2. 첫 삼각형2

쉐이더로 빨갛게 만든 삼각형

 

#SimpleFragmentShader.fragmentshader

#version 330 core
out vec3 color;
void main(){
	color = vec3(1,0,0);
}

#SimpleVertexShader.vertexshader

#version 330 core
layout(location = 0) in vec3 vertexPosition_modelspace;

void main(){
	gl_Position.xyz = vertexPosition_modelspace;
	gl_Position.w = 1.0;
}

#include <stdio.h>
#include <stdlib.h>

#include <GL/glew.h>

#include <GLFW/glfw3.h>
GLFWwindow* window;

#include <glm/glm.hpp>

#include <common/shader.hpp>
using namespace glm;

int main( void )
{
	// Initialise GLFW
	if( !glfwInit() )
	{
		fprintf( stderr, "Failed to initialize GLFW\n" );
		getchar();
		return -1;
	}

	glfwWindowHint(GLFW_SAMPLES, 4);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // To make MacOS happy; should not be needed
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	// Open a window and create its OpenGL context
	window = glfwCreateWindow( 1024, 768, "Playground", NULL, NULL);
	if( window == NULL ){
		fprintf( stderr, "Failed to open GLFW window. If you have an Intel GPU, they are not 3.3 compatible. Try the 2.1 version of the tutorials.\n" );
		glfwTerminate();
		return -1;
	}
	glfwMakeContextCurrent(window);
	glewExperimental = true;

	// Initialize GLEW
	if (glewInit() != GLEW_OK) {
		fprintf(stderr, "Failed to initialize GLEW\n");
		glfwTerminate();
		return -1;
	}

	// Ensure we can capture the escape key being pressed below
	glfwSetInputMode(window, GLFW_STICKY_KEYS, GL_TRUE);

	// Dark blue background
	glClearColor(0.0f, 0.0f, 0.4f, 0.0f);

	GLuint VertexArrayID;
	glGenVertexArrays(1, &VertexArrayID);
	glBindVertexArray(VertexArrayID);

	// 쉐이더들에서 우리의 GLSL 프로그램을 생성하고 컴파일하기
	GLuint programID = LoadShaders("SimpleVertexShader.vertexshader", "SimpleFragmentShader.fragmentshader");


	//3 버텍스들을 표현하는 3 벡터들의 배열
	static const GLfloat g_vertex_buffer_data[] = {
		-1.0f, -1.0f, 0.0f,
		1.0f, -1.0f, 0.0f,
		0.0f, 1.0f, 0.0f,
	};

	// 우리의 버텍스 버퍼를 가리킵니다.
	GLuint vertexbuffer;
	// 버퍼를 하나 생성합니다. vertexbuffer에 결과 식별자를 넣습니다
	glGenBuffers(1, &vertexbuffer);
	// 아래의 명령어들은 우리의 "vertexvbuffer" 버퍼에 대해서 다룰겁니다
	glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
	// 우리의 버텍스들을 OpenGL로 넘겨줍니다
	glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);

	
	do{
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		glUseProgram(programID);

		// Draw nothing, see you in tutorial 2 !
		glEnableVertexAttribArray(0);
		glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
		glVertexAttribPointer(
			0,
			3,
			GL_FLOAT,
			GL_FALSE,
			0,
			(void*)0
		);

		glDrawArrays(GL_TRIANGLES, 0, 3); //버텍스 0에서 시작해서; 총 3개의 버텍스로 -> 하나의 삼각형
		glDisableVertexAttribArray(0);
		// Swap buffers
		glfwSwapBuffers(window);
		glfwPollEvents();

	} // Check if the ESC key was pressed or the window was closed
	while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS &&
		   glfwWindowShouldClose(window) == 0 );

	// Close OpenGL window and terminate GLFW
	glfwTerminate();

	return 0;
}