Android的OpenGL ES的生成质地的圆形网状 [英] Android OpenGL ES generate a circular mesh for texture

问题描述

我是新来的OpenGL ES在Android上，和我有一个关于生成的纹理重新presents了一圈网状的问题。

期望中的左侧网格，和我的纹理右：

如何生成左边的目？然后使其在下面的方式：

  triangle1 {中心点，白点，nextpointclockwise（例如＃1）}，
triangle2 {中心点，点＃1，nextpointclockwise（例如＃2）}，
triangle3 {中心点，点＃2，nextpointclockwise（比如＃3）}
 

解决方案

这将创建一个半径1圈的顶点和纹理坐标（但我没有真正尝试过，因此它可能无法正常工作:)）
然后，你可以画出它们作为TRIANGLE_FAN

 公共无效MakeCircle2d（INT分）
{
    浮动[] =绿党新的浮动[点* 2 + 2];
    浮动[] = txtcord新的浮动[点* 2 + 2];
    绿党[0] = 0;
    绿党[1] = 0;
    txtcord [0] = 0.5F;
    txtcord [1] = 0.5F;
    INT C = 2;
    的for（int i = 0; I＆LT;点;我++）
    {
        科幻浮= 2 * Math.PI * I /分;
        浮动X = Math.cos（FI + Math.PI）;
        浮Y = Math.sin（FI + Math.PI）;        绿党[C] = X;
        绿党[C + 1] = Y;
        txtcord [C] = X * 0.5F + 0.5F; //缩放圈0.5F半径，加上0.5F，因为我们想圆TEX cordinates的中心是在0.5F，0.5F
        txtcord [C + 1] = X * 0.5F + 0.5F;
        C + = 2;
    }
}
 

I'm new to OpenGL-ES on Android, and I have a question regarding generating a mesh for a texture that represents a circle.

Desired mesh on the left, and my Texture on the right:

How do i generate the mesh on the left? and then render it in the following way:

triangle1{Centerpoint, WhitePoint, nextpointclockwise(say #1)},
triangle2{Centerpoint, point#1,    nextpointclockwise(say #2)},
triangle3{Centerpoint, point#2,    nextpointclockwise(say #3)}

解决方案

This will create the vertices and texture coordinates of a 1 radius circle(but i didnt actually tried it so it may not work :) ) Then you can draw them as TRIANGLE_FAN

public void MakeCircle2d(int points)
{
    float[] verts=new float[points*2+2];
    float[] txtcord=new float[points*2+2];


    verts[0]=0;
    verts[1]=0;
    txtcord[0]=0.5f;
    txtcord[1]=0.5f;
    int c=2;
    for (int i = 0; i < points; i++)
    {
        float fi = 2*Math.PI*i/points;
        float x = Math.cos(fi + Math.PI) ;
        float y = Math.sin(fi + Math.PI) ;

        verts[c]=x;
        verts[c+1]=y;
        txtcord[c]=x*0.5f+0.5f;//scale the circle to 0.5f radius and plus 0.5f because we want the center of the circle tex cordinates to be at 0.5f,0.5f
        txtcord[c+1]=x*0.5f+0.5f;
        c+=2;
    }
}

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