安卓openGL ES 2.0场景滚动

Question

我正在为使用openGL es 2.0的安卓开发一个简单的游戏。游戏将是2D的，有点像旧的超级马里奥，玩家可以左右移动/上下移动，但没有深度。

这就是问题所在。

举例说明。当我向右移动屏幕时，当背景的右边缘到达屏幕边缘时，我希望屏幕停止滚动。

我现在能做的最好的事情，就是当“视图”的中心在背景的边缘时停止滚动。但这并不好，因为四分之三的屏幕都是空白的。

这是渲染器的代码。

package com.huntedseas;

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

import android.opengl.GLES20;
import android.opengl.GLSurfaceView.Renderer;
import android.opengl.Matrix;
import android.util.Log;


public class GameRenderer implements Renderer {
    protected LevelGenerator generator;
    protected SquareGL squareGL;

    protected static float angleX;
    protected static float angleY;
    protected static float angleZ;
    protected static float viewX = 0;
    protected static float viewY = 0;
    //private float viewZ = 0;

    private float[] mProjectionMatrix = new float[16]; //Projekcijska matrika
    private float[] mVMatrix = new float[16];
    private float[] mMVPMatrix = new float[16];

    @Override
    public void onSurfaceCreated(GL10 unused, EGLConfig conunused) {
        GLES20.glClearColor(1.0f,1.0f,1.0f,1.0f);

        GLES20.glDisable(GLES20.GL_CULL_FACE); //No culling of back faces  \\ To nevem al je treba da je uklopljeno al ne
        GLES20.glDisable(GLES20.GL_DEPTH_TEST); //No depth testing          \\  --||--
        GLES20.glEnable(GLES20.GL_BLEND); //Blending
        GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA,GLES20.GL_ONE_MINUS_SRC_ALPHA); //Interpolated blending

        generator = new LevelGenerator();
    }

    @Override
    public void onDrawFrame(GL10 unused) {
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
        moveView();
        Matrix.setLookAtM(mVMatrix, 0, viewY, viewX, -10, viewY, viewX, 0, 0.0f, 1.0f, 0.0f); //set view
        Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mVMatrix, 0); //calculate view transformation

        generator.draw(mMVPMatrix);     
    }

    @Override
    public void onSurfaceChanged(GL10 unused, int width, int height) {
        GLES20.glViewport(0, 0, width, height);

        float ratio = (float) width/height;
        float left =-ratio;
        float right = ratio;
        float bottom = -1.0f;
        float top = 1.0f;
        float near = 1.0f;
        float far = 20.0f;      
        Log.d("ratio","ratio: "+left+"  r: "+right+"  w: "+width+"  h: "+height);
        Matrix.frustumM(mProjectionMatrix, 0, left, right, bottom, top, near, far);

    }

    long lastTime = System.currentTimeMillis();
    public void moveView(){
        if((System.currentTimeMillis()-lastTime) >= 33){
            lastTime = System.currentTimeMillis();
            Log.d("viewX","viewX: "+viewX + "viewY:"+viewY);
            if( (viewX - angleX/10) < Level1.viewXP && (viewX - angleX/10) > Level1.viewXM) viewX -= angleX/10; 
            if( (viewY - angleY/10) < Level1.viewYP && (viewY - angleY/10) > Level1.viewYM) viewY -= angleY/10;

            //if(Math.abs(viewX - angleX/10) < 10) viewX-=angleX/10;
            //if(Math.abs(viewY - angleY/10) < 10) viewY-=angleY/10;
            //if(Math.abs(viewZ - (angleZ-5)/10) < 10) viewZ+=(angleZ-5)/10;
        }
    }


}

Answer 1

我已经解决了这个问题，修改了Matrix.frustumM的参数，使它们表示FOV。然后当你知道从中边到边的角度时，你可以用切线函数来计算偏移。

 GLES20.glViewport(0, 0, width, height);

    float ratio = (float) width/height;
    float near = 1.0f;
    float far = 150.0f;
    float fov = 80;
    float top = (float) (Math.tan(fov * Math.PI / 360.0f) * near);
    float bottom = -top;
    float left = ratio * bottom;
    float right = ratio * top;

    offsetY = (float) (Math.tan(Math.PI/180*fov/2) * Math.abs(cameraAway));
    offsetX = offsetY * ratio; //because we know ratio between x and y

    Matrix.frustumM(mProjectionMatrix, 0, left, right, bottom, top, near, far);

也可以使用Matrix.perspectivM()，但只对14+接口有效。