feat: implemented terrain editor plumbing

modules/terrain_editor/terrain_primitive.h

@@ -0,0 +1,102 @@
+#pragma once
+
+#include "core/io/resource.h"
+#include "core/math/expression.h"
+#include "core/object/object.h"
+#include "modules/noise/noise.h"
+#include "terrain_editor/macros.h"
+
+class TerrainPrimitive : public Resource {
+	GDCLASS(TerrainPrimitive, Resource);
+	static void _bind_methods();
+
+public:
+	GDENUM(BlendMode,
+			Peak,
+			Valley,
+			Both)
+
+protected:
+	float blend(float under, float over) const;
+
+public:
+	// evaluate the height of this primitive at point, returns the weight of the effect, out_height will be set to the closest point on the primitive
+	virtual void evaluate(Vector2 at, float &io_height) const;
+
+	void set_blend_mode(BlendMode mode);
+	BlendMode get_blend_mode() const;
+	void set_blend_range(float blend_range);
+	float get_blend_range() const;
+
+private:
+	float blend_range{ 4.f };
+	BlendMode blend_mode{ Peak };
+};
+
+MAKE_TYPE_INFO(TerrainPrimitive::BlendMode, Variant::INT);
+
+class PlanePrimitive : public TerrainPrimitive {
+	GDCLASS(PlanePrimitive, TerrainPrimitive);
+	static void _bind_methods();
+
+public:
+	void evaluate(Vector2 at, float &io_height) const override;
+	void set_baseline(float value);
+	float get_baseline() const;
+
+private:
+	float baseline{ 1.f };
+};
+
+class PointPrimitive : public TerrainPrimitive {
+	GDCLASS(PointPrimitive, TerrainPrimitive);
+	static void _bind_methods();
+
+public:
+	void evaluate(Vector2 at, float &io_height) const override;
+	void set_center(Vector2 center);
+	Vector2 get_center() const;
+	void set_slope(float radius);
+	float get_slope() const;
+	void set_height(float height);
+	float get_height() const;
+
+private:
+	Vector2 center{ 0.f, 0.f };
+	float slope{ -1.f };
+	float height{ 10.f };
+};
+
+class NoisePrimitive : public TerrainPrimitive {
+	GDCLASS(NoisePrimitive, TerrainPrimitive);
+	static void _bind_methods();
+
+public:
+	void evaluate(Vector2 at, float &io_height) const override;
+	void set_noise(Ref<Noise> noise);
+	Ref<Noise> get_noise() const;
+	void set_noise_scale(float pixels_per_meter);
+	float get_noise_scale() const;
+	void set_noise_amplitude(float height);
+	float get_noise_amplitude() const;
+
+private:
+	Ref<Noise> noise{};
+	float noise_scale{ 1.f };
+	float noise_amplitude{ 1.f };
+};
+
+class ExpressionPrimitive : public TerrainPrimitive {
+	GDCLASS(ExpressionPrimitive, TerrainPrimitive);
+	static void _bind_methods();
+
+public:
+	void evaluate(Vector2 at, float &io_height) const override;
+	void set_expression(String expression);
+	String get_expression() const;
+
+private:
+	Ref<Expression> expression{ memnew(Expression) };
+	String expression_string{ "height" };
+	bool valid{ false };
+};