java Lwjgl 3、如何获取当前线程中的OpenGL上下文？
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Lwjgl 3, How to get OpenGL context current in the current thread?
提问by Hyman
I am using OpenGL in LWJGL 3 and I get the following error;
我在 LWJGL 3 中使用 OpenGL，但出现以下错误；
Exception in thread "main" java.lang.IllegalStateException: There is no OpenGL context current in the current thread.
at org.lwjgl.opengl.GL.getCapabilities(GL.java:157)
at org.lwjgl.opengl.GL11.getInstance(GL11.java:1390)
at org.lwjgl.opengl.GL11.glClearColor(GL11.java:1842)
at com.base.engine.RenderUtil.initGraphics(RenderUtil.java:13)
at com.base.engine.Main.<init>(Main.java:14)
at com.base.engine.Main.main(Main.java:24)
Exception in thread "main" java.lang.IllegalStateException: There is no OpenGL context current in the current thread.
at org.lwjgl.opengl.GL.getCapabilities(GL.java:157)
at org.lwjgl.opengl.GL11.getInstance(GL11.java:1390)
at org.lwjgl.opengl.GL11.glClearColor(GL11.java:1842)
at com.base.engine.RenderUtil.initGraphics(RenderUtil.java:13)
at com.base.engine.Main.<init>(Main.java:14)
at com.base.engine.Main.main(Main.java:24)
This is the RenderUtil class where initGraphics is called from the constructor of my main class. I have also tried to call initGraphics after creating a window with GLFW which has also generated a similar error message.
这是 RenderUtil 类，其中从我的主类的构造函数调用 initGraphics。我还尝试在使用 GLFW 创建窗口后调用 initGraphics，该窗口也生成了类似的错误消息。
package com.base.engine;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL30.*;
public class RenderUtil {
public static void clearScreen() {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}
public static void initGraphics() {
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glFrontFace(GL_CW);
glCullFace(GL_BACK);
glEnable(GL_CULL_FACE);
glEnable(GL_DEPTH_TEST);
glEnable(GL_FRAMEBUFFER_SRGB);
}
}
Also, I am not using multithreading. To create a window I call the method Window.createWindow(1366, 768, "Test");from my main method.
另外，我没有使用多线程。要创建一个窗口，我Window.createWindow(1366, 768, "Test");从主方法调用该方法。
private static Long window;
public static String createWindow(int width, int height, String title) {
if (GLFW.glfwInit() == 0) {
return "GLFW failed to initialise.";
}
GLFW.glfwWindowHint(GLFW.GLFW_SAMPLES, 4);
window = GLFW.glfwCreateWindow(width, height, title,
GLFW.glfwGetPrimaryMonitor(), 0);
if (window == null) {
GLFW.glfwTerminate();
return "Failed to create window.";
}
GLFW.glfwMakeContextCurrent(window);
return "GLFW has established a window.";
}
I have tried putting RenderUtil.initGraphics();two different position in my main method, both resulting in errors.
我尝试RenderUtil.initGraphics();在我的主要方法中放置两个不同的位置，都导致错误。
private boolean isRunning = false;
private Game game;
// This is the constructor
public Main() {
// Pos 1 - RenderUtil.initGraphics();
isRunning = false;
game = new Game();
}
public static void main(String[] args) {
System.out.println(Window.createWindow(1366, 768, "Test"));
// Pos 2 - RenderUtil.initGraphics();
Main game = new Main();
game.start();
}
回答by Sri Harsha Chilakapati
Add a call to GLContext.createFromCurrent()at the end of the createWindowmethod.
GLContext.createFromCurrent()在createWindow方法的末尾添加一个调用。
This method is needed to set the context used by the LWJGL GL** classes under the hood.
需要此方法来设置 LWJGL GL** 类在后台使用的上下文。
EDIT:
编辑：
Since the latest nightly (3.0.0b #11) this no longer works, as the GLContextclass no more exists. Instead, add GL.createCapabilities()at the end of the createWindowmethod.
由于最新的每晚 (3.0.0b #11) 这不再有效，因为GLContext该类不再存在。相反，GL.createCapabilities()在createWindow方法的末尾添加。
回答by Alex
I know that this thread is 4 years old but if someone of you still needs a solution here you go:
我知道这个线程已经有 4 年的历史了，但是如果你们中的某个人仍然需要一个解决方案，你可以去：
import org.lwjgl.glfw.*;
import org.lwjgl.opengl.*;
public class Main {
private static long window = 0;
public static void main(String[] args) {
if(!GLFW.glfwInit()) {
throw new RuntimeException("Cannot initialize OPenGL");
}
window = GLFW.glfwCreateWindow(1024, 764, "Ya yeet", 0, 0);
if(0 == window) {
GLFW.glfwTerminate();
throw new RuntimeException("Cannot create window");
}
GLFW.glfwMakeContextCurrent(window);
GL.createCapabilities();
String glVersion = GL11.glGetString(GL11.GL_VERSION);
System.out.println(glVersion);
}
}
回答by kles4eko
To init and use LWJGL 3 you need to do next (code in Kotlin):
要初始化和使用 LWJGL 3，您需要执行下一步（Kotlin 中的代码）：
import org.lwjgl.glfw.GLFW
import org.lwjgl.opengl.GL
import org.lwjgl.opengl.GL11
import org.lwjgl.system.MemoryUtil.NULL
class VersionInfo {
var window: Long = NULL
fun run() {
initGl()
// use openGL
val glVersion = GL11.glGetString(GL11.GL_VERSION)
println("GL version: $glVersion")
}
private fun initGl() {
// check GLFW
if (!GLFW.glfwInit()) {
throw IllegalStateException("Can not initialize GLFW")
}
// create window
window = GLFW.glfwCreateWindow(1024, 764, "glfw", NULL, NULL)
// check window
if (NULL == window) {
GLFW.glfwTerminate()
throw IllegalStateException("Can not create new GLFW window")
}
// make GL context in the current thread
GLFW.glfwMakeContextCurrent(window)
// create capabilities
GL.createCapabilities()
}
companion object {
@JvmStatic
fun main(args: Array<String>) {
VersionInfo().run()
}
}
}
For more information, please, see official get-started guide: http://www.lwjgl.org/guide
Or Wiki: https://github.com/LWJGL/lwjgl3-wiki/wiki
有关更多信息，请参阅官方入门指南：http: //www.lwjgl.org/guide
或 Wiki：https: //github.com/LWJGL/lwjgl3-wiki/wiki
