REXM: ADDED: example: core_undo_redo

examples/core/core_undo_redo.c

@@ -0,0 +1,313 @@
+/*******************************************************************************************
+*
+*   raylib [core] example - undo redo
+*
+*   Example complexity rating: [★★★☆] 3/4
+*
+*   Example originally created with raylib 5.5, last time updated with raylib 5.6
+*
+*   Example contributed by Reamon 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) 2025 Ramon Santamaria (@raysan5)
+*
+********************************************************************************************/
+
+#include "raylib.h"
+
+#include <stdlib.h>     // Required for: calloc(), free()
+#include <string.h>     // Required for: memcpy(), strcmp()
+
+#define MAX_UNDO_STATES             26      // Maximum undo states supported for the ring buffer
+
+#define GRID_CELL_SIZE              24      
+#define MAX_GRID_CELLS_X            30
+#define MAX_GRID_CELLS_Y            13
+
+//----------------------------------------------------------------------------------
+// Types and Structures Definition
+//----------------------------------------------------------------------------------
+// Point struct, like Vector2 but using int
+typedef struct {
+    int x;
+    int y;
+} Point;
+
+// Player state struct
+// NOTE: Contains all player data that needs to be affected by undo/redo
+typedef struct {
+    Point cell;
+    Color color;
+} PlayerState;
+
+//------------------------------------------------------------------------------------
+// Module Functions Declaration
+//------------------------------------------------------------------------------------
+// Draw undo system visualization logic
+static void DrawUndoBuffer(Vector2 position, int firstUndoIndex, int lastUndoIndex, int currentUndoIndex, int slotSize);
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+    
+    // We have multiple options to implement an Undo/Redo system
+    // Probably the most professional one is using the Command pattern to
+    // define Actions and store those actions into an array as the events happen,
+    // raylib internal Automation System actually uses a similar approach,
+    // but in this example we are using another more simple solution,
+    // just record PlayerState changes when detected, checking for changes every certain frames
+    // This approach requires more memory and is more performance costly but it is quite simple to implement
+
+    InitWindow(screenWidth, screenHeight, "raylib [core] example - undo redo");
+
+    // Undo/redo system variables
+    int currentUndoIndex = 0;
+    int firstUndoIndex = 0;
+    int lastUndoIndex = 0;
+    int undoFrameCounter = 0;
+    Vector2 undoInfoPos = { 110, 400 };
+
+    // Init current player state and undo/redo recorded states array
+    PlayerState player = { 0 };
+    player.cell = (Point){ 10, 10 };
+    player.color = RED;
+
+    // Init undo buffer to store MAX_UNDO_STATES states
+    PlayerState *states = (PlayerState *)RL_CALLOC(MAX_UNDO_STATES, sizeof(PlayerState));
+    // Init all undo states to current state
+    for (int i = 0; i < MAX_UNDO_STATES; i++) memcpy(&states[i], &player, sizeof(PlayerState));
+
+    // Grid variables
+    Vector2 gridPosition = { 40, 60 };
+
+    SetTargetFPS(60);
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        // Player movement logic
+        if (IsKeyPressed(KEY_RIGHT)) player.cell.x++;
+        else if (IsKeyPressed(KEY_LEFT)) player.cell.x--;
+        else if (IsKeyPressed(KEY_UP)) player.cell.y--;
+        else if (IsKeyPressed(KEY_DOWN)) player.cell.y++;
+
+        // Make sure player does not go out of bounds
+        if (player.cell.x < 0) player.cell.x = 0;
+        else if (player.cell.x >= MAX_GRID_CELLS_X) player.cell.x = MAX_GRID_CELLS_X - 1;
+        if (player.cell.y < 0) player.cell.y = 0;
+        else if (player.cell.y >= MAX_GRID_CELLS_Y) player.cell.y = MAX_GRID_CELLS_Y - 1;
+
+        // Player color change logic
+        if (IsKeyPressed(KEY_SPACE))
+        {
+            player.color.r = (unsigned char)GetRandomValue(20, 255);
+            player.color.g = (unsigned char)GetRandomValue(20, 220);
+            player.color.b = (unsigned char)GetRandomValue(20, 240);
+        }
+
+        // Undo layout change logic
