03 - ChiSo.cpp

#include <iostream>
#include <glad/glad.h>
#include <GLFW/glfw3.h>

// mã nguồn Vertex Shader
const char* vertexShaderSource = "#version 330 core\n"
"layout (location = 0) in vec3 aPos;\n"
"void main()\n"
"{\n"
"   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
"}\0";
// mã nguồn Fragment Shader
const char* fragmentShaderSource = "#version 330 core\n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
"   FragColor = vec4(0.82f, 0.37f, 0.05f, 1.08f);\n"
"}\n\0";

int main()
{
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	GLFWwindow* window = glfwCreateWindow(800, 800, "3 Tam giac nho thanh 1 Tam giac lon", NULL, NULL);
	if (window == NULL)
		glfwTerminate();

	glfwMakeContextCurrent(window);
	gladLoadGL();
	glViewport(0, 0, 800, 800);

	GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
	glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
	glCompileShader(vertexShader);
	
	GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
	glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
	glCompileShader(fragmentShader);

	GLuint shaderProgram = glCreateProgram();
	glAttachShader(shaderProgram, vertexShader);
	glAttachShader(shaderProgram, fragmentShader);
	glLinkProgram(shaderProgram);

	glDeleteShader(vertexShader);
	glDeleteShader(fragmentShader);

	// tọa độ các điểm
	GLfloat vertices[] =
	{
		// điểm trái dưới
		-0.5f, -0.5f * float(sqrt(5)) / 5, 0.0f,
		// điểm phải dưới
		0.5f, -0.5f * float(sqrt(5)) / 5, 0.0f,
		// điểm trên cùng
		0.0f, 0.5f * float(sqrt(5)) * 3 / 5, 0.0f,
		// trung điểm trái
		-0.5f / 2, 0.5f * float(sqrt(5)) / 5, 0.0f,
		// trung điểm phải
		0.5f / 2, 0.5f * float(sqrt(5)) / 5, 0.0f,
		// trung điểm dưới
		0.0f, -0.5f * float(sqrt(5)) / 5, 0.0f
	};
	// thứ tự các điểm
	GLuint indices[] =
	{
		0, 3, 5, // tam giác trái 
		3, 2, 4, // tam giác phải
		5, 4, 1	 // tam giác trên
	};

	GLuint VAO, VBO, EBO;
	glGenVertexArrays(1, &VAO);
	glGenBuffers(1, &VBO);
	glGenBuffers(1, &EBO);

	glBindVertexArray(VAO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glBindVertexArray(0);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

	while (!glfwWindowShouldClose(window))
	{
		glClearColor(0.15f, 0.02f, 0.18f, 1.5f);
		glClear(GL_COLOR_BUFFER_BIT);

		glUseProgram(shaderProgram);
		glBindVertexArray(VAO);
		glDrawElements(GL_TRIANGLES, 9, GL_UNSIGNED_INT, 0);

		glfwSwapBuffers(window);
		glfwPollEvents();
	}

	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);
	glDeleteBuffers(1, &EBO);
	glDeleteProgram(shaderProgram);

	glfwDestroyWindow(window);
	glfwTerminate();
	return 0;
}