C++ 为什么 glGetString(GL_VERSION) 返回空/零而不是 OpenGL 版本？
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Why does glGetString(GL_VERSION) return null / zero instead of the OpenGL version?
提问by lyra42
I'm on Linux Mint 13 XFCE. My problem is that when I run in terminal the command:
我在 Linux Mint 13 XFCE 上。我的问题是，当我在终端中运行命令时：
glxinfo | grep "OpenGL version"
I get the following output:
我得到以下输出：
OpenGL version string: 3.3.0 NVIDIA 295.40
But when I run the glGetString(GL_VERSION)in my application then the result is null. Why doesn't this code get the gl_version?
但是当我glGetString(GL_VERSION)在我的应用程序中运行时，结果为空。为什么这段代码没有得到gl_version？
#include <stdio.h>
#include <GL/glew.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>
#include <GL/glext.h>
int main(int argc, char **argv) {
glutInit(&argc, argv);
glewInit();
printf("OpenGL version supported by this platform (%s): \n",
glGetString(GL_VERSION));
}
回答by genpfault
glutInit()doesn't create a GL contextormake one current. You need a current GL context for glewInit()and glGetString()to work.
glutInit()不创建GL 上下文或使一个当前。你需要一个当前GL上下文glewInit()和glGetString()工作。
Try this:
尝试这个：
#include <GL/glew.h>
#include <GL/glut.h>
#include <cstdio>
int main(int argc, char **argv)
{
glutInit(&argc, argv);
glutCreateWindow("GLUT");
glewInit();
printf("OpenGL version supported by this platform (%s): \n", glGetString(GL_VERSION));
}
回答by arielhad
You can also use glfwin order to create GL context and then query the version:
您还可以使用glfw为了创建 GL 上下文，然后查询版本：
Include this files:
包括这个文件：
#include "GL/glew.h"
#include "GLFW/glfw3.h"
And then you can do:
然后你可以这样做：
// Initialise GLFW
glewExperimental = true; // Needed for core profile
if (!glfwInit())
{
return "";
}
// We are rendering off-screen, but a window is still needed for the context
// creation. There are hints that this is no longer needed in GL 3.3, but that
// windows still wants it. So just in case.
glfwWindowHint(GLFW_VISIBLE, GL_FALSE); //dont show the window
// Open a window and create its OpenGL context
GLFWwindow* window;
window = glfwCreateWindow(100, 100, "Dummy window", NULL, NULL);
if (window == NULL) {
return "";
}
glfwMakeContextCurrent(window); // Initialize GLEW
if (glewInit() != GLEW_OK)
{
return "";
}
std::string versionString = std::string((const char*)glGetString(GL_VERSION));
