|
|
- /*
- * 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/>.
- */
-
- #include "terrain-system.hpp"
- #include "ecs/components/model-component.hpp"
- #include "ecs/components/collision-component.hpp"
- #include "ecs/components/transform-component.hpp"
- #include "game/cartography/relief-map.hpp"
- #include "renderer/model.hpp"
- #include "geom/mesh.hpp"
- #include "geom/mesh-functions.hpp"
- #include "renderer/vertex-attributes.hpp"
- #include "rasterizer/vertex-attribute-type.hpp"
- #include "rasterizer/drawing-mode.hpp"
- #include "rasterizer/vertex-buffer.hpp"
- #include "resources/resource-manager.hpp"
- #include "resources/image.hpp"
- #include "utility/fundamental-types.hpp"
- #include <limits>
-
- namespace ecs {
-
- terrain_system::terrain_system(ecs::registry& registry, ::resource_manager* resource_manager):
- entity_system(registry),
- resource_manager(resource_manager)
- {
- registry.on_construct<terrain_component>().connect<&terrain_system::on_terrain_construct>(this);
- registry.on_destroy<terrain_component>().connect<&terrain_system::on_terrain_destroy>(this);
-
- heightmap = resource_manager->load<image>("grassland-heightmap.png");
- heightmap_size = 2000.0f;
- heightmap_scale = 150.0f;
- }
-
- terrain_system::~terrain_system()
- {}
-
- void terrain_system::update(double t, double dt)
- {
- registry.view<terrain_component, transform_component>().each(
- [this](ecs::entity entity, auto& terrain, auto& transform)
- {
- transform.local.translation = float3{(float)terrain.x * patch_size, 0.0f, (float)terrain.z * patch_size};
- transform.warp = true;
- });
- }
-
- void terrain_system::set_patch_size(float size)
- {
- patch_size = size;
- }
-
- geom::mesh* terrain_system::generate_terrain_mesh(float size, int subdivisions)
- {
- auto elevation = [](float u, float v) -> float
- {
- return 0.0f;
- };
-
- return cart::map_elevation(elevation, size, subdivisions);
- }
-
- model* terrain_system::generate_terrain_model(geom::mesh* terrain_mesh)
- {
- // Allocate model
- model* terrain_model = new model();
-
- // Get model's VAO and VBO
- vertex_buffer* vbo = terrain_model->get_vertex_buffer();
- vertex_array* vao = terrain_model->get_vertex_array();
-
- // Resize VBO
- int vertex_size = 3 + 2 + 3 + 4 + 3;
- int vertex_stride = vertex_size * sizeof(float);
- vbo->resize(terrain_mesh->get_faces().size() * 3 * vertex_stride, nullptr);
-
- // Bind vertex attributes
- std::size_t offset = 0;
- vao->bind_attribute(VERTEX_POSITION_LOCATION, *vbo, 3, vertex_attribute_type::float_32, vertex_stride, 0);
- offset += 3;
- vao->bind_attribute(VERTEX_TEXCOORD_LOCATION, *vbo, 2, vertex_attribute_type::float_32, vertex_stride, sizeof(float) * offset);
- offset += 2;
- vao->bind_attribute(VERTEX_NORMAL_LOCATION, *vbo, 3, vertex_attribute_type::float_32, vertex_stride, sizeof(float) * offset);
- offset += 3;
- vao->bind_attribute(VERTEX_TANGENT_LOCATION, *vbo, 4, vertex_attribute_type::float_32, vertex_stride, sizeof(float) * offset);
- offset += 4;
- vao->bind_attribute(VERTEX_BARYCENTRIC_LOCATION, *vbo, 3, vertex_attribute_type::float_32, vertex_stride, sizeof(float) * offset);
- offset += 3;
-
- // Create model group
- model_group* model_group = terrain_model->add_group("terrain");
- model_group->set_material(resource_manager->load<material>("grassland-terrain.mtl"));
- model_group->set_drawing_mode(drawing_mode::triangles);
- model_group->set_start_index(0);
- model_group->set_index_count(terrain_mesh->get_faces().size() * 3);
-
- return terrain_model;
- }
-
- void terrain_system::project_terrain_mesh(geom::mesh* terrain_mesh, const terrain_component& component)
- {
-
- float offset_x = (float)component.x * patch_size;
- float offset_z = (float)component.z * patch_size;
-
- for (geom::mesh::vertex* vertex: terrain_mesh->get_vertices())
- {
- int pixel_x = (vertex->position[0] + offset_x + heightmap_size * 0.5f) / heightmap_size * (float)(heightmap->get_width() - 1);
- int pixel_y = (vertex->position[2] + offset_z + heightmap_size * 0.5f) / heightmap_size * (float)(heightmap->get_height() - 1);
-
- pixel_x = std::max<int>(0, std::min<int>(heightmap->get_width() - 1, pixel_x));
- pixel_y = std::max<int>(0, std::min<int>(heightmap->get_height() - 1, pixel_y));
-
- int pixel_index = (pixel_y * heightmap->get_width() + pixel_x) * heightmap->get_channels();
- const unsigned char* pixel = static_cast<const unsigned char*>(heightmap->get_pixels()) + pixel_index;
-
- float elevation = (static_cast<float>(*pixel) / 255.0f - 0.5) * heightmap_scale;
- vertex->position[1] = elevation;
- }
-
- }
-
- void terrain_system::update_terrain_model(model* terrain_model, geom::mesh* terrain_mesh)
- {
- const std::vector<geom::mesh::face*>& faces = terrain_mesh->get_faces();
- const std::vector<geom::mesh::vertex*>& vertices = terrain_mesh->get_vertices();
-
