教程

曲线曲面:参数曲线、参数几何代数形式 https://blog.csdn.net/Jurbo/article/details/75046766

英语专业名词

CS184 教程

Lecture 0, Other notes

Instructor导师,教育者
instructional教学的,教育的
registrar(大学)教务长,教务主任;登记员
Instructors and TAsteacher assistants
roster执勤名单;候选名单
class roster老师的点名册(花名册);名册
teaching staff教职员;教师;教育工作者
user-programmable vertex engine
vertex顶点
fragment shaders像素着色器
as of在……是
as of last semester
niggling issuses微不足道的;(不严重却持续不断的)烦人的
being of importance很重要
treate this assignment as being of utmost importance
piazza(尤指意大利城镇中的) 广场;

Lecture 1, Course Overview

segment 1
spherical harmonic lighting球谐光照
on the faculty of职员之一;(院校)系里的成员
graphics image synthesis
rendering
create realistic images
ACM SIGGRAPH
program 3D computer graphics
OpenGL, which is a graphics API
the OpenGL shading language
a real time scene viewer
ray tracing光线追踪算法
a little bit of a hint of the kinds of things
collage拼贴画;收集品
reflections反射
refractions折射
glass spheres玻璃球
chess boards
initial segment
it's really an intellectually, exciting and challenging field,
Pixar
1995 Toy Story by Pixarfirst completely computer graphics movie
Lighting simulation
one very important area in computer graphics
computer graphics is really critical for visualization.
flight simulators
and so forth.等等
digital visual media
of which computer graphics is an integral part
3D geometric models
Visual media are so prevalent
We have Flickr. YouTube. WebGL
Google earth
very realistic flythroughs of the real world.
Electronic publishing
Online gaming
is perhaps the biggest driver of games
3D printers and fabrication
we are now seeing a vast revolution
print real 3D objects, perhaps with realistic material properties
we can expect to see dramatic advances
new computing methods, new display technologies
  • Lighting simulation lighting simulation is important to create realistic simulations of how the interiors of buildings, interiors of rooms will look. How an automobile will look in an outdoor lighting environment. And computer graphics is used for all of these applications. It can be used for scientific visualization as well as medical visualization.
  • future So, what we have seen here is that computer graphics has numerous applications and it involves fundamental intellectual and technical challenges which make it one of the most exciting areas to study and I hope you will join us in this course.
Segement 2, Outline and Logistics
course logistics
go over some of the course logistics
3D graphics pipeline.
collaborators合作者
humanoid motion人形的
vibrant humanoid motion
assignment任务
homework
assignment logistics
Logistics组织,安排;
后勤
rasterize格栅化,点阵化
raytrace光线追踪
workload工作量
shaders
programmable shaders
our initial lecture on an overview and history.
was coined by由……创造,铸造
a bank of一堆……
a bank of LEDs
in the scene场面,场景
presages预兆
SuperPaint system really presages modern software technologies
alter images by cropping, scaling, compositing them.
add or remove objects.
Sports broadcasts
That's been a quick tour of 2D computer graphics.
Geometric modeling
Geometric modeling is the process of creating 3D geometry,
spline curves and surfaces样条曲线
genus属,类
spout(容器的)嘴;水柱
  • 3D graphics pipeline he graphics pipeline consists of 3 stages: modeling, animation and rendering.

    • Modeling
  • creating geometric models of objects

This could be a simple model of an object like a teapot. It could be a complicated mesh of an object like a cat sculpture. Or it could be a 2 billion polygon mesh of Michelangelo's David that was scanned several years ago by Professor Levoy and collaborators.

  • Animation

The next step if you want the objects to actually move is to consider the animation or the motion of characters. And this is a rich area. We often want vibrant humanoid motion. In other cases we just want motion of objects from one place to another.

  • Rendering

The final step is rendering or creating realistic images, given the geometry and the animation. And there we want to simulate the way the light propagates in the scene to create effects like realistic and intricate shadow details, such as what you see in images on the right.

Assignment or Homework
HW 1

The first assignment deals with transformations and the goal there to place the objects in the world and view them.

In particular, you will write a simple viewer that will view a teapot placed at the center of the screen and you will have to move around the teapot and create images in that way.

  • a simple viewer
HW 2

there you want to be able to view the scene the user specifies, and you want to be able to do it, with realistic lighting, with realistic materials, and as specified by the user.

  • a scene viewer
HW3

you will build a ray tracer which is an offline method to create very visually high quality visually realistic images by tracing rays that arise from the camera and go through each pixel in the image.

  • a ray tracer
Topics
  • I've said "rasterize" and I have said "raytrace."
Rasterize

Rasterization essentially goes through all the geometric primitives and dertermines where in the screen they should go.

Raytrace

Raytracing does the opposite thing which goes to each point or each pixel in the screen and determines which geometric primitive that corresponds to.

  • advantages and disadvantages They each have their advantages and disadvantages, namely raytracing can produce higher quality images, but has historically been slower.
应用场景
  • textual representations
  • GUI
  • Xerox, 1975

    • Drawing
  • Ivan Sutherland's sketch pad system, 1960s, at MIT
  • pop up menus
  • constraint based drawing
  • hierarchical modeling

    • paint systems
  • SuperPaint System, Xerox, in the 1970s
Graphics Rendering

in the 1960's the challenge was handling visibility.

