Cocos2d-lua 初识shader之五：定时器

最新推荐文章于 2021-01-20 11:58:56 发布

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最新推荐文章于 2021-01-20 11:58:56 发布 · 2.5k 阅读

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CC 4.0 BY-SA版权

文章标签：

#cocos2d-x #cocos2dx-lua #shader

本文介绍了在Cocos2d-lua中如何利用GLProgram的内置函数setUniformsForBuiltins将时间传递到shader，通过CC_Time, CC_SinTime和CC_CosTime三个量进行周期性效果的实现，揭示了在shader中处理定时器的方法。" 78005615,5678051,Lua编程：基础语法与数据结构详解,"['编程语言', 'Lua基础', '数据结构', '函数定义']

在GLProgram::setUniformsForBuiltins函数中有下面代码：

 
if(_flags.usesTime) {
    // This doesn't give the most accurate global time value.
    // Cocos2D doesn't store a high precision time value, so this will have to do.
    // Getting Mach time per frame per shader using time could be extremely expensive.
    float time = _director->getTotalFrames() * _director->getAnimationInterval();
        
    setUniformLocationWith4f(_builtInUniforms[GLProgram::UNIFORM_TIME], time/10.0, time, time*2, time*4);
    setUniformLocationWith4f(_builtInUniforms[GLProgram::UNIFORM_SIN_TIME], time/8.0, time/4.0, time/2.0, sinf(time));
    setUniformLocationWith4f(_builtInUniforms[GLProgram::UNIFORM_COS_TIME], time/8.0, time/4.0, time/2.0, cosf(time));
}

即Cocos在刷新时，已经将时间传入进来了，可以在shader 中调用CC_Time，CC_SinTime和CC_CosTime这三个量来进行操作

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