我想制作Java应用程序 . 使用CEF3库 . CEF是在任何应用程序中嵌入Google Chrome浏览器的库 . LWJGL用于在Java中编写GL代码 . 但在使用CEF之前,基本问题是如何混合使用C和Java .
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Java main将C部分称为DLL
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C部分创建窗口并设置GL上下文
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在消息循环中,C再次回调Java部分以在Java中执行一些GL工作 .
以下测试代码失败并显示消息:
本机方法中的致命错误:线程[main,5,main]:没有上下文是当前的,或者调用了当前上下文中不可用的函数 . JVM将中止执行 . 在Main.main(Main.java:10)的Main.cunmain(Native方法)的Main.run(Main.java:18)上的org.lwjgl.opengl.GL11.glColor3f(本机方法)
可能是因为Java部分不知道C部分创建的GL上下文 . 我的问题是如何设置GL上下文,以便C和Java都可以调用GL函数?
Main.java
import org.lwjgl.opengl.GL11;
public class Main implements Runnable {
{
System.loadLibrary("cppgl");
}
public static void main(String[] args) {
Main me = new Main();
me.cppmain(me);
}
private native void cppmain(Runnable callback);
@Override
public void run() {
// callback from cpp
GL11.glColor3f(1.0f, 0.0f, 1.0f);
}
}
cppgl.cpp
#pragma comment(lib, "OpenGL32.lib")
#include <windows.h>
#include <tchar.h>
#include <functional>
#include <gl/gl.h>
#include <jni.h>
#pragma comment(lib, "jvm.lib")
LRESULT CALLBACK WndProc(HWND hWnd, UINT mes, WPARAM wParam, LPARAM lParam) {
if (mes == WM_DESTROY || mes == WM_CLOSE) { PostQuitMessage(0); return 0; }
return DefWindowProc(hWnd, mes, wParam, lParam);
}
extern "C" JNIEXPORT void JNICALL Java_Main_cppmain
(JNIEnv *env, jobject, jobject callback) {
LPCTSTR title = L"gl test";
// prepare JNI call
jclass cls = env->FindClass("Ljava/lang/Runnable;");
jmethodID mid = env->GetMethodID(cls, "run", "()V");
// window class
HINSTANCE hInstance = ::GetModuleHandle(NULL);
WNDCLASSEX wcex;
ZeroMemory(&wcex, sizeof(wcex));
wcex.cbSize = sizeof(wcex);
wcex.style = CS_OWNDC | CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.hInstance = hInstance;
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wcex.lpszClassName = title;
if (!RegisterClassEx(&wcex)) return;
// window
RECT R = { 0, 0, 640, 480 };
AdjustWindowRect(&R, WS_OVERLAPPEDWINDOW, FALSE);
HWND hWnd = CreateWindow(title, title, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, R.right - R.left, R.bottom - R.top,
NULL, NULL, hInstance, NULL);
if (!hWnd) return;
// GL context
PIXELFORMATDESCRIPTOR pfd;
ZeroMemory(&pfd, sizeof(pfd));
pfd.nSize = sizeof(pfd);
pfd.nVersion = 1;
pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = 32;
pfd.cDepthBits = 24;
pfd.iLayerType = PFD_MAIN_PLANE;
HDC dc = GetDC(hWnd);
int format = ChoosePixelFormat(dc, &pfd);
SetPixelFormat(dc, format, &pfd);
HGLRC glRC = wglCreateContext(dc);
if (!wglMakeCurrent(dc, glRC)) return;
// message loop
ShowWindow(hWnd, SW_SHOW);
MSG msg;
do {
if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
else {
wglMakeCurrent(dc, glRC);
glClearColor(0.0f, 0.5f, 1.0f, 1.0f);
// call Java and change clear color here
env->CallVoidMethod(callback, mid);
glClear(GL_COLOR_BUFFER_BIT);
glRectf(-0.5f, -0.5f, 0.5f, 0.5f);
glFlush();
SwapBuffers(dc);
wglMakeCurrent(NULL, NULL);
}
} while (msg.message != WM_QUIT);
// clean up
wglMakeCurrent(NULL, NULL);
wglDeleteContext(glRC);
ReleaseDC(hWnd, dc);
}
1 回答
在从java进行任何渲染之前,你应该在开始时调用一次 .