CS452/552; EE465/505. Finale!

Transcription

1 CS452/552; EE465/505 Finale!

2 Outline! Non-Photorealistic Rendering! What s Next? Read: Angel, Section 6.11 Nonphotorealistic Shading Color Plate 11 Cartoon-shaded teapot Final Exam: Monday, April 27 th, 3:15 to 6:15, SC162

3 Goals of Computer Graphics

4 Non-Photorealistic Rendering

5 Non-Photorealistic Rendering

6 Some NPR Categories! Pen-and-Ink illustration Techniques: cross-hatching, outlines, line art, etc.! Painterly rendering Styles: impressionist, expressionist, pointilist, etc.! Cartoons Effects: cartoon shading, distortion, etc.! Technical Characteristics: matte shading, edge lines, etc.! Scientific Methods: splatting, hedgehogs, etc.

7 Outline! Pen-and-ink Illustrations! Painterly Rendering! Cartoon Shading! Technical Illustrations

8 Hue

9 Tone

10 Pen-and-Ink Illustrations

11 Pen-and-Ink Illustrations

12 Rendering Pipeline: Polygonal Surfaces with NPR

13 Strokes and Stroke Textures! Stroke generated by moving along straight path! Stroke perturbed by Waviness function (straightness) Pressure function (thickness)! Collected in stroke textures Tone dependent Resolution dependent Orientation dependent! How automatic are stroke textures?

14 Stroke Texture Examples

15 Stroke Texture Operations

16 Indication! Selective addition of detail! Difficult to automate! User places detail segments interactively

17 Indication Example

18 Rendering Parametric Surfaces

19 Parametric Surface Example

20 Hatching + Standard Rendering

21 Orientable Textures

22 Orientable Stroke Texture Example

23 Outline! Pen-and-ink Illustrations! Painterly Rendering! Cartoon Shading! Technical Illustrations

24 Painterly Rendering! Physical simulation User applies brushstrokes Computer simulates media (paper + ink)! Automatic painting User provides input image or 3D model User specifies painting parameters Computer generates all strokes

25 Physical Simulation Example

26 Computer-Generated Watercolor

27 Fluid Dynamic Simulation

28 Interactive Painting

29 Automatic Painting Example

30 Automatic Painting from Images! Start from color image: no 3D information! Paint in resolution-based layers Blur to current resolution Select brush based on current resolution Find area of largest error compared to real image Place stroke Increase resolution and repeat! Layers are painted coarse to fine! Styles controlled by parameters

31 Layered Painting

32 Painting Styles! Style determined by parameters Approximation thresholds Brush sizes Curvature filter Blur factor Minimum and maximum stroke lengths Opacity Grid size Color jitter! Encapsulate parameter settings as style

33 Style Examples

34 Some Styles! Impressionist No random color, 4 stroke length 16 Brush sized 8, 4, 2; approximation threshold 100! Expressionist Random factor 0.5, 10 stroke length 16 Brush sizes 8, 4, 2; approximation threshold 50! Pointilist Random factor ~0.75, 0 stroke length 0 Brush sizes 4, 2; approximation threshold 100! Not completely convincing to artists (yet?)

35 Outline! Pen-and-ink Illustrations! Painterly Rendering! Cartoon Shading! Technical Illustrations

36 Cartoon Shading

37 Cartoon Shading as Texture Map

38 Shading Variations

39 Outline! Pen-and-ink Illustrations! Painterly Rendering! Cartoon Shading! Technical Illustrations

40 Technical Illustrations

41 Conventions in Technical Illustrations

42 Technical Illustration Example

43 The Future! Smart graphics Design from the user s perspective HCI, AI, Perception! Artistic graphics More tools for the creative artist New styles and ideas

44 Summary! Beyond photorealism Artistic appeal Technical explanation and illustration Scientific visualization! Use all traditional computer graphics tools! Employ them in novel ways! Have fun!

45 What we can do now! Create basic 3D web applications can integrate with other HTML5 packages! Work with event-driven input! Use a variety of texture-based methods! Make use of off-screen rendering Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

46 What we haven t covered! More OpenGL capabilities! Modeling! Alternate renderers! Integration with Web! Where are things going Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

47 What s in desktop OpenGL! Much more control and many more options Geometry,Tessellation and Compute Shaders Level of Detail (LOD) 1-4 Dimensional Textures Many more texture options! Vertex Array Buffers! Occlusion Queries Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

48 What should we expect soon in APIs! Movement of more desktop OpenGL features to ES and WebGL! WebCL 1.0 released March 2014! ES 3.0 and ES 3.1! ECMA 6 Script draft (new version of JS)! Many JS variants such as Coffee Script Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

49 The Players have Changed! Originally hardware and software was dominated by the scientific and CAD communities SGI key for both hardware and software OpenGL developed by SGI! With PCs and graphics cards leadership moved to Microsoft and game users DirectX Video Toaster Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

50 Players Have Changed! Development of GPUs Nvidia, AMD and Intel dominate OpenGL makes a comeback Cg (Nvidia) leads to GLSL Interactive games control direction of hw and sw! Web and smart phones Google, Mozilla, Nokia and others dominate software ARM dominates smart phone chips Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

51 Advanced Topics! Level of Detail (LOD)! Image based rendering! Light field rendering! Ray Tracing! Volume Rendering! Point Clouds! Particle Systems! Information Visualization Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

52 What about Games?! Need more courses Digital Storytelling Game AI HCI Real-time graphics Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

53 Supercomputing! Fastest supercomputers use GPUs for floating point operations GPGPU OpenCL/WebGL Compute shaders! Low power is a major issue Exascale machine will require 20MW Intel vs ARM? Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

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