Terrain support for customizing amplitude, lacunarity, persistance an…

…d octaves.

Added a Terrain to the starting scene and modified defaults to be more interesting.

source/Component/Terrain.cpp

@@ -6,11 +6,15 @@
 
 #include "imgui.h"
 
-Component::Terrain::Terrain(const glm::vec3& p_position, int p_size_x, int p_size_z) noexcept
+Component::Terrain::Terrain(const glm::vec3& p_position, int p_size_x, int p_size_z, float amplitude) noexcept
 	: m_position{p_position}
 	, m_size_x{p_size_x}
 	, m_size_z{p_size_z}
-	, m_scale_factor{1.f}
+	, m_scale_factor{0.03f}
+	, m_amplitude{amplitude}
+	, m_lacunarity{2.f}
+	, m_persistence{0.5f}
+	, m_octaves{4}
 	, m_texture{}
 	, m_seed{Utility::get_random_number<unsigned int>()}
 	, m_mesh{generate_mesh(m_seed)}
@@ -20,6 +24,10 @@ Component::Terrain::Terrain(const Terrain& p_other) noexcept
 	, m_size_x{p_other.m_size_x}
 	, m_size_z{p_other.m_size_z}
 	, m_scale_factor{p_other.m_scale_factor}
+	, m_amplitude{p_other.m_amplitude}
+	, m_lacunarity{p_other.m_lacunarity}
+	, m_persistence{p_other.m_persistence}
+	, m_octaves{p_other.m_octaves}
 	, m_texture{p_other.m_texture}
 	, m_seed{p_other.m_seed}
 	, m_mesh{generate_mesh(m_seed)} // TODO: Implement a Data::Mesh copy.
@@ -30,15 +38,32 @@ Component::Terrain& Component::Terrain::operator=(const Terrain& p_other) noexce
 	m_size_x       = p_other.m_size_x;
 	m_size_z       = p_other.m_size_z;
 	m_scale_factor = p_other.m_scale_factor;
+	m_amplitude    = p_other.m_amplitude;
+	m_lacunarity   = p_other.m_lacunarity;
+	m_persistence  = p_other.m_persistence;
+	m_octaves      = p_other.m_octaves;
 	m_texture      = p_other.m_texture;
 	m_seed         = p_other.m_seed;
 	m_mesh         = generate_mesh(m_seed); // TODO: Implement a Data::Mesh copy.
 	return *this;
 }
 
-float compute_height(float p_x, float p_z, float p_scale_factor, const siv::PerlinNoise& perlin)
+float Component::Terrain::compute_height(float p_x, float p_z, const siv::PerlinNoise& perlin)
 {
-	return static_cast<float>(perlin.noise2D(p_x * p_scale_factor, p_z * p_scale_factor));
+	float accumulate       = 0.f;
+	float octave_frequency = 1.f;
+	float octave_amplitude = 1.f;
+	float max_value        = 0.f;
+
+	for (int i = 0; i < m_octaves; i++)
+	{
+		accumulate       += static_cast<float>(perlin.noise2D(p_x * m_scale_factor * octave_frequency, p_z * m_scale_factor * octave_frequency)) * octave_amplitude;
+		max_value        += octave_amplitude;
+		octave_amplitude *= m_persistence;
+		octave_frequency *= m_lacunarity;
+	}
+
+	return accumulate / max_value * m_amplitude;
 }
 
 Data::Mesh Component::Terrain::generate_mesh(unsigned int p_seed) noexcept
@@ -52,10 +77,10 @@ Data::Mesh Component::Terrain::generate_mesh(unsigned int p_seed) noexcept
 		for (float z = 0; z < m_size_z; z++)
 		{
 			mb.add_quad(
-				glm::vec3(x + 1, compute_height(x + 1, z,     m_scale_factor, perlin), z),
-				glm::vec3(x + 1, compute_height(x + 1, z + 1, m_scale_factor, perlin), z + 1),
-				glm::vec3(x,     compute_height(x, z,         m_scale_factor, perlin), z),
-				glm::vec3(x,     compute_height(x, z + 1,     m_scale_factor, perlin), z  + 1));
+				glm::vec3(x + 1, compute_height(x + 1, z,     perlin), z),
+				glm::vec3(x + 1, compute_height(x + 1, z + 1, perlin), z + 1),
+				glm::vec3(x,     compute_height(x, z,         perlin), z),
+				glm::vec3(x,     compute_height(x, z + 1,     perlin), z  + 1));
 		}
 