- geom::aabb<float> bounds = calculate_bounds(*terrain_mesh);
- float bounds_width = bounds.max_point.x - bounds.min_point.x;
- float bounds_height = bounds.max_point.y - bounds.min_point.y;
- float bounds_depth = bounds.max_point.z - bounds.min_point.z;
-
- static const float3 barycentric_coords[3] =
- {
- float3{1, 0, 0},
- float3{0, 1, 0},
- float3{0, 0, 1}
- };
-
- int triangle_count = faces.size();
- int vertex_count = triangle_count * 3;
- int vertex_size = 3 + 2 + 3 + 4 + 3;
-
- // Allocate vertex data
- float* vertex_data = new float[vertex_size * vertex_count];
-
- // Allocate and calculate face normals
- float3* face_normals = new float3[faces.size()];
- calculate_face_normals(face_normals, *terrain_mesh);
-
- // Allocate and calculate vertex normals
- float3* vertex_normals = new float3[vertices.size()];
- for (std::size_t i = 0; i < vertices.size(); ++i)
- {
- const geom::mesh::vertex* vertex = vertices[i];
-
- float3 n = {0, 0, 0};
- geom::mesh::edge* start = vertex->edge;
- geom::mesh::edge* edge = start;
- do
- {
- if (edge->face)
- {
- n += face_normals[edge->face->index];
- }
-
- edge = edge->previous->symmetric;
- }
- while (edge != start);
- n = math::normalize(n);
-
- vertex_normals[i] = n;
- }
-
- // Allocate and generate vertex texture coordinates
- float2* vertex_texcoords = new float2[vertices.size()];
- for (std::size_t i = 0; i < vertices.size(); ++i)
- {
- const geom::mesh::vertex* vertex = vertices[i];
- vertex_texcoords[i].x = (vertex->position.x - bounds.min_point.x) / bounds_width;
- vertex_texcoords[i].y = (vertex->position.z - bounds.min_point.z) / bounds_depth;
- }
-
- // Allocate and calculate vertex tangents
- float4* vertex_tangents = new float4[vertices.size()];
- calculate_vertex_tangents(vertex_tangents, vertex_texcoords, vertex_normals, *terrain_mesh);
-
- // Generate vertex data
- float* v = vertex_data;
- for (int i = 0; i < triangle_count; ++i)
- {
- const geom::mesh::face* triangle = faces[i];
- const geom::mesh::vertex* a = triangle->edge->vertex;
- const geom::mesh::vertex* b = triangle->edge->next->vertex;
- const geom::mesh::vertex* c = triangle->edge->previous->vertex;
- const geom::mesh::vertex* abc[] = {a, b, c};
-
- for (int j = 0; j < 3; ++j)
- {
- const geom::mesh::vertex* vertex = abc[j];
- const float3& position = vertex->position;
- const float2& texcoord = vertex_texcoords[vertex->index];
- const float3& normal = vertex_normals[vertex->index];
- const float4& tangent = vertex_tangents[vertex->index];
- const float3& barycentric = barycentric_coords[j];
-
- *(v++) = position.x;
- *(v++) = position.y;
- *(v++) = position.z;
-
- *(v++) = texcoord.x;
- *(v++) = texcoord.y;
-
- *(v++) = normal.x;
- *(v++) = normal.y;
- *(v++) = normal.z;
-
- *(v++) = tangent.x;
- *(v++) = tangent.y;
- *(v++) = tangent.z;
- *(v++) = tangent.w;
-
- *(v++) = barycentric.x;
- *(v++) = barycentric.y;
- *(v++) = barycentric.z;
- }
- }
-
- // Update bounds
- terrain_model->set_bounds(bounds);
-
- // Update VBO
- terrain_model->get_vertex_buffer()->update(0, vertex_count * vertex_size * sizeof(float), vertex_data);
-
- // Free vertex data
- delete[] face_normals;
- delete[] vertex_normals;
- delete[] vertex_texcoords;
- delete[] vertex_tangents;
- delete[] vertex_data;
- }
-
- void terrain_system::on_terrain_construct(ecs::registry& registry, ecs::entity entity, terrain_component& component)
- {
- geom::mesh* terrain_mesh = generate_terrain_mesh(patch_size, component.subdivisions);
- model* terrain_model = generate_terrain_model(terrain_mesh);
- project_terrain_mesh(terrain_mesh, component);
- update_terrain_model(terrain_model, terrain_mesh);
-
- // Assign the entity a collision component with the terrain mesh
- collision_component collision;
- collision.mesh = terrain_mesh;
- collision.bounds = calculate_bounds(*terrain_mesh);
- collision.mesh_accelerator.build(*collision.mesh);
- registry.assign_or_replace<collision_component>(entity, collision);
-
- // Assign the entity a model component with the terrain model
- model_component model;
- model.model = terrain_model;
- model.instance_count = 0;
- model.layers = 1;
- registry.assign_or_replace<model_component>(entity, model);
-
- // Assign the entity a transform component
- transform_component transform;
- transform.local = math::identity_transform<float>;
- transform.local.translation = float3{(float)component.x * patch_size, 0.0f, (float)component.z * patch_size};
- transform.warp = true;
- registry.assign_or_replace<transform_component>(entity, transform);
- }
-
- void terrain_system::on_terrain_destroy(ecs::registry& registry, ecs::entity entity)
- {
- /*
- if (auto it = terrain_map.find(entity); it != terrain_map.end())
- {
- delete std::get<0>(it->second);
- delete std::get<1>(it->second);
- terrain_map.erase(it);
- }
- */
- }
-
- } // namespace ecs
|