在OpenGL中制作2D地形的问题

Question

前段时间我问了这个问题，关于如何用opengl顶点制作2D地形。我得到了一个很好的答案，但是在尝试时它没有绘制任何东西，我无法弄清楚出了什么问题，或者如何解决它。

我现在有这个：

public class Terrain extends Actor {
Mesh mesh;
private final int LENGTH = 1500; //length of the whole terrain
public Terrain(int res) {
    Random r = new Random();
    //res (resolution) is the number of height-points 
    //minimum is 2, which will result in a box (under each height-point there is another vertex)
    if (res < 2)
        res = 2;
    mesh = new Mesh(VertexDataType.VertexArray, true, 2 * res, 50, new VertexAttribute(Usage.Position, 2, "a_position")); 
    float x = 0f;     //current position to put vertices
    float med = 100f; //starting y
    float y = med;
    float slopeWidth = (float) (LENGTH / ((float) (res - 1))); //horizontal distance between 2 heightpoints

    // VERTICES
    float[] tempVer = new float[2*2*res]; //hold vertices before setting them to the mesh
    int offset = 0; //offset to put it in tempVer
    for (int i = 0; i<res; i++) {
        tempVer[offset+0] = x;      tempVer[offset+1] = 0f; // below height
        tempVer[offset+2] = x;      tempVer[offset+3] = y;  // height
        //next position: 
        x += slopeWidth;
        y += (r.nextFloat() - 0.5f) * 50;
        offset +=4;
    }
    mesh.setVertices(tempVer);

    // INDICES
    short[] tempIn = new short[(res-1)*6];
    offset = 0;
    for (int i = 0; i<res; i+=2) {
        tempIn[offset + 0] = (short) (i);       // below height
        tempIn[offset + 1] = (short) (i + 2);   // below next height
        tempIn[offset + 2] = (short) (i + 1);   // height
        tempIn[offset + 3] = (short) (i + 1);   // height
        tempIn[offset + 4] = (short) (i + 2);   // below next height
        tempIn[offset + 5] = (short) (i + 3);   // next height
        offset+=6;
    }
}
@Override
public void draw(SpriteBatch batch, float delta) {
    Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
    mesh.render(GL10.GL_TRIANGLES);
}

这是由 Libgdx 渲染的，它也提供了类 Mesh，但这并不真正相关，因为我相信这工作正常。我的问题在于顶点和索引的生成。 我也真的不知道如何调试它，所以任何人都可以看看它，并帮助我找到为什么没有渲染？

Answer 1

一整天过去了，我已经尝试了一切来解决它，似乎我忘记了实际将索引设置为网格。

mesh.setIndices(tempIn);  

少了一条线，几个小时的痛苦...我是个白痴:)