make clipping be a stateful API, as prep for clipping composites

ezgui/src/drawing.rs

@@ -205,25 +205,21 @@ impl<'a> GfxCtx<'a> {
         // println!("{:?}", backtrace::Backtrace::new());
     }
 
-    pub fn redraw_clipped(&mut self, obj: &Drawable, rect: &ScreenRectangle) {
-        let mut params = self.params.clone();
-        params.scissor = Some(glium::Rect {
+    // TODO Stateful API :(
+    pub fn enable_clipping(&mut self, rect: ScreenRectangle) {
+        assert!(self.params.scissor.is_none());
+        self.params.scissor = Some(glium::Rect {
             left: (self.canvas.hidpi_factor * rect.x1) as u32,
             // Y-inversion
             bottom: (self.canvas.hidpi_factor * (self.canvas.window_height - rect.y2)) as u32,
             width: (self.canvas.hidpi_factor * (rect.x2 - rect.x1)) as u32,
             height: (self.canvas.hidpi_factor * (rect.y2 - rect.y1)) as u32,
         });
-        self.target
-            .draw(
-                &obj.vertex_buffer,
-                &obj.index_buffer,
-                &self.program,
-                &self.uniforms,
-                &params,
-            )
-            .unwrap();
-        self.num_draw_calls += 1;
+    }
+
+    pub fn disable_clipping(&mut self) {
+        assert!(self.params.scissor.is_some());
+        self.params.scissor = None;
     }
 
     // Canvas stuff.

game/src/common/minimap.rs

@@ -209,16 +209,14 @@ impl Minimap {
             ScreenPt::new(inner_rect.x1, inner_rect.y1),
             self.zoom,
         );
-        g.redraw_clipped(&ui.primary.draw_map.boundary_polygon, &inner_rect);
-        g.redraw_clipped(&ui.primary.draw_map.draw_all_areas, &inner_rect);
-        g.redraw_clipped(&ui.primary.draw_map.draw_all_thick_roads, &inner_rect);
-        g.redraw_clipped(
-            &ui.primary.draw_map.draw_all_unzoomed_intersections,
-            &inner_rect,
-        );
-        g.redraw_clipped(&ui.primary.draw_map.draw_all_buildings, &inner_rect);
+        g.enable_clipping(inner_rect);
+        g.redraw(&ui.primary.draw_map.boundary_polygon);
+        g.redraw(&ui.primary.draw_map.draw_all_areas);
+        g.redraw(&ui.primary.draw_map.draw_all_thick_roads);
+        g.redraw(&ui.primary.draw_map.draw_all_unzoomed_intersections);
+        g.redraw(&ui.primary.draw_map.draw_all_buildings);
         if let Some(ref c) = colorer {
-            g.redraw_clipped(&c.unzoomed, &inner_rect);
+            g.redraw(&c.unzoomed);
         }
 
         let mut cache = ui.primary.draw_map.agents.borrow_mut();
@@ -227,7 +225,6 @@ impl Minimap {
             &ui.primary.map,
             &ui.agent_cs,
             g,
-            Some(&inner_rect),
             self.zoom,
             Distance::meters(5.0),
         );
@@ -265,6 +262,7 @@ impl Minimap {
             // TODO Happens when we're quite out-of-bounds. Maybe stop allowing this at all?
             println!("Warning: Minimap cursor is just a point right now");
         }
+        g.disable_clipping();
         g.unfork();
     }
 }

game/src/render/map.rs

@@ -10,7 +10,7 @@ use crate::render::Renderable;
 use crate::ui::Flags;
 use aabb_quadtree::QuadTree;
 use abstutil::{Cloneable, Timer};
-use ezgui::{Color, Drawable, EventCtx, GeomBatch, GfxCtx, ScreenRectangle};
+use ezgui::{Color, Drawable, EventCtx, GeomBatch, GfxCtx};
 use geom::{Bounds, Circle, Distance, Duration, FindClosest, Time};
 use map_model::{
     AreaID, BuildingID, BusStopID, DirectedRoadID, Intersection, IntersectionID, LaneID, Map, Road,
@@ -333,18 +333,13 @@ impl AgentCache {
         map: &Map,
         acs: &AgentColorScheme,
         g: &mut GfxCtx,
-        clip: Option<&ScreenRectangle>,
         cam_zoom: f64,
         radius: Distance,
     ) {
         let now = source.time();
         if let Some((time, z, r, ref orig_acs, ref draw)) = self.unzoomed {
             if cam_zoom == z && now == time && radius == r && acs == orig_acs {
-                if let Some(ref rect) = clip {
-                    g.redraw_clipped(draw, rect);
-                } else {
-                    g.redraw(draw);
-                }
+                g.redraw(draw);
                 return;
             }
         }
@@ -362,11 +357,7 @@ impl AgentCache {
         }
 
         let draw = g.upload(batch);
-        if let Some(ref rect) = clip {
-            g.redraw_clipped(&draw, rect);
-        } else {
-            g.redraw(&draw);
-        }
+        g.redraw(&draw);
         self.unzoomed = Some((now, cam_zoom, radius, acs.clone(), draw));
     }
 }

game/src/ui.rs

@@ -160,7 +160,6 @@ impl UI {
                 &self.primary.map,
                 &self.agent_cs,
                 g,
-                None,
                 g.canvas.cam_zoom,
                 Distance::meters(10.0),
             );