# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

This is an Asteroids-style game originally written in Turbo Pascal 7 for DOS, now being converted to modern C++ with SDL2. The game features a spaceship that must avoid and destroy enemies ("cosinus mesisinus" mounted in UFOs/ORNIs). The codebase contains both the original Pascal implementation and the in-progress C++ port.

**Language**: The code and comments are in Catalan/Valencian.

## Build Commands

**macOS**:
```bash
make macos
./bin/asteroids_macos
```

**Linux**:
```bash
make linux
./bin/asteroids_linux
```

Both commands compile from `source/*.cpp` with `-std=c++11 -Wall -O2` and link against SDL2.

## Architecture

### Code Structure

- `source/ASTEROID.PAS` - Original Turbo Pascal 7 implementation (DOS)
- `source/asteroids.cpp` - C++ port using SDL2 (in progress)

### Core Data Structures

The game uses polar coordinates (`ipunt`) for geometric objects:
- `ipunt` - Polar coordinate point (radius `r`, angle `angle`)
- `punt` - Cartesian coordinate point (x, y)
- `triangle` - The player's ship (3 polar points + center + angle + velocity)
- `poligon` - Generic polygon for enemies and bullets (vector of polar points + center + angle + velocity + rotation)

### Key Game Constants

Defined in `asteroids.cpp`:
- Screen bounds: `MARGE_DALT` (20), `MARGE_BAIX` (460), `MARGE_ESQ` (20), `MARGE_DRET` (620)
- `MAX_ORNIS` (15) - Maximum enemies
- `MAX_BALES` (3) - Maximum bullets
- `VELOCITAT` (2), `VELOCITAT_MAX` (6) - Speed constraints

### Rendering System

The original Pascal code used VGA Mode 13h (320x200, 256 colors) with custom bit-packed framebuffer:
- `pvirt` - Virtual screen buffer (38400 bytes)
- `posa(x,y,color)` - Set pixel in virtual buffer (bit-packed)
- `llig(x,y)` - Read pixel from virtual buffer
- `volca()` - Flip virtual buffer to VGA memory
- Line drawing using Bresenham algorithm

The C++ port uses SDL2 for rendering.

### Game Mechanics

- **Movement**: Ship uses polar velocity - angle determines direction, velocity determines speed
- **Collision**: Line drawing returns collision state; `rota_tri()` returns 1 on pixel collision
- **Death sequence**: Ship shrinks (`nau.p*.r` decreases), explodes into debris (`chatarra_cosmica`), then respawns after 250 frames
- **Enemies**: `orni[]` array of polygons with autonomous movement, random angle adjustments
- **Bullets**: Only one bullet active at a time (`bales[1].esta` flag)

### Pascal-to-C++ Conversion Notes

The C++ file contains hybrid Pascal/C++ syntax that needs completion:
- Lines 63-450 are uncommented Pascal code
- Pascal procedures/functions need conversion to C++ equivalents
- Assembly blocks (`waitretrace`, VGA mode setting) need SDL2 replacements
- Turbo Pascal keyboard handling (`teclapuls`, `instalarkb`) needs SDL event system
- Memory management (`getmem`, pointer segments) needs modern C++ approach

### Game Controls (from README)

- Up Arrow: Accelerate
- Down Arrow: Brake
- Right Arrow: Rotate clockwise
- Left Arrow: Rotate counterclockwise
- Space: Fire
- Esc: Exit

## Development Notes

- The conversion is incomplete - much Pascal code remains in comments
- Focus on SDL2 for cross-platform graphics/input instead of DOS VGA/keyboard
- Original used bit-packed monochrome framebuffer; consider SDL surfaces or textures
- Preserve the polar coordinate geometry system - it's core to the game's physics