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OpenGL OpenGL Windows

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norbs27    122
Does OpenGL have to be run through its own window or can you run it through a section of a window, such as a box within the centre?

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norbs27    122
No, I mean say you have your window setup with your various dialog boxes arranged wherever, can you have OpenGL render to a picturebox (or an equivalent compatible object) or does it have to have its own window?

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nullsquared    126
Original post by norbs27
No, I mean say you have your window setup with your various dialog boxes arranged wherever, can you have OpenGL render to a picturebox (or an equivalent compatible object) or does it have to have its own window?

I'm not really sure what you mean by picturebox but you can set up a view port that takes only part of a window... So then you have all your other stuff somewhere safe where ogl won't overwrite them.

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Kwak    220
It is also possible to create a rendering context for (for example) a panel.
In this program i made 2 panels with each a different rendering context.

Here is some of my code.
I just fooled around with rendering context and device context.
But hey... it works.


hdcGridPanel = GetDC(GridPanel->Handle); // handle to GridPanel device context
hdcWorldPanel = GetDC(WorldPanel->Handle); // handle to WorldPanel device context
hrcGridPanel = wglCreateContext(hdcGridPanel); // create a rendering context for the GridPanel
hrcWorldPanel = wglCreateContext(hdcWorldPanel); // create a rendering context for the WorldPanel
if (hrcGridPanel==NULL) // check if the handles are created
ShowMessage(":-)~ hrcGridPanel == NULL");
if (hrcWorldPanel==NULL)
ShowMessage(":-)~ hrcWorldPanel == NULL");

void __fastcall TMain_Form::SetPixelFormatDescriptor()
// set a pixel format for the device context
sizeof(PIXELFORMATDESCRIPTOR), // Size of this pixel format descriptor
1, // Version number
PFD_DRAW_TO_WINDOW | // Format must support window
PFD_SUPPORT_OPENGL | // Format must support OpenGL
PFD_DOUBLEBUFFER, // Must support double buffering
PFD_TYPE_RGBA, // Request an RGBA format
24, // Select our color depth
0, 0, 0, 0, 0, 0, // Color bits ignored
0, // No alpha buffer
0, // Shift bit ignored
0, // No accumulation buffer
0, 0, 0, 0, // Accumulation bits ignored
32, // 16Bit Z-Buffer (Depth buffer)
0, // No stencil buffer
0, // No auxiliary buffer
PFD_MAIN_PLANE, // Main drawing layer
0, // Reserved
0, 0, 0 // Layer masks ignored
PixelFormat = ChoosePixelFormat(hdcGridPanel, &pfd);
SetPixelFormat(hdcGridPanel, PixelFormat, &pfd);
PixelFormat = ChoosePixelFormat(hdcWorldPanel, &pfd);
SetPixelFormat(hdcWorldPanel, PixelFormat, &pfd);

void __fastcall TMain_Form::CloseMainForm(TObject *Sender,
TCloseAction &Action)
// release Context
wglMakeCurrent(NULL, NULL); // no current rendering context
wglDeleteContext(hrcGridPanel); // free the system resources
ReleaseDC(GridPanel->Handle, hdcGridPanel);
ReleaseDC(WorldPanel->Handle, hdcWorldPanel);

void __fastcall TMain_Form::UpdateGridPanel()
if (wglMakeCurrent(hdcGridPanel, hrcGridPanel) == false) // associate the hrcGridPanel to the
ShowMessage("Could not MakeCurrent: GridPanel"); // hdcGridPanel => draw to GridPanel

void __fastcall setGridViewPort()
glViewport (0, 0, Main_Form->GridPanel->ClientWidth, Main_Form->GridPanel->ClientHeight);
glScissor(0, 0, Main_Form->GridPanel->ClientWidth, Main_Form->GridPanel->ClientHeight);
glEnable(GL_SCISSOR_TEST); // only pixels in box will be affected (standard)
glMatrixMode(GL_PROJECTION); // reset projection matrix
glLoadIdentity(); // reset modelview matrix
// Set orthogonal projection (perspective)
glOrtho(center.x - (Main_Form->GridPanel->ClientWidth/2)*distancePerPixel,
center.x + (Main_Form->GridPanel->ClientWidth/2)*distancePerPixel,
center.y - (Main_Form->GridPanel->ClientHeight/2)*distancePerPixel,
center.y + (Main_Form->GridPanel->ClientHeight/2)*distancePerPixel,
-100.0f, 100.0f);

I hope you find something useful among these snippets of code.

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