💿🐜 Antkeeper source code
https://antkeeper.com
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300 lines
9.9 KiB
300 lines
9.9 KiB
/*
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* Copyright (C) 2021 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "terrain-system.hpp"
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#include "ecs/components/model-component.hpp"
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#include "ecs/components/collision-component.hpp"
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#include "ecs/components/transform-component.hpp"
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#include "cart/relief-map.hpp"
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#include "renderer/model.hpp"
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#include "geom/mesh.hpp"
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#include "geom/mesh-functions.hpp"
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#include "renderer/vertex-attributes.hpp"
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#include "gl/vertex-attribute-type.hpp"
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#include "gl/drawing-mode.hpp"
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#include "gl/vertex-buffer.hpp"
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#include "resources/resource-manager.hpp"
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#include "resources/image.hpp"
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#include "utility/fundamental-types.hpp"
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#include <limits>
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namespace ecs {
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terrain_system::terrain_system(ecs::registry& registry, ::resource_manager* resource_manager):
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entity_system(registry),
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resource_manager(resource_manager)
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{
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registry.on_construct<terrain_component>().connect<&terrain_system::on_terrain_construct>(this);
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registry.on_destroy<terrain_component>().connect<&terrain_system::on_terrain_destroy>(this);
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heightmap = resource_manager->load<image>("grassland-heightmap.png");
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heightmap_size = 2000.0f;
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heightmap_scale = 150.0f;
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}
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terrain_system::~terrain_system()
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{}
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void terrain_system::update(double t, double dt)
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{
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registry.view<terrain_component, transform_component>().each(
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[this](ecs::entity entity, auto& terrain, auto& transform)
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{
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transform.local.translation = float3{(float)terrain.x * patch_size, 0.0f, (float)terrain.z * patch_size};
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transform.warp = true;
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});
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}
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void terrain_system::set_patch_size(float size)
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{
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patch_size = size;
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}
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geom::mesh* terrain_system::generate_terrain_mesh(float size, int subdivisions)
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{
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auto elevation = [](float u, float v) -> float
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{
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return 0.0f;
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};
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return cart::map_elevation(elevation, size, subdivisions);
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}
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model* terrain_system::generate_terrain_model(geom::mesh* terrain_mesh)
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{
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// Allocate model
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model* terrain_model = new model();
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// Get model's VAO and VBO
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gl::vertex_buffer* vbo = terrain_model->get_vertex_buffer();
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gl::vertex_array* vao = terrain_model->get_vertex_array();
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// Resize VBO
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int vertex_size = 3 + 2 + 3 + 4 + 3;
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int vertex_stride = vertex_size * sizeof(float);
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vbo->resize(terrain_mesh->get_faces().size() * 3 * vertex_stride, nullptr);
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// Bind vertex attributes
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std::size_t offset = 0;
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vao->bind_attribute(VERTEX_POSITION_LOCATION, *vbo, 3, gl::vertex_attribute_type::float_32, vertex_stride, 0);
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offset += 3;
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vao->bind_attribute(VERTEX_TEXCOORD_LOCATION, *vbo, 2, gl::vertex_attribute_type::float_32, vertex_stride, sizeof(float) * offset);
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offset += 2;
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vao->bind_attribute(VERTEX_NORMAL_LOCATION, *vbo, 3, gl::vertex_attribute_type::float_32, vertex_stride, sizeof(float) * offset);
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offset += 3;
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vao->bind_attribute(VERTEX_TANGENT_LOCATION, *vbo, 4, gl::vertex_attribute_type::float_32, vertex_stride, sizeof(float) * offset);
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offset += 4;
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vao->bind_attribute(VERTEX_BARYCENTRIC_LOCATION, *vbo, 3, gl::vertex_attribute_type::float_32, vertex_stride, sizeof(float) * offset);
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offset += 3;
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// Create model group
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model_group* model_group = terrain_model->add_group("terrain");
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model_group->set_material(resource_manager->load<material>("grassland-terrain.mtl"));
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model_group->set_drawing_mode(gl::drawing_mode::triangles);
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model_group->set_start_index(0);
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model_group->set_index_count(terrain_mesh->get_faces().size() * 3);
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return terrain_model;
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}
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void terrain_system::project_terrain_mesh(geom::mesh* terrain_mesh, const terrain_component& component)
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{
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float offset_x = (float)component.x * patch_size;
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float offset_z = (float)component.z * patch_size;
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for (geom::mesh::vertex* vertex: terrain_mesh->get_vertices())
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{
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int pixel_x = (vertex->position[0] + offset_x + heightmap_size * 0.5f) / heightmap_size * (float)(heightmap->get_width() - 1);
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int pixel_y = (vertex->position[2] + offset_z + heightmap_size * 0.5f) / heightmap_size * (float)(heightmap->get_height() - 1);
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pixel_x = std::max<int>(0, std::min<int>(heightmap->get_width() - 1, pixel_x));
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pixel_y = std::max<int>(0, std::min<int>(heightmap->get_height() - 1, pixel_y));
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int pixel_index = (pixel_y * heightmap->get_width() + pixel_x) * heightmap->get_channels();
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const unsigned char* pixel = static_cast<const unsigned char*>(heightmap->get_pixels()) + pixel_index;
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float elevation = (static_cast<float>(*pixel) / 255.0f - 0.5) * heightmap_scale;
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vertex->position[1] = elevation;
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}
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}
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void terrain_system::update_terrain_model(model* terrain_model, geom::mesh* terrain_mesh)
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{
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const std::vector<geom::mesh::face*>& faces = terrain_mesh->get_faces();
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const std::vector<geom::mesh::vertex*>& vertices = terrain_mesh->get_vertices();
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geom::aabb<float> bounds = calculate_bounds(*terrain_mesh);
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float bounds_width = bounds.max_point.x - bounds.min_point.x;
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float bounds_height = bounds.max_point.y - bounds.min_point.y;
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float bounds_depth = bounds.max_point.z - bounds.min_point.z;
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static const float3 barycentric_coords[3] =
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{
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float3{1, 0, 0},
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float3{0, 1, 0},
