Add new Teardrop shape

[DallinYauney]

This PR adds Teardrop as an option within the Shape tool. Partially closes #3419

In addition to the parameters for width and height, a slider has been added to adjust the velocity of the shape. This is because, during testing, I found that a variety of aspect ratios/steepnesses/velocities, looked good and thought it would be worth exposing for the user to decide.

Three teardrops, with varying stroke styles, widths, and velocities, the center being the default:

^ I originally recorded a video, but it's just me drawing these shapes slowly so I figured it'd be better to just screenshot the end result.

---

Potential future work

• add gizmos for velocity, as well as location and direction for the top point
• test cases
• set default stroke type to "inside" (is this possible?)
• set shift to constrain to a ratio of ~3:5, rather than 1:1 (is this possible?)

---

Other notes

No AI was used whatsoever throughout this PR.

This code is a modified copy of the implementations for the spiral and ellipse tools, in case that's important.

This is basically my first real pull request, so a little help in making sure I'm going about this the right way / not forgetting anything would be greatly appreciated.

When I started work on this, I forgot to check for other PRs on the same issue. I realize now that other people have also worked on this, and I understand if this PR doesn't get merged because of one of them.

Sorry about splitting some stuff onto multiple lines. My IDE does it automatically, and I was planning on reverting it but I saw one of the other PRs also doing it and it didn't seem to be an issue there, so I ended up leaving it. I'm happy to undo it if that'd be preferable.

[cubic-dev-ai]

4 issues found across 8 files

Confidence score: 2/5

• editor/src/messages/tool/common_functionality/shapes/teardrop_shape.rs can panic in create_node when the Teardrop definition is unregistered, crashing the editor when drawing begins; handle the missing definition locally or propagate the failure instead of calling expect.
• node-graph/nodes/vector/src/generator_nodes.rs allows zero or negative velocity through its soft range, so teardrop_bezpath can divide by an invalid value and generate broken geometry; add a hard lower bound such as #[hard(1..)].
• node-graph/libraries/vector-types/src/vector/algorithms/shapes.rs independently divides by non-positive velocity in circle_center and vertical_handle_offset, producing non-finite path coordinates for typed or graph-provided inputs; validate the value before these calculations.
• editor/src/messages/tool/tool_messages/shape_tool.rs omits the Teardrop velocity control and selection synchronization, preventing users from editing the parameter through the Shape tool; add the control, tool state/update variant, and synchronization.

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="editor/src/messages/tool/common_functionality/shapes/teardrop_shape.rs">

<violation number="1" location="editor/src/messages/tool/common_functionality/shapes/teardrop_shape.rs:17">
P1: When the Teardrop node is not registered, `create_node` panics while starting a draw and brings down the editor. Handle the missing definition locally or propagate the failure instead of calling `expect`.</violation>
</file>

<file name="node-graph/nodes/vector/src/generator_nodes.rs">

<violation number="1" location="node-graph/nodes/vector/src/generator_nodes.rs:93">
P1: When a node input supplies `velocity` at or below zero, the soft range does not prevent invalid geometry: `teardrop_bezpath` divides by this value. Add a hard lower bound such as `#[hard(1..)]` before the soft range.</violation>
</file>

<file name="node-graph/libraries/vector-types/src/vector/algorithms/shapes.rs">

<violation number="1" location="node-graph/libraries/vector-types/src/vector/algorithms/shapes.rs:268">
P2: When `velocity` is zero or negative, this function divides by it in both `circle_center` and `vertical_handle_offset`, emitting non-finite path coordinates. The node declares only a soft range, so typed or graph-provided values are not hard-clamped; validate a finite positive velocity before these calculations.</violation>
</file>

<file name="editor/src/messages/tool/tool_messages/shape_tool.rs">

<violation number="1" location="editor/src/messages/tool/tool_messages/shape_tool.rs:418">
P2: The Shape tool does not expose the teardrop's `velocity` parameter. Add a velocity control, tool state/update variant, and selection synchronization instead of treating Teardrop as a parameterless shape.</violation>
</file>

<sub>Tip: cubic used a learning from your PR history. Let your coding agent read cubic learnings directly with the cubic MCP.

