Render particles
I am trying to create a particle system. I am using transform feedback and at this moment I am just trying to get this to work for one point. The problem is that more than one point is rendered for...
View ArticleTransform Feedback Demo get zero on Xcode
I downloaded a demo from here, in xcode I deleted the glewInit(), and left everything else remained the same. I ran it with no error and no warning, but the output is all zero, why is that? My mac: OS...
View ArticleTransform Feedback Variable Redeclaration Error on iOS OpenGL ES 3.0
I am currently trying to get pixel information back out of the GPU so it can be processed/saved/fed back through the loop. To do this, I am attempting to implement transform feedback. I am...
View ArticleglDrawTransformFeedbackStream, what the stream refers to?
I ported this sample to to jogl from g-truc and it works, everything fine everything nice. But now I am trying to understand exactly what the stream of glDrawTransformFeedbackStream refers to....
View Articlegl_PointCoord compiles and links, but crashes at runtime
I successfully wrote a standard basic transform feedback particle system with point-sprites. No flickering, the particles update from one buffer into the next, which is then rendered, then output...
View ArticleHow do I read back multiple buffers when using GL_SEPARATE_ATTRIBS with...
How do I read back multiple transform feedback buffers when using GL_SEPARATE_ATTRIBS instead of just one like with GL_INTERLEAVED_ATTRIBS? In this example I set up two buffers and setup them for...
View ArticleOpenGL 4.3 or 4.5 Transform Feedback Not Working
There are two debug printf segments. The first one prints out right data but the second does not. Where did I do wrong? Oh, I'm using the same vertex and fragment shader for both getting the vertices...
View ArticleglDrawTransformFeedback not write to buffer
I try to use transform features to create a particle system, so there are 2 tranform buffer and 2 array buffer, use ping-pong to switch. And my shader is simple, just keep add source position....
View ArticleOpengl Transform feedback made correctly on Android
I have been struggling to create a working transform feedback on android. So far, the closest I have gotten had a similar issue to this downvoted question:...
View ArticleTransformFeedback binding multiple output buffers
I'm using the TransformFeedback feature of GL. Is it possible to bind multiple output buffers instead of a single buffer? Assuming I have two output varyings: out vec4 out0; out vec4 out1; And I have...
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OpenGL Transform Feedback with dynamic Geometry
I am currently trying out Transform Feedback with a Geometry Shader. The Geometry Shader takes a Triangle, makes a Prism out of it and also puts a tetraeder on top of it (Think of it like an Obelisk...
View ArticleTransform Feedback: batch several feedbacks together
Target: OpenGL ES >= 3.0. Here's what my app does: generateSeveralMeshes() setupStuff(); for (each Mesh) { glBindBufferBase(GLES30.GL_TRANSFORM_FEEDBACK_BUFFER, 0, myBuf); glBeginTransformFeedback(...
View ArticleOpenGL c++ Transform Feedback values do not update
We are currently working on a GPU Particle System. Something on my implementation is wrong, it seems the Buffers do not get updated or drawn to. I would be very grateful for any help! Particle system...
View ArticleSlow transform feedback-based picking?
I'm trying to implement picking routine using transform feedback. Currently it works ok, but the problem is very low speed (slower than GL_SELECT). How it works now: Bind TBO using glBindBufferRange()...
View ArticleWhere is GLES30.glGetBufferSubData? how to read transform feedback data...
So I am following one of the simplest examples I could find on transform feedback, here, and converting it to Android/Java, but Android seems to be missing the glGetBufferSubData function available in...
View ArticleglGetUniformLocation returning -1 during transform feedback when it is used
The function returns -1, even though Uniform is defined and used within the vertex shader, I suspect the cause may be that the out attributes might not be properly bound with the target buffer (not...
View ArticleOpenGL: Repeated use of transform feedback buffers overwrites already...
I have a working implementation of this technique for view frustum culling of instanced geometry. The gist of the technique is that we use a vertex shader to check if the bounds of an object lie...
View ArticleOpengl: Can we calculate how much percentage of object is shadowed by other...
We are making a simulation of city with lot of buildings. We have requirement to calculate how much percentage of building surface is of directly illuminated by sunlight(direct-light). Is there any...
View ArticleQt OpenGL transform feedback buffer functions missing
I've been following a tutorial series for learning OpenGL, and the current tutorial I'm trying to do involves creating particle systems using the OpenGL transform feedback buffer. In my application...
View ArticleWebgl2 -- Transformfeedback vs. dumping to CPU. Which is faster for...
For a physics particle system simulation, I'm wanting to optimize a WebGL2 program. I want to know if it is faster to adjust vertice positions using a transformfeedback accessing a 3D-texture, setting...
View ArticleVertices indexing in geometry shader & SSBO performance
I'm constructing a shader program & GL host environment that would do a relatively simple task:Run VS -> TCS -> TES -> GS set of shader stages on a number oftriangles (patches). TES/TCS do...
View ArticleglMapBufferRange returns null and produces a GL_INVALID_ENUM?
OpenGL ES 3.0 here. I am trying to read back the contents of a TRANSFORM_FEEDBACK buffer like this:GLES30.glBindBufferBase(GLES30.GL_TRANSFORM_FEEDBACK_BUFFER, 0, tfo );GLES30.glBeginTransformFeedback(...
View ArticleFetch specific pixels in the image from GPU to CPU using some technique like...
I am working on an iOS OpenGLES 3.0 image filter app which need to read the pixel data from a texture, then loop through entire pixels, extract some pixels with some conditions like brightness over a...
View ArticleWhy glBeginTransformFeedback requires to specify the primitive type?
I was trying to think why would OpenGL need to know the primitive type when calling glBeginTransformFeedback. In essence, it's just data that is stored into a buffer.My guess would be that OpenGL...
View ArticleCan't wait on a fence
I'm trying to get some data from TRANSFORM_FEEDBACK_BUFFER with the code below:const transform_feedback = gl.createTransformFeedback();gl.bindTransformFeedback(gl.TRANSFORM_FEEDBACK,...
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Animate vertex positions with webgl2 transform feedback using two programs
I try to follow example from webgl2fundamentals regarding transform feedback.My goal is to create animation of vertex positions in a way that there are two programs:doing animation calculations each...
View ArticleWhen is binding transform feedback object not required?
I have some sample code for a transform buffer object I've been trying to simplify down to the most minimal form and I've found that my code works the same if I omit createTransformFeedback() and...
View ArticleTransform feedback vertices always match order of input buffer
After reading Jason Ekstrand's blog on adding the transform feedback extension to Vulkan, he points out that the primitives in the transform feedback buffer aren't guaranteed to reflect the order and...
View ArticleOpenGL Transform Feedback not returning anything
I am working on a Project to create Geometry by using a Geometry Shader and Transform Feedback.I am currently trying to have the Geometry Shader return its input (1 triangle) without changing/adding...
View ArticleOpenGl transform feedback with GL_SEPARATE_ATTRIBS buffer mode
I use OpenGl's transform feedback (version 3 to remain compatible with macos) to generate vertices from other vertices. In this scenario for example, the generated vertices are at least twice as...
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