Adding documentation for asset database & drawign

Author: BrentFarris

src/engine/assets/database.go

@@ -36,13 +36,43 @@
 
 package assets
 
+// Database defines the contract for asset storage back‑ends used by the engine.
+// Implementations may store assets on disk, in memory, inside an archive, or
+// provide a debug view of the file system. The interface abstracts common
+// operations required by the engine and editor.
 type Database interface {
+	// PostWindowCreate is a hook that is called after a window has been
+	// created. Implementations can use the provided handle to perform any
+	// platform‑specific initialisation. Most implementations are no‑ops.
 	PostWindowCreate(windowHandle PostWindowCreateHandle) error
+
+	// Cache stores the raw byte slice `data` under `key` for fast subsequent
+	// reads. Implementations may choose to ignore this (e.g. DebugContentDatabase)
+	// or provide a real cache (e.g. FileDatabase).
 	Cache(key string, data []byte)
+
+	// CacheRemove removes a cached entry identified by `key`. If the
+	// implementation does not maintain a cache this is a no‑op.
 	CacheRemove(key string)
+
+	// CacheClear clears all cached entries. Implementations without a cache
+	// should simply return.
 	CacheClear()
+
+	// Read returns the raw bytes for the asset identified by `key`. An error is
+	// returned if the asset cannot be found or read.
 	Read(key string) ([]byte, error)
+
+	// ReadText is a convenience wrapper around Read that returns the asset as a
+	// string. It returns any error from Read.
 	ReadText(key string) (string, error)
+
+	// Exists reports whether an asset with the given `key` is available in the
+	// underlying storage. Implementations should check both the cache and the
+	// backing store.
 	Exists(key string) bool
+
+	// Close releases any resources held by the implementation. Implementations
+	// that have no resources may implement this as a no‑op.
 	Close()
 }

src/engine/ui/panel.go

@@ -37,12 +37,13 @@
 package ui
 
 import (
+	"log/slog"
+
 	"kaijuengine.com/engine/assets"
 	"kaijuengine.com/engine/systems/events"
 	"kaijuengine.com/matrix"
 	"kaijuengine.com/platform/profiler/tracing"
 	"kaijuengine.com/rendering"
-	"log/slog"
 )
 
 type PanelScrollDirection = int32
@@ -389,10 +390,8 @@ func (p *Panel) updateShaderVisibility() {
 	if !p.entity.IsActive() {
 		return
 	}
-
 	// Retrieve the current scissor rectangle from the root UI.
 	scissor := p.Base().selfScissor()
-
 	// Compute the panel's world‑space bounds.
 	pos := p.entity.Transform.WorldPosition()
 	size := p.layout.PixelSize()
@@ -401,7 +400,6 @@ func (p *Panel) updateShaderVisibility() {
 	right := pos.X() + half.X()
 	bottom := pos.Y() - half.Y()
 	top := pos.Y() + half.Y()
-
 	// If the panel is completely outside the scissor, deactivate its shader data.
 	if right < scissor.X() || left > scissor.Z() || top < scissor.Y() || bottom > scissor.W() {
 		p.shaderData.Deactivate()

src/rendering/drawing.go

@@ -37,22 +37,35 @@
 package rendering
 
 import (
+	"sort"
+	"sync"
+
 	"kaijuengine.com/klib"
 	"kaijuengine.com/matrix"
 	"kaijuengine.com/platform/profiler/tracing"
-	"sort"
-	"sync"
 )
 
+// Drawing represents a renderable entity in the engine. It bundles together
+// the material, mesh, shader instance data, transform, sorting order, and an
+// optional view culler used during rendering.
 type Drawing struct {
-	Material   *Material
-	Mesh       *Mesh
+	// Material defines the visual appearance and render pass for the drawing.
+	Material *Material
+	// Mesh contains the geometry to be rendered.
+	Mesh *Mesh
+	// ShaderData holds per‑instance data for the shader (e.g., uniforms).
 	ShaderData DrawInstance
-	Transform  *matrix.Transform
-	Sort       int
+	// Transform specifies the transform this drawing follows.
+	Transform *matrix.Transform
+	// Sort determines the draw order within a render pass.
+	Sort int
+	// ViewCuller optionally culls the drawing based on the view frustum.
 	ViewCuller ViewCuller
 }
 
+// IsValid reports whether the Drawing is properly configured for rendering.
+// A Drawing is considered valid if it has a non-nil Material. This check is
+// used before submitting the drawing to the render pipeline.
 func (d *Drawing) IsValid() bool {
 	return d.Material != nil
 }