/*******************************************************************************************
*
* raylib [textures] example - Fog of war
*
* Example complexity rating: [★★★☆] 3/4
*
* Example originally created with raylib 4.2, last time updated with raylib 4.2
*
* 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) 2018-2025 Ramon Santamaria (@raysan5)
*
********************************************************************************************/
#include "raylib.h"
#include <stdlib.h> // Required for: calloc(), free()
#define MAP_TILE_SIZE 32 // Tiles size 32x32 pixels
#define PLAYER_SIZE 16 // Player size
#define PLAYER_TILE_VISIBILITY 2 // Player can see 2 tiles around its position
// Map data type
typedef struct Map {
unsigned int tilesX; // Number of tiles in X axis
unsigned int tilesY; // Number of tiles in Y axis
unsigned char *tileIds; // Tile ids (tilesX*tilesY), defines type of tile to draw
unsigned char *tileFog; // Tile fog state (tilesX*tilesY), defines if a tile has fog or half-fog
} Map;
//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main(void)
{
// Initialization
//--------------------------------------------------------------------------------------
int screenWidth = 800;
int screenHeight = 450;
InitWindow(screenWidth, screenHeight, "raylib [textures] example - fog of war");
Map map = { 0 };
map.tilesX = 25;
map.tilesY = 15;
// NOTE: We can have up to 256 values for tile ids and for tile fog state,
// probably we don't need that many values for fog state, it can be optimized
// to use only 2 bits per fog state (reducing size by 4) but logic will be a bit more complex
map.tileIds = (unsigned char *)calloc(map.tilesX*map.tilesY, sizeof(unsigned char));
map.tileFog = (unsigned char *)calloc(map.tilesX*map.tilesY, sizeof(unsigned char));
// Load map tiles (generating 2 random tile ids for testing)
// NOTE: Map tile ids should be probably loaded from an external map file
for (unsigned int i = 0; i < map.tilesY*map.tilesX; i++) map.tileIds[i] = GetRandomValue(0, 1);
// Player position on the screen (pixel coordinates, not tile coordinates)
Vector2 playerPosition = { 180, 130 };
int playerTileX = 0;
int playerTileY = 0;
// Render texture to render fog of war
// NOTE: To get an automatic smooth-fog effect we use a render texture to render fog
// at a smaller size (one pixel per tile) and scale it on drawing with bilinear filtering
RenderTexture2D fogOfWar = LoadRenderTexture(map.tilesX, map.tilesY);
SetTextureFilter(fogOfWar.texture, TEXTURE_FILTER_BILINEAR);
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
//----------------------------------------------------------------------------------
// Move player around
if (IsKeyDown(KEY_RIGHT)) playerPosition.x += 5;
if (IsKeyDown(KEY_LEFT)) playerPosition.x -= 5;
if (IsKeyDown(KEY_DOWN)) playerPosition.y += 5;
if (IsKeyDown(KEY_UP)) playerPosition.y -= 5;
// Check player position to avoid moving outside tilemap limits
if (playerPosition.x < 0) playerPosition.x = 0;
else if ((playerPosition.x + PLAYER_SIZE) > (map.tilesX*MAP_TILE_SIZE)) playerPosition.x = (float)map.tilesX*MAP_TILE_SIZE - PLAYER_SIZE;
if (playerPosition.y < 0) playerPosition.y = 0;
else if ((playerPosition.y + PLAYER_SIZE) > (map.tilesY*MAP_TILE_SIZE)) playerPosition.y = (float)map.tilesY*MAP_TILE_SIZE - PLAYER_SIZE;
// Previous visited tiles are set to partial fog
for (unsigned int i = 0; i < map.tilesX*map.tilesY; i++) if (map.tileFog[i] == 1) map.tileFog[i] = 2;
// Get current tile position from player pixel position
playerTileX = (int)((playerPosition.x + MAP_TILE_SIZE/2)/MAP_TILE_SIZE);
playerTileY = (int)((playerPosition.y + MAP_TILE_SIZE/2)/MAP_TILE_SIZE);
// Check visibility and update fog
// NOTE: We check tilemap limits to avoid processing tiles out-of-array-bounds (it could crash program)
for (int y = (playerTileY - PLAYER_TILE_VISIBILITY); y < (playerTileY + PLAYER_TILE_VISIBILITY); y++)
for (int x = (playerTileX - PLAYER_TILE_VISIBILITY); x < (playerTileX + PLAYER_TILE_VISIBILITY); x++)
if ((x >= 0) && (x < (int)map.tilesX) && (y >= 0) && (y < (int)map.tilesY)) map.tileFog[y*map.tilesX + x] = 1;
//----------------------------------------------------------------------------------
// Draw
//----------------------------------------------------------------------------------
// Draw fog of war to a small render texture for automatic smoothing on scaling
BeginTextureMode(fogOfWar);
ClearBackground(BLANK);
for (unsigned int y = 0; y < map.tilesY; y++)
for (unsigned int x = 0; x < map.tilesX; x++)
if (map.tileFog[y*map.tilesX + x] == 0) DrawRectangle(x, y, 1, 1, BLACK);
else if (map.tileFog[y*map.tilesX + x] == 2) DrawRectangle(x, y, 1, 1, Fade(BLACK, 0.8f));
EndTextureMode();
BeginDrawing();
ClearBackground(RAYWHITE);
for (unsigned int y = 0; y < map.tilesY; y++)
{
for (unsigned int x = 0; x < map.tilesX; x++)
{
// Draw tiles from id (and tile borders)
DrawRectangle(x*MAP_TILE_SIZE, y*MAP_TILE_SIZE, MAP_TILE_SIZE, MAP_TILE_SIZE,
(map.tileIds[y*map.tilesX + x] == 0)? BLUE : Fade(BLUE, 0.9f));
DrawRectangleLines(x*MAP_TILE_SIZE, y*MAP_TILE_SIZE, MAP_TILE_SIZE, MAP_TILE_SIZE, Fade(DARKBLUE, 0.5f));
}
}
// Draw player
DrawRectangleV(playerPosition, (Vector2){ PLAYER_SIZE, PLAYER_SIZE }, RED);
// Draw fog of war (scaled to full map, bilinear filtering)
DrawTexturePro(fogOfWar.texture, (Rectangle){ 0, 0, (float)fogOfWar.texture.width, (float)-fogOfWar.texture.height },
(Rectangle){ 0, 0, (float)map.tilesX*MAP_TILE_SIZE, (float)map.tilesY*MAP_TILE_SIZE },
(Vector2){ 0, 0 }, 0.0f, WHITE);
// Draw player current tile
DrawText(TextFormat("Current tile: [%i,%i]", playerTileX, playerTileY), 10, 10, 20, RAYWHITE);
DrawText("ARROW KEYS to move", 10, screenHeight-25, 20, RAYWHITE);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
free(map.tileIds); // Free allocated map tile ids
free(map.tileFog); // Free allocated map tile fog state
UnloadRenderTexture(fogOfWar); // Unload render texture
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}