### Load Game Level with Cache Manager in C

Source: https://context7.com/id-software/wolf3d/llms.txt

Demonstrates loading a game level using the cache manager, which handles game assets like graphics, maps, and audio. It includes routines for starting the cache system, loading maps, marking and caching graphics chunks, and caching audio. Dependencies include 'ID_CA.H'. Unused resources can be purged.

```c
#include "ID_CA.H"

#define NUMMAPS 60
#define NUMCHUNKS 256

// Map structure from map files
typedef struct {
    long planestart[3];
    unsigned planelength[3];
    unsigned width, height;
    char name[16];
} maptype;

// Global cache segments
void _seg *grsegs[NUMCHUNKS];        // Graphics segments
byte _seg *audiosegs[NUMSNDCHUNKS];  // Audio segments
unsigned _seg *mapsegs[MAPPLANES];   // Map plane segments

void LoadGameLevel(int levelnum)
{
    byte ca_levelbit = 1 << (levelnum & 7);

    // Startup cache system
    CA_Startup();

    // Load a complete map with all planes
    CA_CacheMap(levelnum);

    // Access map data at coordinates
    int tile = MAPSPOT(32, 16, 0);  // Get tile at x=32, y=16, plane 0

    // Mark graphics chunks needed for this level
    CA_MarkGrChunk(STARTPICS);
    CA_MarkGrChunk(STARTSPRITES);

    // Load all marked chunks into memory
    CA_CacheMarks();

    // Cache specific audio chunk
    CA_CacheAudioChunk(SND_GUNSHOT);

    // When changing levels, purge old graphics
    UNCACHEGRCHUNK(OLDLEVELGFX);

    // Cleanup cache system
    CA_Shutdown();
}

// Expected behavior:
// - Maps are loaded from MAPHEAD/GAMEMAPS files
// - Graphics decompressed from VGAGRAPH
// - Audio loaded from AUDIOHED/AUDIOT
// - Automatic purging of unused resources based on ca_levelbit
```

--------------------------------

### Wolf3D Input System Configuration and Reading (C)

Source: https://context7.com/id-software/wolf3d/llms.txt

This C code snippet details the configuration and reading of player input for the Wolf3D game. It initializes input devices like keyboard, mouse, and joystick, reads control states, and processes them into movement vectors and button states. Dependencies include 'ID_IN.H' and 'WL_DEF.H'. It handles input from arrow keys, mouse deltas, and joystick, clamping values to ensure smooth gameplay.

```c
#include "ID_IN.H"
#include "WL_DEF.H"

// Button definitions
#define bt_attack 0
#define bt_strafe 1
#define bt_use 2
#define bt_run 3
#define NUMBUTTONS 8

// Control configuration
int dirscan[4] = {sc_UpArrow, sc_RightArrow, sc_DownArrow, sc_LeftArrow};
int buttonscan[NUMBUTTONS] = {sc_Control, sc_Alt, sc_RShift, sc_Space, sc_1, sc_2, sc_3, sc_4};
int buttonmouse[4] = {bt_attack, bt_strafe, bt_use, bt_nobutton};
int buttonjoy[4] = {bt_attack, bt_strafe, bt_use, bt_run};

// Input state
int controlx, controly;              // Range -100 to 100
boolean buttonstate[NUMBUTTONS];
boolean buttonheld[NUMBUTTONS];
boolean mouseenabled, joystickenabled;
int mouseadjustment;

void ConfigureInput(void)
{
    // Enable input devices
    mouseenabled = MousePresent;
    joystickenabled = JoysPresent[joystickport];

    // Set mouse sensitivity
    mouseadjustment = 5;  // 0-9 range
}

void ReadPlayerInput(void)
{
    int i;

    // Poll all input devices
    PollControls();

    // Reset control vectors
    controlx = 0;
    controly = 0;

    // Keyboard input
    if (Keyboard[dirscan[0]]) controly = -100;  // Forward
    if (Keyboard[dirscan[2]]) controly = 100;   // Backward
    if (Keyboard[dirscan[3]]) controlx = -100;  // Turn left
    if (Keyboard[dirscan[1]]) controlx = 100;   // Turn right

    // Mouse delta
    if (mouseenabled) {
        controlx += MouseDeltaX * mouseadjustment;
        controly += MouseDeltaY;
    }

    // Check buttons
    for (i = 0; i < NUMBUTTONS; i++) {
        buttonstate[i] = Keyboard[buttonscan[i]];

        if (mouseenabled && i < 4)
            buttonstate[i] |= MouseButtons[buttonmouse[i]];

        if (joystickenabled && i < 4)
            buttonstate[i] |= JoyButtons[buttonjoy[i]];
    }

    // Clamp control values
    if (controlx > 100) controlx = 100;
    if (controlx < -100) controlx = -100;
    if (controly > 100) controly = 100;
    if (controly < -100) controly = -100;
}

