From 44911658d0e7546971f535f28e319312496a42cb Mon Sep 17 00:00:00 2001
From: En Yi <en.yi@tutanota.com>
Date: Sat, 12 Oct 2024 15:02:08 +0800
Subject: [PATCH] Add basic window resizing

---
 engine/engine.c | 35 +++++++++++++++++++++++++++++++++--
 engine/engine.h |  1 +
 main.c          |  1 +
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/engine/engine.c b/engine/engine.c
index 24b787f..d56139a 100644
--- a/engine/engine.c
+++ b/engine/engine.c
@@ -15,6 +15,7 @@ void init_engine(GameEngine_t* engine, Vector2 starting_win_size)
     init_assets(&engine->assets);
     engine->intended_window_size = starting_win_size;
     InitWindow(starting_win_size.x, starting_win_size.y, "raylib");
+    engine->base_canvas = LoadRenderTexture(starting_win_size.x, starting_win_size.y);
 }
 
 void deinit_engine(GameEngine_t* engine)
@@ -24,6 +25,7 @@ void deinit_engine(GameEngine_t* engine)
     sc_queue_term(&engine->key_buffer);
     sc_queue_term(&engine->scene_stack);
     sc_heap_term(&engine->scenes_render_order);
+    UnloadRenderTexture(engine->base_canvas);
     CloseAudioDevice();
     CloseWindow(); 
 }
@@ -239,7 +241,6 @@ static void _internal_render_scene(Scene_t* scene)
         Vector2 draw_pos = {draw_rec.x, draw_rec.y};
         draw_rec.x = 0;
         draw_rec.y = 0;
-        draw_rec.height *= -1;
         DrawTextureRec(
             layer->layer_tex.texture,
             draw_rec,
@@ -251,8 +252,38 @@ static void _internal_render_scene(Scene_t* scene)
 
 inline void render_scene(Scene_t* scene)
 {
-    BeginDrawing();
+    BeginTextureMode(scene->engine->base_canvas);
     _internal_render_scene(scene);
+    EndTextureMode();
+
+    int curr_width = GetRenderWidth();
+    int curr_height = GetRenderHeight();
+    Vector2 original_size = scene->engine->intended_window_size;
+    float wscale = (curr_width / original_size.x);
+    float hscale = (curr_height / original_size.y);
+    float min_dim = (wscale > hscale) ? hscale : wscale;
+    wscale = min_dim;
+    hscale = min_dim;
+
+    Rectangle draw_rec = {
+        0,0,
+        scene->engine->intended_window_size.x,
+        scene->engine->intended_window_size.y
+    };
+    Rectangle draw_pos = {
+        draw_rec.x * wscale, draw_rec.y * hscale,
+        draw_rec.width * wscale, draw_rec.height * hscale
+    };
+    draw_rec.y *= -1;
+
+    BeginDrawing();
+        ClearBackground((Color){0,0,0,255});
+        DrawTexturePro(
+            scene->engine->base_canvas.texture,
+            draw_rec,
+            draw_pos,
+            (Vector2){0,0}, 0.0, WHITE
+        );
     EndDrawing();
 }
 
diff --git a/engine/engine.h b/engine/engine.h
index cfafc5b..4045a54 100644
--- a/engine/engine.h
+++ b/engine/engine.h
@@ -37,6 +37,7 @@ typedef struct GameEngine {
     // This is in case of window scaling, where there needs to be
     // an absolute reference
     Vector2 intended_window_size;
+    RenderTexture2D base_canvas;
 } GameEngine_t;
 
 #define SCENE_ACTIVE_BIT (1 << 0) // Systems Active
diff --git a/main.c b/main.c
index aa197b8..562a55d 100644
--- a/main.c
+++ b/main.c
@@ -26,6 +26,7 @@ int main(void)
 {
     // Initialization
     //--------------------------------------------------------------------------------------
+    SetConfigFlags(FLAG_WINDOW_RESIZABLE);
     init_engine(&engine, (Vector2){screenWidth, screenHeight});
     SetTargetFPS(60);               // Set our game to run at 60 frames-per-second
 #ifndef NDEBUG