more granular docs

Author: asinghvi17

docs/make.jl

@@ -12,9 +12,12 @@ makedocs(
     sitename = "GeometryBasics.jl",
     pages = [
         "index.md",
+        "primitives.md",
         "rectangles.md",
         "polygons.md",
         "meshes.md",
+        "decomposition.md",
+        "distancefields.md",
         "api.md",
     ],
     modules = [GeometryTypes]

docs/src/decomposition.md

@@ -1 +1,45 @@
 # Decomposition
+
+
+## Displaying primitives
+
+To display geometry primitives, they need to be decomposable.
+This can be done for any arbitrary primitive, by overloading the following interface:
+
+```julia
+# Lets take SimpleRectangle as an example:
+# Minimal set of decomposable attributes to build up a triangle mesh
+isdecomposable(::Type{T}, ::Type{HR}) where {T<:Point, HR<:SimpleRectangle} = true
+isdecomposable(::Type{T}, ::Type{HR}) where {T<:Face, HR<:SimpleRectangle} = true
+
+# Example implementation of decompose for points
+function GeometryBasics.decompose(P::Type{Point{3, PT}}, r::SimpleRectangle, resolution=(2,2)) where PT
+    w,h = resolution
+    vec(P[(x,y,0) for x=range(r.x, stop = r.x+r.w, length = w), y=range(r.y, stop = r.y+r.h, length = h)])
+end
+
+function GeometryBasics.decompose(::Type{T}, r::SimpleRectangle, resolution=(2,2)) where T <: Face
+    w,h = resolution
+    Idx = LinearIndices(resolution)
+    faces = vec([Face{4, Int}(
+            Idx[i, j], Idx[i+1, j],
+            Idx[i+1, j+1], Idx[i, j+1]
+        ) for i=1:(w-1), j=1:(h-1)]
+    )
+    decompose(T, faces)
+end
+```
+
+With these methods defined, this constructor will magically work:
+
+```julia
+rect = SimpleRectangle(0, 0, 1, 1)
+m = GLNormalMesh(rect)
+vertices(m) == decompose(Point3f0, rect)
+
+faces(m) == decompose(GLTriangle, rect) # GLFace{3} == GLTriangle
+normals(m) # automatically calculated from mesh
+```
+
+As you can see, the normals are automatically calculated only with the faces and points.
+You can overwrite that behavior, by also defining decompose for the `Normal` type!

docs/src/distancefields.md

@@ -0,0 +1 @@
+# Distance Fields

docs/src/primitives.md

@@ -0,0 +1,22 @@
+# Primitives
+
+## Points and Vectors
+
+## Simplices
+
+## Shapes
+
+```@docs
+Circle
+Sphere
+Cylinder
+```
+
+## Abstract types
+
+```@docs
+GeometryPrimitive
+AbstractSimplex
+AbstractMesh
+AbstractDistanceField
+```