+        undoFrameCounter++;
+
+        // Waiting a number of frames before checking if we should store a new state snapshot
+        if (undoFrameCounter >= 2) // Checking every 2 frames
+        {
+            if (memcmp(&states[currentUndoIndex], &player, sizeof(PlayerState)) != 0)
+            {
+                // Move cursor to next available position of the undo ring buffer to record state
+                currentUndoIndex++;
+                if (currentUndoIndex >= MAX_UNDO_STATES) currentUndoIndex = 0;
+                if (currentUndoIndex == firstUndoIndex) firstUndoIndex++;
+                if (firstUndoIndex >= MAX_UNDO_STATES) firstUndoIndex = 0;
+
+                memcpy(&states[currentUndoIndex], &player, sizeof(PlayerState));
+                lastUndoIndex = currentUndoIndex;
+            }
+
+            undoFrameCounter = 0;
+        }
+
+        // Recover previous state from buffer: CTRL+Z
+        if (IsKeyDown(KEY_LEFT_CONTROL) && IsKeyPressed(KEY_Z))
+        {
+            if (currentUndoIndex != firstUndoIndex)
+            {
+                currentUndoIndex--;
+                if (currentUndoIndex < 0) currentUndoIndex = MAX_UNDO_STATES - 1;
+
+                if (memcmp(&states[currentUndoIndex], &player, sizeof(PlayerState)) != 0)
+                {
+                    memcpy(&player, &states[currentUndoIndex], sizeof(PlayerState));
+                }
+            }
+        }
+
+        // Recover next state from buffer: CTRL+Y
+        if (IsKeyDown(KEY_LEFT_CONTROL) && IsKeyPressed(KEY_Y))
+        {
+            if (currentUndoIndex != lastUndoIndex)
+            {
+                int nextUndoIndex = currentUndoIndex + 1;
+                if (nextUndoIndex >= MAX_UNDO_STATES) nextUndoIndex = 0;
+
+                if (nextUndoIndex != firstUndoIndex)
+                {
+                    currentUndoIndex = nextUndoIndex;
+
+                    if (memcmp(&states[currentUndoIndex], &player, sizeof(PlayerState)) != 0)
+                    {
+                        memcpy(&player, &states[currentUndoIndex], sizeof(PlayerState));
+                    }
+                }
+            }
+        }
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(RAYWHITE);
+
+            // Draw controls info
+            DrawText("[ARROWS] MOVE PLAYER - [SPACE] CHANGE PLAYER COLOR", 40, 20, 20, DARKGRAY);
+
+            // Draw player visited cells recorded by undo
+            // NOTE: Remember we are using a ring buffer approach so,
+            // some cells info could start at the end of the array and end at the beginning
+            if (lastUndoIndex > firstUndoIndex)
+            {
+                for (int i = firstUndoIndex; i < currentUndoIndex; i++)
+                    DrawRectangle(gridPosition.x + states[i].cell.x*GRID_CELL_SIZE, gridPosition.y + states[i].cell.y*GRID_CELL_SIZE,
+                        GRID_CELL_SIZE, GRID_CELL_SIZE, LIGHTGRAY);
+            }
+            else if (firstUndoIndex > lastUndoIndex)
+            {
+                if ((currentUndoIndex < MAX_UNDO_STATES) && (currentUndoIndex > lastUndoIndex))
+                {
+                    for (int i = firstUndoIndex; i < currentUndoIndex; i++)
+                        DrawRectangle(gridPosition.x + states[i].cell.x*GRID_CELL_SIZE, gridPosition.y + states[i].cell.y*GRID_CELL_SIZE,
+                            GRID_CELL_SIZE, GRID_CELL_SIZE, LIGHTGRAY);
+                }
+                else
+                {
+                    for (int i = firstUndoIndex; i < MAX_UNDO_STATES; i++)
+                        DrawRectangle(gridPosition.x + states[i].cell.x*GRID_CELL_SIZE, gridPosition.y + states[i].cell.y*GRID_CELL_SIZE,
+                            GRID_CELL_SIZE, GRID_CELL_SIZE, LIGHTGRAY);
+                    for (int i = 0; i < currentUndoIndex; i++)
+                        DrawRectangle(gridPosition.x + states[i].cell.x*GRID_CELL_SIZE, gridPosition.y + states[i].cell.y*GRID_CELL_SIZE,
+                            GRID_CELL_SIZE, GRID_CELL_SIZE, LIGHTGRAY);
+                }
+            }
+
+            // Draw game grid
+            for (int y = 0; y <= MAX_GRID_CELLS_Y; y++)
+                DrawLine(gridPosition.x, gridPosition.y + y*GRID_CELL_SIZE,