```

--------------------------------

### C: Save and Load Game Configuration

Source: https://context7.com/id-software/wolf3d/llms.txt

Implements functions to write and read game configuration, including high scores, audio settings, input device preferences, key bindings, and other game settings to a binary file named CONFIG.WLF. It handles file operations and ensures data integrity.

```c
#include "WL_DEF.H"
#include <fcntl.h>

#define MaxScores 10

// High score structure
typedef struct {
    char name[24];
    long score;
    int episode;
    int level;
    int difficulty;
} HighScore;

HighScore Scores[MaxScores];

// Configuration filename
char configname[13] = "CONFIG.WLF";

void WriteConfig(void)
{
    int file;
    SDMode sd = sdm_AdLib;      // Sound device mode
    SMMode sm = smm_AdLib;      // Music mode
    SDSMode sds = sds_Off;      // Digitized sound mode

    // Create config file
    file = open(configname, O_CREAT | O_BINARY | O_WRONLY, S_IREAD | S_IWRITE);

    if (file != -1) {
        // Write high scores
        write(file, Scores, sizeof(HighScore) * MaxScores);

        // Write audio configuration
        write(file, &sd, sizeof(sd));
        write(file, &sm, sizeof(sm));
        write(file, &sds, sizeof(sds));

        // Write input device settings
        write(file, &mouseenabled, sizeof(mouseenabled));
        write(file, &joystickenabled, sizeof(joystickenabled));
        write(file, &joypadenabled, sizeof(joypadenabled));
        write(file, &joystickprogressive, sizeof(joystickprogressive));
        write(file, &joystickport, sizeof(joystickport));

        // Write key bindings
        write(file, &dirscan, sizeof(dirscan));
        write(file, &buttonscan, sizeof(buttonscan));
        write(file, &buttonmouse, sizeof(buttonmouse));
        write(file, &buttonjoy, sizeof(buttonjoy));

        // Write game settings
        write(file, &viewsize, sizeof(viewsize));
        write(file, &mouseadjustment, sizeof(mouseadjustment));

        close(file);
    }
}

void ReadConfig(void)
{
    int file;
    SDMode sd;
    SMMode sm;
    SDSMode sds;

    if ((file = open(configname, O_BINARY | O_RDONLY)) != -1) {
        // Read high scores
        read(file, Scores, sizeof(HighScore) * MaxScores);

        // Read audio settings
        read(file, &sd, sizeof(sd));
        read(file, &sm, sizeof(sm));
        read(file, &sds, sizeof(sds));

        // Read input settings
        read(file, &mouseenabled, sizeof(mouseenabled));
        read(file, &joystickenabled, sizeof(joystickenabled));
        read(file, &joypadenabled, sizeof(joypadenabled));
        read(file, &joystickprogressive, sizeof(joystickprogressive));
        read(file, &joystickport, sizeof(joystickport));

        // Read key bindings
        read(file, &dirscan, sizeof(dirscan));
        read(file, &buttonscan, sizeof(buttonscan));
        read(file, &buttonmouse, sizeof(buttonmouse));
        read(file, &buttonjoy, sizeof(buttonjoy));

        // Read game settings
        read(file, &viewsize, sizeof(viewsize));
        read(file, &mouseadjustment, sizeof(mouseadjustment));

        close(file);

        // Validate hardware availability
        if (sd == sdm_AdLib && !AdLibPresent && !SoundBlasterPresent) {
            sd = sdm_PC;
            sm = smm_Off;
        }

        if (!MousePresent)
            mouseenabled = false;
        if (!JoysPresent[joystickport])
            joystickenabled = false;
    }
}

void CheckHighScore(long score, int level)
{
    int i, j;
    char name[24];

    // Check if score qualifies
    for (i = 0; i < MaxScores; i++) {
        if (score > Scores[i].score) {
            // Get player name
            US_LineInput(20, 16, name, 0, true, 20, 0);

            // Shift lower scores down
            for (j = MaxScores - 1; j > i; j--)
                Scores[j] = Scores[j - 1];

            // Insert new score
            strcpy(Scores[i].name, name);
            Scores[i].score = score;
            Scores[i].episode = gamestate.episode;
            Scores[i].level = level;
            Scores[i].difficulty = gamestate.difficulty;

            // Save updated config
            WriteConfig();
            break;
        }
    }
}

// Example config file layout:
// Offset 0x0000: High scores (240 bytes)
// Offset 0x00F0: Sound settings (6 bytes)
// Offset 0x00F6: Input devices (10 bytes)
// Offset 0x0100: Key bindings (48 bytes)
// Offset 0x0130: Game settings (4 bytes)

