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Questions tagged [fbo]

Framebuffer object (FBO) is an OpenGL object type that allows rendering to textures or other user-allocated image buffers. Versions of OpenGL older than 3.0 can access an extension version of this functionality.

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OpenGL + SDL + Cannot Draw to Offscreen FBO

I have 2 programs - both OpenGL 3.x: one is a Win32 program (a modified NeHe tutorial) which creates a Window and GL context via wglCreateContext() and wlgMakeCurrent() one is an SDL2 progam Both programs call this function: int DrawGLScene(…
SparkyNZ
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Android glReadPixels from PBO blocking/performance

I'm having an unusual problem while working on an openGL project. Essentially I require frame data in GRAYSCALE single channel format for some CV stuff. I'm using a custom shader, an FBO and PBO's to get the task done. The flow of the program is as…
David Arayan
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Retrieve color of current texel in fragment shader

I want to retrieve the color of the current texel in my fragment shader so I can adapt the output color depending on it. For example: if the current texel's color is red then set the color to green. Above, you can see there are two triangles. One…
GuiTeK
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Rendering layers of bitmaps with alpha to FBO

I need to draw several "layers" of bitmaps that are semi-transparent to a FBO (for later readback). My current approach is to create a FBO, attach a texture to it and use glTexSubImage2D to "draw" the bitmaps to the FBO, this however, doesn't work…
monoceres
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How to correctly set the width and height of a FrameBuffer in libgdx?

I am using a FrameBuffer to rasterize several TextureRegions in a single TextureRegion, to be drawn on an Image/Actor afterwards. The constructor of a FrameBuffer is the following: FrameBuffer(Pixmap.Format format, int width, int height, boolean…
J. Doe
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Crop Fbo to a bounding box in Openframeworks

I have a drawing inside fbo, and trying to decrease fbo size by cropping to the visible parts using bounding box. Here is a visual representation what I'm trying to achieve: bounding box example I found solution: pass fbo data to pixels and then…
Gordey
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Image Processing on GPU- sucessive shaders for filters - FBO

I'm currently trying to implement in OpenGL image processing algorithms. I would like to successively use several shaders in order to perform several filters (Sobel Gaussian,...). I understood that to do this I had to render to texture thanks to a…
zenna
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Using a FrameBufferObject with several Color Texture attachments

I'm implementing in my program the gaussian blur effect. To do the job I need to render the first blur information (the one on Y axis) in a specific texture (let's call it tex_1) and use this same information contained in tex_1 as input information…
user1364743
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Retrieving FBO data in GLSL

I'm trying to get MRT working in OpenGL to try out deferred rendering. Here's the situation as I understand it. Create 3 render buffers (for example). Two RGBA8 and one Depth32. Create an FBO. Attach render buffers to FBO. ColorAttachment0/1 for…
Tom Savage
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FBO lwjgl bigger than Screen Size - What I'm doing wrong?

I need your help again. I wanna use Frame Buffer Object bigger than the Screen size. When I do it as below FBO size 1024 x 1024 is cut off from the top in resolution 1024 x 768. I couldn't find the solution on my own - that's why I'm asking. First…
Przemek
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Transparent frame buffers in webgl

I'm working on creating an color-trail effect in webgl. Basically I'd like to be able to select a range of colors from a texture and have them trail after the texture as its animated across the screen. My strategy was to both draw the texture to the…
Kev
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Rendering to texture using FBO and shaders OpenGL

I want to load two textures in my FBO, one texture contains a HDR image, and my first target is to "copy" the image from first texture to second (which is empty), and called 'DownSamplingTex'. So I create FBO, load the texture I want to write in…
MikeFadeCrew
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OpenGL: only one FBO at a time works

I'm trying to render to a texture, then copy that texture and run it through post processing, then combine the filtered image with the original. I've got it so I can render to a a texture, then process it and display it, but I can only process it…
Garrett Skelton
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glDeleteFramebuffers explicit call

In OpenGL tutorials I never saw that someone call glDeleteFramebuffers before program finished. Should I delete FrameBuffer before close application? Or OpenGL driver will do this for me? P.S. Same question about texture glDeleteTextures.
tower120
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How to render into FBO after "direct rendering to texture" without affecting the texture

I'm attempting to re-use FBO I have previously used for direct rendering into a texture. I want to render into this FBO, without affecting the texture and grab the pixels using glReadPixels. Normally, I would render anything and get the pixels using…
Jayco
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