unity的经验（杂）

在写shader或者制作shader graph 时候阅读shader代码经常会需要转译。

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内置矩阵 支持的矩阵（float4x4）：

• UNITY_MATRIX_MVP 当前模型视图投影矩阵

• UNITY_MATRIX_MV 当前模型视图矩阵

• UNITY_MATRIX_V 当前视图矩阵。

• UNITY_MATRIX_P 目前的投影矩阵

• UNITY_MATRIX_VP 当前视图*投影矩阵

• UNITY_MATRIX_T_MV 移调模型视图矩阵

• UNITY_MATRIX_IT_MV 模型视图矩阵的逆转

• UNITY_MATRIX_TEXTURE0 纹理变换矩阵
  UNITY_MATRIX_TEXTURE3

• UNITY_LIGHTMODEL_AMBIENT 当前环境的颜色

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在Amplify shader editor 里的坑

如果需要转换以上矩阵，应该使用transform 节点进行转换为最好

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unity 读取文件时
Assestdatabase.LoadAssetsAtPath(“Assets/..”);
Resources.Load(“Assets/Resources/..”);

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在defered lighting 中实现transparency 透射效果.

    //Work out where on screen this pixel in. This tells us where we need to read from in the light buffers

    float2 screenPos = input.PositionCS.xy / input.PositionCS.w;
    float2 texCoord = float2(
         (1 + screenPos.x) / 2 + (0.5 / Resolution.x),
         (1 - screenPos.y) / 2 + (0.5 / Resolution.y)
    );

    //The normal buffer alpha channel set to zero if nothing was written here. Sample the value as use zero-values as an early exit (a kind of stencil buffer)

    float4 sampledNormals = tex2D(normalSampler, texCoord);
    if (sampledNormals.a == 0)
        clip(-1);

    //This is the clever bit for back-face geometry. the depth of this vertex (input.Depth) is the back of the object...
    //...while the value in the depth buffer is the depth from the front of the geometry we rendered before into the gbuffer!
    //Thickness is easy to calculate.

    float backDepth = input.Depth;
    float frontDepth = tex2D(depthSampler, texCoord);
    float thickness = (backDepth - frontDepth) * (FarClip - NearClip);

    //This is the surface colour of the transparent object

    float3 opaque = tex2D(transparencyLightbufferSampler, texCoord).rgb;

    //This is the colour of the scene behind the object

    float3 background = tex2D(lightbufferSample, texCoord).rgb;

    //now blend them. Blending function varies per material

    return Blend(opaque, background, thickness);