如何在Visual Studio 2017单个窗体中打开多个OpenGL窗口及4个体积渲染器？

Absolutely doable! Let’s break down how to achieve both your 4-split volume renderer setup and multiple OpenGL windows within a single Visual Studio 2017 form—two common approaches depending on whether you want shared rendering resources or fully independent contexts.

Option 1: 4-Viewport Split (Single OpenGL Context) #

This is the simplest approach if your volume renderers can share the same OpenGL context (e.g., reuse textures, shaders, or volume data). You’ll divide your form’s client area into four distinct rendering regions:

1. Define your viewport boundaries
   Calculate coordinates for each quadrant based on your form’s size. For an 800x600 form, the quadrants would be:

   • Top-left: (0, 300) to (400, 600)
   • Top-right: (400, 300) to (800, 600)
   • Bottom-left: (0, 0) to (400, 300)
   • Bottom-right: (400, 0) to (800, 300)

2. Render to each viewport in sequence
   In your main render loop, switch between viewports using glViewport() and run each volume renderer’s logic:

   // Clear the entire window first
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   
   // Top-left viewport
   glViewport(0, 300, 400, 300);
   setupCameraForViewport1(); // Adjust projection/view matrices for this quadrant
   renderVolumeRenderer1();
   
   // Top-right viewport
   glViewport(400, 300, 400, 300);
   setupCameraForViewport2();
   renderVolumeRenderer2();
   
   // Bottom-left viewport
   glViewport(0, 0, 400, 300);
   setupCameraForViewport3();
   renderVolumeRenderer3();
   
   // Bottom-right viewport
   glViewport(400, 0, 400, 300);
   setupCameraForViewport4();
   renderVolumeRenderer4();
   
   // Swap buffers to display all renders
   SwapBuffers(hDC);
   

3. Troubleshoot common issues

   • If you see black boxes, double-check that glViewport() uses correct pixel coordinates, and that your volume renderer’s camera matrices match each viewport’s aspect ratio.
   • Ensure depth testing is configured properly to avoid z-fighting between viewports.

Option 2: Multiple Independent OpenGL Windows (Separate Contexts) #

If you need fully isolated OpenGL contexts (e.g., different render states, independent resources), embed multiple OpenGL render targets into your form:

Using WinForms Panels & Raw OpenGL #

1. Add Panel controls to your form
   Drag four Panel controls onto your form, arranging them into a 2x2 grid (use Dock properties or manual positions to create the split).

2. Create independent OpenGL contexts for each Panel
   For each Panel, get its device context (HDC) and create a unique OpenGL rendering context (HGLRC):

   // For Panel 1
   HDC panel1HDC = GetDC(panel1Handle);
   PIXELFORMATDESCRIPTOR pfd = {/* Configure pixel format with desired bits */};
   int pf = ChoosePixelFormat(panel1HDC, &pfd);
   SetPixelFormat(panel1HDC, pf, &pfd);
   HGLRC panel1RC = wglCreateContext(panel1HDC);
   
   // Repeat the same setup for Panels 2-4
   

3. Render to each Panel independently
   Hook into each Panel’s Paint event to switch contexts and run your render logic:

   void panel1_Paint(HWND hwnd) {
       wglMakeCurrent(panel1HDC, panel1RC);
       glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
       renderIndependentVolume1(); // Your isolated volume renderer logic
       SwapBuffers(panel1HDC);
       wglMakeCurrent(NULL, NULL); // Release context after rendering
   }
   
   // Repeat the Paint event handler for Panels 2-4
   

Using Third-Party Controls (Simpler Alternative) #

For a faster setup, use a .NET OpenGL control library like OpenTK.GLControl:

• Install the OpenTK NuGet package in your VS2017 project.
• Drag four GLControl controls onto your form, arranging them into a 2x2 grid.
• Each GLControl has its own Render event where you can run your volume renderer code—no manual context management required.

Key Tips #

• For volume renderers, ensure each viewport/control has its own camera configuration to avoid distorted output.
• When using multiple contexts, avoid sharing OpenGL objects (textures, VAOs) between contexts unless you explicitly use wglShareLists().
• If black boxes persist, verify your OpenGL context is properly initialized, and add debug prints or breakpoints to confirm your render logic is executing.

内容的提问来源于stack exchange，提问作者Johnathan Scott