» 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
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TOC: Of Effects and Shaders

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~6h ago

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~14h ago

vnm: Hi! How can I get PC-name in VVVV?

~21h ago

mediadog: @fleg Yes, will be premiering a new public work at Times Square the 25th - drop a line!

~1d ago

vasilis: Really nice!

~3d ago

fleg: Hi all! Anybody in New York and up for a beer? I´ll be there from 19th-30st.

~4d ago

ravazquez: @sebescudie that's awesome! We need the same for patches...