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#include "terrain.h"
#include "gfx/models/texture.h"
#include <cache.h>
#include <cstddef>
#include <gfx/gl/shader.h>
#include <gfx/image.h>
#include <gfx/models/mesh.h>
#include <gfx/models/vertex.hpp>
#include <glm/glm.hpp>
#include <location.hpp>
#include <maths.h>
#include <random>
#include <stb/stb_image.h>
Terrain::Terrain() : grass {Texture::cachedTexture.get("grass.png")}, water {Texture::cachedTexture.get("water.png")}
{
constexpr auto size {241}; // Vertices
constexpr auto offset {(size - 1) / 2};
constexpr auto verticesCount = size * size;
constexpr auto resolution = 10; // Grid size
std::vector<Vertex> vertices;
vertices.reserve(verticesCount + 4);
vertices.resize(verticesCount, {{}, {}, {}});
// Initial coordinates
for (auto y = 0U; y < size; y += 1) {
for (auto x = 0U; x < size; x += 1) {
auto & vertex = vertices[x + (y * size)];
vertex.pos
= {resolution * (static_cast<int>(x) - offset), resolution * (static_cast<int>(y) - offset), -1.5};
vertex.normal = up;
vertex.texCoord = {x, y};
}
}
// Add hills
std::mt19937 gen(std::random_device {}());
std::uniform_int_distribution<> rpos(2, size - 2);
std::uniform_int_distribution<> rsize(10, 30);
std::uniform_real_distribution<float> rheight(1, 3);
for (int h = 0; h < 500;) {
const glm::ivec2 hpos {rpos(gen), rpos(gen)};
const glm::ivec2 hsize {rsize(gen), rsize(gen)};
if (const auto lim1 = hpos - hsize; lim1.x > 0 && lim1.y > 0) {
if (const auto lim2 = hpos + hsize; lim2.x < size && lim2.y < size) {
const auto height = rheight(gen);
const glm::ivec2 hsizesqrd {hsize.x * hsize.x, hsize.y * hsize.y};
for (auto y = lim1.y; y < lim2.y; y += 1) {
for (auto x = lim1.x; x < lim2.x; x += 1) {
const auto dist {hpos - glm::ivec2 {x, y}};
const glm::ivec2 distsqrd {dist.x * dist.x, dist.y * dist.y};
const auto out {rdiv(sq(x - hpos.x), sq(hsize.x)) + rdiv(sq(y - hpos.y), sq(hsize.y))};
if (out <= 1.0F) {
auto & vertex
= vertices[static_cast<std::size_t>(x) + (static_cast<std::size_t>(y) * size)];
const auto m {1.F / (7.F * out - 8.F) + 1.F};
vertex.pos.z += height * m;
}
}
}
h += 1;
}
}
}
finish(size, size, vertices);
}
Terrain::Terrain(const std::string & fileName) :
grass {Texture::cachedTexture.get("grass.png")}, water {Texture::cachedTexture.get("water.png")}
{
constexpr auto resolution {100};
const Image map {fileName.c_str(), STBI_grey};
std::vector<Vertex> vertices;
vertices.reserve((map.width * map.height) + 4);
for (auto y = 0U; y < map.height; y += 1) {
for (auto x = 0U; x < map.width; x += 1) {
vertices.emplace_back(glm::vec3 {resolution * (x - (map.width / 2)), resolution * (y - (map.height / 2)),
(static_cast<float>(map.data[x + (y * map.width)]) * 0.1F) - 1.5F},
glm::vec2 {(x % 2) / 2.01, (y % 2) / 2.01}, up);
}
}
finish(map.width, map.height, vertices);
}
void
Terrain::finish(unsigned int width, unsigned int height, std::vector<Vertex> & vertices)
{
const auto tilesCount = (width - 1) * (height - 1);
const auto trianglesCount = tilesCount * 2;
const auto indicesCount = trianglesCount * 3;
std::vector<unsigned int> indices;
indices.reserve(indicesCount + 6);
// Indices
for (auto y = 0U; y < height - 1; y += 1) {
for (auto x = 0U; x < width - 1; x += 1) {
indices.push_back(x + (y * width));
indices.push_back((x + 1) + (y * width));
indices.push_back((x + 1) + ((y + 1) * width));
indices.push_back(x + (y * width));
indices.push_back((x + 1) + ((y + 1) * width));
indices.push_back(x + ((y + 1) * width));
}
}
// Normals
auto v = [&vertices](unsigned int width, unsigned int x, unsigned int y) -> Vertex & {
return vertices[x + (y * width)];
};
for (auto y = 1U; y < height - 1; y += 1) {
for (auto x = 1U; x < width - 1; x += 1) {
const auto a = v(width, x - 1, y).pos;
const auto b = v(width, x, y - 1).pos;
const auto c = v(width, x + 1, y).pos;
const auto d = v(width, x, y + 1).pos;
v(width, x, y).normal = -glm::normalize(glm::cross(b - d, a - c));
}
}
meshes.create<Mesh>(vertices, indices);
}
void
Terrain::tick(TickDuration dur)
{
waveCycle += dur.count();
}
void
Terrain::render(const Shader & shader) const
{
shader.setModel(Location {}, Shader::Program::LandMass);
grass->Bind();
meshes.apply(&Mesh::Draw);
shader.setModel(Location {}, Shader::Program::Water);
shader.setUniform("waves", {waveCycle, 0, 0});
water->Bind();
meshes.apply(&Mesh::Draw);
}
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