OpenGL ES2.0实现按住屏幕平移/拖拽视图Android

本篇博文主要是实现用手指拖动OpenGL ES2.0绘图的屏幕，在使用了正摄投影与平移矩阵相结合，捕捉视图的move事件，将手指滑过的屏幕坐标转为绘图坐标系坐标，根据差值，对OpenGL ES绘图坐标系进行平移，从而得到需要的结果。效果图如下图所示：

核心代码如下：

1主要是计算点击事件的坐标差值，最后传递给Render

 @SuppressLint("ClickableViewAccessibility")
    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        if (motionEvent != null) {
            pointerCount = motionEvent.getPointerCount();
            final float normalizedX =
                    (motionEvent.getX() / (float) view.getWidth()) * 2 - 1;
            final float normalizedY =
                    -((motionEvent.getY() / (float) view.getHeight()) * 2 - 1);
            switch (motionEvent.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    Log.e(TAG, "点击事件");

                    X = normalizedX;
                    Y = normalizedY;
                    break;
                case MotionEvent.ACTION_MOVE:
                    Log.e(TAG, "移动事件");

                    move(normalizedX - X, normalizedY - Y);
                    X = normalizedX;
                    Y = normalizedY;
                    break;
                case MotionEvent.ACTION_UP:
                    Log.e(TAG, "抬起事件");
                    break;
                case MotionEvent.ACTION_SCROLL:
                    Log.e(TAG, "滚动事件");
                    break;
                default:
                    break;
            }
            return true;
        } else {
            return false;
        }

    }

2.进行计算与渲染

package com.map.core;

import android.opengl.GLSurfaceView;
import android.util.Log;

import com.map.brush.Brush;

import java.util.ArrayList;
import java.util.List;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
import static android.opengl.GLES20.GL_COLOR_BUFFER_BIT;
import static android.opengl.GLES20.glClear;
import static android.opengl.GLES20.glClearColor;
import static android.opengl.GLES20.glViewport;
import static android.opengl.Matrix.multiplyMM;
import static android.opengl.Matrix.orthoM;
import static android.opengl.Matrix.setIdentityM;
import static android.opengl.Matrix.translateM;

public final class MapRender implements GLSurfaceView.Renderer {
    private final static String TAG="地图渲染器";

    private final float[] projectionMatrix = new float[16];
    private final float[] modelMatrix = new float[16];
    private List brushes;//绘制任务



    public MapRender() {
        this.brushes = new ArrayList<>();
    }

    @Override
    public void onSurfaceCreated(GL10 gl10, EGLConfig eglConfig) {
        glClearColor(0.0f, 1.0f, 1.0f, 1.0f);
    }

    @Override
    public void onSurfaceChanged(GL10 gl10, int width, int height) {
        glViewport(0, 0, width, height);
        //设置支持横竖屏转换，正交投影矩阵
        final float aspectRatio = width > height ?
                (float) width / (float) height :
                (float) height / (float) width;

        if (width > height) {
            // Landscape
            orthoM(projectionMatrix, 0, -aspectRatio, aspectRatio, -1f, 1f, -1f, 1f);
        } else {
            // Portrait or square
            orthoM(projectionMatrix, 0, -1f, 1f, -aspectRatio, aspectRatio, -1f, 1f);
        }
        //初始化平移矩阵为单位矩阵
        setIdentityM(modelMatrix,0);//建立单位矩阵
    }

    @Override
    public void onDrawFrame(GL10 gl10) {
        glClear(GL_COLOR_BUFFER_BIT);

        //平移支持
        //两个矩阵相乘
        final float[] temp = new float[16];
        multiplyMM(temp, 0, projectionMatrix, 0, modelMatrix, 0);

        Log.e(TAG,"重新绘制");
        for(int i=0;i

完整的代码在码云https://gitee.com/GISuser/MoveView