# HG changeset patch
# User sam <sam@basx.dev>
# Date 1717320112 -25200
# Node ID a52e924e5666ebffe22953744f4d06c5c9886398
# Parent  7f2c477ae1f4de5c6d3cdbc03323478b873d2fcf
add: function to generate circle-mesh data (not mesh object)

diff -r 7f2c477ae1f4 -r a52e924e5666 semicongine/mesh.nim
--- a/semicongine/mesh.nim	Thu May 23 02:26:37 2024 +0700
+++ b/semicongine/mesh.nim	Sun Jun 02 16:21:52 2024 +0700
@@ -489,6 +489,16 @@
   result[].initVertexAttribute("color", @[colorVec, colorVec, colorVec])
   `material=`(result[], material)
 
+proc CircleMesh*(nSegments: int): (seq[Vec3f], seq[array[3, uint16]]) =
+  let
+    rX = 0.5
+    rY = 0.5
+    step = (2'f32 * PI) / float32(nSegments)
+  result[0] = @[newVec3f(0, 0), newVec3f(rX, 0)]
+  for i in 1 .. nSegments:
+    result[0].add newVec3f(cos(float32(i) * step) * rX, sin(float32(i) * step) * rY)
+    result[1].add [uint16(0), uint16(i), uint16(i + 1)]
+
 proc circle*(width = 1'f32, height = 1'f32, nSegments = 12, color = "ffffffff", material = EMPTY_MATERIAL.initMaterialData()): Mesh =
   assert nSegments >= 3
   result = Mesh(