Apply the camera projection method to solid textures

Set Projection to CAMERA. The Projection Texture Parameters window expands, listing all cameras that have an image plane. (You can only use the CAMERA projection method for cameras that have an image plane.)
Click the Projective Camera toggle box for the camera you want to create a Projection texture for.
Click the Create button. A Stencil texture representing the image plane is automatically mapped to Source Texture.

Source Texture: The two-dimensional texture or image file projected to create a three-dimensional texture.

If you map Source Texture with a File texture, make sure that the File texture’s Filter parameter is set to either NONE or BLEND. Higher order filters (QUADRATIC, QUARTIC, and GAUSSIAN) give unpredictable projections.

Although you can use an environment texture or solid texture as a Source Texture, the results are unpredictable.