graphics lec 3

Lighting scene

process of light simulation and how the light emits to the objects in the scene. It is crucial to provide a mood and making a visually appealing output.

No lighting

There are no lights in the scene and there is no interaction between the light and the object in the scene.

Ambient Light

It is a non-directional light sources and the light reflects many times from many surfaces which it appears equally from all directions.

Camera Models

mathematical descriptions of how a 3D scene is projected onto a 2D image.

Camera Models

They allow us to control the viewpoint, perspective, and field of view, just like a real camera which are essential for rendering virtual environments.

Orthographic Projection

all the projection lines are parallel, and there's no perspective foreshortening.

Perspective Projection

The most common type of camera model and it's designed to mimic how our eyes see the world

Perspective Projection

we have a Pinhole Camera Model, the simplest perspective camera model which uses similar geometry to project 3D points onto a 2D image plane.

Diffuse Reflection (Lambertian Reflection)

When it uses a point light where it comes from a specific direction. It reflects equally in all direction. While, if it uses a directional light, is known faster than the point light, no computation needed for each polygon.

point light

emits light in all directions

directional light

has parallel rays, all from the same direction

Specular Reflection

It is a reflection off of shiny surfaces such as shiny metal or plastic that is high in specular component. The position of the viewer is very important

Lighting and Shading

provides additional mood, realistic, and visually appearing scene we see in the screen.

Hard Lighting

creates a sharp and well-defined shadows.

soft lighting

produces more gradual transitions between the light and shadow.

Directional Light

A light that is produced by a light source where the light rays emanating from a single parallel direction.

Point Light

Provides an equal amount of light in all directions.

Spotlight

It radiates the light in a cone shape which is like a flash light.

Shading Models

This determines the color of a 3D objects surface by calculating the lighting, material properties, etc. which creates a realistic scene. Crucial to provide a realistic and appealing visualization.

Flat Shading (Constant Shading)

It calculates the color once of each face of 3D polygon. Very fast but unrealistic.

Gouraud Shading (Interpolated Shading)

It calculates the color in each vertex then interpolate these colors across the face.

Provide smoother appearance of shading.

Phong Shading (Normal Interpolation Shading)

It interpolates the surface normal across the polygon and calculate the lighting equation at each pixel.

It creates more accurate and realistic shading.