Merge pull request #80887 from lawnjelly/cpuparticles2d_fix_double_xform

[3.x] CPUParticles2D - fix interpolated transforms and culling

scene/2d/canvas_item.cpp

@@ -732,7 +732,7 @@ void CanvasItem::set_canvas_item_use_identity_transform(bool p_enable) {
 	_set_use_identity_transform(p_enable);
 
 	// Let VisualServer know not to concatenate the parent transform during the render.
-	VisualServer::get_singleton()->canvas_item_set_ignore_parent_transform(get_canvas_item(), p_enable);
+	VisualServer::get_singleton()->canvas_item_set_use_identity_transform(get_canvas_item(), p_enable);
 
 	if (is_inside_tree()) {
 		if (p_enable) {

servers/visual/rasterizer.h

@@ -1006,7 +1006,7 @@ public:
 		bool light_masked : 1;
 		bool on_interpolate_transform_list : 1;
 		bool interpolated : 1;
-		bool ignore_parent_xform : 1;
+		bool use_identity_xform : 1;
 		mutable bool custom_rect : 1;
 		mutable bool rect_dirty : 1;
 		mutable bool bound_dirty : 1;
@@ -1262,7 +1262,7 @@ public:
 			update_when_visible = false;
 			on_interpolate_transform_list = false;
 			interpolated = true;
-			ignore_parent_xform = false;
+			use_identity_xform = false;
 			local_bound_last_update_tick = 0;
 		}
 		virtual ~Item() {

servers/visual/visual_server_canvas.cpp

@@ -29,6 +29,7 @@
 /**************************************************************************/
 
 #include "visual_server_canvas.h"
+#include "core/fixed_array.h"
 #include "core/math/transform_interpolator.h"
 #include "visual_server_globals.h"
 #include "visual_server_raster.h"
@@ -277,10 +278,57 @@ void VisualServerCanvas::_calculate_canvas_item_bound(Item *p_canvas_item, Rect2
 	}
 }
 
+Transform2D VisualServerCanvas::_calculate_item_global_xform(const Item *p_canvas_item) {
+	// If we use more than the maximum scene tree depth, we are out of luck.
+	// But that would be super inefficient anyway.
+	FixedArray<const Transform2D *, 64> transforms;
+
+	while (p_canvas_item) {
+		// Should only happen if scene tree depth too high.
+		if (transforms.is_full()) {
+			WARN_PRINT_ONCE("SceneTree depth too high for hierarchical culling.");
+			break;
+		}
+
+		// Note this is only using the CURRENT transform.
+		// This may have implications for interpolated bounds - investigate.
+		transforms.push_back(&p_canvas_item->xform_curr);
+
+		if (canvas_item_owner.owns(p_canvas_item->parent)) {
+			p_canvas_item = canvas_item_owner.get(p_canvas_item->parent);
+		} else {
+			p_canvas_item = nullptr;
+		}
+	}
+
+	Transform2D tr;
+	for (int n = (int)transforms.size() - 1; n >= 0; n--) {
+		tr *= *transforms[n];
+	}
+	return tr;
+}
+
 void VisualServerCanvas::_finalize_and_merge_local_bound_to_branch(Item *p_canvas_item, Rect2 *r_branch_bound) {
 	if (r_branch_bound) {
 		Rect2 this_rect = p_canvas_item->get_rect();
 
+		// Special case .. if the canvas_item has use_identity_xform,
+		// we need to transform the rect from global space to local space,
+		// because the hierarchical culling expects local space.
+		if (p_canvas_item->use_identity_xform) {
+			// This is incredibly inefficient, but should only occur for e.g. CPUParticles2D,
+			// and is difficult to avoid because global transform is not usually kept track of
+			// in VisualServer (only final transform which is combinated with camera, and that
+			// is only calculated on render, so is no use for culling purposes).
+			Transform2D global_xform = _calculate_item_global_xform(p_canvas_item);
+			this_rect = global_xform.affine_inverse().xform(this_rect);
+
+			// Note that the efficiency will depend linearly on the scene tree depth of the
+			// identity transform item.
+			// So e.g. interpolated global CPUParticles2D may run faster at lower depths
+			// in extreme circumstances.
+		}
+
 		// If this item has a bound...
 		if (!p_canvas_item->local_bound.has_no_area()) {
 			// If the rect has an area...
@@ -340,13 +388,19 @@ void VisualServerCanvas::_render_canvas_item_cull_by_item(Item *p_canvas_item, c
 		TransformInterpolator::interpolate_transform_2d(ci->xform_prev, ci->xform_curr, final_xform, f);
 	}
 
-	if (!p_canvas_item->ignore_parent_xform) {
-		final_xform = p_transform * final_xform;
+	// Always calculate final transform as if not using identity xform.
+	// This is so the expected transform is passed to children.
+	// However, if use_identity_xform is set,
+	// we can override the transform for rendering purposes for this item only.
+	final_xform = p_transform * final_xform;
+
+	Rect2 global_rect;
+	if (!p_canvas_item->use_identity_xform) {
+		global_rect = final_xform.xform(rect);
 	} else {
-		final_xform = _current_camera_transform * final_xform;
+		global_rect = _current_camera_transform.xform(rect);
 	}
 