```

--------------------------------

### Initialize Memory System in C

Source: https://context7.com/id-software/wolf3d/llms.txt

Initializes the memory management system for Wolfenstein 3D, which handles dynamic allocation across conventional, EMS, and XMS memory pools. It includes startup routines, memory allocation, setting purge and lock flags, and displaying memory statistics. Dependencies include 'ID_MM.H'.

```c
#include "ID_MM.H"

// Initialize memory manager at program startup
void InitializeMemorySystem(void)
{
    mminfotype mminfo;
    memptr bufferseg;

    // Startup memory manager - detects and configures EMS/XMS
    MM_Startup();

    // Allocate a general purpose buffer (4KB)
    MM_GetPtr(&bufferseg, BUFFERSIZE);

    // Check available memory across all pools
    long freeMemory = MM_UnusedMemory();
    long totalFree = MM_TotalFree();

    // Set purge level for a memory block (allows caching system to free it)
    MM_SetPurge(&bufferseg, 3);

    // Lock critical memory blocks to prevent swapping
    MM_SetLock(&bufferseg, true);

    // Display memory statistics for debugging
    MM_ShowMemory();

    // Cleanup on exit
    MM_Shutdown();
}

// Example output when running:
// Near heap: 65536 bytes
// Far heap: 524288 bytes
// EMS memory: 2097152 bytes available
// XMS memory: 1048576 bytes available
```

