滚动的大背景中的OpenGL ES [英] Large scrolling background in OpenGL ES

问题描述

我工作的一个2D卷轴游戏的iPhone。我有一个大的图像背景，说480×6000像素，只有一部分是可见的（只有一个屏幕的价值，480×320像素）。是什么让屏幕在这样的背景下最好的方法是什么？

I am working on a 2D scrolling game for iPhone. I have a large image background, say 480×6000 pixels, of only a part is visible (exactly one screen’s worth, 480×320 pixels). What is the best way to get such a background on the screen?

目前我有后台拆分成几个纹理（来绕过最大纹理尺寸的限制），并绘制每一帧作为纹理的三角形带的整个背景。滚动是通过翻译模型视图矩阵完成。剪刀框设置为窗口大小，480×320像素。这并不意味着要快，我只是想要一个工作code之前，我得到优化。

Currently I have the background split into several textures (to get around the maximum texture size limit) and draw the whole background in each frame as a textured triangle strip. The scrolling is done by translating the modelview matrix. The scissor box is set to the window size, 480×320 pixels. This is not meant to be fast, I just wanted a working code before I get to optimizing.

我想，也许OpenGL实现将足够聪明丢弃背景的无形部分，但据一些测量code我写它看起来像背景需要7毫秒借鉴平均84毫秒最大。 （这是衡量模拟器。）这是对整个的一半渲染循环，即。对我来说相当缓慢。

I thought that maybe the OpenGL implementation would be smart enough to discard the invisible portion of the background, but according to some measuring code I wrote it looks like background takes 7 ms to draw on average and 84 ms at maximum. (This is measured in the simulator.) This is about a half of the whole render loop, ie. quite slow for me.

绘制背景应作为复制来自VRAM的一个部分约480×320像素到另一个，或者，换句话说，速度极快的那样容易。什么是更接近这样的表现的最好方法是什么？

Drawing the background should be as easy as copying some 480×320 pixels from one part of the VRAM to another, or, in other words, blazing fast. What is the best way to get closer to such performance?

推荐答案

这就是做这件事的快速方法。事情可以做，以提高性能：

That's the fast way of doing it. Things you can do to improve performance:

• 尝试不同的纹理格式。 presumably的SDK文档对preferred格式的详细信息，以及presumably越小越好。
• 在卡尔出完全离屏砖自己
• 图象分成更小的纹理

我假设你正在绘制的1：1的放大级;是这样吗？

I'm assuming you're drawing at a 1:1 zoom-level; is that the case?

编辑：糟糕。有更多的仔细阅读你的问题，我所提供的另一个忠告：做在模拟器上的时序是毫无价值

Oops. Having read your question more carefully, I have to offer another piece of advice: Timings made on the simulator are worthless.

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