Questions tagged [opengl]
OpenGL (Open Graphics Library) is a graphics standard and API which is platform-independent and available for desktop, workstation and mobile devices. It is designed to provide hardware-accelerated rendering, and hence gives greatly improved performance over traditional software rendering. OpenGL is used for applications like CAD software and computer games. The OpenGL standard, as well as OpenGL ES, is controlled by the Khronos group.
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Why does my implementation of a sinusoidally time-varying color work so slowly?
I've been following TheCherno's OpenGL tutorials and I got to the point where I could render a square by using an index buffer. Now I wanted to vary the color of the square by using $$\frac{\sin(t) + ...
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How to implement camera translation arround object using gluLookAt?
I'm trying to move my camera around the object, a house, using some keyboard keys and the gluLookAt() function.
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How to correctly handle rendering of ~600000, arbitrary colored 2D squares with WebGL?
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I have to render a map, that is rendered as a 2d collection of squares of different color, separated by white lines horizontally and vertically. There may be ~600000 squares surrounded by ...
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How are multisample samples partitioned in OpenGL, and at which points does interpolation take place?
As I understand it, with glEnable(GL_MULTISAMPLE), glEnable(GL_SAMPLE_SHADING) and ...
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Are stencil buffer dimensions required to match render target dimensions?
I may not need as precise pixel-perfect stenciling as my render target during stencil tested render pass. I could be okay with stencil test happening at half or quarter of resolution to save bandwidth,...
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Is it possible to fill in Stencil Buffer programmatically via fragment shader?
I've never worked with stencil buffers, but I'm researching if it is the right tool for my task.
Basically I don't understand yet if stencil buffer can only be filled in by some hardcoded rules during ...
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Vertex attribute alignment <4 bytes
I know that vertex attributes sourced from vertex buffers in OpenGL need to adhere to the basic alignment requirements of their base types, so e.g. 4 bytes for floats or uints. However, I am unable to ...
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interpolated normal vectors after tessellation. How to hash patch corner / edge vertices?
I have a 3D geometry (an asteroid) that is to be tessellated with respect to the camera position. Each vertex in the original mesh has a unique position and is stored once (VBO with IBO)
In the ...
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Tessellation evaluation shader: vertex duplicates on triangle tessellation
I was very surprised when I ran my tessellation evaluation shader, which only counts the number of vertices through an atomicAdd command.
for the following tessellation levels:
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OpenGL texture unit bindings - Why is a single texture mapped to both texture units when each are individually assigned?
I am using NVIDIA Nsight to debug my OpenGL state. In the screenshots below:
I generate a single texture with the ID 10.
I activate ...
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Is MultiDrawElementsBaseVertex bound by index type?
With glMultiDrawElementsBaseVertex it becomes possible to render multiple sets of indices in one draw call. When using for instance ...
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Find good gl_TessLevel for edge distance and edge length
I have a triangular mesh that is read from an ".obj" file and is to be tessellated with respect to the camera position.
I try to avoid T-junctions by tessellating common edges with the same ...
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is there an universal way to set a uniform?
so I'm working on a game engine.
It's partially python and c++.
One part that is currently a pain point is setting the uniforms for shaders.
Currently I have to define a behavior for all 50+ methods ...
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Is glDeleteBuffers/glGenBuffers needed if I want to resize the buffer?
Firstly the VBO was initialized like below:
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How to scale down noise frequency?
I'm making a space game and so far what I have is a system to generate spheres with noise on them, making them planets. I make a sphere, create noise data, write that data to an image file, and then ...
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My projection matrix for OpenGL fails on non-symmetric boundaries
Assuming my viewing volume has x coordinates varies from l to r, and y varies from top to bottom, and finally z-axis varies n to f, I derived the following projection matrix:
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How is the alpha value treated when blending?
I'm struggling with understanding how blending works. Here's what I understand:
when I set the following
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Can I copy one texture to another perfectly with texelFetch()
Imagine I have two uncompressed, 2D textures A and B with identical sizes and formats. I bind A to texture unit 0, and B to a framebuffer object.
If I draw a full-size polygon in that framebuffer with ...
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Given 2d control points, how to write a vertex shader that evaluates a cubic bezier curve?
I need to write a program that evaluates a cubic bezier curve, using threejs and vertex shader.
I tried to calculate the bezier curve based on the x axis and the control points using the cubic bezier ...
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OpenGL compute local size vs. performance
Does anybody know if using very small local sizes in compute shaders will hurt performance?
eg. If I do this in a shader:
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OpenGL compute for sizes that aren't a multiple of "local_size"
I've been going round in circles trying to understand OpenGL compute shader "work groups" and it's doing my head in. It's all about as clear as mud.
In my compute program I have to set a ...
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Why do I get a black scene in OpenGL in Python?
I'm building a scene: a cylinder, and a torus and an icosahedron spin around it, enter the fog and exit the fog. Using a file with a fog texture (any). However, I get a black scene at the exit - why ...
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Intel UHD extremely slow copy operations
Is there a way to make copy operations such as CopyResurce(d3d11) and glBlitFramebuffer(ogl) on multi-sample resources faster ...
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Why can't I get fog on OpenGL?
I am creating a cylinder, and there is fog around it. I can't handle two things:
the inner surface of the cylinder, realized as a smaller diameter cylinder, actually gives me just a second cylinder ...
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Optimal Command Ordering for CPU/GPU concurrency
I am writing a renderer that uses a deferred clustered shading technique.
On the CPU I group lights, decals, and environment maps into 3 seperate clustered structures (functionally, arrays of unsigned ...
