core_random_sequence.c

/*******************************************************************************************
*
*   raylib [core] example - Generates a random sequence
*
*   Example complexity rating: [★☆☆☆] 1/4
*
*   Example originally created with raylib 5.0, last time updated with raylib 5.0
*
*   Example contributed by Dalton Overmyer (@REDl3east) and reviewed by Ramon Santamaria (@raysan5)
*
*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
*   BSD-like license that allows static linking with closed source software
*
*   Copyright (c) 2023-2025 Dalton Overmyer (@REDl3east)
*
********************************************************************************************/

#include "raylib.h"
#include "raymath.h"

#include <stdlib.h> // Required for: malloc() and free()

typedef struct ColorRect {
    Color c;
    Rectangle r;
} ColorRect;

//------------------------------------------------------------------------------------
// Module functions declaration
//------------------------------------------------------------------------------------
static Color GenerateRandomColor();
static ColorRect *GenerateRandomColorRectSequence(float rectCount, float rectWidth, float screenWidth, float screenHeight);
static void ShuffleColorRectSequence(ColorRect *rectangles, int rectCount);
static void DrawTextCenterKeyHelp(const char *key, const char *text, int posX, int posY, int fontSize, Color color);

//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main(void)
{
    // Initialization
    //--------------------------------------------------------------------------------------
    const int screenWidth = 800;
    const int screenHeight = 450;

    InitWindow(screenWidth, screenHeight, "raylib [core] example - Generates a random sequence");

    int rectCount = 20;
    float rectSize = (float)screenWidth/rectCount;
    ColorRect *rectangles = GenerateRandomColorRectSequence((float)rectCount, rectSize, (float)screenWidth, 0.75f*screenHeight);

    SetTargetFPS(60);
    //--------------------------------------------------------------------------------------

    // Main game loop
    while (!WindowShouldClose()) // Detect window close button or ESC key
    {
        // Update
        //----------------------------------------------------------------------------------
        if (IsKeyPressed(KEY_SPACE)) ShuffleColorRectSequence(rectangles, rectCount);

        if (IsKeyPressed(KEY_UP))
        {
            rectCount++;
            rectSize = (float)screenWidth/rectCount;
            free(rectangles);
            rectangles = GenerateRandomColorRectSequence((float)rectCount, rectSize, (float)screenWidth, 0.75f*screenHeight);
        }

        if (IsKeyPressed(KEY_DOWN))
        {
            if (rectCount >= 4)
            {
                rectCount--;
                rectSize = (float)screenWidth/rectCount;
                free(rectangles);
                rectangles = GenerateRandomColorRectSequence((float)rectCount, rectSize, (float)screenWidth, 0.75f*screenHeight);
            }
        }
        //----------------------------------------------------------------------------------

        // Draw
        //----------------------------------------------------------------------------------
        BeginDrawing();

            ClearBackground(RAYWHITE);

            int fontSize = 20;
            for (int i = 0; i < rectCount; i++)
            {
                DrawRectangleRec(rectangles[i].r, rectangles[i].c);
                DrawTextCenterKeyHelp("SPACE", "to shuffle the sequence.", 10, screenHeight - 96, fontSize, BLACK);
                DrawTextCenterKeyHelp("UP", "to add a rectangle and generate a new sequence.", 10, screenHeight - 64, fontSize, BLACK);
                DrawTextCenterKeyHelp("DOWN", "to remove a rectangle and generate a new sequence.", 10, screenHeight - 32, fontSize, BLACK);
            }

            const char *rectCountText = TextFormat("%d rectangles", rectCount);
            int rectCountTextSize = MeasureText(rectCountText, fontSize);
            DrawText(rectCountText, screenWidth - rectCountTextSize - 10, 10, fontSize, BLACK);

            DrawFPS(10, 10);

        EndDrawing();
        //----------------------------------------------------------------------------------
    }

    // De-Initialization
    //--------------------------------------------------------------------------------------
    free(rectangles);
    CloseWindow(); // Close window and OpenGL context
    //--------------------------------------------------------------------------------------

    return 0;
}

//------------------------------------------------------------------------------------
// Module functions definition
//------------------------------------------------------------------------------------
static Color GenerateRandomColor()
{
    Color color = { 
        GetRandomValue(0, 255), 
        GetRandomValue(0, 255),
        GetRandomValue(0, 255),
        255
    };

    return color;
}

static ColorRect *GenerateRandomColorRectSequence(float rectCount, float rectWidth, float screenWidth, float screenHeight)
{
    ColorRect *rectangles = (ColorRect *)malloc((int)rectCount*sizeof(ColorRect));
    int *seq = LoadRandomSequence((unsigned int)rectCount, 0, (unsigned int)rectCount - 1);
    float rectSeqWidth = rectCount*rectWidth;
    float startX = (screenWidth - rectSeqWidth)*0.5f;

    for (int i = 0; i < rectCount; i++)
    {
        int rectHeight = (int)Remap((float)seq[i], 0, rectCount - 1, 0, screenHeight);
        
        rectangles[i].c = GenerateRandomColor();
        rectangles[i].r = CLITERAL(Rectangle){ startX + i*rectWidth, screenHeight - rectHeight, rectWidth, (float)rectHeight };
    }
    
    UnloadRandomSequence(seq);
    
    return rectangles;
}

static void ShuffleColorRectSequence(ColorRect *rectangles, int rectCount)
{
    int *seq = LoadRandomSequence(rectCount, 0, rectCount -  1);
    
    for (int i1 = 0; i1 < rectCount; i1++)
    {
        ColorRect *r1 = &rectangles[i1];
        ColorRect *r2 = &rectangles[seq[i1]];

        // Swap only the color and height
        ColorRect tmp = *r1;
        r1->c = r2->c;
        r1->r.height = r2->r.height;
        r1->r.y = r2->r.y;
        r2->c = tmp.c;
        r2->r.height = tmp.r.height;
        r2->r.y = tmp.r.y;
    }
    
    UnloadRandomSequence(seq);
}

static void DrawTextCenterKeyHelp(const char *key, const char *text, int posX, int posY, int fontSize, Color color)
{
    int spaceSize = MeasureText(" ", fontSize); 
    int pressSize = MeasureText("Press", fontSize); 
    int keySize = MeasureText(key, fontSize); 
    int textSize = MeasureText(text, fontSize); 
    int textSizeCurrent = 0;

    DrawText("Press", posX, posY, fontSize, color);
    textSizeCurrent += pressSize + 2*spaceSize;
    DrawText(key, posX + textSizeCurrent, posY, fontSize, RED);
    DrawRectangle(posX + textSizeCurrent, posY + fontSize, keySize, 3, RED);
    textSizeCurrent += keySize + 2*spaceSize;
    DrawText(text, posX + textSizeCurrent, posY, fontSize, color);
}