/*******************************************************************************************
*
*   raylib [core] example - window scale letterbox
*
*   This example has been created using raylib 2.5 (www.raylib.com)
*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
*   Copyright (c) 2019 Anata and Ramon Santamaria (@raysan5)
*
********************************************************************************************/

#include "raylib.h"

#define max(a, b) ((a)>(b)? (a) : (b))
#define min(a, b) ((a)<(b)? (a) : (b))

int main()
{
    const int windowWidth = 800;
    const int windowHeight = 450;

    // Enable config flags for resizable window and vertical synchro
    SetConfigFlags(FLAG_WINDOW_RESIZABLE | FLAG_VSYNC_HINT);
    InitWindow(windowWidth, windowHeight, "raylib [core] example - window scale letterbox");
    SetWindowMinSize(320, 240);

    int gameScreenWidth = 640;
    int gameScreenHeight = 480;
    
    // Render texture initialization
    RenderTexture2D target = LoadRenderTexture(gameScreenWidth, gameScreenHeight);
    SetTextureFilter(target.texture, FILTER_BILINEAR);  // Texture scale filter to use
    
    Color colors[10] = { 0 };
    for (int i = 0; i < 10; i++) colors[i] = (Color){ GetRandomValue(100, 250), GetRandomValue(50, 150), GetRandomValue(10, 100), 255 };
    
    SetTargetFPS(60);
    //--------------------------------------------------------------------------------------
    
    // Main game loop
    while( !WindowShouldClose() )       // Detect window close button or ESC key
    {
        // Update
        //----------------------------------------------------------------------------------
        // Compute required framebuffer scaling
        float scale = min((float)GetScreenWidth()/gameScreenWidth, (float)GetScreenHeight()/gameScreenHeight);
        
        if (IsKeyPressed(KEY_SPACE)) 
        {
            // Recalculate random colors for the bars
            for (int i = 0; i < 10; i++) colors[i] = (Color){ GetRandomValue(100, 250), GetRandomValue(50, 150), GetRandomValue(10, 100), 255 };
        }
        //----------------------------------------------------------------------------------
        
        // Draw
        //----------------------------------------------------------------------------------
        BeginDrawing();
            ClearBackground(BLACK);
            
            // Draw everything in the render texture
            BeginTextureMode(target);
            
                ClearBackground(RAYWHITE);         // Clear render texture background color
                
                for (int i = 0; i < 10; i++) DrawRectangle(0, (gameScreenHeight/10)*i, gameScreenWidth, gameScreenHeight/10, colors[i]);
                
                DrawText("You can resize the window,\nand see the screen scaling!", 10, 25, 20, WHITE);
            
            EndTextureMode();

            // Draw RenderTexture2D to window, properly scaled
            DrawTexturePro(target.texture, (Rectangle){ 0.0f, 0.0f, (float)target.texture.width, (float)-target.texture.height },
                           (Rectangle){ (GetScreenWidth() - ((float)gameScreenWidth*scale))*0.5, (GetScreenHeight() - ((float)gameScreenHeight*scale))*0.5, 
                           (float)gameScreenWidth*scale, (float)gameScreenHeight*scale }, (Vector2){ 0, 0 }, 0.0f, WHITE);
                           
        EndDrawing();
        //--------------------------------------------------------------------------------------
    }
    
    // De-Initialization
    //--------------------------------------------------------------------------------------
    UnloadRenderTexture(target);    // Unload render texture
    
    CloseWindow();                  // Close window and OpenGL context
    //--------------------------------------------------------------------------------------
    
    return 0;
}