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Having trouble rendering entire sphere
I'm working on a program where I need to draw spheres. The method I'm using is creating an octahedron
And using tessellation shaders to subdivide it into a sphere, however there is a patch of the ...
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How to get back project point cloud from rendered rgbd images by rgbd?
Given a sequence of RGB-D images rendered by blender and the camera parameters for the blender camera(Perspective Projection camera).
How can I back project the RGB images with depth map to a RGB ...
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OpenGL get default depthbuffer
I have an application that uses only the default opengl framebuffer. It is initialized with color and depth buffer.
I want to use the depth buffer as a uniform within a shader to access the current ...
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How does changes in vertex data work?
I have been learning computer graphics and for some time and can't seem to wrap my head around one concept. How to handle vertex data changes?
Ex. 1. I have a text rendering on a screen. And up on ...
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How does Unreal Engine 5's Lumen (most likely) implement reflections?
In this YouTube video, the creator mentions that reflections in Unreal Engine 5's Lumen "work by tracing the path of light as it bounces off of surfaces in the game world." Does this mean ...
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Do GL compute shaders trigger TDR if they crash. Not just timeout?
I'm getting a TDR trigger after 4ms with a GL4.3 compute shader. tdrDelay is currently set to 30 secs, this obviously isn't long enough to get a timeout with the default Windows 11 tdrDelay value let ...
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OpenGL 3.0 is not supported by the OpenGL driver - RizomUV
I have a problem with RizomUV 2022.0. When the program starts, it comes up with pop-up "OpenGL 3.0 is not supported by the OpenGL driver", so I can't import any geometry and work. I'm ...
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What happens when we select lower resolutions on a high-resolution monitor?
I have a monitor with a resolution of 1360x768 (16:9), When I set the resolution to 1280x768 (5:3), 1024x768 (4:3), 800x600 (4:3), even 1920x1080 (16:9) it completely covers the screen and the monitor ...
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Raytracing in OpenGL or Vulkan?
I was looking at this glass ball rendering with an image inside of it (zoom out to see the glass ball), and noticed that it looks like they simulate the refraction of light as it crosses from inside ...
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Which coding strategies exist to handle opengl texture size limit?
I recently hit the roof for maximum texture size for my opengl implementation (GL_MAX_TEXTURE_SIZE contains $3379$) when I wanted to create a texture for a 4k resolution video frame ($3840 \times 2160$...
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Does OpenGL allocate on glBegin/glEnd?
You can enclose arbitrary amount of vertices within glBegin/glEnd statements. Does OpenGL limit the number of vertices you create or it allocates memory for more?
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Query the size of an array of non-basic types using interface query in OpenGL
Consider the following code in an OpenGL shader:
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Opengl binding different mipmap levels of same texture2darray for use in compute shader. How to handle variable nr of levels?
So I want to make a compute shader that uses a coarse-to-fine approach.
As I have learned about open gl mipmap levels it seems they could be very useful.
However the only binding method which I have ...
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Loading Gltf model pbr texture produces insane results
I built a gltf-viewer on my own, but the functionality for loading glf was implemented by referencing gltf-viewer-tutorial, the result is not correct. Below is my ouput for ToyCar.gltf .
The ouput of ...
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How can I test my GLSL code on different hardware?
I've written a game engine in OpenGL and developed it on my computer with an NVidia GTX 1060. I'm now ready to start releasing it into the wild but I'm worried about hardware issues. I compile my ...
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How to properly create textures using DSA for ImageTexture in OpenGL
For the old approach, generating a texture for the ImageTexture for compute shaders would look like this:
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convert right handed matrix into left handed forward/up/right vectors
I have an openGL style matrix (column major, right handed ) that needs to be converted into two vectors (forward and up)
I've managed to find, in a weird way, a solution that matches the the ...
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Best practice for per-vertex updates for mass-spring simulation?
I am new to graphics and physics simulation.
I am trying to perform a mass-spring simulation on CPU on individual vertices inside a mesh, and wondering how to best handle this.
If working with a rigid ...
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Where does the OpenGL driver get the glGet values from?
I know that the OpenGL driver is implemented by hardware vendors, so this questions may not have a consistent answer.
If I use one of the glGet methods, does OpenGL get the information from the GPU or ...
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GLSL trying to bind two different layers from the same texture array as images. Should it work and if so what am I doing wrong?
I am new at this particular site in the SE ecosystem, but not to computer graphics in general. If I'm in the wrong spot feel free to redirect me.
My question regards glsl programming and binding two ...
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Best way for rendering Voronoi diagram from Delaunay graph mesh
I have a set of points, which I triangulate to a Delaunay graph to make a mesh.
Every mesh vertex has a unique colour, and I can render it without any problem. But I want Voronoi rendering to be ...
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Why shouldn't I discard faces during Tessellation control stage
In the discussion Here there was said, that discarding faces during Tessellation stage should be avoided. What are the reasons for that?
Right now, I am rendering a 3D geometry using Vertex, ...
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Why does my uniform only update once?
I have a work thread function which updates the value of a float called scale:
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Why are my OpenGL mipmaps and MSAA bad?
Questions:
Why does the wavy white line on the tennis ball texture seem to be at the wrong mip level, with blocky artifacts ? For example, at 'A' in the picture.
The basketball and football textures ...
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How to instanced and indirect render geometry [OpenGL]
I've a lots of objects, which have the same geometry. Right now I am using instanced rendering to render these objects. This is working very well. But I am trying to increase the performance of the ...
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