SMAA算法详解SMAABlendingWeightCalculationVS

/*** Blend Weight Calculation Vertex Shader*/
void SMAABlendingWeightCalculationVS(float2 texcoord,out float2 pixcoord,out float4 offset[3]) {


1. 计算当前纹理左边对应的纹理像素值位置。

pixcoord &＃61; texcoord * SMAA_RT_METRICS.zw;


2. 计算偏移值其中的 0.125, 0.25, 1.25 等偏移值用于双线性采样。

// We will use these offsets for the searches later on (see &＃64;PSEUDO_GATHER4):
offset[0] &＃61; mad(SMAA_RT_METRICS.xyxy, float4(-0.25, -0.125, 1.25, -0.125), texcoord.xyxy);
offset[1] &＃61; mad(SMAA_RT_METRICS.xyxy, float4(-0.125, -0.25, -0.125, 1.25), texcoord.xyxy);


偏移值图示
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4. 计算搜索终点由于使用了纹理双线性采样&＃xff0c;所以搜索长度 &＃61; 搜索步数 * 2

// And these for the searches, they indicate the ends of the loops:
offset[2] &＃61; mad(SMAA_RT_METRICS.xxyy,float4(-2.0, 2.0, -2.0, 2.0) * float(SMAA_MAX_SEARCH_STEPS),float4(offset[0].xz, offset[1].yw));