android - 使用 GL_POINTS 生成多个点

Question

我正在尝试在 Android 中使用 OpenGL ES 生成随机等高线图。我创建了一个 Point 类用于在屏幕上绘制点，但我不知道绘制随机点的方法应该是什么。

例如，为了显示 2 个点，我创建了 2 个对象

mPoint = new Point();

mPoint2 = new Point();

在我的渲染器中并在 onDrawFrame 方法中绘制它们

mPoint.draw(scratch,0.0f,0.0f,0.0f);
mPoint2.draw(scratch,0.0f,0.5f,0.0f);

我现在要生成 500 个点，创建 500 个可能重叠的对象(相同的 x、y、z 坐标)听起来不合适。到目前为止，我的画点方法正确吗？我应该如何继续创建包含大量点的 View ？

我的积分等级

public class Point {
private  int mProgram, mPositionHandle, mColorHandle, mMVPMatrixHandle;


private final String vertexShaderCode =
        // This matrix member variable provides a hook to manipulate
        // the coordinates of the objects that use this vertex shader
        "uniform mat4 uMVPMatrix;" +
                "uniform vec4 vPosition;" +
        "void main() {" +
                "   gl_Position = uMVPMatrix * vPosition;" +
                "   gl_PointSize = 20.0;" +
                "}";

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


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

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

    // create empty OpenGL ES Program
    mProgram = GLES20.glCreateProgram();

    // create empty OpenGL ES Program
    mProgram = GLES20.glCreateProgram();

    // add the vertex shader to program
    GLES20.glAttachShader(mProgram, vertexShader);

    // add the fragment shader to program
    GLES20.glAttachShader(mProgram, fragmentShader);

    // creates OpenGL ES program executables
    GLES20.glLinkProgram(mProgram);
}

public void draw(float[] mvpMatrix,float px,float py,float pz) {
    float positionCoords[] = {px,py,pz,1.0f};

    // Add program to OpenGL ES environment
    GLES20.glUseProgram(mProgram);

    // get handle to vertex shader's vPosition member
    mPositionHandle = GLES20.glGetUniformLocation(mProgram, "vPosition");

    mColorHandle = GLES20.glGetUniformLocation(mProgram,"vColor");

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

    GLES20.glUniform4fv(mPositionHandle, 1, positionCoords, 0);

    // get handle to shape's transformation matrix
    mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");

    //TRANSLATION
    float[] transMatrix = new float[16];

    Matrix.setIdentityM(transMatrix,0);
    Matrix.translateM(transMatrix,0,0.5f,0,0);
    Matrix.multiplyMM(transMatrix,0,mvpMatrix,0,transMatrix,0);


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

    GLES20.glDrawArrays(GLES20.GL_POINTS, 0, 1);
}

}

编辑:我希望能够每 10 秒生成一次。

Answer 1

这不是一个好方法。每个点一次绘制调用将产生巨大的驱动程序开销和整体糟糕的 GPU 性能。您应该将您的位置和颜色批量放入一个唯一的顶点缓冲区中，并且只绘制一次。

此外，GetUniformLocation() 意味着在链接着色器程序后每个制服调用一次。它可能真的很慢，或者驱动程序可以缓存它们，但你自己做也没什么坏处。