Camera controls, fix some math; lighting probably broken

src/main.zig

@@ -47,6 +47,8 @@ fn init() callconv(.c) void {
         .logger = .{ .func = sokolLogFn },
     });
 
+    sapp.lockMouse(true);
+
     game.init();
 }
 
@@ -66,7 +68,7 @@ fn frame() callconv(.c) void {
         .dpi_scale = sapp.dpiScale(),
     });
 
-    game.update(dt);
+    game.update(@floatCast(dt));
 
     // --- BEGIN IMGUI PASS ---
 
@@ -90,6 +92,13 @@ fn event(_ev: [*c]const sapp.Event) callconv(.c) void {
         if (ev.type == .KEY_DOWN and !ev.key_repeat) {
             game.onKeyDown(ev.key_code, ev.modifiers);
         }
+        if (ev.type == .KEY_UP and !ev.key_repeat) {
+            game.onKeyUp(ev.key_code, ev.modifiers);
+        }
+    }
+
+    if (ev.type == .MOUSE_MOVE) {
+        game.onMouseMove(ev.mouse_dx, ev.mouse_dy);
     }
 }