我尝试绘制简单的三角形，但我能以某种方式看到该三角形
这是我的文件确实创建了窗口，但其中没有三角不知道为什么
#include <iostream>
#include "GLFWManager.h"
#include <stdio.h>
#include <stdlib.h>
int main()
{
std::cout << "Hello World!\n";
GLFWManager gLFWManager;
gLFWManager.Init();
GLuint vbo;
GLuint vao;
GLfloat vertices[] = {
0.0f, 0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
-0.5f, -0.5f, 0.0f,
// second triangle
0.0f, -0.5f, 0.0f, // left
0.9f, -0.5f, 0.0f, // right
0.45f, 0.5f, 0.0f // top
};
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
// note that this is allowed, the call to glVertexAttribPointer registered VBO as the vertex attribute's bound vertex buffer object so afterwards we can safely unbind
// glBindBuffer(GL_ARRAY_BUFFER, 0);
// You can unbind the VAO afterwards so other VAO calls won't accidentally modify this VAO, but this rarely happens. Modifying other
// VAOs requires a call to glBindVertexArray anyways so we generally don't unbind VAOs (nor VBOs) when it's not directly necessary.
// glBindVertexArray(0);
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
int shaderProgram = gLFWManager.createShader();
// Set the clear color
glClearColor(1.0f, 0.0f, 0.0f, 0.0f);
while (!glfwWindowShouldClose(gLFWManager.window))
{
glClearColor(1.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
// draw our first triangle
glUseProgram(shaderProgram);
glBindVertexArray(vao); // seeing as we only have a single VAO there's no need to bind it every time, but we'll do so to keep things a bit more organized
glDrawArrays(GL_TRIANGLES, 0,6); // set the count to 3 since we're drawing 3 vertices
// glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
// -------------------------------------------------------------------------------
glfwSwapBuffers(gLFWManager.window);
glfwPollEvents();
}
// optional: de-allocate all resources once they've outlived their purpose:
// ------------------------------------------------------------------------
glDeleteVertexArrays(1, &vao);
glDeleteBuffers(1, &vbo);
// glfw: terminate, clearing all previously allocated GLFW resources.
// ------------------------------------------------------------------
}
和这一个：
#include "GLFWManager.h"
#include "stdio.h"
#include "stdlib.h"
int GLFWManager::windowHight = 300;
int GLFWManager::windowWidth = 300;
void GLFWManager::errorCallback(int error, const char* description)
{
fprintf(stderr, "Error: %s\n", description);
}
void GLFWManager::windowSizeCallbackcallback(GLFWwindow* window, int width, int height)
{
if (width > 0 && height > 0) {
windowHight = height;
windowWidth = width;
}
}
static void KeyCallback(GLFWwindow* window, int key, int, int action, int mods)
{
switch (key)
{
case GLFW_KEY_ESCAPE:
{
if (action == GLFW_RELEASE)
{
glfwSetWindowShouldClose(window, GLFW_PRESS);
}
}
}
}
GLFWManager::GLFWManager()
{
window = nullptr;
}
GLFWManager::~GLFWManager()
{
}
void GLFWManager::Init()
{
glfwSetErrorCallback(GLFWManager::errorCallback);
if (!glfwInit())
{
exit(EXIT_FAILURE);
}
setWindowsHints();
createWindow();
glfwSetKeyCallback(window, KeyCallback);
glfwSetWindowSizeCallback(window, GLFWManager::windowSizeCallbackcallback);
const GLFWvidmode *vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());
glfwSetWindowPos(window, (vidmode->width - windowWidth) /2 , (vidmode->height - windowHight) /2);
glfwGetFramebufferSize(window, &windowWidth, &windowHight);
glfwMakeContextCurrent(window);
glfwSwapInterval(1);
glfwShowWindow(window);
loadGlad();
}
void GLFWManager::setWindowsHints()
{
glfwDefaultWindowHints();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE); // the window will stay hidden after creation
glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE); // the window will be resizable
}
void GLFWManager::createWindow()
{
window = glfwCreateWindow(windowWidth,windowHight, "Test", NULL, NULL);
if (!window)
{
exit(EXIT_FAILURE);
}
}
void GLFWManager::loadGlad()
{
// glad: load all OpenGL function pointers
// ---------------------------------------
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
fprintf(stderr, "Failed to initialize GLAD");
exit(EXIT_FAILURE);
}
// get version info
const GLubyte* renderer = glGetString(GL_RENDERER); // get renderer string
const GLubyte* version = glGetString(GL_VERSION); // version as a string
printf("Renderer: %s\n", renderer);
printf("OpenGL version supported %s\n", version);
}
int GLFWManager::createShader()
{
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"
"}\n\0";
// build and compile our shader program
// ------------------------------------
// vertex shader
int vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);
// check for shader compile errors
int success;
char infoLog[512];
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
printf("ERROR::SHADER::VERTEX::COMPILATION_FAILED\n %s\n ",infoLog);
}
// fragment shader
int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
// check for shader compile errors
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
printf("ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n %s \n",infoLog);
}
// link shaders
int shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
// check for linking errors
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
if (!success) {
glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
printf("ERROR::SHADER::PROGRAM::LINKING_FAILED\n %s \n",infoLog);
}
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
return shaderProgram;
}
glVertexAttribPointer和glVertexAttribPointer指定并启用顶点属性数据的数组，并在当前绑定的glEnableVertexAttribArray的状态向量中设置状态。您必须先绑定顶点数组对象（glEnableVertexAttribArray），然后才能指定顶点数组：
Vertex Array Object
注意，在调用glBindVertexArray之前，必须绑定顶点数组对象和glBindVertexArray，因为// Create vertex buffer object
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
// Create Vertex array object
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
// specify array of generic vertex array data
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
将当前绑定到glVertexAttribPointer目标的缓冲区与具有指定索引的属性相关联在当前绑定的VAO的状态向量中。