Passing info from SMeshBufferTangents to GLSL 1.1 vertex shader.

[Andrey01]

I'm working on an own material whose shaders mainly calculate PBR lighting. GLSL of version 1.1. is used. But I also want to include in them a simple normal mapping implementation. That would require passing normals, tangents and binormals that pre-calculated from createMeshWithTangents() method for each vertex into the vertex shader. It is necessary for a matrix that would transform the normals of the normal map from the tangent space to the world one. However, I don't know a way Irrlicht passes (and whether passes at all?) that info (tangents/binormals) from SMeshBufferTangents during the drawing. I know I can access gl_Position, gl_Normal, gl_TexCoord of a corresponding vertex from vertex shader, but how to access tangents and binormals?

[CuteAlien]

It's a bit hidden in the S3DVertexTangents documentation, but those are passed as TEXCOORD1 and TEXCOORD2. Thought it's also possible to directly calculate them in shader. In the following thread look for my code with the struct STangentSpace for an example how to do that: viewtopic.php?p=307008

[Andrey01]

Wow, thank you. I used the calculations of the new normals from tangent into world space in the fragment shader as in that example and the result is really nice

[CuteAlien]

Glad it worked and looks good. As a guy used to CPU coding the dFdx/dFdy functions in shaders still feel a bit crazy to me, but they allow for some clever stuff.