android - 无法让 opengl es 2.0 渲染三角形

Question

我一直在尝试学习 opengl，我似乎无法得到一个三角形来渲染我的代码应该工作它将渲染我设置的 clearColor 但不是三角形，我的顶点和 fragment 着色器没有返回错误任何人都可以看到有问题谢谢

public class MainActivity extends Activity implements GLSurfaceView.Renderer
{
    public static int POSITION_ATTRIBUTE = 0;
    public int program;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);

    GLSurfaceView glSurfaceView = new GLSurfaceView(this);
    glSurfaceView.setEGLContextClientVersion(2);
    glSurfaceView.setEGLConfigChooser(8, 8, 8, 8, 0, 0);
    glSurfaceView.setRenderer(this);
    setContentView(glSurfaceView);
}

@Override
public void onSurfaceCreated(GL10 unused, EGLConfig config)
{
    // Vertex Shader Source Code
    String vertexShaderSource = "" +
        "attribute vec2 position; \n" +
        "\n" +
        "void main() \n" +
        "{ \n" +
        "   gl_Position = vec4(position.x, position.y, 0.0, 1.0); \n" +
        "} \n" +
        "\n";

    String fragmentShaderSource = "" +
        "\n" +
        "\n" +
        "void main() \n" +
        "{ \n" +
        "   gl_FragColor = vec4(1.0, 1.0, 0.0, 1.0); \n" +
        "} \n" +
        "\n";

    // Write and compile vertex shader
    int vertexShader = GLES20.glCreateShader(GLES20.GL_VERTEX_SHADER);
    GLES20.glShaderSource(vertexShader, vertexShaderSource);
    GLES20.glCompileShader(vertexShader);
    Log.i("Vertex Shader", "Compile Log: " + GLES20.glGetShaderInfoLog(vertexShader));

    // Write and compile fragment shader
    int fragmentShader = GLES20.glCreateShader(GLES20.GL_FRAGMENT_SHADER);
    GLES20.glShaderSource(fragmentShader, fragmentShaderSource);
    GLES20.glCompileShader(fragmentShader);
    Log.i("Fragment Shader", "Compile Log: " + GLES20.glGetShaderInfoLog(fragmentShader));

    // Link the shaders into a program object
    program = GLES20.glCreateProgram();
    GLES20.glAttachShader(program, vertexShader);
    GLES20.glAttachShader(program, fragmentShader);
    // Links the variables
    GLES20.glBindAttribLocation(program, POSITION_ATTRIBUTE, "position");
    GLES20.glLinkProgram(program);
    Log.i("Link", "Link Log: " + GLES20.glGetProgramInfoLog(program));

    GLES20.glClearColor(0.8f, 0.3f, 0.2f, 1.0f);
    GLES20.glEnableVertexAttribArray(POSITION_ATTRIBUTE);
}

@Override
public void onSurfaceChanged(GL10 unused, int width, int height)
{

}

@Override
public void onDrawFrame(GL10 unused)
{
    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);

    // Give OpenGl a triangle to render
    float[] geometry = new float[]{
        -0.2f, 0.3f,
        0.4f, 0.5f,
        0.1f, 0.1f,
    };

    ByteBuffer geometryByteBuffer = ByteBuffer.allocateDirect(geometry.length * 4);
    geometryByteBuffer.order(ByteOrder.nativeOrder());
    FloatBuffer geometryBuffer = geometryByteBuffer.asFloatBuffer();
    geometryBuffer.put(geometry);
    geometryBuffer.rewind();
    GLES20.glVertexAttribPointer(POSITION_ATTRIBUTE, 2, GLES20.GL_FLOAT, false, 0, geometryBuffer);

    GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, geometry.length / 2);
}

Answer 1

问题是我忘记了 GLES20 .gl_Useprogram(program);