Stencil and TOpenGLControl
lazarus / 70-OpenGL

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Mathias · 2023-10-19 11:31

I want to get Stencil to work with OpenGLControl.
With SDL2 this works as follows.
     Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3); 
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3); 
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
SDL_GL_CONTEXT_PROFILE_CORE); 
SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 1);
Now I wanted to try it with OpenGLControl and did the following.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  
 OpenGLControl1.OpenGLMinorVersion := 3; 
 OpenGLControl1.OpenGLMajorVersion := 3;   OpenGLControl1.StencilBits
:= 1;Only then will unfortunately nothing be drawn at all.

If I don't do any of this at all, then Stencil is simply ignored, so
it must be related to context creation.

Anyone have an idea how to do it with OpenGLControl?

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Lulu · 2023-12-10 19:57

Hi Mathias, I just read your post.
I use stencil buffer with OpenGLControl (to clip child surface when
drawing them on their parent)
with:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
OpenGLControl1.StencilBits := 8; // I need 8 bits on
stencil...glClear(GL_COLOR_BUFFER_BIT or GL_STENCIL_BUFFER_BIT); //
clear the buffer color and stencilglEnable(GL_STENCIL_TEST);some
drawing...
No problem here (windows10) with OpenGLControl.

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Mathias · 2024-03-04 18:16

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
OpenGLControl1 . SchabloneBits : = 8 Thanks, that was exactly the
problem.