Update Grid-System wiki for dynamic layer system, mouse events, performance improvements

Grid-System.-.md

@@ -5,16 +5,17 @@ The Grid System is McRogueFace's core spatial container for roguelike game maps.
 ## Quick Reference
 
 **Related Issues:**
-- [#124](../../issues/124) - Grid Point Animation (Tier 1 - Active)
+- [#113](../../issues/113) - Batch Operations for Grid (Open - Tier 1)
-- [#123](../../issues/123) - Grid Subgrid System (Tier 1 - Active)  
+- [#124](../../issues/124) - Grid Point Animation (Open - Tier 1)
-- [#114](../../issues/114) - CellView API (Tier 1 - Active)
+- [#150](../../issues/150) - User-driven Layer Rendering (Closed - Implemented)
-- [#113](../../issues/113) - Batch Operations for Grid (Tier 1 - Active)
+- [#148](../../issues/148) - Dirty Flag RenderTexture Caching (Closed - Implemented)
-- [#64](../../issues/64) - Grid-Entity-GridPointState TCOD Updates
+- [#147](../../issues/147) - Dynamic Layer System (Closed - Implemented)
-- [#50](../../issues/50) - Grid Background Color (Closed - Implemented)
+- [#123](../../issues/123) - Chunk-based Grid Rendering (Closed - Implemented)
 
 **Key Files:**
 - `src/UIGrid.h` / `src/UIGrid.cpp` - Main grid implementation
-- `src/UIGridPoint.h` - Individual grid cell (visual layer)
+- `src/GridLayers.h` / `src/GridLayers.cpp` - ColorLayer and TileLayer
+- `src/UIGridPoint.h` - Individual grid cell (walkability, transparency)
 - `src/UIGridPointState.h` - Per-entity perspective/knowledge
 - `src/UIEntity.h` / `src/UIEntity.cpp` - Entity system (lives on grid)
 
@@ -28,10 +29,11 @@ The Grid System is McRogueFace's core spatial container for roguelike game maps.
 
 The Grid System uses a three-layer architecture for sophisticated roguelike features:
 
-1. **Visual Layer** (`UIGridPoint`)
+1. **Visual Layer** (Rendering Layers)
-   - What's displayed: tile sprite, colors, animations
+   - What's displayed: tile sprites, colors, overlays
-   - Shared by all viewers
+   - Implemented via `ColorLayer` and `TileLayer` objects
-   - File: `src/UIGridPoint.h`
+   - Multiple layers per grid with z_index ordering
+   - Files: `src/GridLayers.h`, `src/GridLayers.cpp`
 
 2. **World State Layer** (`TCODMap`)
    - Physical properties: walkable, transparent, cost
@@ -42,9 +44,41 @@ The Grid System uses a three-layer architecture for sophisticated roguelike feat
    - Per-entity knowledge: what each entity has seen/explored
    - Enables fog of war, asymmetric information
    - File: `src/UIGridPointState.h`
+   - **Note:** Python access currently limited - see Known Issues
 
 This architecture follows proven patterns from Caves of Qud, Cogmind, and DCSS.
 
+### Dynamic Layer System
+
+Grids support multiple rendering layers that can be added/removed at runtime:
+
+| Layer Type | Purpose | Methods |
+|------------|---------|---------|
+| `ColorLayer` | Solid colors per cell (fog, highlights) | `set(x, y, color)`, `at(x, y)`, `fill(color)` |
+| `TileLayer` | Texture sprites per cell (terrain, items) | `set(x, y, sprite_index)`, `at(x, y)`, `fill(index)` |
+
+**z_index semantics:**
+- Negative z_index: Renders **below** entities
+- Zero or positive z_index: Renders **above** entities
+- Lower z_index renders first (behind higher z_index)
+
+```python
+# Create grid with no default layers
+grid = mcrfpy.Grid(grid_size=(50, 50), pos=(100, 100), size=(400, 400), layers={})
+
+# Add layers explicitly
+background = grid.add_layer("color", z_index=-2)    # Furthest back
+tiles = grid.add_layer("tile", z_index=-1)          # Above background, below entities
+fog_overlay = grid.add_layer("color", z_index=1)    # Above entities (fog of war)
+
+# Access existing layers
+for layer in grid.layers:
+    print(f"{type(layer).__name__} at z={layer.z_index}")
+
+# Remove a layer
+grid.remove_layer(fog_overlay)
+```
+
 ### Grid → Entity Relationship
 
