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- /*
- * Copyright (C) 2021 Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * Antkeeper source code is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
- */
-
- #ifndef ANTKEEPER_GAME_SYSTEM_TERRAIN_HPP
- #define ANTKEEPER_GAME_SYSTEM_TERRAIN_HPP
-
- #include "game/system/updatable.hpp"
- #include "game/component/terrain.hpp"
- #include "entity/id.hpp"
- #include "math/quaternion.hpp"
- #include "geom/quadtree.hpp"
- #include "geom/mesh.hpp"
- #include "utility/fundamental-types.hpp"
- #include "render/model.hpp"
- #include "render/material.hpp"
- #include "scene/model-instance.hpp"
- #include "scene/collection.hpp"
- #include "geom/view-frustum.hpp"
- #include <unordered_map>
-
- namespace game {
- namespace system {
-
- /**
- * Generates terrain patches and performs terrain patch LOD selection.
- */
- class terrain: public updatable
- {
- public:
- terrain(entity::registry& registry);
- ~terrain();
-
- virtual void update(double t, double dt);
-
- /**
- * Sets the size of a patch.
- *
- * @param length Side length of a patch.
- */
- void set_patch_side_length(float length);
-
- /**
- * Sets the number of subdivisions of a patch. Zero subdivisions results in a single quad, one subdivison results in four quads, etc.
- *
- * @param n Number of subdivisions.
- */
- void set_patch_subdivisions(std::size_t n);
-
- /**
- * Sets the material of each patch.
- *
- * @param material Patch material.
- */
- void set_patch_material(::render::material* material);
-
- /**
- * Sets the terrain elevation function.
- *
- * @param f Function which returns the terrain height (Y-coordinate) given X- and Z-coordinates.
- */
- void set_elevation_function(const std::function<float(float, float)>& f);
-
- /**
- * Sets the scene collection into which terrain patch model instances will be inserted.
- */
- void set_scene_collection(scene::collection* collection);
-
- private:
- typedef geom::quadtree32 quadtree_type;
- typedef quadtree_type::node_type quadtree_node_type;
-
- struct patch
- {
- geom::mesh* mesh;
- ::render::model* model;
- scene::model_instance* model_instance;
- };
-
- void on_terrain_construct(entity::registry& registry, entity::id entity_id);
- void on_terrain_update(entity::registry& registry, entity::id entity_id);
- void on_terrain_destroy(entity::registry& registry, entity::id entity_id);
-
- float get_patch_size(quadtree_node_type node) const;
- float3 get_patch_center(quadtree_node_type node) const;
-
- void rebuild_patch_base_mesh();
-
-
-
- void visit_quadtree(const geom::bounding_volume<float>& volume, quadtree_node_type node);
-
-
-
- /**
- * Generates a mesh for a terrain patch given the patch's quadtree node
- */
- geom::mesh* generate_patch_mesh(quadtree_node_type node) const;
-
- /**
- * Generates a model for a terrain patch given the patch's mesh.
- */
- ::render::model* generate_patch_model(quadtree_node_type node) const;
-
- patch* generate_patch(quadtree_node_type node);
-
- float patch_side_length;
- std::size_t patch_subdivisions;
- std::size_t patch_cell_count;
- std::size_t patch_triangle_count;
- std::size_t patch_vertex_size;
- std::size_t patch_vertex_stride;
- float* patch_vertex_data;
-
- struct patch_vertex
- {
- float3 position;
- float2 uv;
- float3 normal;
- float3 tangent;
- float3 bitangent;
- float bitangent_sign;
- };
-
- mutable std::vector<std::vector<patch_vertex>> patch_vertex_buffer;
-
-
- ::render::material* patch_material;
- std::function<float(float, float)> elevation_function;
- scene::collection* scene_collection;
-
- geom::mesh* patch_base_mesh;
-
- /// Quadtree describing level of detail
- quadtree_type quadtree;
- float quadtree_node_size[quadtree_type::max_depth + 1];
-
- /// Map linking quadtree nodes to terrain patches
- std::unordered_map<quadtree_node_type, patch*> patches;
- };
-
- } // namespace system
- } // namespace game
-
- #endif // ANTKEEPER_GAME_SYSTEM_TERRAIN_HPP
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