Forward rendering and deferred rendering are two different techniques used in computer graphics for rendering scenes in 3D graphics applications.

1. **Forward Rendering**:
- In forward rendering, each object in the scene is rendered individually in a single pass.
- It involves iterating over all objects in the scene and calculating lighting and shading for each object.
- This method is straightforward and easy to implement, making it suitable for simpler scenes or scenes with few objects.
- However, it can be computationally expensive, especially when dealing with complex scenes or large numbers of objects, as it requires rendering each object separately and performing lighting calculations for each object in each pass.

2. **Deferred Rendering**:
- Deferred rendering, on the other hand, separates the rendering process into multiple passes.
- In the first pass, the geometry of each object is rendered to a set of buffers known as the G-buffer. These buffers store information such as position, normals, color, and material properties for each pixel in the scene.
- In subsequent passes, lighting calculations are performed using the information stored in the G-buffer.
- Deferred rendering can be more efficient than forward rendering for scenes with a large number of objects or complex lighting effects because it reduces the number of times lighting calculations need to be performed, as they are done per pixel rather than per object.
- However, deferred rendering may have challenges with transparency and anti-aliasing, and it requires more memory due to the G-buffer.

In summary, forward rendering renders objects individually in a single pass, while deferred rendering separates the rendering process into multiple passes, storing intermediate information in buffers for efficient lighting calculations. Each method has its advantages and disadvantages depending on the specific requirements of the scene.

Forward rendering processes lighting per object during rendering, while deferred rendering separates rendering and lighting calculations, allowing for more efficient handling of scenes with multiple lights.