Create and manage OpenGL rendering contexts for use in macOS, and perform operations on drawable objects.

Posts under OpenGL tag

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Why is an OpenGL positional (spot) light interfering with non-positional light
I have a legacy OpenGL fixed-pipeline app which has been ported from Windows (32-bit) to MacOS 64-bit. The problem is that if I have a scene with a non-positional light, everything works great. If I add a positional spotlight the two lights interact, and I get incorrect results. This problem does not occur on X86_64 Macs. It does occur when the app is X86_64 running under Rosetta or native ARM64. So it's either an Apple Silicon OpenGL driver behaviour my code is triggering, or something with the on-chip Apple Silicon graphics. Here is the "normal" case: the spotlight is to the right: Here, I have moved the spotlight down (Y = 1). Notice the black areas on the cube. That's incorrect. Now, I turn off the spotlight by commenting out the "makeALight" call for the spotlight (light 6). Now, the cube is evenly lit. Here is the test code I use to generate the lights. You will need to install glfw with brew to build it. main.cpp
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420
Sep ’24
How is CAShapeLayer implemented
Hello, I want to create a painting app for iOS and I saw many examples use a CAShapeLayer to draw a UIBezierPath. As I understand CoreAnimation uses the GPU so I was wondering how is this implemented on the GPU? Or in other words, how would you do it with Metal or OpenGL? I can only think of continuously updating a texture in response to the user's drawing but that would be a very resource intensive operation... Thanks
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411
Sep ’24
Deferred Rendering Supported?
Using Unreal Engine 5.4 for Apple Vision Pro. Creating a fully immersive VR Experience. When deploying a VR Application, can you use deferred rendering for the Apple Vision Pro? Or do you need to use forward shading, like for mobile devices? My goal would be to use deferred rendering, because of the much better shader options and quality. And I hope that the Apple Vision Pro with the integrated CPU and GPU could handle deferred rendering, that like a MacBook or a powerful Gaming PC, Workstation. I couldn't find any information on that. Have been mainly developing VR Applications for Quest, but would love to create apps for the Apple Vision Pro. But I would need to know if defered rendering will work when deploying VR Apps from the Unreal Engine to the Apple Vision Pro system. Thanks a lot for any more information on that topic, appreciate it! all the best, Bernhard
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577
May ’24
freeglut throws error "failed to open display''
Sorry for my rudimentary question. Environment: ・Xcode 15.3 ・C++ ・Freeglut 3.4.0 ・XQuartz 2.8.6_beta2 (already started) Current status: The following problems occurred at the time of upgrading from Xcode 14.2 to Xcode 15.3. Despite setting DISPLAY appropriately in the user environment variable, an error message " failed to open display '' " is thrown when RUN with Xcode. However, if I run the binary built with Xcode directly in the terminal, it works fine. Question: Why is the DISPLAY environment variable not being passed to Xcode internals properly when RUN in Xcode?
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618
Apr ’24
segmentation error caused by libGL.dylib`(glViewport)
OS: Sonoma 14.2.1 (23C71), I am porting a linux code (that uses C++, QT) to mac OS. after compiling the code on mac, I get segmentation error due to libGL.dylib. My question is how to avoid the segmentation error. debug messages when I run it using lldb: 2024-03-21 13:13:17.957964+0530 EdgeMarker[10094:150997] SecTaskCopyDebugDescription: EdgeMarker[10094]/0#-1 LF=0 2024-03-21 13:13:18.962117+0530 EdgeMarker[10094:150997] SecTaskLoadEntitlements failed error=22 cs_flags=20, pid=10094 2024-03-21 13:13:18.962246+0530 EdgeMarker[10094:150997] SecTaskCopyDebugDescription: EdgeMarker[10094]/0#-1 LF=0 Process 10094 stopped * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0xa80) frame #0: 0x00007ffa1c1295a4 libGL.dylib`glViewport + 22 libGL.dylib`glViewport: -> 0x7ffa1c1295a4 <+22>: movq 0xa80(%rax), %r9 0x7ffa1c1295ab <+29>: movq (%rax), %rdi 0x7ffa1c1295ae <+32>: popq %rbp 0x7ffa1c1295af <+33>: jmpq *%r9 Target 0: (EdgeMarker) stopped. Backtrace snippet: * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0xa80) * frame #0: 0x00007ffa1c1295a4 libGL.dylib`glViewport + 22 frame #1: 0x000000010000c427 EdgeMarker`MyGLCanvas::initializeGL(this=0x00007f8e4f857710) at MyGLCanvas.cpp:33:2 The error occurs when initializing an opengl window: void MyGLCanvas::initializeGL() { m_width = this->frameGeometry().width(); m_height = this->frameGeometry().height(); m_initialized = true; m_Eye[0] = 0.0f; m_Eye[1] = 0.0f; m_Eye[2] = -2.0f; //Actual code m_PerspectiveAngleDegrees = 45.0f; m_NearPlane = 0.01f; m_FarPlaneOffset = 100.0f; glViewport(0, 0, (GLint)m_width, (GLint)m_height); Before calling MyGLcanvas::initializeGL() there is a call to setFocus() function. SetFocus is a function used in GUI programming to give focus to a specific window or control within a window. My second question : Is setFocus valid is mac OS or is there an equivalent?
