use the pts/indices for rendering

docs/TODO_ux.md

@@ -66,12 +66,13 @@
 ## Switch to OpenGL (for speed)
 
 - speed
-	- make polygon store points and indices efficiently
 	- change ezgui API to allow uploading geometry once
-	- event loop feels sticky
+		- what about color then? get fancy and plumb an override color uniform?
+	- sleep better in the event loop
 		- first make UserInput borrow state and not need to consume
 	- experiment with batching and not passing colors
 	- measure performance of huge maps
+	- specialized things for common shapes like circles?
 - quality
 	- need padding around text
 	- text entry needs to draw the cursor differently

ezgui/src/lib.rs

@@ -214,27 +214,15 @@ impl<'a> GfxCtx<'a> {
     }
 
     pub fn draw_polygon(&mut self, color: Color, poly: &Polygon) {
-        let mut vertices: Vec<Vertex> = Vec::new();
-        let mut indices: Vec<u32> = Vec::new();
-        for (idx, tri) in poly.triangles().into_iter().enumerate() {
-            vertices.push(Vertex {
-                position: [tri.pt1.x() as f32, tri.pt1.y() as f32],
+        let (pts, raw_indices) = poly.raw_for_rendering();
+        let vertices: Vec<Vertex> = pts
+            .iter()
+            .map(|pt| Vertex {
+                position: [pt.x() as f32, pt.y() as f32],
                 color: color.0,
-            });
-            vertices.push(Vertex {
-                position: [tri.pt2.x() as f32, tri.pt2.y() as f32],
-                color: color.0,
-            });
-            vertices.push(Vertex {
-                position: [tri.pt3.x() as f32, tri.pt3.y() as f32],
-                color: color.0,
-            });
-
-            let i = (3 * idx) as u32;
-            indices.push(i);
-            indices.push(i + 1);
-            indices.push(i + 2);
-        }
+            })
+            .collect();
+        let indices: Vec<u32> = raw_indices.iter().map(|i| *i as u32).collect();
 
         let vertex_buffer = glium::VertexBuffer::new(self.display, &vertices).unwrap();
         let index_buffer = glium::IndexBuffer::new(

geom/src/polygon.rs

@@ -94,6 +94,10 @@ impl Polygon {
         triangles
     }
 
+    pub fn raw_for_rendering(&self) -> (&Vec<Pt2D>, &Vec<usize>) {
+        (&self.points, &self.indices)
+    }
+
     pub fn contains_pt(&self, pt: Pt2D) -> bool {
         self.triangles().into_iter().any(|tri| tri.contains_pt(pt))
     }