old way
The old render pipeline used to directly transport the rendered pixel results to the screen, without providing a way to save the rendered image.
Before using Deferred Rendering, we used to calculate the mesh information required for lighting in one shader. This method is efficient when there is a constant number of lights in the scene, as we only need to run one shader for each model to properly apply lighting.
But we have 2 defect
The number of lights in the shader needs to be constant because the shader has to be compiled at runtime for each frame.
The same information used to calculate lighting for a mesh (such as mesh normal and mesh color) cannot be shared with another shader, such as a post-processing shader. Therefore, the same information needs to be recalculated in each shader that uses it.
lanx06 changed 7 months agoView mode Like Bookmark
brdf
brdf
In computer graphics have investigated the material interactions with the light and Summarized the equation which is called brdf(bidirectional reflectance distribution function).
Phong model
$V:\text{surface to the view direction}$
$N:\text{surface normal direction}$
$L:\text{surface to the light direction}$
$R:\text{the direction of light reflect to surface normal}$