--------------------------------

### C Positional Audio Engine Implementation

Source: https://context7.com/id-software/wolf3d/llms.txt

Implements a 3D positional audio system using pre-calculated lookup tables for stereo panning. It translates sound source coordinates into player-relative positions and determines left/right channel volumes for stereo output. Dependencies include WL_DEF.H and ID_SD.H.

```c
#include "WL_DEF.H"
#include "ID_SD.H"

#define ATABLEMAX 15

// Stereo channel output values (0-8, 8=full volume)
int leftchannel, rightchannel;
fixed globalsoundx, globalsoundy;

// Pre-calculated stereo panning lookup tables
byte righttable[ATABLEMAX][ATABLEMAX * 2];
byte lefttable[ATABLEMAX][ATABLEMAX * 2];

void SetSoundLoc(fixed gx, fixed gy)
{
    fixed xt, yt;
    int x, y;

    // Translate sound position to view-centered coordinates
    gx -= viewx;
    gy -= viewy;

    // Rotate into player's reference frame
    // Calculate x position relative to view
    xt = FixedByFrac(gx, viewcos);
    yt = FixedByFrac(gy, viewsin);
    x = (xt - yt) >> TILESHIFT;

    // Calculate y position (distance)
    xt = FixedByFrac(gx, viewsin);
    yt = FixedByFrac(gy, viewcos);
    y = (yt + xt) >> TILESHIFT;

    // Clamp to table boundaries
    if (y >= ATABLEMAX)
        y = ATABLEMAX - 1;
    else if (y <= -ATABLEMAX)
        y = -ATABLEMAX;
    if (x < 0)
        x = -x;
    if (x >= ATABLEMAX)
        x = ATABLEMAX - 1;

    // Look up stereo volumes from pre-calculated tables
    leftchannel = lefttable[x][y + ATABLEMAX];
    rightchannel = righttable[x][y + ATABLEMAX];
}

void PlayPositionalSound(int soundnum, objtype *soundobj)
{
    fixed soundx, soundy;

    // Get sound source position
    if (soundobj == player) {
        // Player sounds are centered
        leftchannel = rightchannel = 8;
    } else {
        // Calculate 3D position
        soundx = soundobj->x;
        soundy = soundobj->y;

        // Set global sound coordinates
        globalsoundx = soundx;
        globalsoundy = soundy;

        // Calculate stereo positioning
        SetSoundLoc(soundx, soundy);
    }

    // Play sound with calculated stereo volumes
    SD_PlaySound(soundnum, leftchannel, rightchannel);
}

// Example usage in game
void EnemyAttack(objtype *enemy)
{
    // Play gunshot sound at enemy position
    PlayPositionalSound(SND_GUNSHOT, enemy);

    // Sound will be louder/quieter and panned left/right
    // based on enemy position relative to player view
}

// Expected output:
// - Sounds from left side: leftchannel=8, rightchannel=0-3
// - Sounds from right side: leftchannel=0-3, rightchannel=8
// - Distant sounds: both channels=2-4
// - Close sounds: both channels=6-8
// - Player sounds: both channels=8

```

--------------------------------

### Wolfenstein 3D Raycasting 3D Renderer Core (C)

Source: https://context7.com/id-software/wolf3d/llms.txt

Implements a raycasting engine to project a 2D map into a first-person 3D view with texture-mapped walls. It uses fixed-point math and lookup tables for performance. The renderer calculates wall heights based on distance to prevent distortion. Expected output is a 320x200 VGA display.

```c
#include "WL_DEF.H"

// View configuration constants
#define FOCALLENGTH 0x5700l
#define VIEWWIDTH 256
#define VIEWHEIGHT 144
#define ANGLES 360
#define FINEANGLES 3600
#define MINDIST 0x5800l

// Global rendering state
fixed viewx, viewy;           // Player position in fixed-point
int viewangle;                // Player viewing angle
fixed viewsin, viewcos;       // Precomputed trig values
unsigned wallheight[MAXVIEWWIDTH];
int pixelangle[MAXVIEWWIDTH];

// Raycasting variables
int xtile, ytile;
int xtilestep, ytilestep;
long xintercept, yintercept;
long xstep, ystep;
unsigned tilehit;

void RenderFrame(void)
{
    // Build sine/cosine lookup tables
    BuildTables();

    // Set player position and viewing angle
    viewx = player->x;
    viewy = player->y;
    viewangle = player->angle;
    viewsin = sintable[viewangle];
    viewcos = costable[viewangle];

    // Clear the screen buffer
    ClearScreen();

    // Main 3D rendering function - raycasts for each column
    ThreeDRefresh();

    // Draw scaled sprites (enemies, items)
    DrawScaleds();

    // Calculate frame timing
    CalcTics();
}

// Ray intersection calculation for a single vertical slice
void CastRay(int angle)
{
    fixed xt, yt;
    int x, y;

    // Calculate ray direction
    xt = FixedByFrac(viewx, costable[angle]);
    yt = FixedByFrac(viewy, sintable[angle]);

    // Step through map until wall hit
    while (!tilehit) {
        xintercept += xstep;
        yintercept += ystep;
        xtile = xintercept >> TILESHIFT;
        ytile = yintercept >> TILESHIFT;
        tilehit = tilemap[xtile][ytile];
    }

    // Calculate wall height based on distance
    // Distance calculation prevents fish-eye effect
}

// Expected output: 320x200 VGA display at 35-70 FPS (286-486)

