3D objects have coordinates X, Y and Z.
3D projection - Process of flattening objects into 2D plane
Wireframe rendering - Connecting the dots
Orthographic projection - Parallel sides in the cube appear as parallel
Perspective projection - Parallel lines converge as they get futher from the viewer
Polygons - Triangles
- Three points unambiguously defien a plane.
Mesh - Collection of polygons
Game designers have to balance model fidelity vs polygon count for smooth framerate.
Rendering
Scanline rendering
Fillrate - Rate at which computer fills polyons with pixels
Jaggies - Rough edges
Anti-aliasing - Instead of filling pixels in a polygon with the same color, we can adjust the color based on how much the polygon cuts through each pixel.
- Antialiasing is used all over the place including 2D graphics, like fonts and icons.
Occlusion - Objects hiding behind other algorithm
Painter's algorithm - A sort algorithm that arranges all the polygons from farthest to nearest, then render them in that order.
Z-buffering - keeps track of the closest distance to a polygon for every pixel in the scene by maintaining a Z-buffer.
Z-fighting - flickering effect
Back-face culling - Ignoring back-side of polygons to save processing time
Shading
Surface normal - direction of polygons
Flat shading - using surface normal to calculate shading
Gouraud shading, Phong shading - vary color across the surface
Texture
Texture mapping - Simplest texturing algorithm
Ways to make precessing faster
- Having special hardware just for graphical computations
- Divide up 3D scene into many smaller parts, and then render all the pieces in parallel rather than sequentially
GPU - Graphics Processing Unit, special processors just for graphics
Vocabulary
- converge - 모여들다, 만나다, 수렴되다.
- fidelity - 충실함, 정확도
- occlude - 가리다
Thoughts
- 게임학원에서는 3D 의 기본 개념들을 제대로 가르쳐주지 않아서 뭐가 뭔지 몰랐는데, PBS CS 를 통해 너무 쉽게 이해할 수 있었다.