I want to eliminate the lines that I cannot see. And this is a challenge in art as well to create images that convey the notion of depth perception.

  • hidden line algorithms
  • hidden line elimination

    • hidden surface algorithms
    • specular lighting
  • 镜面高光
  • or Phong shading, and Phong illumination and Phong shading,

    • Z-Buffer 算法
  • Z 缓冲器算法也叫深度缓冲器算法
  • or the hidden surface algorithm

    • Global illumination
  • 全域光照
  • recursive ray-tracing algorithm

    • radiosity

the red wall here reflects energy onto the box

  • Cornell Box

    • rendering equation
    torus环形曲面
    hidden line elimination.
    facet部份
    the geometry that's being used to approximate the sphere
    polygonal outlines
    matte不光泽的
    they still looked like matte, or clay.
    diffuse漫反射的
    body color component
    specular highlight
    reflections, refractions
    synopsis大纲,概要
    animation

Lecture 2

Segement 1
core mathematical ideas
technical ideas
some of the core mathematical and technical ideas
  • books The standard red book for OpenGL, and the orange book for the

GL shading language.

  • Basic Math

    • linear algebra
    • vectors
  • dot product
  • cross product

    • matrix
  • matrix-vector and matrix-matrix multiplication

    • 应用场景

Assume for example that you have a point that you want to translate to a different region. This comes up all the time, you have a character, you want to move it somewhere else in the scene. You can regard the point as a vector and we'll see how an operation like translation, rotation can be written as a matrix-vector mulitiplication.

Vectors
vector symbolthey are often written in bold
norm symbol
vector addition
parallelogram平行四边形
diagonal对角线的,斜线的
the diagonal对角线
the addition
If you don't want to think in terms of parallelograms
Cartesian component笛卡儿分量
Pythagorean relationship毕达哥拉斯关系
即:勾股定理 c^2 = a^2 + b^2
right-handed coordinates右手坐标系
  • 用途

Vectors are used to store offsets, displacements and locations

  • 坐标的英语解说

And you can see in this case, it has 4 units along the X axis and 3 units along the Y axis. (4, 3) —> 4i + 3j

  • 右手定则

类似安培的右手定则:四指从 x 轴转向 y 轴,那么大拇指的指向就是 z 轴

向量

  • magnitude
  • the norm of a
  • the magnitude of a

用途

offsets, displacements, locations

运算

vector addition

向量加法

Cartesian Coordinates笛卡儿坐标
orthogonal正交的,直角的
coordinate system

vector multiplication

向量乘法

dot product
  • 点积
  • scalar product
  • 两种运算

    • k ・ a, 乘以常数 k
    • a ・ b, 两个向量相乘
    • 英语说法: a dot b
  • 英语说法
运算对应
times乘以
plus加上
  • a*b + c a times b plus c
  • cos<a,b> = (a ・ b)/(||a||・||b||)
应用
  • find angle between two vectors (e.g. cosine of angle between light source and surface for shading)
  • 计算两个向量之间的夹角

    • find projection of one vector on another (e.g. coordinates of point in ordinary coordinate system).
  • 计算,一个向量在另一个向量上的投影

    projection投影
  • 投影

the projection of vector b lies on a. 向量 b 在 a 上的投影

  • b –> a
  • b 在 a 上的投影
  • bcos<a,b> == a ・ b /a
  • 用小于||a||

    • b –> a
  • b 在 a 上的投影向量

    • b –> a・(a /a) = a ・ b/a2 ・ a
cross product

叉积

Orthonormal bases and Coordinate frames

正交基 与 坐标系框架 We use right-handed (standard) coordinates

相关概念

位置矢量

即坐标

切矢量

切线对应的矢量

  • 单位切矢量

法矢量

主法矢

在曲线所在平面内侧的法线

副法矢

垂直与 曲线所在平面

法平面

垂直于切线

密切面

即曲线所在平面,过切线

从切面

垂直于密切面,并过切线

曲率

在主法线方向,对于对于弧长的转动率

挠率

在副法线方向,对于对于弧长的转动率

插值

插值曲线

由插入数据点构造的曲线,就是插值曲线

  • 线性插值
  • 抛物线插值

拟合

光顺

意指,曲线的拐点不能太多

  • 注意,说的不是驻点

曲线连续性

相交处连续性 p(i), p(i+1)

参数连续性

相交处

0 阶参数连续性

分段曲线方程,间断点(连接点)数值相等

1 阶参数连续性

曲线段方程,连接点,一阶导数 “也” 相等

2 阶参数连续性

曲线段方程,连接点,一阶二阶导数 “都” 相等

几何连续性

  • 要求相对参数连续性,更宽松
  • 只要求,在曲线段 “相交处”,参数导数成比例即可
0 阶几何连续性

与 0 阶参数连续性完全一致

  • 注意

    • 0 阶,要数值,完全一致
1 阶几何连续性

1 阶导数成比例

2 阶几何连续性

1 阶导数成比例,并且曲率相等

参数化

节点

各个参数值 t0, t1, t2, …

型值点

插值点 p0, p1, p2, …