feat: started work on terrain editor tools

modules/terrain/terrain_modifier.h

@@ -0,0 +1,51 @@
+#pragma once
+
+#include "core/object/object.h"
+#include "core/variant/variant.h"
+#include "macros.h"
+#include "scene/3d/node_3d.h"
+#include "scene/resources/curve.h"
+
+class TerrainModifier : public Node3D {
+	GDCLASS(TerrainModifier, Node3D);
+	static void _bind_methods();
+
+public:
+	GDENUM(BlendMode, Add, Subtract, Override);
+
+protected:
+	float blend(float under, float over, float weight);
+
+public:
+	virtual float evaluate_at(Vector2 world_coordinate, float before);
+
+private:
+	float blend_distance{ 1.0 };
+	BlendMode blend_mode{ Add };
+
+public:
+	GET_SET_FNS(float, blend_distance);
+	GET_SET_FNS(BlendMode, blend_mode);
+};
+
+MAKE_TYPE_INFO(TerrainModifier::BlendMode, Variant::INT);
+
+class TerrainModifierDistance : public TerrainModifier {
+	GDCLASS(TerrainModifierDistance, TerrainModifier);
+	static void _bind_methods();
+
+protected:
+	virtual float distance_at(Vector2 const &world_coordinate);
+
+public:
+	float evaluate_at(Vector2 world_coordinate, float before) override;
+	PackedStringArray get_configuration_warnings() const override;
+
+private:
+	Ref<Curve> distance_weight_curve{};
+	Ref<Curve> distance_height_curve{};
+
+public:
+	GET_SET_FNS_EX(Ref<Curve>, distance_weight_curve, update_configuration_warnings());
+	GET_SET_FNS_EX(Ref<Curve>, distance_height_curve, update_configuration_warnings());
+};