aego/modules/scripting/stdlib/query.go

package stdlib

import (
	"aego/contracts/physics2d"
	"aego/core/ids"
	"aego/core/mathx"
	"aego/engine"
	"aego/scene"
	"aego/schema"
	"aego/script/bind"
)

func copyOut(out bind.Out[scene.NodeHandle], src []scene.NodeHandle) int {
	for i, h := range src {
		out.Set(i, h)
	}
	return len(src)
}

func componentNamed(s *scene.Scene, name string) (schema.TypeID, bool) {
	reg := s.Registry()
	if td, ok := reg.ByName(name); ok && td.Kind == schema.TypeComponent {
		return td.ID, true
	}
	if td, ok := reg.ComponentNamed(name); ok {
		return td.ID, true
	}
	return 0, false
}

func installQueries(m *bind.Module) {
	var buf []scene.NodeHandle
	grow := func(n int) []scene.NodeHandle {
		if cap(buf) < n {
			buf = make([]scene.NodeHandle, n)
		}
		return buf[:n]
	}
	bind.Func2(m, "WithTag", func(c *bind.Ctx, tag string, out bind.Out[scene.NodeHandle]) int {
		s, ok := sceneOf(c)
		if !ok || out.Cap() == 0 {
			return 0
		}
		b := grow(out.Cap())
		return copyOut(out, b[:s.WithTag(tag, b)])
	}, bind.Doc("WithTag writes enabled nodes with the tag into out and returns the count; Enemy also finds Enemy.Flying. Nodes come in the order they got the tag."),
		bind.Params("tag", "out"), bind.Example("n := scene.WithTag(\"Enemy\", enemies)"))
	bind.Func2(m, "WithComponent", func(c *bind.Ctx, name string, out bind.Out[scene.NodeHandle]) int {
		s, ok := sceneOf(c)
		if !ok || out.Cap() == 0 {
			return 0
		}
		t, ok := componentNamed(s, name)
		if !ok {
			c.Failf("unknown or ambiguous component %q", name)
			return 0
		}
		b := grow(out.Cap())
		return copyOut(out, b[:s.WithComponent(t, b)])
	}, bind.Doc("WithComponent writes enabled nodes that have the component into out and returns the count."),
		bind.Params("component", "out"), bind.Example("n := scene.WithComponent(\"Body2D\", bodies)"))
	bind.Func3(m, "InArea", func(c *bind.Ctx, r mathx.Rect, mask int, out bind.Out[scene.NodeHandle]) int {
		s, ok := sceneOf(c)
		if !ok || out.Cap() == 0 {
			return 0
		}
		b := grow(out.Cap())
		if c.World != nil {
			if q, ok := engine.ServiceOf[physics2d.Queries](c.World, physics2d.ServiceID); ok {
				half := mathx.Vec2{X: r.W / 2, Y: r.H / 2}
				f := physics2d.QueryFilter{LayerMask: uint32(mask)}
				return copyOut(out, b[:q.OverlapBox(mathx.Vec2{X: r.X + half.X, Y: r.Y + half.Y}, half, 0, f, b)])
			}
		}
		return copyOut(out, b[:s.InRect(r, b)])
	}, bind.Doc("InArea writes the bodies touching the rectangle on the layers in mask into out. Without physics it writes every enabled 2D node whose position lies in the rectangle, ignoring mask."),
		bind.Params("rect", "mask", "out"), bind.Example("n := scene.InArea(Rect{x - 2, y - 2, 4, 4}, -1, near)"))
	bind.Func1(m, "ByID", func(c *bind.Ctx, id string) scene.NodeHandle {
		s, ok := sceneOf(c)
		if !ok {
			return scene.NodeHandle{}
		}
		nid, err := ids.ParseNodeID(id)
		if err != nil {
			return scene.NodeHandle{}
		}
		return orNil(s, s.Handle(nid))
	}, bind.Doc("ByID returns the node with this id, as written in the scene file, or nil."), bind.Params("id"))
}

func installTags(n *bind.Module) {
	bind.Func2(n, "HasTag", func(c *bind.Ctx, h scene.NodeHandle, tag string) bool {
		s, ok := alive(c, h)
		return ok && s.HasTag(h, tag)
	}, bind.Doc("HasTag reports whether the node has the tag or a tag under it: Enemy matches Enemy.Flying."),
		bind.Params("tag"), bind.Example("if other.HasTag(\"Enemy\") {"))
	bind.Func2(n, "AddTag", func(c *bind.Ctx, h scene.NodeHandle, tag string) bool {
		s, ok := alive(c, h)
		return ok && s.AddTag(h, tag)
	}, bind.Doc("AddTag adds a tag and returns false when it is malformed."), bind.Params("tag"),
		bind.Example("node.AddTag(\"Enemy.Stunned\")"))
	bind.Func2(n, "RemoveTag", func(c *bind.Ctx, h scene.NodeHandle, tag string) bool {
		s, ok := alive(c, h)
		return ok && s.RemoveTag(h, tag)
	}, bind.Doc("RemoveTag removes a tag and returns whether the node had it."), bind.Params("tag"))
}