» cn.Tutorial Effects - Mr. Wiggle
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cn.Tutorial Effects - Mr. Wiggle

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TOC: Of Effects and Shaders
Back: Vertexshader Preparations
Next: Function Printing


让我们与著名的“抖动先生”的例子开始,通过正弦波扭曲网格:

网格上的每个顶点调用顶点着色器。正如你学过的那样here,顶点着色器的输入是储存在网格中的顶点,这些现在要用于处理:

vs2ps VS(
    float4 PosO  : POSITION,
    float4 TexCd : TEXCOORD0)
{
...
}

这里我们的兴趣点转移到 PosO向量,它是当前顶点的位置。我们要根据它的垂直位置(y坐标)来决定x坐标的偏移:

PosO.x += sin(PosO.y);

为了控制抖动的波浪,我们添加了一些参数:

PosO.x += sin(PosO.y * Frequency + Phase) * Amplitude;

那么顶点着色器和它的输入参数像这样:

float Frequency = 10;
float Phase = 0;
float Amplitude = 0.01;
 
vs2ps VS(
    float4 PosO  : POSITION,
    float4 TexCd : TEXCOORD0)
{
    //declare output struct
    vs2ps Out;
 
    //offset x coordinate
    PosO.x += sin(PosO.y * Frequency + Phase) * Amplitude;
 
    //transform position
    Out.Pos = mul(PosO, tWVP);
 
    //transform texturecoordinates
    Out.TexCd = mul(TexCd, tTex);
 
    return Out;
}

相应的程序片如下:

mr wiggle patch

Next: Function Printing
Back: Vertexshader Preparations
TOC: Of Effects and Shaders

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~7d ago

joreg: @beyon too bad. but from now on we have a fixed schedule: every 4th tuesday in the month! hope this helps to plan evvvveryones visits

~7d ago

beyon: joreg: ah, bad timing, I would be happy to attend but I doesn't look like it will work out

~7d ago

joreg: @beyon any chance you can add 2 days to stay? would be great to have you at the (not yet announced) #vvvv meetup on the 23rd!

~7d ago

~8d ago

beyon: I'll be in Berlin July 13-22 - anything interesting going on in that time frame?

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~9d ago

joreg: moments later: admin fixed it. back to normal.

~9d ago

joreg: indeed. site broken. hope to get this sorted soon. sorry for the inconvenience.