android - 绘图 GL_POINTS

Question

我正在 View 中间绘制(我想绘制)一个点，我在 AVD(Nexus 4、Android 4.4.2 - API 级别 19、Intel Atom (x86)、RAM 768 ，使用主机 GPU)，但我在真实设备 [Nexus 5、Nexus 7(2012 版)] 上绘制时遇到问题。在真实设备上只有空白(清晰的颜色) View ，中间没有任何点。

这是完整的代码。比较简单。请注意，我还尝试通过 glVertexAttribPointer (glEnableVertexAttribArray) 推送点数据(位置)。

你能帮我解决这个问题吗？

package com.example.point.app;

import android.app.Activity;
import android.content.Context;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import android.os.Bundle;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new PointView(this));
    }

    class PointView extends GLSurfaceView {

        public PointView(Context context) {
            super(context);
            setEGLContextClientVersion(2);
            setEGLConfigChooser(8, 8, 8, 8, 16, 0);
            setRenderer(new PointRenderer());
        }

        class PointRenderer implements Renderer {

            private void checkError(String message) {
                int err = GLES20.glGetError();
                if (err != GLES20.GL_NO_ERROR) {
                    throw new RuntimeException(message + " -> " + err);
                }
            }

            private int createShader(int type, String source) {
                int shader = GLES20.glCreateShader(type);
                GLES20.glShaderSource(shader, source);
                checkError("glShaderSource");
                GLES20.glCompileShader(shader);
                checkError("glCompileShader");
                return shader;
            }

            @Override
            public void onSurfaceCreated(GL10 unused, EGLConfig config) {
                int vertex = createShader(GLES20.GL_VERTEX_SHADER, "" +
                        "void main() {" +
                        "   gl_Position = vec4(0, 0, 0, 1);" +
                        "   gl_PointSize = 100;" +
                        "}");
                int fragment = createShader(GLES20.GL_FRAGMENT_SHADER, "" +
                        "precision mediump float;" +
                        "void main() {" +
                        "   gl_FragColor = vec4(1, 0, 1, 1);" +
                        "}");
                program = GLES20.glCreateProgram();
                checkError("glCreateProgram");
                GLES20.glAttachShader(program, vertex);
                checkError("glAttachShader(vertex)");
                GLES20.glAttachShader(program, fragment);
                checkError("glAttachShader(fragment)");
                GLES20.glLinkProgram(program);
                checkError("glLinkProgram");
            }

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

            }

            @Override
            public void onDrawFrame(GL10 unused) {
                GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
                GLES20.glUseProgram(program);
                GLES20.glDrawArrays(GLES20.GL_POINTS, 0, 1);
            }

            private int program;

        }

    }

}

Answer 1

我读取错误并使用了 float

"gl_PointSize = 100;" -> "gl_PointSize = 100.0;"

此更改后，我看到了预期的结果。