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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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GL_ERROR: 0x0502

I hope to create an offScreen FBO, and use glReadPixels() to get the value of RGBA in this offScreen FBO. unfortunately, I got the error: GL_ERROR:0x0502 #import "ViewController.h" #define BUFFER_OFFSET(i) ((char *)NULL + (i)) @interface…
smith
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How can I bind the default FBO in GLKViewController

I'm a new for OpenGL ES with GLKit, I want to create two FBO for my program. but I don't know how to bind the default FBO, anyone who can help me ? Any help or advice would be much appreciated.
smith
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GLSL shared depth buffer seems to not be working

I'm trying to use a shared depth texture for two FBOS when I'm doing tiled forward shading. What I'm doing is a prez pass that fills a depth buffer, then I run a compute shader just to do some calculatons and then I run my forward shader where I'm…
Johan
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Why does QMatrix4x4::lookAt() result in a upside down camera

I have a got a simple OpenGL program which sets up the camera as follows : void SimRenderer::render() { glDepthMask(true); glClearColor(0.5f, 0.5f, 0.7f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glTexParameteri(GL_TEXTURE_2D,…
safe_malloc
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OpenGL FBO performance issue

i'm working on a school project and I've come across an issue with my FBO. game is rendered in 2 passes: 1) I render to the shadow map texture using an FBO. 2) I render scene normally to the default FBO. Issue is, for some reason, binding the FBO…
user3349448
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glBlendFunc and framebuffer object

Alpha blending is not working as expected when I draw to a framebuffer object. Specifically, calling glBlendFunc has no effect on what pixels are in the framebuffer. I check what is in the framebuffer before and after drawing using glReadPixels. The…
Little Endian
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Calling multiple glReadPixels & glDrawArrays on a FBO, in Opengl ES

In OpenGL ES, is it possible to call glReadPixels and glDrawArrays on a FBO several times one after the other? The issue I'm facing is that I'm getting the image all garbled. Sample Code: // Activate Off-Screen FBO glBindFramebuffer(GL_FRAMEBUFFER,…
PerracoLabs
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Fullscreen blur GLSL shows diagonal line (OpenGL core)

In OpenGL 2.1, we could create a post-processing effect by rendering to a FBO using a fullscreen quad. OpenGL 3.1 removes GL_QUADS, so we have to emulate this using two triangles instead. Unfortunately, I am getting a strange issue when trying to…
The Fiddler
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Use FBO's position buffer and color buffer for rendering (post-rendering 3D warp)

I want to implement post-rendering 3D warp using position data and color data stored in a FBO. How to do it efficiently in modern OpenGL? By position data, they are camera-relative XYZ coordinates. I have two FBOs, say fbo1 and fbo2. fbo1 is for…
Feng
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attach two images to fbo for mrt rendering

I want to attach two render targets to a fbo, so I can render to two targets at once. I have one function that accepts two render targets. void render(struct glhexbutton *_this, GLuint target0, GLuint target1) { GLenum buffers[2]; GLfloat…
user2798943
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OpenGL & multiple textures as output

I'm having an issue when trying to pass multiple textures through my offscreen buffer. The problem being that the other texture is not being written up properly. The task that I've been assigned is deferred rendering of the sponza scene. Could you…
Ilari S
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Creating an FBO using LWJGL on an iMac running OSX 10.8.5

I am attempting to create an FBO to render to a texture in lwjgl. The code works fine on Linux and Windows, but falls flat on my iMac. The relevant line is the following System.out.println(GLContext.getCapabilities().GL_EXT_framebuffer_object); …
Bergasms
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OpenGL + PBO + FBO + some ATI cards - color and pixel shifting

We are developing software for slide show creation and use OpenGL. We use FBO + PBO for fast data reading from VGA to RAM but on some video cards from ATI we faced with the following problems: swapping RGB components pixel shifting There are no…
okarpov
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opengl: rendering to texture goes wrong

I've written a program for testing rendering a texture with the framebuffer. In the function render_texture() I want to render a triangle on to a texture, but when I display the rendered texture in the display function, I get just a simple yellow…
user2798943
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Problem using FBO: Only first pass renders. A possible problem at setting render target back?

I have a huge problem with using FBO. I have a multi-pass display using FBOs and multitexturing. Everything seems to work fine until the end of first execution of display. I set the render target back to screen using…
isildoga
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