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| Procedurally Swiching Shaders http://horde3d.org/forums/viewtopic.php?f=1&t=1632 |
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| Author: | ptilton [ 28.01.2012, 03:57 ] |
| Post subject: | Procedurally Swiching Shaders |
Hello all, I am working on a project that involves picking mesh objects in 3D space and I am looking for a way to convey to the user which rendered object is currently selected by having the object glow, or distinguish itself in a similar way. I have already created a simple shader in a context called "PICKED" and am attempting to use API calls similar to the one below to accomplish this. h3dSetResParamStr(shaderMatRes, ContextElem, 0, ContNameStr, "PICKED"); The following call gives me the string name of the context that I want to replace, but I cannot seem to figure out how to replace it procedurally. h3dGetResParamStr(shaderMatRes, ContextElem, 0, ContNameStr); The message boards and Wiki pages have been an invaluable resource, but I've been unable to find a solution to this task so far. Any guidance or advice would be greatly appreciated! Thanks! |
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| Author: | Volker [ 28.01.2012, 12:51 ] |
| Post subject: | Re: Procedurally Swiching Shaders |
ContNameStr is a read only attribute as mentioned in the docs. I guess you might want to use uniforms or different materials with different ShaderFlags? |
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| Author: | ptilton [ 31.01.2012, 01:08 ] |
| Post subject: | Re: Procedurally Swiching Shaders |
I was able to utilize a uniform to tell the shader to change it's behavior. I ended up finding a solution to procedurally switching the shader by using the follownig: Code: //materialRes: texture resource attached to the selected node (cube) //specularShaderRes: resource handle to shader added with h3dAddResource h3dSetResParamI(materialRes, MaterialElem, 0, MatShaderI, specularShaderRes); I guess the thing I can't get my head is around is how to dynamically shade an unknown number of cubes. My project can have anywhere from 1 to about 2000+ cubes render at a time. The user can select a subset of cubes which will glow after being selected. As cubes timeout I would like them to gradually fade out by adjusting their alpha over a timeout. I know I can use a uniform to communicate timing information for the fading to a shader. I'm just not sure how to do this dynamically for each cube. Are there any resources that cover similar situations? Thanks again for your help! |
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| Author: | Volker [ 31.01.2012, 12:14 ] |
| Post subject: | Re: Procedurally Swiching Shaders |
Maybe you can use the model specific uniforms via h3dSetNodeUniforms as mentioned here. Unfortunately they are not part of the official beta 5, but only in the current svn trunk. |
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| Author: | ptilton [ 01.02.2012, 16:43 ] |
| Post subject: | Re: Procedurally Swiching Shaders |
Fantastic! Thanks again for all of your help. |
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