java - OpenGL ES 2.0 2D-图像显示

Question

我已关注official OpenGL ES tutorial创建一个工作 OpenGL 环境。除了显示 2D 图像之外，我已经能够做任何我想做的事情。为此，我完成了this教程并提出以下内容:

这是我的 Sprite 类:

public class Sprite
{
    //Reference to Activity Context
    private final Context mActivityContext;

    //Added for Textures
    private final FloatBuffer mCubeTextureCoordinates;
    private int mTextureUniformHandle;
    private int mTextureCoordinateHandle;
    private final int mTextureCoordinateDataSize = 2;
    private int mTextureDataHandle;

    private final String vertexShaderCode =
        "attribute vec2 a_TexCoordinate;" +
                "varying vec2 v_TexCoordinate;" +
                "uniform mat4 uMVPMatrix;" +
                "attribute vec4 vPosition;" +
                "void main() {" +
                "  gl_Position = vPosition * uMVPMatrix;" +
                "v_TexCoordinate = a_TexCoordinate" +
                "}";

    private final String fragmentShaderCode =
        "precision mediump float;" +
                "uniform vec4 vColor;" +
                "uniform sampler2D u_Texture;" +
                "varying vec2 v_TexCoordinate;" +
                "void main() {" +
                "gl_FragColor = (vColor * texture2D(u_Texture, v_TexCoordinate));" +
                "}";

    private final int shaderProgram;
    private final FloatBuffer vertexBuffer;
    private final ShortBuffer drawListBuffer;
    private int mPositionHandle;
    private int mColorHandle;
    private int mMVPMatrixHandle;

    // number of coordinates per vertex in this array
    static final int COORDS_PER_VERTEX = 2;
    static float spriteCoords[] = { -0.5f,  0.5f,   // top left
        -0.5f, -0.5f,   // bottom left
        0.5f, -0.5f,   // bottom right
        0.5f,  0.5f }; //top right

    private short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; //Order to draw vertices
    private final int vertexStride = COORDS_PER_VERTEX * 4; //Bytes per vertex

    // Set color with red, green, blue and alpha (opacity) values
    float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 1.0f };

    public Sprite(final Context activityContext)
    {
        mActivityContext = activityContext;

        //Initialize Vertex Byte Buffer for Shape Coordinates / # of coordinate values * 4 bytes per float
        ByteBuffer bb = ByteBuffer.allocateDirect(spriteCoords.length * 4);
        //Use the Device's Native Byte Order
        bb.order(ByteOrder.nativeOrder());
        //Create a floating point buffer from the ByteBuffer
        vertexBuffer = bb.asFloatBuffer();
        //Add the coordinates to the FloatBuffer
        vertexBuffer.put(spriteCoords);
        //Set the Buffer to Read the first coordinate
        vertexBuffer.position(0);

        // S, T (or X, Y)
        // Texture coordinate data.
        // Because images have a Y axis pointing downward (values increase as you move down the image) while
    // OpenGL has a Y axis pointing upward, we adjust for that here by flipping the Y axis.
    // What's more is that the texture coordinates are the same for every face.
    final float[] cubeTextureCoordinateData =
            {
                -0.5f,  0.5f,
                -0.5f, -0.5f,
                0.5f, -0.5f,
                0.5f,  0.5f
            };

    mCubeTextureCoordinates = ByteBuffer.allocateDirect(cubeTextureCoordinateData.length * 4).order(ByteOrder.nativeOrder()).asFloatBuffer();
    mCubeTextureCoordinates.put(cubeTextureCoordinateData).position(0);

    //Initialize byte buffer for the draw list
    ByteBuffer dlb = ByteBuffer.allocateDirect(spriteCoords.length * 2);
    dlb.order(ByteOrder.nativeOrder());
    drawListBuffer = dlb.asShortBuffer();
    drawListBuffer.put(drawOrder);
    drawListBuffer.position(0);

    int vertexShader = MyGLRenderer.loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
    int fragmentShader = MyGLRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);

    shaderProgram = GLES20.glCreateProgram();
    GLES20.glAttachShader(shaderProgram, vertexShader);
    GLES20.glAttachShader(shaderProgram, fragmentShader);

    //Texture Code
    GLES20.glBindAttribLocation(shaderProgram, 0, "a_TexCoordinate");

    GLES20.glLinkProgram(shaderProgram);

    //Load the texture
    mTextureDataHandle = loadTexture(mActivityContext, R.drawable.ic_launcher);
}

public void draw(float[] mvpMatrix)
{
    //Add program to OpenGL ES Environment
    GLES20.glUseProgram(shaderProgram);

    //Get handle to vertex shader's vPosition member
    mPositionHandle = GLES20.glGetAttribLocation(shaderProgram, "vPosition");

    //Enable a handle to the triangle vertices
    GLES20.glEnableVertexAttribArray(mPositionHandle);

    //Prepare the triangle coordinate data
    GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, vertexBuffer);

    //Get Handle to Fragment Shader's vColor member
    mColorHandle = GLES20.glGetUniformLocation(shaderProgram, "vColor");

    //Set the Color for drawing the triangle
    GLES20.glUniform4fv(mColorHandle, 1, color, 0);

