Lecture computer graphics and virtual reality slides lesson 2 graphics systems
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Lesson 2
Graphics systems
Trinh Thanh Trung
School of ICT, HUST
Content
1. Graphics pipeline
2. Graphics software
3. Graphics hardware
1.
Graphics pipeline
Object representation
■ To display an object to the screen…
Modeling
Rendering
Displaying
Modeling
■ Describing (to the computer)
□ What is a table, a car…
□ Concerned with:
▫ geometric info, color models, material property,
lighting property
Rendering
■ Draw the description
□ Create 2D image from 2D / 3D models
□ Concerned with:
▫ viewing & projection
▫ drawing & clipping primitives
▫ local illumination & shading
▫ texture mapping, global rendering
Displaying
■ Generate image on the screen
□ Concerned with:
▫ hardware
▫ rasterization
Graphics pipeline
■ Three stages
□ Application stage
□ Geometry stage
□ Rasterization stage
Application stage
■ Entirely done in software by the CPU
■ Load Data: world geometry, user’s input
■ In response to the user’s input, the application
stage change the view or scene
Geometry stage
■ Applying transformations to the object vertices
(scaling, rotating, translating)
■ View transformation (viewing from the camera)
■ Illumination and shading
Rasterization stage
■ Converting the continuous representation
(curves and lines) into the discrete representation
(pixels)
■ Anti-aliasing
■ Texture mapping
■ Bump mapping
■ Illumination and shading (per pixel)
Example scene
1. Modeling objects
•
Define polygons, parametric
curves/surfaces, etc. & its
own coordinate system
2. Model transformation
•
Applying translation, scaling and
rotation
3. Perspective projection
•
Convert from 3D coordinates to
2D coordinates
4. Hidden surface removal
•
Objects occluded by other objects
must not be drawn
5. Shading and lighting
•
Define the colour of each pixel
6. Rasterization
•
Convert vertex information
into pixel information
•
Anti-aliasing
7. Texture mapping
•
Map textures on objects
8. Others
•
Bump-mapping
•
Reflections
•
Shadows
