Small refactor as well as an overlay scene

src/game.odin

@@ -2,7 +2,6 @@ package game
 
 import rl "vendor:raylib"
 
-// 16:9 internal res, window scales up to 1080/4k etc
 VIEWPORT_W   :: 1280
 VIEWPORT_H   :: 720
 WINDOW_W     :: 2560
@@ -10,66 +9,74 @@ WINDOW_H     :: 1440
 WINDOW_TITLE :: "Pong"
 
 Game :: struct {
-    viewport:     rl.RenderTexture2D,
-    scene:        Scene,
-    paused:       bool,
+    viewport:      rl.RenderTexture2D,
+    // base scene (gameplay, mainmenu)
+    scene:         Scene,         
+    // active overlay (pause, settings, or nil)
+    overlay_scene: Maybe(Overlay_Scene), 
 }
 
 // ------------------------------------------------------------------------------
-// Game initializes and sets up any needed state
-//  - Then we load in the initial scene
+// Game Lifecycle
 // ------------------------------------------------------------------------------
 game_init :: proc(game: ^Game) {
-	// Window configs
     rl.InitWindow(WINDOW_W, WINDOW_H, WINDOW_TITLE)
     rl.SetTargetFPS(60)
 
-    // initial state
     game.viewport = rl.LoadRenderTexture(VIEWPORT_W, VIEWPORT_H)
-    game.paused = false
-
-    // initial scene (should be menu when setup)
     game.scene = init_gameplay_scene()
 }
 
-// ------------------------------------------------------------------------------
-// Game loop update phase
-//  - TODO: get inputs pressed and store them
-//  - apply any updates to the current scene
-// ------------------------------------------------------------------------------
 game_update :: proc(game: ^Game) {
     dt := rl.GetFrameTime()
     input := poll_input()
 
-    // Update the current scene
-    scene_update(game, input, dt)
+    // update the overlay if active, otherwise update base scene
+    if game.overlay_scene != nil {
+        overlay_update(game, input, dt)
+    } else {
+        scene_update(game, input, dt)
+    }
 }
 
-// ------------------------------------------------------------------------------
-// Game loop integration phase
-//  - after the states and scene has been updated render whats active
-// ------------------------------------------------------------------------------
 game_render :: proc(game: ^Game) {
     rl.BeginDrawing()
     rl.ClearBackground(rl.BLACK)
 
-    // render the current scene
-    scene_render(game)
+    // offscreen pass render everything into virtual 1280x720 target
+    rl.BeginTextureMode(game.viewport)
+        rl.ClearBackground(rl.BLACK)
+        scene_render(game)   // Renders base scene (Level field or Main Menu)
+        overlay_render(game) // Renders active overlay on top if present
+    rl.EndTextureMode()
+
+    // upscale pass stretch virtual buffer onto physical window display
+    render_game_to_window(game.viewport.texture)
 
     rl.EndDrawing()
 }
 
-// ------------------------------------------------------------------------------
-// Game shutdown
-//  - before closing windows etc we cleanup free anything that was allocated
-// ------------------------------------------------------------------------------
 game_quit :: proc(game: ^Game) {
-	// TODO: any cleanup goes here before 
-	// shutting down the window
-
+    rl.UnloadRenderTexture(game.viewport)
     rl.CloseWindow()
 }
 
 game_should_run :: proc() -> bool {
     return !rl.WindowShouldClose()
+}
+
+// ------------------------------------------------------------------------------
+// Window Upscale Render 
+// ------------------------------------------------------------------------------
+render_game_to_window :: proc(texture: rl.Texture) {
+    rl.DrawTexturePro(
+        texture, 
+        // src: inverted y coordinate flips opengl texture buffer correctly
+        rl.Rectangle{0, 0, f32(texture.width), -f32(texture.height)},
+        // dst: scales viewport canvas to fill window resolution
+        rl.Rectangle{0, 0, f32(WINDOW_W), f32(WINDOW_H)},
+        rl.Vector2{},
+        0,
+        rl.WHITE,
+    ) 
 }