gamnit and related: improve doc

[nit.git] / lib / gamnit / depth / more_meshes.nit

diff --git a/lib/gamnit/depth/more_meshes.nit b/lib/gamnit/depth/more_meshes.nit
index 9f2318a..0a4d53c 100644 (file)
--- a/lib/gamnit/depth/more_meshes.nit
+++ b/lib/gamnit/depth/more_meshes.nit
@@ -17,6 +17,7 @@ module more_meshes
 
 import geometry
 import depth_core
+import model_dimensions
 
 # Simple flat mesh, sits on the axes X and Z, normal on Y
 class Plane
@@ -79,6 +80,8 @@ class Plane
 end
 
 # Cube, with 6 faces
+#
+# Occupies `[-0.5..0.5]` on all three axes.
 class Cube
        super Mesh
 
@@ -124,9 +127,75 @@ class Cube
                var d = [1.0, 0.0]
 
                var texture_coords = new Array[Float]
-               for v in [c, d, a, a, d, b] do for i in 6.times do texture_coords.add_all v
+               var face = [a, c, d, a, d, b]
+               for i in 6.times do for v in face do texture_coords.add_all v
                return texture_coords
        end
 
        redef var center = new Point3d[Float](0.0, 0.0, 0.0) is lazy
 end
+
+# Sphere with `radius` and a number of faces set by `n_meridians` and `n_parallels`
+class UVSphere
+       super Mesh
+
+       # Distance between the center and the vertices
+       var radius: Float
+
+       # Number of vertices on a full circle around the Z axis
+       var n_meridians: Int
+
+       # Number of vertices on an arc between both poles
+       var n_parallels: Int
+
+       init
+       do
+               var w = n_meridians
+               var h = n_parallels
+
+               var vertices = new Array[Float].with_capacity(w*h*3)
+               self.vertices = vertices
+
+               var texture_coords = new Array[Float].with_capacity(w*h*2)
+               self.texture_coords = texture_coords
+
+               var normals = new Array[Float].with_capacity(w*h*3)
+               self.normals = normals
+
+               # Build vertices
+               for m in [0..w[ do
+                       for p in [0..h[ do
+                               var u = m.to_f * 2.0 * pi / (w-1).to_f
+                               var v = p.to_f * pi / (h-1).to_f
+
+                               vertices.add radius * u.cos * v.sin
+                               vertices.add radius * v.cos
+                               vertices.add radius * u.sin * v.sin
+
+                               texture_coords.add (1.0 - m.to_f/(w-1).to_f)
+                               texture_coords.add(p.to_f/(h-1).to_f)
+
+                               normals.add u.cos * v.sin
+                               normals.add v.cos
+                               normals.add u.sin * v.sin
+                       end
+               end
+
+               # Build faces
+               var indices = new Array[Int].with_capacity((w-1)*(h-1)*6)
+               self.indices = indices
+               for m in [0..w-1[ do
+                       for p in [0..h-1[ do
+                               var a = m*h + p
+
+                               indices.add a
+                               indices.add a+h
+                               indices.add a+1
+
+                               indices.add a+h
+                               indices.add a+h+1
+                               indices.add a+1
+                       end
+               end
+       end
+end