middle click scrolling in map editor

src/gsa_render_to_screen.rs

@@ -1,3 +1,5 @@
+use std::usize;
+
 use crate::{
     Background, Gsa, Rgb, BACKGROUND_MAX_SIZE, EMPTY_TILE, HALF_TILE_SIZE, MAX_BACKGROUNDS,
     SCREEN_HEIGHT, SCREEN_WIDTH, TILESET_SIZE, TILE_SIZE, TRANSPARENT,
@@ -24,8 +26,7 @@ fn draw_tile(
         for x in (startx - pos.x)..(endx - pos.x) {
             let p = tileset[(x as usize + tx) + (y as usize + ty) * (TILESET_SIZE * TILE_SIZE)];
             if p != TRANSPARENT {
-                target[(x as usize + pos.x as usize)
+                target[(x + pos.x) as usize + (y + pos.y) as usize * screen_size.x as usize] = p;
-                    + (y as usize + pos.y as usize) * screen_size.x as usize] = p;
             }
         }
     }

src/mapedit.rs

@@ -51,9 +51,11 @@ pub(crate) fn run_mapedit() {
     window.request_redraw();
     let mut mouse_pos = IVec2::ZERO;
     let mut left_down = false;
+    let mut middle_down = false;
     event_loop.run(move |event, _, control_flow| {
         let mouse_pos = &mut mouse_pos;
         let left_down = &mut left_down;
+        let middle_down = &mut middle_down;
         match event {
             Event::WindowEvent { event, .. } => match event {
                 WindowEvent::KeyboardInput {
@@ -73,22 +75,37 @@ pub(crate) fn run_mapedit() {
                     (winit::event::ElementState::Released, winit::event::MouseButton::Left) => {
                         *left_down = false;
                     }
+                    (winit::event::ElementState::Pressed, winit::event::MouseButton::Middle) => {
+                        *middle_down = true;
+                    }
+                    (winit::event::ElementState::Released, winit::event::MouseButton::Middle) => {
+                        *middle_down = false;
+                    }
                     _ => {}
                 },
                 WindowEvent::CursorMoved { position, .. } => {
-                    *mouse_pos = IVec2 {
+                    let new_pos = IVec2 {
                         x: position.x as i32,
                         y: position.y as i32,
                     };
+                    let delta = new_pos - *mouse_pos;
+                    if *middle_down {
+                        gsa.bgs[0].scroll -= delta;
+                        gsa.bgs[1].scroll -= delta;
+                        gsa.bgs[2].scroll -= delta;
+                    }
+                    *mouse_pos = new_pos;
                 }
                 _ => {}
             },
 
             Event::MainEventsCleared => {
                 if *left_down {
-                    let tile_x = mouse_pos.x as usize / TILE_SIZE;
+                    let tile_x = (mouse_pos.x + gsa.bgs[0].scroll.x) as usize / TILE_SIZE;
-                    let tile_y = mouse_pos.y as usize / TILE_SIZE;
+                    let tile_y = (mouse_pos.y + gsa.bgs[0].scroll.y) as usize / TILE_SIZE;
-                    gsa.bgs[0].tiles[tile_x][tile_y] = 0;
+                    if tile_x < BACKGROUND_MAX_SIZE && tile_y < BACKGROUND_MAX_SIZE {
+                        gsa.bgs[0].tiles[tile_x][tile_y] = 0;
+                    }
                 }
 
                 // render