From ebe6b317f2af4a492cbfa0312f0f89889ceeb03a Mon Sep 17 00:00:00 2001
From: Jarrod Doyle <thejarroddoyle@gmail.com>
Date: Fri, 22 Sep 2023 11:14:15 +0100
Subject: [PATCH] Add basic cylinder brush generator

---
 editor/src/main.rs | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/editor/src/main.rs b/editor/src/main.rs
index 6363b1a..a557dfb 100644
--- a/editor/src/main.rs
+++ b/editor/src/main.rs
@@ -55,6 +55,38 @@ fn generate_pyramid_brush(position: Vec3, height: f32, side_count: u32) -> Brush
     Brush::new(&brush_planes)
 }
 
+fn generate_cylinder_brush(position: Vec3, height: f32, radius: f32, side_count: u32) -> Brush {
+    let mut brush_planes = vec![];
+
+    // Top/bottom planes
+    for normal in &[Vec3::Y, Vec3::NEG_Y] {
+        let point = position + *normal * (height * 0.5);
+        brush_planes.push(BrushPlane {
+            plane: Plane::from_point_normal(point, *normal),
+            ..Default::default()
+        });
+    }
+
+    // Side planes
+    for i in 0..side_count {
+        let angle = (i as f32 / side_count as f32) * 360.0_f32.to_radians();
+        let rot_mat = Mat3::from_cols(
+            Vec3::new(angle.cos(), 0.0, -angle.sin()),
+            Vec3::Y,
+            Vec3::new(angle.sin(), 0.0, angle.cos()),
+        );
+        let normal = rot_mat * Vec3::new(1.0, 0.0, 0.0);
+        let point = position + radius * normal;
+
+        brush_planes.push(BrushPlane {
+            plane: Plane::from_point_normal(point, normal),
+            ..Default::default()
+        });
+    }
+
+    Brush::new(&brush_planes)
+}
+
 fn main() {
     let mut brush = generate_box_brush(Vec3::new(1.0, 0.0, 0.0), Vec3::new(1.0, 2.0, 1.0));
     brush.rebuild();
@@ -67,4 +99,10 @@ fn main() {
     let vs = brush.get_vertices();
 
     println!("Vertices: {vs:?}");
+
+    let mut brush = generate_cylinder_brush(Vec3::ZERO, 2.0, 1.0, 64);
+    brush.rebuild();
+    let vs = brush.get_vertices();
+
+    println!("Vertices: {vs:?}");
 }