docs: implementation document

IMPLEMENTATION.md

@@ -0,0 +1,35 @@
+# Implementation
+
+A document detailing the implementation the project from rendering, to game logic, to build systems.
+
+## Rendering
+
+1. Map
+    - May require procedural text generation later on (cacheable?)
+2. Pacman
+3. Ghosts
+    - Requires colors
+4. Items
+5. Interface
+    - Requires fonts
+
+## Grid System
+
+1. How does the grid system work?
+
+The grid is 28 x 36 (although, the map texture is 28 x 37), and each cell is 24x24 (pixels).
+Many of the walls in the map texture only occupy a portion of the cell, so some items are able to render across multiple cells.
+24x24 assets include pellets, the energizer, and the map itself ()
+
+2. What constraints must be enforced on Ghosts and PacMan?
+
+3. How do movement transitions work?
+
+All entities store a precise position, and a direction. This position is only used for animation, rendering, and collision purposes. Otherwise, a separate 'cell position' (which is 24 times less precise, owing to the fact that it is based on the entity's position within the grid).
+
+When an entity is transitioning between cells, movement directions are acknowledged, but won't take effect until the next cell has been entered completely.
+
+4. Between transitions, how does collision detection work?
+
+It appears the original implementation used cell-level detection.
+I worry this may be prone to division errors. Make sure to use rounding (50% >=).