// LabDemo2Js (Beta) :: "render Floor Textures.js"

// LabDemo2Js (Beta) :: "Render Floor Textures"

// Function to map screen pixels in the floor to board coordinates and texture pixels
function renderFloorTextures(canvas) {

    if (!canvas || !(canvas instanceof HTMLCanvasElement)) {
        console.error('Invalid canvas element.');
        return;
    }

    const context = canvas.getContext('2d');

    const cosang = Math.cos(player.angle);
    const sinang = Math.sin(player.angle);

    const rayDirX0 = cosang - sinang;
    const rayDirY0 = sinang + cosang;
    const rayDirX1 = cosang + sinang;
    const rayDirY1 = sinang - cosang;

    for (let sy = YDIM / 2; sy < YDIM; sy++) {
        for (let sx = 0; sx < XDIM; sx++) {

            const correctedY = sy - YDIM / 2;
            const dist = player.z / correctedY;
            const screenX = 2 * sx / XDIM - 1;

            const rayDirX = rayDirX0 + screenX * (rayDirX1 - rayDirX0);
            const rayDirY = rayDirY0 + screenX * (rayDirY1 - rayDirY0);

            const floorX = player.x + dist * rayDirX;
            const floorY = player.y + dist * rayDirY;

            const boardX = Math.floor(floorX);
            const boardY = Math.floor(floorY);

            context.fillStyle = checkerBoardTile(boardX,boardY);
            context.fillRect(sx, sy, 1, 1);

            /*
            if (board[boardX] && board[boardX][boardY] && board[boardX][boardY][1]) {

                const mockKey = board[boardX][boardY][1];

                if (mockData[mockKey] && mockData[mockKey].variants[YDIM]) {

                    const mock = mockData[mockKey].variants[YDIM];

                    if (mock.complete) {

                        const textureX = Math.floor((floorX - boardX) * mock.width) % mock.width;
                        const textureY = Math.floor((floorY - boardY) * mock.height) % mock.height;
                        context.drawImage(mock, textureX, textureY, 1, 1, sx, sy, 1, 1);

                    } else {

                        context.fillStyle = 'rgba(0, 0, 0, 0.5)';
                        context.fillRect(sx, sy, 1, 1);

                    }
                }
            }
            */
        }
    }
}

function checkerBoardTile ( x, y ) {
    switch ((x ^ y ^ 1) & 1) {
        case 0:
            return `rgba(0, 0, 0, 1.0)`; // Black
        default:
            return `rgba(255, 255, 255, 1.0)`; // White
    }
}