So, I can render with OpenGL or DirectX. Everything looks as expected with OpenGL, but when I render with DirectX it seems like my near clipping plane isn't as close as it is with OpenGL. This is especially problematic when I try to render the cascades in my shadow mapping implementation; when I tightly bound the frustums to the scene, I am clipping too much of the scene with the near plane.
I figure this has to do with the difference in GL/DX clipspace (-1 to 1 for GL and 0 to 1 for DX), or with the difference in half-pixel offsets between the APIs. Does anyone have any experience with the difference between the APIs in terms of the clipping of the view frustum? I'm unsure how to create the appropriate projection and model matrices to get exactly the same clipping in OpenGL or DirectX.