tbd-station-14/Content.Client/Weapons/Melee/MeleeWindupOverlay.cs

using Content.Shared.Weapons.Melee;
using Robust.Client.GameObjects;
using Robust.Client.Graphics;
using Robust.Client.Player;
using Robust.Shared.Enums;
using Robust.Shared.Prototypes;
using Robust.Shared.Timing;
using Robust.Shared.Utility;

namespace Content.Client.Weapons.Melee;

public sealed class MeleeWindupOverlay : Overlay
{
    private readonly IEntityManager _entManager;
    private readonly IGameTiming _timing;
    private readonly IPlayerManager _player;
    private readonly SharedMeleeWeaponSystem _melee;
    private readonly SharedTransformSystem _transform;

    public override OverlaySpace Space => OverlaySpace.WorldSpaceBelowFOV;

    private readonly Texture _texture;
    private readonly ShaderInstance _shader;

    public MeleeWindupOverlay(IEntityManager entManager, IGameTiming timing, IPlayerManager playerManager, IPrototypeManager protoManager)
    {
        _entManager = entManager;
        _timing = timing;
        _player = playerManager;
        _melee = _entManager.EntitySysManager.GetEntitySystem<SharedMeleeWeaponSystem>();
        _transform = _entManager.EntitySysManager.GetEntitySystem<SharedTransformSystem>();
        var sprite = new SpriteSpecifier.Rsi(new ResourcePath("/Textures/Interface/Misc/progress_bar.rsi"), "icon");
        _texture = _entManager.EntitySysManager.GetEntitySystem<SpriteSystem>().Frame0(sprite);
        _shader = protoManager.Index<ShaderPrototype>("unshaded").Instance();
    }

    protected override void Draw(in OverlayDrawArgs args)
    {
        var owner = _player.LocalPlayer?.ControlledEntity;

        if (!_entManager.TryGetComponent<TransformComponent>(owner, out var ownerXform) ||
            ownerXform.MapID != args.MapId)
        {
            return;
        }

        if (!_melee.TryGetWeapon(owner.Value, out var meleeUid, out var comp))
            return;

        var handle = args.WorldHandle;
        var rotation = args.Viewport.Eye?.Rotation ?? Angle.Zero;
        var spriteQuery = _entManager.GetEntityQuery<SpriteComponent>();
        var xformQuery = _entManager.GetEntityQuery<TransformComponent>();

        // If you use the display UI scale then need to set max(1f, displayscale) because 0 is valid.
        const float scale = 1f;
        var scaleMatrix = Matrix3.CreateScale(new Vector2(scale, scale));
        var rotationMatrix = Matrix3.CreateRotation(-rotation);
        handle.UseShader(_shader);
        var currentTime = _timing.CurTime;

        if (comp.WindUpStart == null ||
            comp.Attacking)
        {
            return;
        }

        if (!xformQuery.TryGetComponent(meleeUid, out var xform) ||
            xform.MapID != args.MapId)
        {
            return;
        }

        var worldPosition = _transform.GetWorldPosition(xform);
        var worldMatrix = Matrix3.CreateTranslation(worldPosition);
        Matrix3.Multiply(scaleMatrix, worldMatrix, out var scaledWorld);
        Matrix3.Multiply(rotationMatrix, scaledWorld, out var matty);

        handle.SetTransform(matty);
        var offset = -_texture.Height / scale;

        // Use the sprite itself if we know its bounds. This means short or tall sprites don't get overlapped
        // by the bar.
        float yOffset;
        if (spriteQuery.TryGetComponent(meleeUid, out var sprite))
        {
            yOffset = -sprite.Bounds.Height / 2f - 0.05f;
        }
        else
        {
            yOffset = -0.5f;
        }

        // Position above the entity (we've already applied the matrix transform to the entity itself)
        // Offset by the texture size for every do_after we have.
        var position = new Vector2(-_texture.Width / 2f / EyeManager.PixelsPerMeter,
            yOffset / scale + offset / EyeManager.PixelsPerMeter * scale);

        // Draw the underlying bar texture
        handle.DrawTexture(_texture, position);

        // Draw the items overlapping the texture
        const float startX = 2f;
        const float endX = 22f;

        // Area marking where to release
        var releaseWidth = 2f * SharedMeleeWeaponSystem.GracePeriod / (float) comp.WindupTime.TotalSeconds * EyeManager.PixelsPerMeter;
        const float releaseMiddle = (endX - startX) / 2f + startX;

        var releaseBox = new Box2(new Vector2(releaseMiddle - releaseWidth / 2f, 3f) / EyeManager.PixelsPerMeter,
            new Vector2(releaseMiddle + releaseWidth / 2f, 4f) / EyeManager.PixelsPerMeter);

        releaseBox = releaseBox.Translated(position);
        handle.DrawRect(releaseBox, Color.LimeGreen);

        // Wraps around back to 0
        var totalDuration = comp.WindupTime.TotalSeconds * 2;

        var elapsed = (currentTime - comp.WindUpStart.Value).TotalSeconds % (2 * totalDuration);
        var value = elapsed / totalDuration;

        if (value > 1)
        {
            value = 2 - value;
        }

        var fraction = (float) value;

        var xPos = (endX - startX) * fraction + startX;

        // In pixels
        const float width = 2f;
        // If we hit the end we won't draw half the box so we need to subtract the end pos from it
        var endPos = xPos + width / 2f;

        var box = new Box2(new Vector2(Math.Max(startX, endPos - width), 3f) / EyeManager.PixelsPerMeter,
            new Vector2(Math.Min(endX, endPos), 4f) / EyeManager.PixelsPerMeter);

        box = box.Translated(position);
        handle.DrawRect(box, Color.White);

        handle.UseShader(null);
        handle.SetTransform(Matrix3.Identity);
    }
}