Camera forward vector in shader

The near clip plane doesn't have a single normal in world space unless you're using an orthographic projection. You're dealing with a frustum, and not necessarily even an isosceles one.

Hmm, well then forget that near clipping plane's normal stuff. I would still like the camera's forward vector in the surface shader though - if it's possible to do it without sending it as a uniform.

Unity provides the matrix that transforms from view to object space, so you can get the vector you want, without calculations (you'll need to rotate again if you need it in world space). I don't know surface shaders, so can't tell you what the uniform is called, in them, or if you can just grab the [2].xyz of it, though I suspect so. In GLSL, it's called gl_ModelViewMatrixInverseTranspose, and it may be UNITY_MATRIX_IT_MV in a surface shader.

UNITY_MATRIX_IT_MV[2].xyz works great, thx.

@$$anonymous$$eavenk @Jessy Thanks guys, UNITY_MATRIX_IT_MV[2].xyz worked for me too. Maybe turn it into an answer for other users?