Intro to 3D Graphics - Chris Ryan - NDC Oslo 2024

3D graphics fundamentally work with triangles (polygons) rather than curves or complex shapes - triangles are used because 3 points always define a plane

Key coordinate spaces in the graphics pipeline:

• Model space (object’s local coordinates)
• World space (global coordinates)
• View/camera space
• Perspective/screen space

Matrix transformations are used to:

• Scale objects (make bigger/smaller)
• Rotate objects around axes
• Translate (move) objects in space
• Convert between different coordinate spaces

Depth buffering (Z-buffer) tracks how far each pixel is from the camera to determine which objects are visible/hidden

Rasterization is the process of converting 3D triangles into 2D pixels on screen through interpolation

Points vs Vectors:

• Points represent specific locations in space
• Vectors represent direction and magnitude but no specific position
• Important to keep types separate for correct math operations

Performance considerations:

• Matrix multiplication order matters for efficiency
• Combining multiple transformations into a single matrix is faster
• Memory transfer between CPU/GPU can be a bottleneck
• Floating point math is sufficient for most 3D graphics

Textures are 2D images mapped onto 3D surfaces to add visual detail

Basic 3D engine components:

• Mesh data structure (collection of triangles)
• Matrix math operations
• Rasterizer
• Depth buffer
• Frame buffer

Perspective projection makes distant objects appear smaller through perspective divide operation