARGB.  We need about 30ms for the bulk get(), and another
        // 270ms for the color swap.
        //
        // Making this even more interesting is the upside-down nature of GL, which means we
        // may want to flip the image vertically here.
        ByteBuffer buf = ByteBuffer.allocateDirect(width * height * 4);
        buf.order(ByteOrder.LITTLE_ENDIAN);
        GLES20.glReadPixels(0, 0, width, height, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, buf);
        buf.rewind();
        int pixelCount = width * height;
        int[] colors = new int[pixelCount];
        buf.asIntBuffer().get(colors);
        for (int i = 0; i < pixelCount; i++) {
            int c = colors[i];
            colors[i] = (c & 0xff00ff00) | ((c & 0x00ff0000) >> 16) | ((c & 0x000000ff) << 16);
        }
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(filename);
            Bitmap bmp = Bitmap.createBitmap(colors, width, height, Bitmap.Config.ARGB_8888);
            bmp.compress(Bitmap.CompressFormat.PNG, 90, fos);
            bmp.recycle();
        } catch (IOException ioe) {
            throw new RuntimeException("Failed to write file " + filename, ioe);
        } finally {
            try {
                if (fos != null) fos.close();
            } catch (IOException ioe2) {
                throw new RuntimeException("Failed to close file " + filename, ioe2);
            }
        }
        Log.d(TAG, "Saved " + width + "x" + height + " frame as '" + filename + "'");
    }
}  

异常抛出:

E/ExtractDecodeEditEncodeMuxTest: error while releasing muxer
                                   java.lang.IllegalStateException: Can't stop due to wrong state.
                                   at android.media.MediaMuxer.stop(MediaMuxer.java:231)
                                   at com.example.name.videoeditortest.ExtractDecodeEditEncodeMuxTest.extractDecodeEditEncodeMux(ExtractDecodeEditEncodeMuxTest.java 434)
                                   at com.example.name.videoeditortest.ExtractDecodeEditEncodeMuxTest.access$000(ExtractDecodeEditEncodeMuxTest.java:58)
                                   at com.example.name.videoeditortest.ExtractDecodeEditEncodeMuxTest$TestWrapper.run(ExtractDecodeEditEncodeMuxTest.java:171)
                                   at java.lang.Thread.run(Thread.java:841)

如果我在 drawFrame 中评论 GLES20.glActiveTexture(GLES20.GL_TEXTURE_2D);，视频会正确呈现但没有位图。如果我在 drawFrame 中评论 GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextureBitmapID); 我会得到以下异常:

java.lang.RuntimeException: glVertexAttribPointer maPosition: glError 1280
at com.example.name.videoeditortest.TextureRender.checkGlError(TextureRender.java:259)
at com.example.name.videoeditortest.TextureRender.drawFrame(TextureRender.java:111)
at com.example.name.videoeditortest.OutputSurface.drawImage(OutputSurface.java:252)
at com.example.name.videoeditortest.ExtractDecodeEditEncodeMuxTest.doExtractDecodeEditEncodeMux(ExtractDecodeEditEncodeMuxTest.java:793)
at com.example.name.videoeditortest.ExtractDecodeEditEncodeMuxTest.extractDecodeEditEncodeMux(ExtractDecodeEditEncodeMuxTest.java:341)
at com.example.name.videoeditortest.ExtractDecodeEditEncodeMuxTest.access$000(ExtractDecodeEditEncodeMuxTest.java:58)
at com.example.name.videoeditortest.ExtractDecodeEditEncodeMuxTest$TestWrapper.run(ExtractDecodeEditEncodeMuxTest.java:171)
at java.lang.Thread.run(Thread.java:841)

最佳答案

我看到两件事对我来说似乎是错误的。

1. 您正在尝试同时绑定(bind)所有内容，并希望一次调用 GLES20.glDrawArrays() 即可绘制所有内容。

2. 您只有一个着色器，而您应该有两个:一个用于进行视频纹理渲染，另一个用于位图层渲染。

你必须知道的是，可以通过多次调用 glDrawArrays 来绘制一个框架，每次调用只会在之前绘制的东西上绘制一小部分(基本上)。

在您的情况下渲染框架的第一部分应该看这个:

# init

loadShaderForVideo()

loadShaderForBitmapLayer()

prepareYourArraysEtc()

...

#loop

GLClear()

updateVideoTexture()

drawFrame(){
   drawVideo()
   drawBitmap()
}
drawVideo(){

    bindYourActiveTextureToVideo()

    setYourVertexAttribAndUniform()

    GLES20.glDrawArrays()

}

drawBitmap() {

    bindYourActiveTextureToBitmap()

    setYourVertexAttribAndUniform() // This should be the same as above for video
    // Considering you want to draw above your video, consider activating the blending for transparency :

    GLES20.glEnable(GLES20.GL_BLEND);
    GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);

    GLES20.glDrawArrays()

}

关于着色器，看看这些:

一个通用的 Vertex Shader :

public static final String vertexDefaultShaderCode =
        "uniform mat4 uVPMatrix;" +
                "uniform mat4 uModelMatrix;" + // uniform = input const
                "attribute vec3 aPosition;" +  // attribute = input property different for each vertex
                "attribute vec2 aTexCoordinate;" +
                "varying vec2 vTexCoordinate;" +// varying = output property different for each pixel

                "void main() {" +
                "vTexCoordinate = aTexCoordinate;" +
                "gl_Position = uVPMatrix * uModelMatrix * vec4(aPosition,1.0);" +
                "}";

然后是基本的 fragment 着色器(用于位图 2D 纹理):

    public static final String fragmentDefaultShaderCode =
        "precision mediump float;" +
                "uniform sampler2D uTexture;" +
                "varying vec2 vTexCoordinate;" +

                "void main() {" +
                "  gl_FragColor = texture2D(uTexture, vTexCoordinate);" +
                "}";

然后是一个不同的视频渲染版本:

    public static final String fragmentExternalShaderCode =
        "#extension GL_OES_EGL_image_external : require\n" +
                "precision mediump float;" +
                "uniform samplerExternalOES sTexture;" +
                "varying vec2 vTexCoordinate;" +

                "void main() {" +
                "  gl_FragColor = texture2D(sTexture, vTexCoordinate);" +
                "}";

因此您将需要两个程序，一个带有 defaultVertexShader + defaultFragmentShader，另一个带有 defaultVertexShader + fragmentExternalShaderCode。

关于java - Opengl es 2.0 在视频上绘制位图叠加，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39589247/