 **Entity Lifecycle:**
@@ -59,10 +93,9 @@ This architecture follows proven patterns from Caves of Qud, Cogmind, and DCSS.
 
 ## Sub-Pages
 
-- [[Grid-Rendering-Pipeline]] - How grid renders each frame
+- [[Grid-Rendering-Pipeline]] - How grid renders each frame (chunks, dirty flags, caching)
 - [[Grid-TCOD-Integration]] - FOV, pathfinding, walkability
 - [[Grid-Entity-Lifecycle]] - Entity creation, movement, removal
-- [[Grid-Performance-Optimization]] - Dirty flags, culling, batch ops
 
 ## Common Tasks
 
@@ -71,91 +104,142 @@ This architecture follows proven patterns from Caves of Qud, Cogmind, and DCSS.
 ```python
 import mcrfpy
 
-# Create 50x50 grid with 16x16 tile size
+# Create grid with default tile layer
-grid = mcrfpy.Grid(50, 50, 16, 16)
+grid = mcrfpy.Grid(
-grid.texture = mcrfpy.createTexture("tileset.png")
+    grid_size=(50, 50),      # 50x50 cells
-grid.pos = (100, 100)  # Screen position
+    pos=(100, 100),          # Screen position
+    size=(400, 400),         # Viewport size in pixels
+    texture=my_texture       # Texture for default TileLayer
+)
+
+# Or create with specific layer configuration
+grid = mcrfpy.Grid(
+    grid_size=(50, 50),
+    pos=(100, 100),
+    size=(400, 400),
+    layers={"terrain": "tile", "highlights": "color"}
+)
+
+# Or start empty and add layers manually
+grid = mcrfpy.Grid(grid_size=(50, 50), pos=(100, 100), size=(400, 400), layers={})
+terrain = grid.add_layer("tile", z_index=-1, texture=my_texture)
 
 # Add to scene
 mcrfpy.sceneUI("game").append(grid)
 ```
 
-**Details:** See `src/UIGrid.cpp::PyInit()` for constructor implementation
-
 ### Setting Tile Properties
 
 ```python
-# Access individual cell
+# Access layers for visual properties
-cell = grid.at((x, y))
+tile_layer = grid.layers[0]  # First layer (usually tiles)
+tile_layer.set(x, y, 42)     # Set sprite index at cell
 
-# Visual properties
+color_layer = grid.add_layer("color", z_index=-2)
-cell.tilesprite = 42  # Sprite index in texture
+color_layer.set(x, y, mcrfpy.Color(64, 64, 128))  # Blue tint
-cell.color = mcrfpy.Color(255, 255, 255)
 
-# World properties (TCOD integration)
+# Access grid point for world properties
-grid.walkable((x, y), True)   # Can entities walk here?
+point = grid.at(x, y)
-grid.transparent((x, y), True)  # Can see through?
+point.walkable = True      # Can entities walk here?
+point.transparent = True   # Can see through for FOV?
 ```
 
-**Implementation:** `src/UIGrid.cpp::walkable()`, `src/UIGrid.cpp::transparent()`
-
 ### FOV and Pathfinding
 
 ```python
-# Compute field of view from entity position
+# Compute field of view from position
-grid.compute_fov(entity.x, entity.y, radius=10)
+grid.compute_fov(entity.grid_x, entity.grid_y, radius=10)
+
+# Check if cell is visible
+if grid.is_in_fov(target_x, target_y):
+    print("Target is visible!")
 
 # A* pathfinding
-path = entity.path_to(target_x, target_y)
+path = grid.find_path(start_x, start_y, end_x, end_y)
+
+# Dijkstra maps for AI
+grid.compute_dijkstra([(goal_x, goal_y)])
+distance = grid.get_dijkstra_distance(entity.grid_x, entity.grid_y)
+path_to_goal = grid.get_dijkstra_path(entity.grid_x, entity.grid_y)
 ```
 