```

--------------------------------

### Wolf3D Player Movement Application (C)

Source: https://context7.com/id-software/wolf3d/llms.txt

This C code snippet outlines how player movement is applied based on the processed input. It calculates movement speed, updates player orientation, and handles actions like moving, turning, and attacking. It also includes logic for preventing button repeat actions using a 'buttonheld' state. Dependencies include game-specific functions like 'Cmd_Fire' and 'TryMove'.

```c
void ApplyPlayerMovement(void)
{
    int movespeed = PLAYERSPEED;
    int angle;

    // Run button doubles speed
    if (buttonstate[bt_run])
        movespeed = RUNSPEED;

    // Turn player
    angle = player->angle + (controlx * tics / 200);
    angle %= ANGLES;
    player->angle = angle;

    // Move forward/backward
    if (controly) {
        fixed xmove = FixedMul(controly * movespeed, costable[angle]);
        fixed ymove = FixedMul(controly * movespeed, sintable[angle]);
        TryMove(player, xmove, ymove);
    }

    // Attack button
    if (buttonstate[bt_attack] && !buttonheld[bt_attack]) {
        Cmd_Fire();
        buttonheld[bt_attack] = true;
    } else if (!buttonstate[bt_attack]) {
        buttonheld[bt_attack] = false;
    }
}

```

--------------------------------

### Wolf3D C Game Loop Implementation

Source: https://context7.com/id-software/wolf3d/llms.txt

Implements the main game loop, handling frame timing, input, game state updates, and rendering. It manages player actions, checks for level completion or death, and handles pausing. Dependencies include WL_DEF.H for definitions.

```c
#include "WL_DEF.H"

// Game state enumeration
typedef enum {
    ex_stillplaying,
    ex_completed,
    ex_died,
    ex_warped,
    ex_resetgame,
    ex_loadedgame,
    ex_victorious,
    ex_abort,
    ex_demodone,
    ex_secret
} exit_t;

// Global game state
typedef struct {
    int episode;
    int mapon;
    int difficulty;
    long score;
    int lives;
    int health;
    int ammo;
    int keys;
    int weapons;
    long TimeCount;
} gametype;

gametype gamestate;
exit_t playstate;
unsigned tics;
boolean ingame;

void GameLoop(void)
{
    boolean done = false;

    while (!done) {
        // Calculate elapsed tics (1/70th second units)
        CalcTics();

        // Process player input
        PollControls();

        // Update game state
        if (!gamestate.victoryflag) {
            // Move player
            if (controlx || controly)
                MovePPlayer();

            // Update all actors (AI, physics)
            UpdateActors();

            // Handle player actions
            if (buttonstate[bt_use])
                PerformUse();
            if (buttonstate[bt_attack])
                PerformAttack();

            // Check for player death
            if (gamestate.health <= 0) {
                playstate = ex_died;
                done = true;
            }

            // Check for level completion
            if (gamestate.leveldone) {
                playstate = ex_completed;
                done = true;
            }
        }

        // Render frame
        ThreeDRefresh();

        // Draw status bar
        UpdateStatusBar();

        // Check for pause/menu
        if (Keyboard[sc_Escape]) {
            ControlPause();
        }
    }
}

void PlayGame(void)
{
    // Initialize level
    SetupGameLevel();

    // Draw play screen
    DrawPlayScreen();

    // Run main loop
    playstate = ex_stillplaying;
    GameLoop();

    // Handle exit condition
    switch (playstate) {
        case ex_completed:
            // Advance to next level
            gamestate.mapon++;
            LevelCompleted();
            break;

        case ex_died:
            // Lose a life
            gamestate.lives--;
            if (gamestate.lives > 0)
                Died();
            else
                GameOver();
            break;

        case ex_warped:
            // Debug warp to different level
            break;
    }
}

void MainGameLoop(void)
{
    boolean exitgame = false;

    // Initialize systems
    InitGame();

    while (!exitgame) {
        // Show main menu
        US_ControlPanel();

        if (startgame) {
            // Set initial game state
            gamestate.lives = 3;
            gamestate.health = 100;
            gamestate.ammo = 8;
            gamestate.mapon = 0;

            // Play through episodes
            while (gamestate.lives > 0) {
                PlayGame();

                if (playstate == ex_abort)
                    break;
            }
        }

        if (Keyboard[sc_Escape])
            exitgame = true;
    }

    // Cleanup
    Quit(NULL);
}

// Timing example:
// - Target: 70 FPS (14ms per frame)
// - Actual: 35-70 FPS depending on CPU
// - tics variable contains elapsed time units
// - All movement/animation scaled by tics value

