In most rendering systems, area light sources are decomposed into many point light sources, which requires heavy computation to produce realistic results. In this paper, we propose a novel approach to approximate an area light source with a point light source for each component of the shading model. The position and intensity of the point light source is dependent on the position and orientation of scene points. Thus the scene is shaded using on-the-fly point light sources. The key contribution of our work is that we are able to shade with area light sources of arbitrary shape and arbitrary intensity distribution in real time and the shading model can be generic. And the computation cost is independent of the complexity of the area light source. Experimental results show that our approach creates results comparable to the ground truth. Our approach could be extended to other kinds of local light sources such as curved light sources and volume light sources.