-	Rect2 global_rect = final_xform.xform(rect);
 	global_rect.position += p_clip_rect.position;
 
 	if (ci->use_parent_material && p_material_owner) {
@@ -422,7 +476,7 @@ void VisualServerCanvas::_render_canvas_item_cull_by_item(Item *p_canvas_item, c
 
 	if ((!ci->commands.empty() && p_clip_rect.intersects(global_rect, true)) || ci->vp_render || ci->copy_back_buffer) {
 		//something to draw?
-		ci->final_transform = final_xform;
+		ci->final_transform = !p_canvas_item->use_identity_xform ? final_xform : _current_camera_transform;
 		ci->final_modulate = Color(modulate.r * ci->self_modulate.r, modulate.g * ci->self_modulate.g, modulate.b * ci->self_modulate.b, modulate.a * ci->self_modulate.a);
 		ci->global_rect_cache = global_rect;
 		ci->global_rect_cache.position -= p_clip_rect.position;
@@ -481,15 +535,21 @@ void VisualServerCanvas::_render_canvas_item_cull_by_node(Item *p_canvas_item, c
 		TransformInterpolator::interpolate_transform_2d(ci->xform_prev, ci->xform_curr, final_xform, f);
 	}
 
-	if (!p_canvas_item->ignore_parent_xform) {
-		final_xform = p_transform * final_xform;
+	// Always calculate final transform as if not using identity xform.
+	// This is so the expected transform is passed to children.
+	// However, if use_identity_xform is set,
+	// we can override the transform for rendering purposes for this item only.
+	final_xform = p_transform * final_xform;
+
+	Rect2 global_rect;
+	if (!p_canvas_item->use_identity_xform) {
+		global_rect = final_xform.xform(rect);
 	} else {
-		final_xform = _current_camera_transform * final_xform;
+		global_rect = _current_camera_transform.xform(rect);
 	}
 
-	Rect2 global_rect = final_xform.xform(rect);
 	ci->global_rect_cache = global_rect;
-	ci->final_transform = final_xform;
+	ci->final_transform = !p_canvas_item->use_identity_xform ? final_xform : _current_camera_transform;
 
 	global_rect.position += p_clip_rect.position;
 
@@ -955,11 +1015,11 @@ void VisualServerCanvas::canvas_item_set_draw_behind_parent(RID p_item, bool p_e
 	_check_bound_integrity(canvas_item);
 }
 
-void VisualServerCanvas::canvas_item_set_ignore_parent_transform(RID p_item, bool p_enable) {
+void VisualServerCanvas::canvas_item_set_use_identity_transform(RID p_item, bool p_enable) {
 	Item *canvas_item = canvas_item_owner.getornull(p_item);
 	ERR_FAIL_COND(!canvas_item);
 
-	canvas_item->ignore_parent_xform = p_enable;
+	canvas_item->use_identity_xform = p_enable;
 	_make_bound_dirty(canvas_item);
 }
 

servers/visual/visual_server_canvas.h

@@ -181,6 +181,7 @@ private:
 	void _prepare_tree_bounds(Item *p_root);
 	void _calculate_canvas_item_bound(Item *p_canvas_item, Rect2 *r_branch_bound);
 
+	Transform2D _calculate_item_global_xform(const Item *p_canvas_item);
 	void _finalize_and_merge_local_bound_to_branch(Item *p_canvas_item, Rect2 *r_branch_bound);
 	void _merge_local_bound_to_branch(Item *p_canvas_item, Rect2 *r_branch_bound);
 
@@ -227,7 +228,7 @@ public:
 	void canvas_item_set_self_modulate(RID p_item, const Color &p_color);
 
 	void canvas_item_set_draw_behind_parent(RID p_item, bool p_enable);
-	void canvas_item_set_ignore_parent_transform(RID p_item, bool p_enable);
+	void canvas_item_set_use_identity_transform(RID p_item, bool p_enable);
 
 	void canvas_item_set_update_when_visible(RID p_item, bool p_update);
 

servers/visual/visual_server_raster.h

@@ -690,7 +690,7 @@ public:
 	BIND2(canvas_item_set_self_modulate, RID, const Color &)
 
 	BIND2(canvas_item_set_draw_behind_parent, RID, bool)
-	BIND2(canvas_item_set_ignore_parent_transform, RID, bool)
+	BIND2(canvas_item_set_use_identity_transform, RID, bool)
 
 	BIND6(canvas_item_add_line, RID, const Point2 &, const Point2 &, const Color &, float, bool)
 	BIND5(canvas_item_add_polyline, RID, const Vector<Point2> &, const Vector<Color> &, float, bool)

servers/visual/visual_server_wrap_mt.h

@@ -594,7 +594,7 @@ public:
 	FUNC2(canvas_item_set_self_modulate, RID, const Color &)
 
 	FUNC2(canvas_item_set_draw_behind_parent, RID, bool)
-	FUNC2(canvas_item_set_ignore_parent_transform, RID, bool)
+	FUNC2(canvas_item_set_use_identity_transform, RID, bool)
 
 	FUNC6(canvas_item_add_line, RID, const Point2 &, const Point2 &, const Color &, float, bool)
 	FUNC5(canvas_item_add_polyline, RID, const Vector<Point2> &, const Vector<Color> &, float, bool)

servers/visual_server.h

@@ -1024,7 +1024,7 @@ public:
 	virtual void canvas_item_set_self_modulate(RID p_item, const Color &p_color) = 0;
 
 	virtual void canvas_item_set_draw_behind_parent(RID p_item, bool p_enable) = 0;
-	virtual void canvas_item_set_ignore_parent_transform(RID p_item, bool p_enable) = 0;
+	virtual void canvas_item_set_use_identity_transform(RID p_item, bool p_enable) = 0;
 
 	enum NinePatchAxisMode {
 		NINE_PATCH_STRETCH,