android 上的 OpenGL ES 在调用 glCreateShader() 时崩溃

Question

I've basically followed the guide on the android docs religiously, other than a couple variable names, and that I'm rendering in a fragment. I've been spending a bit off time commenting out lines and I managed to figure out that

 public static int loadShader(int type, String shaderCode) {
        int shader = GLES20.glCreateShader(type);
        //System.out.println(shader + " ass");

        //GLES20.glShaderSource(shader, shaderCode);
        //GLES20.glCompileShader(shader);

        //return shader;
        return 0;
    }

the glCreateShader method crashes the app. It doesn't return anything, it just crashes. The type inputs are always either GLES20.GL_VERTEX_SHADER or GLES20.GL_FRAGMENT_SHADER it crashes with both.

The rest of my renderer class looks like this

public class OpenGLRenderer implements GLSurfaceView.Renderer {

    private Triangle trangle;

    @Override
    public void onSurfaceCreated(GL10 gl10, EGLConfig eglConfig) {
        GLES20.glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
        trangle = new Triangle();
    }

    @Override
    public void onSurfaceChanged(GL10 gl10, int i, int i1) {

    }

    @Override
    public void onDrawFrame(GL10 gl10) {
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
        //trangle.draw();
    }


    public static int loadShader(int type, String shaderCode) {
        int shader = GLES20.glCreateShader(type);
        //System.out.println(shader + " ass");

        //GLES20.glShaderSource(shader, shaderCode);
        //GLES20.glCompileShader(shader);

        //return shader;
        return 0;
    }

And here's my triangle class:

public class Triangle {
    private FloatBuffer vertexBuffer;
    private final int shaderProgram;

    private final String vertexShaderCode =
            "attribute vec4 vPosition;" +
            "void main() {" +
            "   gl_Position = vPosition;" +
            "}";
    private final String fragmentShaderCode =
            "precision mediump float;" +
            "uniform vec4 vColor;" +
            "void main() {" +
            "   gl_FragColor = vColor;" +
            "}";

    static float[] triangleCoords = {
            0.0f, 0.5f, 0.0f,
            -0.5f,-0.3f, 0.0f,
            0.5f, -0.3f, 0.0f
    };

    static final int coordsInVertex = 3, vertexCount = triangleCoords.length / coordsInVertex, vertexStride = coordsInVertex * 4;

    private int positionHandle, colorHandle;

    float color[] = {1f, 0f, 0f, 1f};

    public Triangle () {
        ByteBuffer byteBuffer = ByteBuffer.allocateDirect(triangleCoords.length*4);
        byteBuffer.order(ByteOrder.nativeOrder());

        vertexBuffer = byteBuffer.asFloatBuffer();
        vertexBuffer.put (triangleCoords);
        vertexBuffer.position(0);

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

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

    public void draw () {
        GLES20.glUseProgram(shaderProgram);
        positionHandle = GLES20.glGetAttribLocation(shaderProgram, "vPosition");
        GLES20.glEnableVertexAttribArray(positionHandle);
        GLES20.glVertexAttribPointer(positionHandle, coordsInVertex, GLES20.GL_FLOAT, false, vertexStride, vertexBuffer);
        colorHandle = GLES20.glGetUniformLocation(shaderProgram, "vColor");
        GLES20.glUniform4fv(colorHandle, 1, color, 0);
        GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
        GLES20.glDisableVertexAttribArray(positionHandle);
    }
}

Could someone shed some light?

Answer 1

Not found any issue or error in the aforementioned sources that you provided, and it is completely workable when connects with a GLSurfaceView.

I think the issue is on configuring GLSurfaceView where you must explicitly set the EGLContextClientVersion of OpenGL-ES context before setRenderer ; without eglContext program will not be performed any GL operations.

GLSurfaceView view = findViewById(R.id.glview);
view.setEGLContextClientVersion(2);
view.setRenderer(new OpenGLRenderer());