我当前正在运行opengl 4.5。
我从互联网上复制粘贴代码以绘制三角形，效果很好。我玩了着色器，一切都很棒。
然后我有了一个好主意，为什么不画一个正方形，所以我尝试了一下，只是渲染了背景。
这是代码：
and以防万一，我只向缓冲区添加了一个顶点，然后将 glfwGetFramebufferSize(window, &width, &height);
glViewport(0, 0, width, height);
// Build and compile our shader program
// Vertex shader
vertexShaderSource = read_file("res/shaders/vxShader.vert").c_str();
fragmentShaderSource = read_file("res/shaders/fgShader.frag").c_str();
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);
// Check for compile time errors
GLint success;
GLchar infoLog[512];
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
}
// Fragment shader
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
// Check for compile time errors
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
}
// Link shaders
GLuint 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);
std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
}
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
// Set up vertex data (and buffer(s)) and attribute pointers
GLfloat vertices[] = {
0.5f, 0.5f, 0.0f, // Left
0.0f, 0.5f, 0.0f, // Right
0.0f, 0.0f, 0.0f, // Top
0.5f, 0.0f, 0.0f // Top
};
GLuint VBO, VAO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0); // Note that this is allowed, the call to glVertexAttribPointer registered VBO as the currently bound vertex buffer object so afterwards we can safely unbind
glBindVertexArray(0); // Unbind VAO (it's always a good thing to unbind any buffer/array to prevent strange bugs)
// Game loop
while (!glfwWindowShouldClose(window))
{
// Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions
glfwPollEvents();
// Render
// Clear the colorbuffer
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// Draw our first triangle
glUseProgram(shaderProgram);
glBindVertexArray(VAO);
glDrawArrays(GL_POLYGON, 0, 4);
glBindVertexArray(0);
// Swap the screen buffers
glfwSwapBuffers(window);
}
// Properly de-allocate all resources once they've outlived their purpose
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
// Terminate GLFW, clearing any resources allocated by GLFW.
glfwTerminate();
return 0;
参数从glDrawArrays更改为GL_TRIANGLE。我想我忘了做某事。
答案 0 :(得分：0)
不推荐使用原始类型run，并且仅由兼容性配置文件OpenGL context支持。如果使用核心配置文件OpenGL上下文，则必须使用OpenGL基本类型GL_TRIANGLE_FAN：
GL_POLYGON
glDrawArrays(GL_POLYGON, 0, 4);请注意，OpenGL仅可渲染点，线和三角形。如果要渲染多边形，则必须通过三角形进行组装。一个四边形可以由2个三角形组成。参见Primitive。