I love the matcap mode in Blender for modelling, because it allows me to get a good idea of the shape of the model I'm working on as the 'lighting' is fixed to the camera and changes as I move it around (similar to the default lighting mode in Maya). However, when I want to view textures, I either have to set the shadeless flag (no lighting), or place lights in the scene, which is both annoying, and static, so it's still quite hard to appreciate the effect the texture is having on the perceived shape of the model. What I would love to have, is a way to have either default lighting that is fixed to the camera, or some way to blend the texture with a white matcap (or any matcap) to simulate that default lighting. Ideally this would be great as a default feature in Blender, but I'll take a workaround for now :)
Ok, so I've found an acceptable workaround thanks to Gandalf3's comment to the question, which references another question that asks how regular materials can be made to work like a matcap. Here is how I set up my material to get both a texture using the main UV map, and camera dependent shading, by blending it with a matcap.
These steps assume you have already created a material and assigned a texture to it in the first (top) texture slot. Also, make sure you are using the GLSL display mode ('n' to open display panel, then select from the 'Shading' section) and are viewing in textured mode ('alt + z'). You needn't have any lights in your scene for this to work.
- Check the material's 'Shadeless' parameter. We don't want lighting, because the matcap will be assigned to provide a faked lighting effect that is dependent on the surface normal relative to the camera.
- Add a new texture in slot 2 (below slot 1) and assign a matcap texture. You can find some matcap textures here: https://svn.blender.org/svnroot/bf-blender/trunk/blender/release/datafiles/matcaps/
Set the coordinates of the matcap to 'Normal' in the 'Mapping' section of the texture properties. If you look in the viewport now, it will appear like a regular matcap in shaded mode.
The matcap needs to be blended with the texture, so set the 'Blend' parameter in the 'Influence' section to 'Multiply'.
If you have done this correctly, when you move the camera around, the matcap should provide some kind of lighting to the model, allowing you to see the shape of the model with the texture applied much more clearly. Note that you may need to adjust the matcap to make the lighting effect more obvious. I used the default Blender matcap (mc01.jpg from the link above) and increased the contrast in an image editor to get darker shading.
As a temporary solution:
Try parenting a spot to your camera.
In object mode select the spot, then ctrl+p.
This should give the effect you're looking for with textured view.
If you use this solution, you could use the outliner view to disable that lamp from rendering.
The drawback is that this only give the effect you need when you're actually looking through the camera.