TODO.md

Global

• Performance
  • OPTIMIZATION (minor): Use PGO in g++

3d Engine

• Graphics API
  • OPTIMIZATION (medium): Use bind-less rendering technique to bind almost everything at frame start (see https://www.youtube.com/watch?v=SVm0HanVTRw and https://vkguide.dev/docs/gpudriven/gpu_driven_engines/)
  • OPTIMIZATION (medium): Use sub-passes for deferred rendering (see https://www.saschawillems.de/blog/2018/07/19/vulkan-input-attachments-and-sub-passes/)
  • OPTIMIZATION (medium): Check secondary command buffers usage for better performance
  • OPTIMIZATION (minor): Use shader constants instead of uniform for values infrequently refreshed
  • OPTIMIZATION (minor): Use Vulkan 1.2 timeline semaphores instead of semaphores/fences
• Rendering
  • NEW FEATURE (medium): Implement a better culling technique (GPU driven rendering: https://vkguide.dev/docs/gpudriven/gpu_driven_engines/, coherent hierarchical culling revisited, software occlusion culling)
  • NEW FEATURE (medium): Use sRGB format for color/albedo framebuffers and swap chain
  • NEW FEATURE (minor): Use reverse depth for far distant view (see https://outerra.blogspot.com/2012/11/maximizing-depth-buffer-range-and.html)
  • OPTIMIZATION (minor): Avoid sending shader variables values at each frame when there is no change in Renderer3d#deferredRendering
• Model
  • OPTIMIZATION (major): Remove the ModelInstanceDisplayer in ModelSetDisplayer#removeModelFromDisplayer() for models not displayed for a long time
  • OPTIMIZATION (medium): Draw calls batching
    • Tips: different types of batching are possible: static, dynamic, for shadow map (see https://docs.unity3d.com/Manual/DrawCallBatching.html)
  • OPTIMIZATION (medium): Parallelize the creation of the ModelDisplayer
  • OPTIMIZATION (medium): Models LOD
• Lighting & Shadow
  • NEW FEATURE (major): Shadow on omnidirectional light (check Sascha Willems: deferredshadows)
  • OPTIMIZATION (medium): Avoid to render all the frustum models for each cascade: use the split frustum models instead
  • OPTIMIZATION (medium): Create shadow map texture only for visible lights
  • OPTIMIZATION (minor): Use models LOD
  • OPTIMIZATION (minor): Create specific render passes with less restrictive memory barrier between the shadow map cascades rendering
  • NEW FEATURE (minor): Implement scalable ambient obscurance
• Anti-aliasing
  • NEW FEATURE (medium): Implement TAA (see https://sugulee.wordpress.com/2021/06/21/temporal-anti-aliasingtaa-tutorial/)
• Landscape
  • OPTIMIZATION (medium): Terrain class should have methods for LOD (usable for physics and AI)
  • NEW FEATURE (minor): Use material textures (normal map...) for terrain
  • NEW FEATURE (minor): Add auto shadow on terrain
  • NEW FEATURE (minor): Water transparency (see https://www.youtube.com/watch?v=HusvGeEDU_U&list=PLRIWtICgwaX23jiqVByUs0bqhnalNTNZh)
• UI
  • OPTIMIZATION (major): Remove the WidgetInstanceDisplayer in WidgetSetDisplayer#removeWidgetFromDisplayer() for widgets not displayed for a long time
  • NEW FEATURE (medium): Render UI into texture to avoid depth shift in 3d UI
  • IMPROVEMENT (medium): Add missing characters dynamically in the atlas texture(s)
  • IMPROVEMENT (medium): Dynamic scaling of characters (see https://github.com/Chlumsky/msdfgen or distance field font)
  • IMPROVEMENT (minor): Handle scrollable containers in UI 3d
  • NEW FEATURE (minor): Combo list

AI engine

• Navigation mesh
  • BUG (major): Surrounded faces are not walkable (NavMeshGeneratorTest#surroundedWalkableFace)
  • BUG (major): Union of room walls create wrong polygons (PolygonsUnionTest#roomPolygonsUnion)
  • NEW FEATURE (major): Add possibility to exclude dynamic objects from navigation mesh
    • Note: worth it only when steering behaviour will be implemented in pathfinding
  • BUG (medium): Jump from an edge created by an obstacle should be allowed only if target is this obstacle and vice versa
  • BUG (medium): Jump links visualization are not exact
  • OPTIMIZATION (medium): Exclude very small objects from navigation mesh
  • NEW FEATURE (medium): Create jump/drop links from an edge to a walkable surface (+ update AABBTree margin accordingly)
  • NEW FEATURE (medium): Insert bevel planes during Polytope#buildExpanded* (see BrushExpander.cpp from Hesperus)
  • OPTIMIZATION (minor): Reduce memory allocation in NavMeshGenerator#createNavigationPolygon()
  • OPTIMIZATION (minor): TerrainObstacleService: apply a rough simplification on self obstacles polygons
  • NEW FEATURE (minor): Exclude fast moving objects as walkable face
  • OPTIMIZATION (minor): NavMeshGenerator#computePolytopeFootprint: put result in cache
• Pathfinding
  • NEW FEATURE (major): Implement steering behaviour (see https://gamedevelopment.tutsplus.com/tutorials/understanding-steering-behaviors-collision-avoidance--gamedev-7777)
  • NEW FEATURE (major): AICharacterController should refresh path points each time the path request is updated
  • OPTIMIZATION (medium): When compute A* G score: avoid to execute funnel algorithm from start each time
  • OPTIMIZATION (medium): When search start and end triangles: use AABBox Tree algorithm

Network engine

Physics engine

• Broad phase
  • OPTIMIZATION (medium): Implement double AABBox trees: static and dynamic (see Bullet)
  • OPTIMIZATION (medium): Re-balance AABBox tree for better performance
• Narrow phase
  • NEW FEATURE (medium): Support joints between shapes
  • OPTIMIZATION (minor): GJK, don't test voronoi region opposite to last point added (2D: A, B, AB | 3D: ABC)
  • OPTIMIZATION (minor): EPA, add new point on convex hull to improve thanks to adjacent edges: find faster the triangles visible by the new point (see Reactphysics3d code)
• Island
  • BUG (medium): A body balancing from one side to the other side (e.g.: cone on his base) could be disabled when velocity reach zero
    • Tips: don't disable bodies when there is only one contact point
• Constraints solver
  • BUG (medium): A restitution of 1.0 introduce new force in the system. Example: a superball bounces higher and higher at each collision
    • Tips: possible cause described in https://youtu.be/ZOfMA8h4qO8?t=109
• Character
  • NEW FEATURE (medium): Handle stair for character controller
  • NEW FEATURE (medium): Apply impulse on objects hit by character or falling on the character

Sound engine

• Sound trigger
  • NEW FEATURE (medium): Support convex hull sound shape
  • NEW FEATURE (medium): Support portal IN and portal OUT to trigger sound
• Listener
  • NEW FEATURE (minor): Define a velocity to the listener

Aggregation

• Object entity
  • NEW FEATURE (major): Attach a sound component to an object entity (or create new game object)
  • NEW FEATURE (major): Generate collision convex hull shapes from meshes inside a urchinMesh file

Map editor

• Render
  • NEW FEATURE (medium): When change orientation of cylinder/capsule: resize physics shape to fit the object size
  • NEW FEATURE (medium): Make objects without physics selectable with left click
  • NEW FEATURE (medium): Display box around objects which don't have mesh (allow to select them easily with left click)
• UI
  • NEW FEATURE (minor): Allow undoing the actions