+                    gridPosition.x + MAX_GRID_CELLS_X*GRID_CELL_SIZE, gridPosition.y + y*GRID_CELL_SIZE, GRAY);
+            for (int x = 0; x <= MAX_GRID_CELLS_X; x++)
+                DrawLine(gridPosition.x + x*GRID_CELL_SIZE, gridPosition.y,
+                    gridPosition.x + x*GRID_CELL_SIZE, gridPosition.y + MAX_GRID_CELLS_Y*GRID_CELL_SIZE, GRAY);
+
+            // Draw player
+            DrawRectangle(gridPosition.x + player.cell.x*GRID_CELL_SIZE, gridPosition.y + player.cell.y*GRID_CELL_SIZE,
+                GRID_CELL_SIZE + 1, GRID_CELL_SIZE + 1, player.color);
+
+            // Draw undo system buffer info
+            DrawText("UNDO STATES:", undoInfoPos.x - 85, undoInfoPos.y + 9, 10, DARKGRAY);
+            DrawUndoBuffer(undoInfoPos, firstUndoIndex, lastUndoIndex, currentUndoIndex, 24);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    RL_FREE(states);        // Free undo states array
+
+    CloseWindow();          // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}
+
+//------------------------------------------------------------------------------------
+// Module Functions Definition
+//------------------------------------------------------------------------------------
+// Draw undo system visualization logic
+// NOTE: Visualizing the ring buffer array, every square can store a player state
+static void DrawUndoBuffer(Vector2 position, int firstUndoIndex, int lastUndoIndex, int currentUndoIndex, int slotSize)
+{
+    // Draw index marks
+    DrawRectangle(position.x + 8 + slotSize*currentUndoIndex, position.y - 10, 8, 8, RED);
+    DrawRectangleLines(position.x + 2 + slotSize*firstUndoIndex, position.y + 27, 8, 8, BLACK);
+    DrawRectangle(position.x + 14 + slotSize*lastUndoIndex, position.y + 27, 8, 8, BLACK);
+
+    // Draw background gray slots
+    for (int i = 0; i < MAX_UNDO_STATES; i++)
+    {
+        DrawRectangle(position.x + slotSize*i, position.y, slotSize, slotSize, LIGHTGRAY);
+        DrawRectangleLines(position.x + slotSize*i, position.y, slotSize, slotSize, GRAY);
+    }
+
+    // Draw occupied slots: firstUndoIndex --> lastUndoIndex
+    if (firstUndoIndex <= lastUndoIndex)
+    {
+        for (int i = firstUndoIndex; i < lastUndoIndex + 1; i++)
+        {
+            DrawRectangle(position.x + slotSize*i, position.y, slotSize, slotSize, SKYBLUE);
+            DrawRectangleLines(position.x + slotSize*i, position.y, slotSize, slotSize, BLUE);
+        }
+    }
+    else if (lastUndoIndex < firstUndoIndex)
+    {
+        for (int i = firstUndoIndex; i < MAX_UNDO_STATES; i++)
+        {
+            DrawRectangle(position.x + slotSize*i, position.y, slotSize, slotSize, SKYBLUE);
+            DrawRectangleLines(position.x + slotSize*i, position.y, slotSize, slotSize, BLUE);
+        }
+
+        for (int i = 0; i < lastUndoIndex + 1; i++)
+        {
+            DrawRectangle(position.x + slotSize*i, position.y, slotSize, slotSize, SKYBLUE);
+            DrawRectangleLines(position.x + slotSize*i, position.y, slotSize, slotSize, BLUE);
+        }
+    }
+
+    // Draw occupied slots: firstUndoIndex --> currentUndoIndex
+    if (firstUndoIndex < currentUndoIndex)
+    {
+        for (int i = firstUndoIndex; i < currentUndoIndex; i++)
+        {
+            DrawRectangle(position.x + slotSize*i, position.y, slotSize, slotSize, GREEN);
+            DrawRectangleLines(position.x + slotSize*i, position.y, slotSize, slotSize, LIME);
+        }
+    }
+    else if (currentUndoIndex < firstUndoIndex)
+    {
+        for (int i = firstUndoIndex; i < MAX_UNDO_STATES; i++)
+        {
+            DrawRectangle(position.x + slotSize*i, position.y, slotSize, slotSize, GREEN);
+            DrawRectangleLines(position.x + slotSize*i, position.y, slotSize, slotSize, LIME);
+        }
+
+        for (int i = 0; i < currentUndoIndex; i++)
+        {
+            DrawRectangle(position.x + slotSize*i, position.y, slotSize, slotSize, GREEN);
+            DrawRectangleLines(position.x + slotSize*i, position.y, slotSize, slotSize, LIME);
+        }
+    }
+
+    // Draw current selected UNDO slot
+    DrawRectangle(position.x + slotSize*currentUndoIndex, position.y, slotSize, slotSize, GOLD);
+    DrawRectangleLines(position.x + slotSize*currentUndoIndex, position.y, slotSize, slotSize, ORANGE);
+}