raylib-src/examples/core/core_window_letterbox.c

/*******************************************************************************************
*
*   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)
*
*   Example contributed by Anata (@anatagawa) and reviewed by Ramon Santamaria (@raysan5)
*
*   Copyright (c) 2019 Anata (@anatagawa) 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(void)
{
    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);               // Set our game to run at 60 frames-per-second
    //--------------------------------------------------------------------------------------

    // 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("If executed inside a window,\nyou 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;
}