aboutsummaryrefslogtreecommitdiff
path: root/src/main.cc
blob: 034d026ad4623c04052835208cc23b98bf83e0ad (plain)
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
183
184
185
186
187
188
189
190
191
192
193
194
#include <GL/glew.h>
#include <GLFW/glfw3.h>

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>

#include <random>
#include <memory>
#include <algorithm>

#include "particle_vertex_buffer.h"
#include "texture_display_buffer.h"

#include "graphic_shader.h"
#include "compute_shader.h"
#include "texture_buffer.h"

#include "shader/vertex.glsl"
#include "shader/fragment.glsl"
#include "shader/compute.glsl"

#include "shader/display_vertex.glsl"
#include "shader/display_fragment.glsl"

const unsigned int particle_count = 5000;
const unsigned int max_ups        = 100;
const unsigned int texture_count  = 10;

unsigned int window_width  = 800;
unsigned int window_height = 600;
float world_width, world_height;
glm::mat4 MVP;

std::vector<std::unique_ptr<TextureBuffer>> textureBuffers;
std::unique_ptr<ParticleVertexBuffer> particleBuffer;

void updateMVP() {
	world_width  = 20.f;
	world_height = world_width / window_width * window_height;

	glm::mat4 projection = glm::ortho(
		-(world_width /2), world_width/2,
		-(world_height/2), world_height/2,
		0.1f, 100.0f
	);

	glm::mat4 view = glm::lookAt(
		glm::vec3(0,0,20),
		glm::vec3(0,0,0),
		glm::vec3(0,1,0)
	);

	MVP = projection * view;
}

void window_size_callback(GLFWwindow*, int width, int height) {
	window_width  = width;
	window_height = height;

	for ( auto& textureBuffer : textureBuffers ) {
		textureBuffer->resize(width, height);
	}

	updateMVP();
}

std::vector<GLfloat> makeInitialParticles(std::size_t count) {
	std::vector<GLfloat> buffer;
	buffer.reserve(3*count);

	std::random_device rd;
	std::mt19937 gen(rd());
	std::uniform_real_distribution<GLfloat> distX(-world_width/2., world_width/2.);
	std::uniform_real_distribution<GLfloat> distY(-world_height/2., world_height/2.);
	std::uniform_real_distribution<GLfloat> distAge(0., 5.);

	for ( std::size_t i = 0; i < count; ++i ) {
		buffer.emplace_back(distX(gen));
		buffer.emplace_back(distY(gen));
		buffer.emplace_back(distAge(gen));
	}

	return buffer;
}

int main() {
	if( !glfwInit() ) {
		std::cerr <<  "Failed to initialize GLFW" << std::endl;
		return -1;
	}

	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	GLFWwindow* const window = glfwCreateWindow(window_width, window_height, "computicle", NULL, NULL);

	if( window == nullptr ){
		std::cerr << "Failed to open GLFW window." << std::endl;
		glfwTerminate();
		return -1;
	}
	glfwSetWindowSizeCallback(window, window_size_callback);
	glfwMakeContextCurrent(window);

	if ( glewInit() != GLEW_OK ) {
		std::cerr << "Failed to initialize GLEW" << std::endl;
		glfwTerminate();
		return -1;
	}

	glfwSetInputMode(window, GLFW_STICKY_KEYS, GL_TRUE);

	updateMVP();

	for ( unsigned int i = 0; i < texture_count; ++i ) {
		textureBuffers.emplace_back(
			new TextureBuffer(window_width, window_height));
	}

	particleBuffer = std::make_unique<ParticleVertexBuffer>(
		makeInitialParticles(particle_count));

	GraphicShader sceneShader(VERTEX_SHADER_CODE, FRAGMENT_SHADER_CODE);

	ComputeShader computeShader(COMPUTE_SHADER_CODE);
	computeShader.workOn(particleBuffer->getBuffer());

	GraphicShader displayShader(DISPLAY_VERTEX_SHADER_CODE,
	                            DISPLAY_FRAGMENT_SHADER_CODE);
	TextureDisplayBuffer displayBuffer;

	auto lastFrame  = std::chrono::high_resolution_clock::now();
	auto lastRotate = std::chrono::high_resolution_clock::now();
	bool justRotated = true;

	std::vector<GLuint> textures;
	for ( auto& textureBuffer : textureBuffers ) {
		textures.emplace_back(textureBuffer->getTexture());
	}

	do {
		if ( util::millisecondsSince(lastFrame) >= 1000/max_ups ) {
			auto guard = computeShader.use();

			computeShader.setUniform("world", world_width, world_height);
			computeShader.dispatch(particle_count);

			lastFrame = std::chrono::high_resolution_clock::now();
		}

		if ( util::millisecondsSince(lastRotate) >= 1000/10 ) {
			std::rotate(textures.begin(), textures.end()-1, textures.end());
			std::rotate(textureBuffers.begin(), textureBuffers.end()-1, textureBuffers.end());
			justRotated = true;
			lastRotate = std::chrono::high_resolution_clock::now();
		}

		{
			auto texGuard = textureBuffers[0]->use();
			auto sdrGuard = sceneShader.use();

			sceneShader.setUniform("MVP", MVP);

			if ( justRotated ) {
				glClear(GL_COLOR_BUFFER_BIT);
				justRotated = false;
			}

			particleBuffer->draw();
		}

		{
			auto guard = displayShader.use();

			for ( unsigned int i = 0; i < textures.size(); ++i ) {
				displayShader.setUniform("screen_texture_" + std::to_string(i), i);
			}

			glClear(GL_COLOR_BUFFER_BIT);

			displayBuffer.draw(textures);
		}

		glfwSwapBuffers(window);
		glfwPollEvents();
	}
	while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS &&
	       glfwWindowShouldClose(window) == 0 );

	glfwTerminate();

	return 0;
}