Adding multiple lights

In this recipe, we will implement a lighting pass that reads in the G-Buffer attributes while processing each light. The lights will be rendered using a light volume, where appropriate, in order to process only those pixels that lie within the bounds of the light. By utilizing an additive blend state, we can accumulate the light contribution for each light. When rendering many lights, it becomes important that we are only performing the expensive lighting operations on pixels that are actually affected by the current light. By implementing light volumes that approximate the light's range, shape, and attenuation, we can improve performance by utilizing the culling and clipping features of the graphics pipeline to limit the operations to pixels that require them.

A point light represents a light positioned in space with a limited range, and emits light equally in all directions. With this type of light, we are able to easily represent its area of effect with a bounding...