world view ray casting

internal/world/block.go

@@ -23,7 +23,8 @@ type BlockAppearance struct {
 	NotSolid    bool   // Is block not solid, i.e., has no hitbox at all? (this makes the zero value reasonable)
 	Light       int    // The light level it emits, 0 is none
 
-	Hitbox []itype.Boxd // Hitbox, in block-local coordinates; empty slice means a default hitbox of 1x1x1
+	Hitbox  []itype.Boxd // Hitbox, in block-local coordinates; empty slice means a default hitbox of 1x1x1
+	Lookbox []itype.Boxd // Selection hitbox, hit only by the view ray; empty means Hitbox[]
 
 	RenderType BlockRenderType // Rendering type, defaults to OneTexture (zero value)
 
@@ -130,6 +131,9 @@ func GetBlockAppearance(position itype.Vec3i, id, aux int, data itype.Dataset, w
 				SizeX: 1, SizeY: 1, SizeZ: 1,
 			}}
 		}
+		if len(app.Lookbox) == 0 {
+			app.Lookbox = app.Hitbox
+		}
 		return app
 	}
 
@@ -146,6 +150,9 @@ func GetBlockAppearance(position itype.Vec3i, id, aux int, data itype.Dataset, w
 			SizeX: 1, SizeY: 1, SizeZ: 1,
 		}}
 	}
+	if len(app.Lookbox) == 0 {
+		app.Lookbox = app.Hitbox
+	}
 	return app
 }
 
@@ -172,6 +179,16 @@ func (b Block) Appearance(position itype.Vec3i) BlockAppearance {
 			SizeX: 1, SizeY: 1, SizeZ: 1,
 		}}
 	}
+	if len(app.Lookbox) == 0 {
+		if len(app.Hitbox) == 0 {
+			app.Lookbox = []itype.Boxd{{
+				OffX: 0, OffY: 0, OffZ: 0,
+				SizeX: 1, SizeY: 1, SizeZ: 1,
+			}}
+		} else {
+			app.Lookbox = app.Hitbox
+		}
+	}
 	return app
 }