Spherical environment ing for highlights

When looking at the wow model some time ago, there was a strange rendering status switch in the render flag, and this status was not mentioned in wowdev.

Pass. useenvmap = (texunitlookup [Tex [J]. texunit] =-1) & (RF. Flags & 0x10 )! = 0) & RF. Blend> 2; // & RF. Blend <5; // use environmental reflection effects? <Br/>

After tracking, we found that several models will switch to this "spheremap" only when a certain type of texture is used. The file name is usually like armorreflect4.blp.

At that time, I only knew that it was used for highlights, but I didn't take a closer look at the implementation.

Later, I accidentally discovered in the project that I also used this technology to know that apart from {
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} "Href =" http://msdn.microsoft.com/en-us/library/ee415223 (vs.85). aspx "> outside of cubic environment mapping, There Is {
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} "Href =" http://msdn.microsoft.com/en-us/library/ee422438 (vs.85). aspx "> spherical environment mapping.

According to the dx sdk, the UV coordinates are calculated as follows:

Where NX and NY are the XY components of the camera's space vertex normal. the original wow model was not successfully tested, so the texture was treated as a normal texture. No wonder the dragon teeth and claws shown in the figure do not look as sharp as the wowmodelviewer @_@. it seems that I have not changed the normal to the camera space.

I tried a teapot in rendermonkey. The result is correct:

Float4x4 matviewprojection; <br/> float4x4 matview; </P> <p> struct vs_input <br/>{< br/> float4 position: position0; <br/> float3 normal: normal; <br/> float2 texcoord: texcoord0; <br/>}; </P> <p> struct vs_output <br/>{< br/> float4 position: position0; <br/> float2 texcoord: texcoord0; <br/> float2 sphereuv: texcoord1; <br/>}; </P> <p> vs_output vs_main (vs_input input) <br/>{< br/> vs_output output; </P> <p> output. position = MUL (input. position, matviewprojection); <br/> output. texcoord = input. texcoord; <br/> float3 viewnormal = MUL (input. normal, matview); <br/> output. sphereuv = viewnormal. XY * 0.5 + 0.5; </P> <p> return (output); <br/>}

Sampler2d basemap; <br/> sampler2d spheremap; </P> <p> struct ps_input <br/>{< br/> float2 texcoord: texcoord0; <br/> float2 shpereuv: texcoord1; <br/>}; </P> <p> float4 ps_main (ps_input input): color0 <br/>{< br/> float4 diffuse = tex2d (basemap, input. texcoord); <br/> float4 envmap = tex2d (spheremap, input. shpereuv); </P> <p> return diffuse + envmap; <br/>}

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