 	return mb.get_mesh();
@@ -83,7 +108,11 @@ void Component::Terrain::draw_UI(System::AssetManager& p_asset_manager)
 		changed |= ImGui::Slider("Position", m_position, -100.f, 100.f, "%.3fm");
 		changed |= ImGui::Slider("Size X", m_size_x, 1, 1000, "%dm");
 		changed |= ImGui::Slider("Size Z", m_size_z, 1, 1000, "%dm");
-		changed |= ImGui::Slider("Scale factor", m_scale_factor, 0.01f , 10.f);
+		changed |= ImGui::Slider("Scale factor", m_scale_factor, 0.01f , 0.15f);
+		changed |= ImGui::Slider("Amplitude", m_amplitude, 0.01f, 100.f);
+		changed |= ImGui::Slider("Lacunarity", m_lacunarity, 0.01f, 4.f);
+		changed |= ImGui::Slider("Persistence", m_persistence, 0.01f, 1.f);
+		changed |= ImGui::Slider("Octaves", m_octaves, 1, 10);
 		changed |= ImGui::InputScalar("Seed", ImGuiDataType_U32, &m_seed);
 		ImGui::SameLine();
 		if (ImGui::Button("Rand"))

source/Component/Terrain.hpp

@@ -3,6 +3,10 @@
 #include "Component/Texture.hpp"
 #include "Component/Mesh.hpp"
 
+#include "Utility/PerlinNoise.hpp"
+
+
+
 namespace System
 {
 	class AssetManager;
@@ -20,18 +24,23 @@ namespace Component
 		int m_size_x;
 		int m_size_z;
 		float m_scale_factor;
+		float m_amplitude;
+		float m_lacunarity;
+		float m_persistence;
+		int m_octaves;
 		TextureRef m_texture;
 		unsigned int m_seed; // Seed used to generate m_mesh.
 		Data::Mesh m_mesh;
 
-		Terrain(const glm::vec3& p_position, int p_size_x, int p_size_z) noexcept;
+		Terrain(const glm::vec3& p_position, int p_size_x, int p_size_z, float amplitude) noexcept;
 		// Copy constructor has to be implemented because Data::Mesh GL members are not copyable.
 		Terrain(const Terrain& p_other) noexcept;
 		// Copy assignment operator has to be implemented because Data::Mesh GL members are not copyable.
 		Terrain& operator=(const Terrain& p_other) noexcept;
 		Terrain(Terrain&& p_other) noexcept            = default;
 		Terrain& operator=(Terrain&& p_other) noexcept = default;
 
+		float compute_height(float p_x, float p_z, const siv::PerlinNoise& perlin);
 		void draw_UI(System::AssetManager& p_asset_manager);
 	};
 } // namespace Component

source/System/SceneSystem.cpp

@@ -29,6 +29,10 @@ namespace System
 		set_current_scene(scene);
 		add_default_camera(scene);
 		construct_2_sphere_scene(scene);
+
+		Component::Terrain terrain({0.f, 5.f, -100.f}, 100, 100, 20);
+		terrain.m_texture = m_asset_manager.get_texture(Config::Texture_Directory / "GrassTile.png");
+		scene.m_entities.add_entity(terrain);
 	}
 
 	void SceneSystem::set_current_scene(const Scene& p_scene)
@@ -209,9 +213,6 @@ namespace System
 			auto particle_emitter = Component::ParticleEmitter{m_asset_manager.get_texture(Config::Texture_Directory / "smoke.png")};
 			p_scene.m_entities.add_entity(Component::Label{"Particle emitter"}, particle_emitter);
 		}
-		{ // Terrain
-			p_scene.m_entities.add_entity(Component::Label{"Terrain"}, Component::Terrain{glm::vec3(0.f), 100, 100});
-		}
 	}
 
 	void SceneSystem::constructBoxScene(Scene& p_scene)
@@ -283,15 +284,15 @@ namespace System
 		p_scene.m_entities.add_entity(
 			Component::Label{"Sphere 1"},
 			Component::RigidBody{},
-			Component::Transform{glm::vec3(2.f, 0.f, 0.f)},
+			Component::Transform{glm::vec3(50.f, 30.f, -50.f)},
 			Component::Mesh{icosphere_meshref},
 			Component::Texture{glm::vec4(0.5f, 0.5f, 0.5f, 0.6f)}, // Grey
 			Component::Collider{});
 
 		p_scene.m_entities.add_entity(
 			Component::Label{"Sphere 2"},
 			Component::RigidBody{},
-			Component::Transform{glm::vec3(5.f, 0.f, 0.f)},
+			Component::Transform{glm::vec3(55.f, 30.f, -50.f)},
 			Component::Mesh{icosphere_meshref},
 			Component::Texture{glm::vec4(1.f, 0.647f, 0.f, 0.6f)}, // Orange
 			Component::Collider{});

source/UI/Editor.cpp

@@ -670,7 +670,7 @@ namespace UI
 					{
 						m_scene_system.get_current_scene_entities().add_entity(
 							Component::Label{"Terrain"},
-							Component::Terrain{*m_cursor_intersection, 10, 10});
+							Component::Terrain{*m_cursor_intersection, 10, 10, 5.f});
 					}
 					ImGui::EndMenu();
 				}