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delphiopenglfiremonkey

How to prevent a firemonkey form to draw itself (for calling an own drawing function)?

I try to convert an existing OpenGL-Application from VCL-based forms to FMX-based forms in C++ Builder XE3.

For this purpose I use the handle of a Firemonkey-form to create the OpenGL device context and make this form a child of another form to mimic the panel inside the form which I had in my VCL-based application.

The problem is now that after a resize-event or in general after calling Invalidate() the form is rendered with its background. This causes a flickering or even worse: sometimes the background is shown instead of my OpenGL rendered scene.

How can I prevent the repaint of the region at the position of my Firemonkey-OpenGL-form. Alternatively, can I define an Ownerdraw-function or something else?

Please note, that it is no option for me to use a Firemonkey-3d-Form.

Solution

  • After hours of experimenting I found the solution: The "TCommonCustomForm" has the needed properties: (1) it does not draw itself, (2) it has a handle which can be used for OpenGL initialization.

    I hope this information will help others.