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float3{0, 0, 1}
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};
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int triangle_count = faces.size();
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int vertex_count = triangle_count * 3;
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int vertex_size = 3 + 2 + 3 + 4 + 3;
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// Allocate vertex data
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float* vertex_data = new float[vertex_size * vertex_count];
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// Allocate and calculate face normals
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float3* face_normals = new float3[faces.size()];
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calculate_face_normals(face_normals, *terrain_mesh);
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// Allocate and calculate vertex normals
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float3* vertex_normals = new float3[vertices.size()];
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for (std::size_t i = 0; i < vertices.size(); ++i)
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{
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const geom::mesh::vertex* vertex = vertices[i];
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float3 n = {0, 0, 0};
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geom::mesh::edge* start = vertex->edge;
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geom::mesh::edge* edge = start;
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do
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{
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if (edge->face)
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{
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n += face_normals[edge->face->index];
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}
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edge = edge->previous->symmetric;
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}
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while (edge != start);
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n = math::normalize(n);
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vertex_normals[i] = n;
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}
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// Allocate and generate vertex texture coordinates
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float2* vertex_texcoords = new float2[vertices.size()];
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for (std::size_t i = 0; i < vertices.size(); ++i)
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{
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const geom::mesh::vertex* vertex = vertices[i];
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vertex_texcoords[i].x = (vertex->position.x - bounds.min_point.x) / bounds_width;
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vertex_texcoords[i].y = (vertex->position.z - bounds.min_point.z) / bounds_depth;
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}
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// Allocate and calculate vertex tangents
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float4* vertex_tangents = new float4[vertices.size()];
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calculate_vertex_tangents(vertex_tangents, vertex_texcoords, vertex_normals, *terrain_mesh);
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// Generate vertex data
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float* v = vertex_data;
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for (int i = 0; i < triangle_count; ++i)
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{
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const geom::mesh::face* triangle = faces[i];
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const geom::mesh::vertex* a = triangle->edge->vertex;
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const geom::mesh::vertex* b = triangle->edge->next->vertex;
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const geom::mesh::vertex* c = triangle->edge->previous->vertex;
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const geom::mesh::vertex* abc[] = {a, b, c};
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for (int j = 0; j < 3; ++j)
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{
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const geom::mesh::vertex* vertex = abc[j];
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const float3& position = vertex->position;
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const float2& texcoord = vertex_texcoords[vertex->index];
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const float3& normal = vertex_normals[vertex->index];
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const float4& tangent = vertex_tangents[vertex->index];
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const float3& barycentric = barycentric_coords[j];
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*(v++) = position.x;
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*(v++) = position.y;
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*(v++) = position.z;
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*(v++) = texcoord.x;
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*(v++) = texcoord.y;
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*(v++) = normal.x;
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*(v++) = normal.y;
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*(v++) = normal.z;
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*(v++) = tangent.x;
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*(v++) = tangent.y;
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*(v++) = tangent.z;
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*(v++) = tangent.w;
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*(v++) = barycentric.x;
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*(v++) = barycentric.y;
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*(v++) = barycentric.z;
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}
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}
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// Update bounds
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terrain_model->set_bounds(bounds);
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// Update VBO
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terrain_model->get_vertex_buffer()->update(0, vertex_count * vertex_size * sizeof(float), vertex_data);
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// Free vertex data
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delete[] face_normals;
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delete[] vertex_normals;
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delete[] vertex_texcoords;
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delete[] vertex_tangents;
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delete[] vertex_data;
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}
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void terrain_system::on_terrain_construct(ecs::registry& registry, ecs::entity entity, terrain_component& component)
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{
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geom::mesh* terrain_mesh = generate_terrain_mesh(patch_size, component.subdivisions);
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model* terrain_model = generate_terrain_model(terrain_mesh);
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project_terrain_mesh(terrain_mesh, component);
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update_terrain_model(terrain_model, terrain_mesh);
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// Assign the entity a collision component with the terrain mesh
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collision_component collision;
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collision.mesh = terrain_mesh;
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collision.bounds = calculate_bounds(*terrain_mesh);
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collision.mesh_accelerator.build(*collision.mesh);
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registry.assign_or_replace<collision_component>(entity, collision);
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// Assign the entity a model component with the terrain model
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model_component model;
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model.model = terrain_model;
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model.instance_count = 0;
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model.layers = 1;
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registry.assign_or_replace<model_component>(entity, model);
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// Assign the entity a transform component
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transform_component transform;
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transform.local = math::identity_transform<float>;
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transform.local.translation = float3{(float)component.x * patch_size, 0.0f, (float)component.z * patch_size};
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transform.warp = true;
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registry.assign_or_replace<transform_component>(entity, transform);
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}
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void terrain_system::on_terrain_destroy(ecs::registry& registry, ecs::entity entity)
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{
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/*
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if (auto it = terrain_map.find(entity); it != terrain_map.end())
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{
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delete std::get<0>(it->second);
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delete std::get<1>(it->second);
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terrain_map.erase(it);
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}
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*/
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}
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} // namespace ecs
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