```

--------------------------------

### Wolfenstein 3D Actor Management System (C)

Source: https://context7.com/id-software/wolf3d/llms.txt

Manages all dynamic entities in the game, including the player, enemies, projectiles, and interactive objects. It uses a linked list to store actor data and supports spawning, updating AI, and removing actors. The system is designed to handle up to 150 simultaneous actors.

```c
#include "WL_DEF.H"

#define MAXACTORS 150
#define MAXSTATS 400

// Object type definitions
typedef enum {
    guardobj,
    officerobj,
    ssobj,
    dogobj,
    bossobj,
    playerobj,
    // ... more types
} classtype;

// Actor structure
typedef struct objstruct {
    int tilex, tiley;           // Tile position
    fixed x, y;                 // Exact position
    int angle;                  // Facing direction
    int hitpoints;              // Health
    int speed;                  // Movement speed
    classtype obclass;          // Actor type
    statetype state;            // Current animation state
    byte flags;                 // FL_SHOOTABLE, FL_VISABLE, etc.
    struct objstruct *next;     // Linked list pointer
} objtype;

// Global actor list
objtype objlist[MAXACTORS];
objtype *player, *newobj, *killerobj;

void InitializeActors(void)
{
    // Initialize object free list
    InitObjList();

    // Spawn player at starting position
    player = &objlist[0];
    player->x = 32 << TILESHIFT;
    player->y = 32 << TILESHIFT;
    player->angle = 90;
    player->hitpoints = 100;
    player->obclass = playerobj;
    player->flags = FL_SHOOTABLE;
}

void SpawnEnemy(int tilex, int tiley, classtype type)
{
    objtype *newobj;

    // Get free object from list
    if (objfreelist) {
        newobj = objfreelist;
        objfreelist = objfreelist->next;
    }

    // Initialize enemy
    newobj->tilex = tilex;
    newobj->tiley = tiley;
    newobj->x = tilex << TILESHIFT;
    newobj->y = tiley << TILESHIFT;
    newobj->obclass = type;
    newobj->hitpoints = 25;
    newobj->speed = 2048;
    newobj->angle = 0;
    newobj->flags = FL_SHOOTABLE | FL_VISABLE;

    // Add to active list
    newobj->next = objlist;
}

void UpdateActors(void)
{
    objtype *obj;

    // Iterate through all active actors
    for (obj = objlist; obj != NULL; obj = obj->next) {
        // Update AI state machine
        if (obj->obclass == guardobj) {
            // Check line of sight to player
            if (CheckLine(obj, player)) {
                obj->flags |= FL_ATTACKMODE;
            }

            // Move toward player
            if (obj->flags & FL_ATTACKMODE) {
                MoveActor(obj, obj->speed);
            }
        }
    }
}

void RemoveDeadActor(objtype *gone)
{
    RemoveObj(gone);
    gone->next = objfreelist;
    objfreelist = gone;
}

// Typical execution:
// - Scans map info plane for actor placement codes
// - Spawns up to 150 simultaneous actors
// - Updates AI and physics each frame
// - Removes actors when killed, returns to free pool

```

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