1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
#include "terrain.h"
#include "gfx/models/texture.h"
#include <array>
#include <cache.h>
#include <cmath>
#include <cstddef>
#include <gfx/gl/shader.h>
#include <gfx/gl/transform.h>
#include <gfx/image.h>
#include <gfx/models/vertex.hpp>
#include <glm/glm.hpp>
#include <random>
#include <stb_image.h>
Terrain::Terrain() :
m_vertexArrayObject {}, m_vertexArrayBuffers {}, texture {Texture::cachedTexture.get("terrain.png")}
{
constexpr auto size {241}; // Vertices
constexpr auto offset {(size - 1) / 2};
constexpr auto verticesCount = size * size;
constexpr auto resolution = 10; // Grid size
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
vertices.reserve(verticesCount + 4);
vertices.resize(verticesCount, {{}, {}, {}});
// Initial coordinates
for (auto z = 0; z < size; z += 1) {
for (auto x = 0; x < size; x += 1) {
auto & vertex = vertices[x + (z * size)];
vertex.pos = {resolution * (x - offset), -1.5, resolution * (z - offset)};
vertex.normal = {0, 1, 0};
vertex.texCoord = {(x % 2) / 2.01, (z % 2) / 2.01};
}
}
// Add hills
std::mt19937 gen(std::random_device {}());
std::uniform_int_distribution<> rpos(2, size - 2);
std::uniform_int_distribution<> rsize(10, 20);
std::uniform_int_distribution<> 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) {
auto height {rheight(gen)};
const glm::ivec2 hsizesqrd {hsize.x * hsize.x, hsize.y * hsize.y};
for (auto z = lim1.y; z < lim2.y; z += 1) {
for (auto x = lim1.x; x < lim2.x; x += 1) {
const auto dist {hpos - glm::ivec2 {x, z}};
const glm::ivec2 distsqrd {dist.x * dist.x, dist.y * dist.y};
if ((pow(x - hpos.x, 2) / pow(hsize.x, 2)) + (pow(z - hpos.y, 2) / pow(hsize.y, 2)) <= 1.0) {
auto & vertex = vertices[x + (z * size)];
vertex.pos.y += height;
}
}
}
h += 1;
}
}
}
finish(size, size, resolution);
}
Terrain::Terrain(const std::string & fileName) :
m_vertexArrayObject {}, m_vertexArrayBuffers {}, texture {Texture::cachedTexture.get("terrain.png")}
{
constexpr auto resolution {100};
const Image map {fileName.c_str(), STBI_grey};
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
vertices.reserve((map.width * map.height) + 4);
for (auto z = 0; z < map.height; z += 1) {
for (auto x = 0; x < map.width; x += 1) {
vertices.emplace_back(
glm::vec3 {resolution * (x - (map.width / 2)), ((float)map.data[x + (z * map.width)] * 0.1F) - 1.5F,
resolution * (z - (map.height / 2))},
glm::vec2 {(x % 2) / 2.01, (z % 2) / 2.01}, glm::vec3 {0, 1, 0});
}
}
finish(map.width, map.height, resolution);
}
void
Terrain::finish(unsigned int width, unsigned int height, unsigned int resolution)
{
const auto tilesCount = (width - 1) * (height - 1);
const auto trianglesCount = tilesCount * 2;
const auto indicesCount = trianglesCount * 3;
indices.reserve(indicesCount + 6);
// Indices
for (auto z = 0U; z < height - 1; z += 1) {
for (auto x = 0U; x < width - 1; x += 1) {
indices.push_back(x + (z * width));
indices.push_back((x + 1) + ((z + 1) * width));
indices.push_back((x + 1) + (z * width));
indices.push_back(x + (z * width));
indices.push_back(x + ((z + 1) * width));
indices.push_back((x + 1) + ((z + 1) * width));
}
}
// Normals
for (auto z = 1U; z < height - 1; z += 1) {
for (auto x = 1U; x < width - 1; x += 1) {
const auto a = v(width, x - 1, z).pos;
const auto b = v(width, x, z - 1).pos;
const auto c = v(width, x + 1, z).pos;
const auto d = v(width, x, z + 1).pos;
v(width, x, z).normal = -glm::normalize(glm::cross(c - a, d - b));
}
}
const auto verticesCount = vertices.size();
// Add water
const auto extentx {(int)((width - 1) * resolution / 2)};
const auto extentz {(int)((height - 1) * resolution / 2)};
vertices.emplace_back(glm::vec3 {-extentx, 0, -extentz}, glm::vec2 {0.5, 0.0}, glm::vec3 {0, 1, 0});
vertices.emplace_back(glm::vec3 {-extentx, 0, extentz}, glm::vec2 {0.5, 0.5}, glm::vec3 {0, 1, 0});
vertices.emplace_back(glm::vec3 {extentx, 0, extentz}, glm::vec2 {1, 0.5}, glm::vec3 {0, 1, 0});
vertices.emplace_back(glm::vec3 {extentx, 0, -extentz}, glm::vec2 {1, 0.0}, glm::vec3 {0, 1, 0});
indices.push_back(verticesCount);
indices.push_back(verticesCount + 1);
indices.push_back(verticesCount + 2);
indices.push_back(verticesCount);
indices.push_back(verticesCount + 2);
indices.push_back(verticesCount + 3);
glGenVertexArrays(1, &m_vertexArrayObject);
glBindVertexArray(m_vertexArrayObject);
glGenBuffers(2, m_vertexArrayBuffers.data());
glBindBuffer(GL_ARRAY_BUFFER, m_vertexArrayBuffers[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * vertices.size(), vertices.data(), GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)offsetof(Vertex, pos));
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)offsetof(Vertex, texCoord));
glEnableVertexAttribArray(2);
glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)offsetof(Vertex, normal));
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_vertexArrayBuffers[1]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices[0]) * indices.size(), indices.data(), GL_STATIC_DRAW);
glBindVertexArray(0);
}
Vertex &
Terrain::v(unsigned int width, unsigned int x, unsigned int z)
{
return vertices[x + (z * width)];
}
Terrain::~Terrain()
{
glDeleteBuffers(NUM_BUFFERS, m_vertexArrayBuffers.data());
glDeleteVertexArrays(1, &m_vertexArrayObject);
}
static const Transform identity {};
static const auto identityModel {identity.GetModel()};
void
Terrain::render(const Shader & shader) const
{
shader.setModel(identityModel);
texture->Bind();
glBindVertexArray(m_vertexArrayObject);
glDrawElementsBaseVertex(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, nullptr, 0);
glBindVertexArray(0);
}
|