Re-trigger cubic</sub>

[cubic-dev-ai]

P1: When the Teardrop node is not registered, create_node panics while starting a draw and brings down the editor. Handle the missing definition locally or propagate the failure instead of calling expect.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At editor/src/messages/tool/common_functionality/shapes/teardrop_shape.rs, line 17:

<comment>When the Teardrop node is not registered, `create_node` panics while starting a draw and brings down the editor. Handle the missing definition locally or propagate the failure instead of calling `expect`.</comment>

<file context>
@@ -0,0 +1,50 @@
+
+impl Teardrop {
+	pub fn create_node() -> NodeTemplate {
+		let node_type = resolve_proto_node_type(graphene_std::vector::generator_nodes::teardrop::IDENTIFIER).expect("Teardrop node can't be found");
+		node_type.node_template_input_override([None, Some(NodeInput::value(TaggedValue::F64(0.5), false)), Some(NodeInput::value(TaggedValue::F64(0.5), false))])
+	}
</file context>

[cubic-dev-ai]

P1: When a node input supplies velocity at or below zero, the soft range does not prevent invalid geometry: teardrop_bezpath divides by this value. Add a hard lower bound such as #[hard(1..)] before the soft range.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At node-graph/nodes/vector/src/generator_nodes.rs, line 93:

<comment>When a node input supplies `velocity` at or below zero, the soft range does not prevent invalid geometry: `teardrop_bezpath` divides by this value. Add a hard lower bound such as `#[hard(1..)]` before the soft range.</comment>

<file context>
@@ -77,6 +77,39 @@ fn spiral(
+	height: Item<f64>,
+	#[default(1.7)]
+	#[range]
+	#[soft(1.4..3.8)]
+	velocity: Item<f64>,
+) -> Item<Vector> {
</file context>

Suggested change

	#[soft(1.4..3.8)]
	#[hard(1..)]
	#[soft(1.4..3.8)]

[cubic-dev-ai]

P2: When velocity is zero or negative, this function divides by it in both circle_center and vertical_handle_offset, emitting non-finite path coordinates. The node declares only a soft range, so typed or graph-provided values are not hard-clamped; validate a finite positive velocity before these calculations.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At node-graph/libraries/vector-types/src/vector/algorithms/shapes.rs, line 268:

<comment>When `velocity` is zero or negative, this function divides by it in both `circle_center` and `vertical_handle_offset`, emitting non-finite path coordinates. The node declares only a soft range, so typed or graph-provided values are not hard-clamped; validate a finite positive velocity before these calculations.</comment>

<file context>
@@ -260,6 +260,41 @@ pub fn spiral_bezpath(a: f64, outer_radius: f64, turns: f64, start_angle: f64, d
+	let size = (corner1 - corner2).abs();
+
+	// the bottom half of the teardrop is a circle, upon which these calculations are heavily based
+	let circle_center = DVec2::new((corner1.x + corner2.x) / 2., (corner1.y + (2. * velocity - 1.) * corner2.y) / (2. * velocity));
+
+	let top = DVec2::new(circle_center.x, corner1.y);
</file context>

Suggested change

	let circle_center = DVec2::new((corner1.x + corner2.x) / 2., (corner1.y + (2. * velocity - 1.) * corner2.y) / (2. * velocity));
	\tlet velocity = if velocity.is_finite() && velocity > 0. { velocity } else { 1.7 };\n\tlet circle_center = DVec2::new((corner1.x + corner2.x) / 2., (corner1.y + (2. * velocity - 1.) * corner2.y) / (2. * velocity));

[cubic-dev-ai]

P2: The Shape tool does not expose the teardrop's velocity parameter. Add a velocity control, tool state/update variant, and selection synchronization instead of treating Teardrop as a parameterless shape.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At editor/src/messages/tool/tool_messages/shape_tool.rs, line 418:

<comment>The Shape tool does not expose the teardrop's `velocity` parameter. Add a velocity control, tool state/update variant, and selection synchronization instead of treating Teardrop as a parameterless shape.</comment>

<file context>
@@ -407,7 +415,7 @@ fn sync_shape_options_from_selection(options: &mut ShapeToolOptions, tool_data:
 			}
 		}
-		ShapeType::Ellipse | ShapeType::Rectangle | ShapeType::Line | ShapeType::Circle => {}
+		ShapeType::Ellipse | ShapeType::Rectangle | ShapeType::Line | ShapeType::Circle | ShapeType::Teardrop => {}
 	}
 
</file context>