Goodluck / API Reference

system_control_mouse_drag

Handle mouse input when dragging with one of the buttons pressed. Good for cameras overlooking the scene.

When the mouse is dragged with the left mouse button pressed, the entity pans. When it is dragged with the right mouse button pressed, the entity rotates.

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import {DEG_TO_RAD, Quat, Vec3} from "../../lib/math.js";
import {quat_from_axis, quat_multiply} from "../../lib/quat.js";
import {Entity} from "../../lib/world.js";
import {Game} from "../game.js";
import {Has} from "../world.js";

const QUERY = Has.Move | Has.ControlPlayer | Has.Transform;
const MOUSE_SENSITIVITY = 0.1;

export function sys_control_mouse_drag(game: Game, delta: number) {
    for (let i = 0; i < game.World.Signature.length; i++) {
        if ((game.World.Signature[i] & QUERY) === QUERY) {
            update(game, i);
        }
    }
}

const axis_x: Vec3 = [1, 0, 0];
const axis_y: Vec3 = [0, 1, 0];
const rotation: Quat = [0, 0, 0, 0];

function update(game: Game, entity: Entity) {
    let control = game.World.ControlPlayer[entity];
    let move = game.World.Move[entity];

    if (control.Move && game.InputDistance["Mouse0"] > 10) {
        if (game.InputDelta["MouseX"]) {
            let amount = game.InputDelta["MouseX"] * MOUSE_SENSITIVITY;
            move.Direction[0] += amount;
        }

        if (game.InputDelta["MouseY"]) {
            let amount = game.InputDelta["MouseY"] * MOUSE_SENSITIVITY;
            move.Direction[2] += amount;
        }
    }

    if (control.Yaw && game.InputDistance["Mouse2"] > 10 && game.InputDelta["MouseX"]) {
        // Scale the mouse input by the sensitivity.
        let amount = game.InputDelta["MouseX"] * control.Yaw;
        // Treat the pixels traveled by the mouse in this frame as literal Euler
        // angles. This happens to work well and gives the mouse control an
        // instant and precise feel. Note that the rotation won't be passed to
        // sys_move; instead it's applied here and ignores Move.RotationSpeed on
        // purpose.
        quat_from_axis(rotation, axis_y, -amount * DEG_TO_RAD);

        let transform = game.World.Transform[entity];
        // Yaw is pre-multiplied, i.e. applied relative to the entity's local
        // space; the Y axis is not affected by its current orientation.
        quat_multiply(transform.Rotation, rotation, transform.Rotation);
        game.World.Signature[entity] |= Has.Dirty;
    }

    if (control.Pitch && game.InputDistance["Mouse2"] > 10 && game.InputDelta["MouseY"]) {
        let amount = game.InputDelta["MouseY"] * control.Pitch;
        quat_from_axis(rotation, axis_x, amount * DEG_TO_RAD);

        let transform = game.World.Transform[entity];
        // Pitch is post-multiplied, i.e. applied relative to the entity's self
        // space; the X axis is always aligned with its left and right sides.
        quat_multiply(transform.Rotation, transform.Rotation, rotation);
        game.World.Signature[entity] |= Has.Dirty;
    }
}