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531
Mar ’24
OpenGL and NSScreen.mainScreen.backingScaleFactor
I init openGL now i wanna set glPixelZoom(pixelSizeX, -pixelSizeY); to dispaly a image with width and height to the entire window for this I do: rect:= window.frame; WindowBackingRect := window.convertRectToBacking(rect); pixelSizeX := WindowBackingRect.size.width / width / NSScreen.mainScreen.backingScaleFactor; pixelSizeY := WindowBackingRect.size.height / height / NSScreen.mainScreen.backingScaleFactor; under High Sierra 10.13.6 on an intel mac from 2011 NSScreen.mainScreen.backingScaleFactor return 1 because there is no retina. under Sonoma 14.3 an an intel mac from 2020 NSScreen.mainScreen.backingScaleFactor return 2 because of retina. this works correct. under Venture 13.6 on an aarch64 mac from 2020 NSScreen.mainScreen.backingScaleFactor returns 2 BUT the image is only half so big as it should be. (if i let the scale factor away on the new intel mac, the image is twice big as it should be. On the new AArch64 mac it is correct.) what to do?
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526
Feb ’24
Mesa with LLVM on MacOS
Hi, I have a MacBook Pro with an Intel Iris Plus Graphics 640, which gives maximum 4.1 OpenGL context. Thus, I would like to use Mesa as an alternative for getting higher contexes e.g. 4.5 or 4.6. I don’t care about performance in this phase. I have built Mesa with LLVM (llvm-config… etc…) but even by placing the built libGL.dylib in the same folder with executable or setting DYLD_LIBRARY_PATH or DYLD_INSERT_LIBRARIES, I am not able to get the Mesa renderer. Does Apple support this overriding of libGL with a custom one? Any help/guidance would be really appreciated. Thanks
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649
Jan ’24
Leaking WebGLRenderer when rerendering on iOS
I have created a react-three-fiber web-app which uses webgl canvas. When the canvas is forced to rerender due to external change, a new canvas context is being created and the previous one is not lost. This leads to safari refresh and crash as the no of active canvas contexts goes beyond the max limit alongwith the memory. This issue is specific to Safari only and (chrome only on iOS). Does Safari have a different garbage collection mechanism and not include webgl context clear automatically? If it doesnt, is there an API to invoke the same?
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920
Nov ’23
OpenGL on future iPhones and Macs?
Hello everyone! After some time to think about I proceed with graphics api, I figured opengl will be my first since I'm completely new to graphics programming. As in my last post you may find, I was speaking on moltenvk and might just use metal instead, along with the demos I found using metal. So for now, and I know this is said MANY TIMES, apple deprecated opengl but wish to use it because I'm new to graphics programming and want to develop an app(a rendering engine really) for the iPhone 14 Pro Max and macOS Ventura 13.2(I think this is the latest). So what do you guys think? Can I still use opengl es on the 14 max, along with opengl 4+ on latest macOS even though is deprecated?
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6.4k
Dec ’23