OpenGL ES的纹理映射

问题描述

我要画圈圈在我的Andr​​oid应用程序。其实这是一个吃豆子游戏，我需要绘制片。由于有现场许多药片我决定提请各平板电脑一个多边形。

I need to draw circles in my Android application. Actually it is a Pacman game and I need to draw tablets. Since there are many tablets on field I decided to draw each tablet with a single polygon.

下面是我的想法的说明：

Here is the illustration of my idea:

顶点coordrs：

//  (x, y)
0 : -R, R * (Math.sqrt(2) + 1)
1 : -R, -R
2 : R * (Math.sqrt(2) + 1), -R

COORDS顶点相对于圆心计算放置圈轻松更高版本。

Vertex coords are calculated relative to circle center to place circles with ease later.

问题出在纹理贴图，根据我的计算UV的应该是这样的。

The problem is in texture mapping, according to my calculations UVs should be like this

0 : 0, -(Math.sqrt(2) + 0.5)
1 : 0, 1
2 : 1, (Math.sqrt(2) + 0.5)

但负V值会导致应用程序只显示黑屏。这就是为什么我认为我失去了一些东西还是我走错路了...

But negative V value causes application to show only black screen. That is why I think that I'm missing something or I'm going the wrong way…

我的问题是：是否有可能呈现以这种方式还是不质地？如果是不可能的，什么是画小点的最佳方式？

My question is: Is it possible to render the texture in that way or not? If it isn't possible, what is the best way to draw small dots?

P.S：我与OpenGL ES 2.0的Andr​​oid上工作

P.S: I'm working with OpenGL ES 2.0 on Android.

在我看来，这家伙正在试图做的。

Seems to me, that this guy is trying to do the same.

推荐答案

的 GL_TEXTURE_WRAP_S 和 GL_TEXTURE_WRAP_T 纹理参数默认设置为 GL_REPEAT 。它们设置为 GL_CLAMP_TO_EDGE ，而不是让你在寻找（请参阅）

The GL_TEXTURE_WRAP_S and GL_TEXTURE_WRAP_T texture parameters are set to GL_REPEAT by default. Set them to GL_CLAMP_TO_EDGE instead to get the effect you're looking for (see the glTexParameter documentation)

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