How is OpenGL fragment shading performed?

I have a 3D object I've created in Maya (and exported to OBJ and MTL files) and I've created a model viewer app in OGL to view it. If my assumptions are correct (and you know what they say about assumptions...) then because I haven't specified my own GLSL shader, OGL should be using the FFP to determine the fragment colour for each pixel? Is this correct?

In my understanding, the FFP must be implement some sort of default shader because it is able to display specular highlights and reflections etc. Can someone give me some information on this and perhaps tell me how this shading is done?

I understand the material definitions are used to set the properties of the materials of the objects, but I'm unsure of how to the final effects of the lights interacting with material display in the OGL window, without manually specifying a shader (hence my belief that t开发者_运维知识库here is some default shader).

In the case of 3rd generation and later GPUs all your assumptions are correct, indeed. As long as no custom shader is specified the driver provides the GPU with a default shader mimicking the FFP.

The default shader usually implements a Phong Lighting model, with the exact details depending on the set parameters of texture environment and such.

For older GPU generations the fixed function pipeline is hardwired.