From 3428be29ae1ac663dd173109d16d472811f21a90 Mon Sep 17 00:00:00 2001
From: Lukian <lulul7018@gmail.com>
Date: Tue, 28 Jan 2025 12:57:36 +0100
Subject: [PATCH] draw the first triangle

---
 src/main.cpp | 150 +++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 115 insertions(+), 35 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 7b7807d..c21fae1 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -7,56 +7,136 @@ void processInput(GLFWwindow *window);
 
 int main()
 {
-  glfwInit();
-  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
-  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
-  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
-  //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
+	glfwInit();
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+	//glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
 
-  GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
-  if (window == NULL)
-  {
-    std::cout << "Failed to create GLFW window" << std::endl;
-    glfwTerminate();
-    return -1;
-  }
-  glfwMakeContextCurrent(window);
+	GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
+	if (window == NULL)
+	{
+		std::cout << "Failed to create GLFW window" << std::endl;
+		glfwTerminate();
+		return -1;
+	}
+	glfwMakeContextCurrent(window);
 
-  if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
-  {
-    std::cout << "Failed to initialize GLAD" << std::endl;
-    return -1;
-  }
+	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
+	{
+		std::cout << "Failed to initialize GLAD" << std::endl;
+		return -1;
+	}
 
-  glViewport(0, 0, 800, 600);
+	glViewport(0, 0, 800, 600);
 
-  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 
-  while(!glfwWindowShouldClose(window))
-  {
-    processInput(window);
+	float vertices[] = {
+		-0.5f, -0.5f, 0.0f,
+		 0.5f, -0.5f, 0.0f,
+		 0.0f,  0.5f, 0.0f
+	};
 
-    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
-    glClear(GL_COLOR_BUFFER_BIT);
+	unsigned int VBO;
+	glGenBuffers(1, &VBO);
+	glBindBuffer(GL_ARRAY_BUFFER, VBO);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
 
-    glfwSwapBuffers(window);
-    glfwPollEvents();    
-  }
+	unsigned int VAO;
+	glGenVertexArrays(1, &VAO);
+	glBindVertexArray(VAO);
 
-  glfwTerminate();
+	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
+	glEnableVertexAttribArray(0); 
 
-  return 0;
+	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";
+
+	const char *fragmentShaderSource = "#version 330 core\n"
+		"out vec4 FragColor;\n"
+		"void main()\n"
+		"{\n"
+    		"FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
+		"}\0";
+
+	unsigned int vertexShader;
+	vertexShader = glCreateShader(GL_VERTEX_SHADER);
+	glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
+
+	unsigned int fragmentShader;
+	fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+	glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
+
+	int  success;
+	char infoLog[512];
+
+	glCompileShader(vertexShader);
+
+	glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
+	if(!success)
+	{
+	    glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
+	    std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
+	}
+
+	glCompileShader(fragmentShader);
+
+	glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
+	if(!success)
+	{
+	    glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
+	    std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
+	}
+
+	unsigned int shaderProgram;
+	shaderProgram = glCreateProgram();
+
+	glAttachShader(shaderProgram, vertexShader);
+	glAttachShader(shaderProgram, fragmentShader);
+	glLinkProgram(shaderProgram);
+	glDeleteShader(vertexShader);
+	glDeleteShader(fragmentShader);
+
+	glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+	if(!success) {
+	    glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
+	    std::cout << "ERROR::SHADER_PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
+	}
+
+	while(!glfwWindowShouldClose(window))
+	{
+		processInput(window);
+
+		glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+		glClear(GL_COLOR_BUFFER_BIT);
+
+		glUseProgram(shaderProgram);
+		glBindVertexArray(VAO);
+		glDrawArrays(GL_TRIANGLES, 0, 3);
+
+		glfwSwapBuffers(window);
+		glfwPollEvents();    
+	}
+
+	glfwTerminate();
+
+	return 0;
 }
 
 void framebuffer_size_callback(GLFWwindow* window, int width, int height)
 {
-  glViewport(0, 0, width, height);
+	glViewport(0, 0, width, height);
 }
 
 void processInput(GLFWwindow *window)
 {
-  if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
-  {
-    glfwSetWindowShouldClose(window, true);
-  }
+	if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+	{
+		glfwSetWindowShouldClose(window, true);
+	}
 }