CG-Review
有一份复习课的PPT，主要按照上面列出的点来复习。痛快地背单词及考默写阶段。期末考完没有骂，估计是考到复习的内容了。
Understanding of basic algorithms and operations introduced in the lecture. (~27%)
2 questions about transformation requiring very simple calculations. (~33%)
Ray tracing, illumination model, aliasing (~40%)
比较重要的是[CG-02], [CG-03], [CG-04], [CG-06], [CG-07]
1 Three type of Rendering
- Rasterization based rendering pipeline 光栅化
- Ray tracing and radiosity 光线追踪、辐射
- Real-time Rendering 实时渲染
2 Rasterization based rendering pipeline
2.1 Object Modeling 对象建模
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2D drawing - line, circle 2D绘图——直线、圆
- 直线绘制
- 使用算法（如Bresenham算法）优化像素选择，通过整数运算高效绘制直线。
- 判断线段与像素的接近程度，选择最接近的像素进行着色。
- 圆形绘制
- 通过对称性减少计算量，逐步绘制圆的像素。
- 直线绘制
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Representations of 3D object (8种)
- 3D Point Clouds 点云
- Polygon Meshes 多边形网格（可定向/不可定向，欧拉公式）
- 不可定向 - 莫比乌斯环、克莱因瓶
- Subdivision Surfaces 细分曲面
- Implicit Surfaces 隐式曲面
- Parametric Surfaces 参数曲面
- Voxel Representation 体素
- Constructive Solid Geometry (CSG) 构造实体几何
- Fractals 分形
2.2 [Transformation]⭐
- Homogeneous coordinates 齐次坐标
- 2D transformations 2D变换
- Translation 平移
- Scaling 缩放
- uniform/non-uniform, simple/general case 均匀/非均匀，简单/一般情况
- Rotation 旋转
- rotation orientation, simple/general case, three-step trick: move to origin point 旋转方向，简单/一般，三步法技巧
- Shearing 错切
- 3D transformations 3D变换
- Translation, scaling, rotation around x, y and z-axis 平移，缩放，旋转
- Inverse transformation 逆变换
- The order of transformation 变换顺序
2.3 Projection 投影
- The elements of projections 投影元素
- COP, projector, projection plane 摄影中心、投影体、投影平面
- Parallel projection平行投影
- Orthographic projection and the corresponding projection 正交投影及对应投影矩阵
- Oblique projection 斜投影
- Perspective projection 透视投影
- Vanish point 消失点
- One/two/three-point perspectibe projection 一点/两点/三点透视投影
Perspective Transformation 透视变换
- After the transformation, the z coordinates keep unchanged 变换后z坐标保持不变
- Its advantages (2):
- make clipping easy
- 深度值 z 被保留，用于后续的深度测试（如隐藏面去除）
- The transformation matrix
Relationship btw xx projection and pesp transfmt
2.4 Hidden/Back Surface Removal 隐面/背面移除（算法理解）
- Object space algorithm 对象空间算法
- Back-face culling 背面剔除算分
- Image spcae algorithm 图像空间算法
- Depth-sorting (or Painter’s) , limitation (overlap problem) 深度排序（画家算法）重叠问题
- Z/Depth-Buffering Z缓冲算法
After the perspective transformation
- Using the z componet of the normal vector of a typical face 利用典型面的法向量的z分量
2.5 Clipping 裁剪（算法理解）
- The Cohen-Sutherland line-clipping 线段裁剪（期中考了三维的）
- The Sutherland Hodgman polygon-clipping 多边形裁剪
After the perspective transformation
- The 6 clipping planes become parallel to the 3 axises, making the clipping easier. 6个裁剪平面与三轴平行，简化裁剪
2.6 Rasterization 光栅化
- The process of taking a primitive and figuring out which pixels it covers 处理基元，确定覆盖哪些像素
2.7 Aliasing 锯齿效应
- Spatical aliasing 空间锯齿
- Temporal alisaing 时间锯齿
- Introduced by spactical aliasing 由空间锯齿导致
- Understanding in the time domain 时间采样不足
2.8 Anti-aliasing 抗锯齿技术
- Supersampling 超采样
- Accumulation buffer 累积缓冲区
- Stochastic sampling 随机采样
- Catmull’s algorithm Catmull算法
- The A-buffer method A-缓冲方法
2.9 Illumination model 光照模型
- Light sources 光源
- Ambient/point/area/spotlight 环境光/点光源/面积光/聚光灯
- Phone illumination model Phong光照模型
- Ambient reflection 环境反射
- Diffuse reflection 漫反射
- Specular reflection 镜面反射
2.10 Shading method 着色方法
- Flat shading 平面着色
- Smooth shading 平滑着色
- Gouraud shading
- Phong shading
2.11 Ray Tracing 光线追踪
- The process 过程
- How to calculate the color of a pixel 计算像素颜色
- The advantages and disavantages 优缺点
- Acceleration 加速技巧
- Bounding volumes 包围体
- Space subdivision 空间细分
2.12 Radiosity 辐射度
- The process 过程
- The advantages and disavantages 优缺点
3 Real-Time Rendering 实时渲染
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Progressive rending technique 渐进式渲染技术
- Discrete LoD 离散细节层次（LoD）
- Progressive mesh 渐进网格
- Edge collapse 边坍塌
- Vertex split 顶点分裂
- Selective refinement 选择性细化
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Ways to estimate the visual quality and rendering cost 视觉质量与渲染成本估计方法
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Shadows 阴影
- Hard shadows 硬阴影
- Shadow volume and shadow map 阴影体和阴影贴图
- Soft shadows 软阴影
- Hard shadows 硬阴影
4 GPU and Animation GPU与动画
4.1 GPU
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CPU vs GPU
- data-intensive tasks 控制密集型任务 vs control-heavy tasks 数据密集型任务
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Efficient computation: Data-level parallelism and task-level parallelism 高效计算：数据级并行和任务级并行
- GPU支持数据级并行（同一操作作用于不同数据子集）和任务级并行（多个独立阶段流水线处理）
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Efficient communication 高效通信
- CPU与GPU之间通信是性能瓶颈，优化策略包括批量传输数据流、应用管线化设计、深度流水线来隐藏数据访问延迟
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GPU architecture GPU架构
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Traditional hardware graphics pipeline 传统硬件图形流水线
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Advanced hardware graphics pipeline 进阶硬件图形流水线
(Programmable vertex processer, rasterizer, programmable fragment processors (which processor performs which tasks?)) 可编程顶点处理器、光栅器、可编程片段处理器
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4.2 Computer animation 计算机动画
- Key frame 关键帧
- Procedure 过程动画
- Motion capture 动作捕捉
5 Point Cloud Processing 【不考】
The irregular structure of point cloud data makes it challenging to design
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