    //Set Texture Handles and bind Texture
    mTextureUniformHandle = GLES20.glGetAttribLocation(shaderProgram, "u_Texture");
    mTextureCoordinateHandle = GLES20.glGetAttribLocation(shaderProgram, "a_TexCoordinate");

    //Set the active texture unit to texture unit 0.
    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);

    //Bind the texture to this unit.
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextureDataHandle);

    //Tell the texture uniform sampler to use this texture in the shader by binding to texture unit 0.
    GLES20.glUniform1i(mTextureUniformHandle, 0);

    //Pass in the texture coordinate information
    mCubeTextureCoordinates.position(0);
    GLES20.glVertexAttribPointer(mTextureCoordinateHandle, mTextureCoordinateDataSize, GLES20.GL_FLOAT, false, 0, mCubeTextureCoordinates);
    GLES20.glEnableVertexAttribArray(mTextureCoordinateHandle);

    //Get Handle to Shape's Transformation Matrix
    mMVPMatrixHandle = GLES20.glGetUniformLocation(shaderProgram, "uMVPMatrix");

    //Apply the projection and view transformation
    GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0);

    //Draw the triangle
    GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer);

    //Disable Vertex Array
    GLES20.glDisableVertexAttribArray(mPositionHandle);
}

public static int loadTexture(final Context context, final int resourceId)
{
    final int[] textureHandle = new int[1];

    GLES20.glGenTextures(1, textureHandle, 0);

    if (textureHandle[0] != 0)
    {
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inScaled = false;   // No pre-scaling

        // Read in the resource
        final Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), resourceId, options);

        // 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);

        // Recycle the bitmap, since its data has been loaded into OpenGL.
        bitmap.recycle();
    }

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

    return textureHandle[0];
}
}

这是 MyGLRenderer.java:

public class MyGLRenderer implements GLSurfaceView.Renderer {

private static final String TAG = "MyGLRenderer";
private Context context;

private Sprite sprite;

// mMVPMatrix is an abbreviation for "Model View Projection Matrix"
private final float[] mMVPMatrix = new float[16];
private final float[] mProjectionMatrix = new float[16];
private final float[] mViewMatrix = new float[16];

public MyGLRenderer(Context ctx) {
    this.context = ctx;
}

@Override
public void onSurfaceCreated(GL10 unused, EGLConfig config) {

    // Set the background frame color
    GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

    sprite = new Sprite(context);
}


@Override
public void onDrawFrame(GL10 unused) {
    sprite.draw(mMVPMatrix);
}

@Override
public void onSurfaceChanged(GL10 unused, int width, int height) {
    // Adjust the viewport based on geometry changes,
    // such as screen rotation
    GLES20.glViewport(0, 0, width, height);

    float ratio = (float) width / height;

    // this projection matrix is applied to object coordinates
    // in the onDrawFrame() method
    Matrix.frustumM(mProjectionMatrix, 0, -ratio, ratio, -1, 1, 2, 7);

}

public static int loadShader(int type, String shaderCode){

    // create a vertex shader type (GLES20.GL_VERTEX_SHADER)
    // or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
    int shader = GLES20.glCreateShader(type);

    // add the source code to the shader and compile it
    GLES20.glShaderSource(shader, shaderCode);
    GLES20.glCompileShader(shader);

    return shader;
}

public static void checkGlError(String glOperation) {
    int error;
    while ((error = GLES20.glGetError()) != GLES20.GL_NO_ERROR) {
        Log.e(TAG, glOperation + ": glError " + error);
        throw new RuntimeException(glOperation + ": glError " + error);
    }
}




//NEW
public static int loadTexture(final Context context, final int resourceId)
{
    final int[] textureHandle = new int[1];

    GLES20.glGenTextures(1, textureHandle, 0);

    if (textureHandle[0] != 0)
    {
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inScaled = false;   // No pre-scaling

        // Read in the resource
        final Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), resourceId, options);

        // 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);

        // Recycle the bitmap, since its data has been loaded into OpenGL.
        bitmap.recycle();
    }

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

    return textureHandle[0];
}

}

我遇到的问题是应用程序崩溃了

java.lang.RuntimeException: glGetUniformLocation: glError 1282

在它打开之前。感谢您提前提供的任何帮助!

编辑:我不知道这是否有帮助，但是当我在 AVD 中启动应用程序时，出现以下错误:

../../sdk/emulator/opengl//host/libs/Translator/GLES_V2//GLESv2Imp.cpp:glGetAttribLocation:857 error 0x502
../../sdk/emulator/opengl//host/libs/Translator/GLES_V2//GLESv2Imp.cpp:glGetUniformLocation:1442 error 0x502
../../sdk/emulator/opengl//host/libs/Translator/GLES_V2//GLESv2Imp.cpp:glGetUniformLocation:1442 error 0x502
../../sdk/emulator/opengl//host/libs/Translator/GLES_V2//GLESv2Imp.cpp:glGetAttribLocation:857 error 0x502
../../sdk/emulator/opengl//host/libs/Translator/GLES_V2//GLESv2Imp.cpp:glGetUniformLocation:1442 error 0x502

Answer 1

由于缺少 OpenGL 编译器，我忘记了分号。所以这个

"v_TexCoordinate = a_TexCoordinate" +

应该是这样的:

"v_TexCoordinate = a_TexCoordinate;" +

阿尔珀·西纳尔 (Alper Cinar) 的回答也是正确的。