SandGame/steam.js

import { grid, cols, rows } from './state.js';
import { config } from './config.js';
import { move, swap } from './actions.js';
import { createCell } from './physics.js';

export function updateSteam(x, y, cell) {
    const above = y - 1;
    
    // Check if we can move up
    if (above >= 0) {
        const cellAbove = grid[x][above];
        if (!cellAbove) {
            move(x, y, x, above);
            // Turbulence while rising
            if (Math.random() < 0.4) {
                const dir = Math.random() < 0.5 ? -1 : 1;
                const nx = x + dir;
                if (nx >= 0 && nx < cols && !grid[nx][above]) {
                    move(x, above, nx, above);
                }
            }
            return;
        } else if (cellAbove.type === 'water' || cellAbove.type === 'acid' || cellAbove.type === 'oil' || cellAbove.type === 'dirt' || cellAbove.type === 'sand') {
            swap(x, y, x, above);
            return;
        }
    } else {
        // Escapes into sky at y < 0
        grid[x][y] = null;
        return;
    }
    
    // If blocked up, try sideways
    const leftIdx = x - 1;
    const rightIdx = x + 1;
    
    const leftFree = leftIdx >= 0 && (!grid[leftIdx][y] || isPermeable(grid[leftIdx][y]));
    const rightFree = rightIdx < cols && (!grid[rightIdx][y] || isPermeable(grid[rightIdx][y]));

    if (leftFree && rightFree) {
        const dir = Math.random() < 0.5 ? -1 : 1;
        const nx = x + dir;
        executeSteamMove(x, y, nx, y);
    } else if (leftFree) {
        executeSteamMove(x, y, leftIdx, y);
    } else if (rightFree) {
        executeSteamMove(x, y, rightIdx, y);
    }

    // Condense into water
    if (Math.random() < config.steam.condenseChance) {
        grid[x][y] = createCell('water');
    }
}

function isPermeable(cell) {
    return cell && (cell.type === 'water' || cell.type === 'acid' || cell.type === 'oil' || cell.type === 'dirt' || cell.type === 'sand');
}

function executeSteamMove(x1, y1, x2, y2) {
    if (grid[x2][y2]) {
        swap(x1, y1, x2, y2);
    } else {
        move(x1, y1, x2, y2);
    }
}