batching sidewalk lines. fix the very silly batching bug

editor/src/render/lane.rs

@@ -143,21 +143,20 @@ fn calculate_sidewalk_lines(lane: &Lane) -> Marking {
 
     let length = lane.length();
 
-    let mut lines = Vec::new();
+    let mut draw = Vec::new();
     // Start away from the intersections
     let mut dist_along = tile_every;
     while dist_along < length - tile_every {
         let (pt, angle) = lane.dist_along(dist_along);
         // Reuse perp_line. Project away an arbitrary amount
         let pt2 = pt.project_away(1.0, angle);
-        lines.push(perp_line(Line::new(pt, pt2), LANE_THICKNESS));
+        draw.push(perp_line(Line::new(pt, pt2), LANE_THICKNESS).make_polygons(0.25));
         dist_along += tile_every;
     }
 
     Box::new(move |g, cs| {
-        for line in &lines {
+        let color = cs.get_def("sidewalk lines", Color::grey(0.7));
-            g.draw_line(cs.get_def("sidewalk lines", Color::grey(0.7)), 0.25, line);
+        g.draw_polygon_batch(draw.iter().map(|poly| (color, poly)).collect())
-        }
     })
 }
 

ezgui/src/drawing.rs

@@ -102,7 +102,7 @@ impl<'a> GfxCtx<'a> {
     // Use graphics::Line internally for now, but make it easy to switch to something else by
     // picking this API now.
     pub fn draw_line(&mut self, color: Color, thickness: f64, line: &Line) {
-        self.draw_polygon(color, &line.to_polyline().make_polygons(thickness));
+        self.draw_polygon(color, &line.make_polygons(thickness));
     }
 
     pub fn draw_rounded_line(&mut self, color: Color, thickness: f64, line: &Line) {
@@ -110,7 +110,7 @@ impl<'a> GfxCtx<'a> {
         self.draw_circle(color, &Circle::new(line.pt1(), thickness / 2.0));
         self.draw_circle(color, &Circle::new(line.pt2(), thickness / 2.0));
         /*self.draw_polygon_batch(vec![
-            (color, &line.to_polyline().make_polygons(thickness)),
+            (color, &line.make_polygons(thickness)),
             (
                 color,
                 &Circle::new(line.pt1(), thickness / 2.0).to_polygon(TRIANGLES_PER_CIRCLE),
@@ -168,6 +168,7 @@ impl<'a> GfxCtx<'a> {
         let mut indices: Vec<u32> = Vec::new();
 
         for (color, poly) in list {
+            let idx_offset = vertices.len();
             let (pts, raw_indices) = poly.raw_for_rendering();
             for pt in pts {
                 vertices.push(Vertex {
@@ -175,9 +176,8 @@ impl<'a> GfxCtx<'a> {
                     color: color.0,
                 });
             }
-            let offset = indices.len();
             for idx in raw_indices {
-                indices.push((offset + *idx) as u32);
+                indices.push((idx_offset + *idx) as u32);
             }
         }
 

geom/src/line.rs

@@ -1,4 +1,4 @@
-use crate::{line_intersection, Angle, PolyLine, Pt2D, EPSILON_DIST};
+use crate::{line_intersection, Angle, PolyLine, Polygon, Pt2D, EPSILON_DIST};
 use dimensioned::si;
 use serde_derive::{Deserialize, Serialize};
 use std::fmt;
@@ -30,6 +30,10 @@ impl Line {
         PolyLine::new(self.points())
     }
 
+    pub fn make_polygons(&self, thickness: f64) -> Polygon {
+        self.to_polyline().make_polygons(thickness)
+    }
+
     // TODO valid to do euclidean distance on world-space points that're formed from
     // Haversine?
     pub fn length(&self) -> si::Meter<f64> {