Refactor camera to batch render

src/main.rs

@@ -5,7 +5,6 @@
 extern crate lazy_static;
 
 mod ai;
-pub mod camera;
 mod colors;
 mod components;
 mod damage_system;

src/map.rs

@@ -1,4 +1,5 @@
 //! An object to hold the state of the current level's map
+pub mod camera;
 mod dungeon;
 mod themes;
 mod tiletype;

src/map/camera.rs

@@ -1,6 +1,7 @@
 //! Handle rendering of the viewport
-use rltk::{Point, Rltk};
-use specs::prelude::*;
+use ::rltk::prelude::*;
+use ::rltk::{Point, Rltk};
+use ::specs::prelude::*;
 
 use crate::components::{Hidden, Position, Renderable, Target, TileSize};
 use crate::map::tile_glyph;
@@ -28,6 +29,7 @@ pub fn get_screen_bounds(ecs: &World, _ctx: &mut Rltk) -> (i32, i32, i32, i32) {
 
 /// Render the current viewport
 pub fn render_camera(ecs: &World, ctx: &mut Rltk) {
+    let mut draw_batch = DrawBatch::new();
     let map = ecs.fetch::<Map>();
     let (min_x, max_x, min_y, max_y) = get_screen_bounds(ecs, ctx);
 
@@ -35,23 +37,22 @@ pub fn render_camera(ecs: &World, ctx: &mut Rltk) {
     let map_width = map.width - 1;
     let map_height = map.height - 1;
 
-    let mut y = 0;
-    #[allow(clippy::explicit_counter_loop)]
-    for ty in min_y..max_y {
-        let mut x = 0;
-        for tx in min_x..max_x {
+    for (y, ty) in (min_y..max_y).enumerate() {
+        for (x, tx) in (min_x..max_x).enumerate() {
             if tx > 0 && tx < map_width && ty > 0 && ty < map_height {
                 let idx = map.xy_idx(tx, ty);
                 if map.revealed_tiles[idx] {
                     let (glyph, fg, bg) = tile_glyph(idx, &*map);
-                    ctx.set(x, y, fg, bg, glyph);
+                    draw_batch.set(Point::new(x, y), ColorPair::new(fg, bg), glyph);
                 }
             } else if SHOW_BOUNDARIES {
-                ctx.set(x, y, colors::GRAY, colors::BLACK, rltk::to_cp437('·'));
+                draw_batch.set(
+                    Point::new(x, y),
+                    ColorPair::new(colors::GRAY, colors::BLACK),
+                    rltk::to_cp437('·'),
+                );
             }
-            x += 1;
         }
-        y += 1;
     }
 
     // Render entities
@@ -82,11 +83,9 @@ pub fn render_camera(ecs: &World, ctx: &mut Rltk) {
                             && entity_screen_y > 0
                             && entity_screen_y < map_height
                         {
-                            ctx.set(
-                                entity_screen_x + 1,
-                                entity_screen_y + 1,
-                                render.fg,
-                                render.bg,
+                            draw_batch.set(
+                                Point::new(entity_screen_x + 1, entity_screen_y + 1),
+                                ColorPair::new(render.fg, render.bg),
                                 render.glyph,
                             );
                         }
@@ -103,11 +102,9 @@ pub fn render_camera(ecs: &World, ctx: &mut Rltk) {
                     && entity_screen_y > 0
                     && entity_screen_y < map_height
                 {
-                    ctx.set(
-                        entity_screen_x,
-                        entity_screen_y,
-                        render.fg,
-                        render.bg,
+                    draw_batch.set(
+                        Point::new(entity_screen_x, entity_screen_y),
+                        ColorPair::new(render.fg, render.bg),
                         render.glyph,
                     );
                 }
@@ -117,22 +114,22 @@ pub fn render_camera(ecs: &World, ctx: &mut Rltk) {
         if targets.get(*entity).is_some() {
             let entity_screen_x = pos.x - min_x;
             let entity_screen_y = pos.y - min_y;
-            ctx.set(
-                entity_screen_x - 1,
-                entity_screen_y,
-                colors::RED,
-                colors::YELLOW,
+            draw_batch.set(
+                Point::new(entity_screen_x - 1, entity_screen_y),
+                ColorPair::new(colors::RED, colors::YELLOW),
                 ::rltk::to_cp437('['),
             );
-            ctx.set(
-                entity_screen_x + 1,
-                entity_screen_y,
-                colors::RED,
-                colors::YELLOW,
+            draw_batch.set(
+                Point::new(entity_screen_x + 1, entity_screen_y),
+                ColorPair::new(colors::RED, colors::YELLOW),
                 ::rltk::to_cp437(']'),
-            )
+            );
         }
     }
+
+    draw_batch
+        .submit(0)
+        .expect("Failed to batch draw the camera");
 }
 
 pub fn render_debug_map(map: &Map, ctx: &mut Rltk) {
@@ -150,11 +147,8 @@ pub fn render_debug_map(map: &Map, ctx: &mut Rltk) {
     let map_width = map.width - 1;
     let map_height = map.height - 1;
 
-    let mut y = 0;
-    #[allow(clippy::explicit_counter_loop)]
-    for ty in min_y..max_y {
-        let mut x = 0;
-        for tx in min_x..max_x {
+    for (y, ty) in (min_y..max_y).enumerate() {
+        for (x, tx) in (min_x..max_x).enumerate() {
             if tx > 0 && tx < map_width && ty > 0 && ty < map_height {
                 let idx = map.xy_idx(tx, ty);
                 if map.revealed_tiles[idx] {
@@ -164,8 +158,6 @@ pub fn render_debug_map(map: &Map, ctx: &mut Rltk) {
             } else if SHOW_BOUNDARIES {
                 ctx.set(x, y, colors::GRAY, colors::BLACK, rltk::to_cp437('·'));
             }
-            x += 1;
         }
-        y += 1;
     }
 }

src/state.rs

@@ -582,5 +582,6 @@ impl GameState for State {
         }
 
         damage_system::delete_the_dead(&mut self.ecs);
+        ::rltk::render_draw_buffer(ctx).expect("Failed to render the Rltk buffer");
     }
 }