Chapter3_Hardware
Graphics_Notes
Rendering
Shading
$$
I = I_ak_a + \sum_i I_ik_d(L_i \cdot N) + \sum_iI_ik_s(R_i\cdot V)^n
$$
Ambient illumination
In computer graphics, ambient illumination is a lighting model that simulates the way light is reflected off of objects and fills a scene. It is called “ambient” because it is meant to represent the indirect light in a scene that comes from all directions, rather than from a specific light source.
In other words, ambient illumination is the base level of lighting in a scene that fills in the shadows and gives objects a sense of overall brightness. It is typically implemented as a low-intensity, uniform light that is applied to all objects in a scene.
The ambient terms models indirect illumination; the light coming from other surfaces rather than directly from the light sources. The parameter $k_a$ controls what portion of ambient light the surface reflects and the $I_a$ in the global intensity of the ambient light
Diffuse shading
In computer graphics, diffuse shading is a technique used to simulate the way light is scattered and absorbed by an object’s surface. It is based on the idea that light is absorbed and scattered in all directions by a rough surface, such as a matte paint finish.
Diffuse shading is typically implemented using the Phong lighting model, which calculates the intensity of the diffuse reflection for each pixel on an object’s surface based on the angle between the surface normal (a vector perpendicular to the surface) and the light source.
The diffuse term models Lambertian reflection where the incoming light in reflected uniformly in all directions. The paramter $k_d$ controls the amount of light that is reflected in a diffuse manner. Scalar $I_i$ describes the intensity of the incoming light
Imperfect specular reflection
In computer graphics, imperfect specular reflection is a technique used to simulate the way light is reflected off of an object’s surface in a more realistic manner. It is based on the idea that the reflection of light off of an object’s surface is not always perfect and that there are often small imperfections or irregularities that can affect the reflection.
The specular term models imperfect mirror-like reflection, in which the reflected light is distributed around the direction of reflection $R_i$. The paramter $K_s$ controls the amount of light that is reflected in a specular manner. The paramter $n$ models the shape of that distribution; high $n$ will result in tighter distribution and the behaviour that is closer to a perfect mirror light reflection. Scalar $I_i$ describes the intensity of the incoming light
LaTeX Personal CheatSheet
| Key formulae | Explanation | Example formulae | Representation |
|---|---|---|---|
\limits_a^b |
Setting limits for the integral | $\int\limits_a^b {1\over 1+x^2}dx$ |
$\int\limits_a^b {1\over 1+x^2}dx$ |
\\ |
start a new line | $1=1\\2=2$ |
$1=1$ $2=2$ |
\frac{a}{b} |
Fraction | $\frac{-b\pm \sqrt{b^2-4ac}}{2a}$ |
$\frac{-b\pm \sqrt{b^2-4ac}}{2a}$ |
\times |
The multiplication sign | $a \times b$ |
$a \times b$ |
\div |
The division sign | $a \div b$ |
$a \div b$ |
\text{} |
Allows for text with space | $\text{Hello World!}$ |
$\text{Hello World!}$ |
\hat{} |
The hat accent | $\hat{y}$ |
$\hat{y}$ |
\partial{} |
The partial derivative sign | $\frac{\partial}{\partial \theta_j}$ |
$\frac{\partial}{\partial \theta_j}$ |
