雷采摘的OpenGL ES 2.0 [英] Ray-picking in OpenGL ES 2.0

问题描述

我想实现光线采摘的OpenGL ES 2.0，以确定对象是否被点击或不。到目前为止，我只是想检查是否有特定的三角形已经pssed $ P $。 我真的使用本网站为动机的http://android-raypick.blogspot.ca/2012/04/first-i-want-to-state-this-is-my-first.html

I'm trying to implement ray-picking in OpenGL ES 2.0 to determine if an object has been clicked or not. So far I'm just trying to check if a specific triangle has been pressed. I`m using this site as a motivation http://android-raypick.blogspot.ca/2012/04/first-i-want-to-state-this-is-my-first.html

这是我到目前为止有：

public void onClick(float x, float y)
{
    float[] temp = new float[4];
    float[] temp2 = new float[4];
    System.out.println("X coordinate: " + x);
    System.out.println("Y coordinate: " + y);
    float[] pos = new float[4];

    y = (float) viewport[3] - y;

    int res = GLU.gluUnProject(x, y, 1.0f, 
            mMVPMatrix, 0,
            mProjectionMatrix, 0,
            viewport, 0, 
            temp, 0);

    Matrix.multiplyMV(temp2, 0, mMVPMatrix, 0, temp, 0);
    float[] nearCoOrds = new float[3];

    if(res == GLES20.GL_TRUE)
    {
        nearCoOrds[0] = temp2[0] / temp2[3];
        nearCoOrds[1] = temp2[1] / temp2[3];
        nearCoOrds[2] = temp2[2] / temp2[3];
        System.out.println("Near0: " + nearCoOrds[0]);
        System.out.println("Near1: " + nearCoOrds[1]);
        System.out.println("Near2: " + nearCoOrds[2]);
    }

    res = GLU.gluUnProject(x, y, 0,
            mMVPMatrix, 0,
            mProjectionMatrix, 0,
            viewport, 0,
            temp, 0);

    Matrix.multiplyMV(temp2,0,mMVPMatrix, 0, temp, 0);
    float[] farCoOrds = new float[3];

    if(res == GLES20.GL_TRUE)
    {
        farCoOrds[0] = temp2[0] / temp2[3];
        farCoOrds[1] = temp2[1] / temp2[3];
        farCoOrds[2] = temp2[2] / temp2[3];
        System.out.println("Far0: " + farCoOrds[0]);
        System.out.println("Far1: " + farCoOrds[1]);
        System.out.println("Far2: " + farCoOrds[2]);
    }

    float[] coords = new float[3];

    coords[0] = farCoOrds[0]-nearCoOrds[0];
    coords[1] = farCoOrds[1]-nearCoOrds[1];
    coords[2] = farCoOrds[2]-nearCoOrds[2];

    System.out.println("REAL COORDS 0: " + coords[0]);
    System.out.println("REAL COORDS 1: " + coords[1]);
    System.out.println("REAL COORDS 2: " + coords[2]);

}

在 X 和是浮子的x和在手指pressed y坐标屏幕。函数的onClick 是从叫 MainActivity 。

The x and the y float is the x and the y coordinate of where the finger pressed the screen. The function onClick is called from the MainActivity.

在

 GLU.gluUnProject(x, y, 1.0f, 
            mMVPMatrix, 0,
            mProjectionMatrix, 0,
            viewport, 0, 
            temp, 0);

mMVPMatrix 是模型视图矩阵。 mProjectionMatrix 的投影矩阵和视的值{0,0，screenhwidth，screenheight}

mMVPMatrix is the Modelview Matrix. mProjectionMatrix is the Projection Matrix and the viewport has the values {0,0,screenhwidth,screenheight}.

输出的例子我得到的是（在屏幕中间感动）：

Example of output I get is (touched around middle of the screen):

REAL COORDS 0: -0.21542415
REAL COORDS 1: 0.31117013
REAL COORDS 2: 9.000003

我的问题/话题是，我不知道如果我在正确的轨道上吗？我是否得到了正确的观念或它似乎是我误解的东西吗？ 还是有什么其他的方式，我可以实现触摸检测上的三角形？

My question/topic is that I don't know if I'm on the right track here? Have I gotten the right idea or does it seem that I have misunderstood something? Or are there any other ways I can achieve touch detection on triangles?

感谢您的帮助和指导！

推荐答案

有一个出色的OpenGL的框架，为Android称为的拉贾瓦利。它支持对象采摘，样品$ C $ Ç看起来很简单，你应该尝试一下。

There is an excellent OpenGL framework for Android called Rajawali. It supports object picking, the sample code looks very simple, you should try it.

这篇关于雷采摘的OpenGL ES 2.0的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！