From ee9e3f1da0b3919ffa723f968a9eb40c918ff693 Mon Sep 17 00:00:00 2001
From: Marc Planard <case@corpsmoderne.net>
Date: Sat, 1 Jul 2023 16:01:11 +0200
Subject: [PATCH] add homography transformer

---
 src/conf.rs                   |  8 +++++---
 src/transformer.rs            |  2 ++
 src/transformer/homography.rs | 36 +++++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 3 deletions(-)
 create mode 100644 src/transformer/homography.rs

diff --git a/src/conf.rs b/src/conf.rs
index 1cc1b3e..815211c 100644
--- a/src/conf.rs
+++ b/src/conf.rs
@@ -46,8 +46,9 @@ pub enum TransformConf {
     #[serde(rename = "flip_vertical")] 
     FlipV(transformer::FlipVertical),    
     #[serde(rename = "grid")] 
-    Grid(transformer::Grid)
-
+    Grid(transformer::Grid),
+    #[serde(rename = "homography")] 
+    Homography(transformer::Homography)
 }
 
 
@@ -70,7 +71,8 @@ impl Conf {
 		TransformConf::Rotate(r) => Box::new(*r),
 		TransformConf::FlipH(r) => Box::new(*r),
 		TransformConf::FlipV(r) => Box::new(*r),		
-		TransformConf::Grid(r) => Box::new(*r)
+		TransformConf::Grid(r) => Box::new(*r),
+		TransformConf::Homography(r) => Box::new(*r),
 	    };
 	    v.push(t);
 	}
diff --git a/src/transformer.rs b/src/transformer.rs
index 6132658..aa25291 100644
--- a/src/transformer.rs
+++ b/src/transformer.rs
@@ -5,6 +5,7 @@ mod rotate;
 mod flip_horizontal;
 mod flip_vertical;
 mod grid;
+mod homography;
 
 use crate::point::Point;
 use crate::worldstate::WorldState;
@@ -16,6 +17,7 @@ pub use rotate::Rotate;
 pub use flip_horizontal::FlipHorizontal;
 pub use flip_vertical::FlipVertical;
 pub use grid::Grid;
+pub use self::homography::Homography;
 
 pub trait Transformers {
     fn apply(
diff --git a/src/transformer/homography.rs b/src/transformer/homography.rs
new file mode 100644
index 0000000..bda21c3
--- /dev/null
+++ b/src/transformer/homography.rs
@@ -0,0 +1,36 @@
+use crate::transformer::Transformers;
+use crate::point::Point;
+use crate::worldstate::WorldState;
+use serde::{Serialize,Deserialize};
+use log::info;
+use nalgebra::Matrix3;
+
+/// Homography
+
+#[derive(Serialize,Deserialize,Debug,Clone,Copy)]
+pub struct Homography {}
+
+impl Transformers for Homography {
+    fn apply(&self, point_list: &[Point], ws: &WorldState) -> Vec<Point> {	
+	let m = ws.edh.matrix;
+
+	point_list.iter()
+	    .map(| point | {
+
+		// THIS IS CERTAINLY ALL WRONG! NEEDS DEBUGING!!!
+		
+		let p = Matrix3::new(point.x, point.y, 1.0,
+				     1.0, 1.0, 1.0,
+				     1.0, 1.0, 1.0);
+		let dot = p.tr_dot(&m);
+		let new_p = Point { x: point.x / dot, y: point.y / dot,
+				    ..*point
+		};
+
+		info!("{:?} => {:?}", point, new_p);
+		
+		new_p
+	    })
+	    .collect()
+    }
+}