-**Implementation:** 
+### Mouse Events
-- FOV: `src/UIGrid.cpp::compute_fov()` (TCOD integration)
+
-- Pathfinding: `src/UIEntity.cpp::path_to()` (uses TCOD A*)
+Grids support mouse interaction at both the grid level and cell level:
+
+```python
+# Grid-level events (screen coordinates)
+def on_grid_click(x, y, button):
+    print(f"Grid clicked at pixel ({x}, {y}), button {button}")
+
+grid.on_click = on_grid_click
+grid.on_enter = lambda: print("Mouse entered grid")
+grid.on_exit = lambda: print("Mouse left grid")
+grid.on_move = lambda x, y: print(f"Mouse at ({x}, {y})")
+
+# Cell-level events (grid coordinates)
+def on_cell_click(grid_x, grid_y):
+    print(f"Cell ({grid_x}, {grid_y}) clicked!")
+    point = grid.at(grid_x, grid_y)
+    # Do something with the cell...
+
+grid.on_cell_click = on_cell_click
+grid.on_cell_enter = lambda x, y: print(f"Entered cell ({x}, {y})")
+grid.on_cell_exit = lambda x, y: print(f"Left cell ({x}, {y})")
+
+# Query currently hovered cell
+if grid.hovered_cell:
+    hx, hy = grid.hovered_cell
+    print(f"Hovering over ({hx}, {hy})")
+```
+
+### Camera Control
+
+```python
+# Center viewport on a position (pixel coordinates within grid space)
+grid.center = (player.grid_x * 16 + 8, player.grid_y * 16 + 8)
+
+# Or set components individually
+grid.center_x = player.grid_x * 16 + 8
+grid.center_y = player.grid_y * 16 + 8
+
+# Zoom (1.0 = normal, 2.0 = 2x zoom in, 0.5 = zoom out)
+grid.zoom = 1.5
+```
 
 ## Performance Characteristics
 
-**Current:**
+**Implemented Optimizations:**
-- Grid rendering: O(visible_cells) - renders only viewport
+- **Chunk-based rendering** ([#123](../../issues/123)): Large grids divided into chunks, only visible chunks rendered
-- Entity rendering: O(entities) - culls out-of-bounds (see `src/UIGrid.cpp::render()`)
+- **Dirty flag system** ([#148](../../issues/148)): Layers track changes, skip redraw when unchanged
-- Static grids: Inefficient - redraws unchanged cells every frame
+- **RenderTexture caching**: Each chunk cached to texture, reused until dirty
+- **Viewport culling**: Only cells within viewport are processed
 
-**Optimizations In Progress:**
+**Current Performance:**
-- [#116](../../issues/116): Dirty flag system - only redraw on changes
+- Grids of 1000x1000+ cells render efficiently
-- [#113](../../issues/113): Batch operations - reduce Python/C++ boundary crossings  
+- Static scenes near-zero CPU (cached textures reused)
-- [#115](../../issues/115): SpatialHash - O(1) entity spatial queries
+- Entity rendering: O(visible entities)
-- [#123](../../issues/123): Subgrid system - divide large grids into chunks
 
-**Profiling:** Press F3 in-game to see grid render metrics (see [[Performance-and-Profiling]])
+**Profiling:** Use the F3 overlay or `mcrfpy.setTimer()` with `mcrfpy.getMetrics()` to measure grid performance. See [[Performance-and-Profiling]].
-
-## Design Proposals
-
-Active architectural evolution:
-
-- [[Proposal-Next-Gen-Grid-Architecture]] - Subgrid system, tile animation
-- [[Proposal-Next-Gen-Entity-System]] - Flexible entity content, multi-tile entities
 
 ## Known Issues & Limitations
 
 **Current Limitations:**
-- No tile-level animation (planned: [#124](../../issues/124))
+- **FOV Python access limited:** `compute_fov()` works but fog-of-war overlay must be managed manually via color layers. Per-entity perspective (`UIGridPointState`) not yet exposed to Python. See [#113 discussion](../../issues/113).
-- Large grids (>200x200) can have rendering overhead
+- No tile-level animation yet (planned: [#124](../../issues/124))
-- Entity iteration is O(n) for spatial queries
+- Entity spatial queries are O(n) (planned: SpatialHash [#115](../../issues/115))
 
 **Workarounds:**
-- Keep grids reasonably sized (< 100x100 for best performance)
+- For fog of war: Use a `ColorLayer` with positive z_index, update cell colors based on `is_in_fov()` results
-- Use entity culling (automatically enabled in `UIGrid::render()`)
+- For entity queries: Use list comprehension filtering on `grid.entities`
-- Profile with F3 overlay to identify bottlenecks
 
 ## Related Systems
 
 - [[UI-Component-Hierarchy]] - Grid inherits from UIDrawable
-- [[Animation-System]] - Grid properties are animatable (pos, zoom, etc)
+- [[Animation-System]] - Grid properties are animatable (pos, zoom, center, etc.)
-- [[Performance-and-Profiling]] - Grid rendering instrumented with ScopedTimer
+- [[Performance-and-Profiling]] - Grid rendering instrumented with metrics
-- [[Entity-Management]] - Entity use case depends on Grid system
+- [[Entity-Management]] - Entities live within Grid containers
 
 ---
 
-**See Also:**
+*Last updated: 2025-11-29*
-- Tutorial: [McRogueFace Does The Entire Roguelike Tutorial](../../roguelike_tutorial/)
-- Build Guide: CLAUDE.md in repository root