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Questions tagged [fragment-shader]

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7 votes
1 answer
708 views

How to match Blenders polynomial lens distortion model with GLSL?

I'm trying to re-implement Blenders (libmv) polynomial lens distortion model using shadertoy, in order to apply the lens distortion in another application ideally by generating a STMap for that. I ...
brockmann's user avatar
6 votes
0 answers
1k views

OpenGL texelFetch causes black stripes

THE SHORT VERSION In my fragment shader I'm reading (using texelFetch) multiple times the same texel from a texture (created by another fragment shader) and write it to the output render buffer. ...
Christian_B's user avatar
5 votes
1 answer
2k views

Manually fetching 8 neighboring texels from 3D texture greatly decreases performance

I'm implementing manual interpolation between texels in a 3D texture to be able to discard some of them when needed. Compared to hardware interpolation, this process takes a lot of time. If I simply ...
Pavlo Muratov's user avatar
3 votes
0 answers
84 views

Trying to optimize texture mapping

We are developing a PPI plot for a radar system, similar to the following: NOTE: 1 radial is defined as a single slice of data within the circle, and 1 range gate is defined as a single point along a ...
Matthew Herndon's user avatar
2 votes
0 answers
363 views

Calculate the distance between two 3d points in screen coordinates

Given the Point A with the coordinates gl_FragCoord.xy, I have to find the distance to the Center of the cube face to which it belongs in screen coordinates. ...
keepyourweb's user avatar
2 votes
0 answers
129 views

How can I draw a line whose position is given in UV space and its width in screen space?

In a fragment shader, I need to draw a line at a given value of u. The shader is applied to a planar polygon mesh that's being drawn in the scene with a perspective camera. (It isn't a full-screen ...
Dan Hulme's user avatar
  • 6,840
1 vote
0 answers
43 views

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 ...
Simon's user avatar
  • 183
1 vote
0 answers
26 views

How can I see the whole shader's text content, with all the prepended code by Three.js, when using ShaderMaterial or RawShaderMaterial (r148)?

I know that Three.js prepends the shader text you provide with some code that includes definitions etc. I am not a big fan of "magic" and I would like to be able to see the final text ...
mkole's user avatar
  • 115
1 vote
1 answer
313 views

Undo barycentric interpolation

How do I undo the interpolation of vertex attributes? I'm using unity shader graph which doesn't support nointerpolation. I assume I need to store 3 float3 with one component of each float3 being 1 ...
Shiv-iwnl's user avatar
1 vote
0 answers
217 views

What are the main concepts behind building the plasma effect with GSLS?

By the plasma effect I mean an animation that looks like this: I have seen some codes, like these https://www.shadertoy.com/view/Xst3zN https://www.shadertoy.com/view/4tdGWX and messed with the code ...
Jonas's user avatar
  • 31
1 vote
0 answers
379 views

How could I remove this colour interpolation artefact across a quad?

I've been reading up on a vulkan tutorial online, here: https://vulkan-tutorial.com. This question should apply to any 3D rendering API however. In this lesson https://vulkan-tutorial.com/...
FShrike's user avatar
  • 205
1 vote
0 answers
63 views

Anti aliasing thin features in textures

Assume I have a texture with a repeating line pattern. The lines are exactly 2 texels wide (really thin). Ans very spaced out (50 texels in between each line). I am now struggling with the ...
Makogan's user avatar
  • 1,726
1 vote
0 answers
170 views

Veldrid: Only execute fragment shader

Having an HLSL shader like this: ...
Tau's user avatar
  • 121
0 votes
0 answers
56 views

Pixilate/Quantize UV coordinates in world space?

The effect I'm trying to achieve is to have it so that the texture is pixilated/quantized, but the "grid," stays aligned to world coordinates even as the object with it's own UV coordinates ...
zachThePerson's user avatar
0 votes
0 answers
47 views

How to interpolate alpha from CURRENT_ALPHA to TARGET_ALPHA for each pixel in shader language? (Godot/GLSL)

I want to make "trails" of objects on my shader that appear and disappear gradually. I am getting pixels (for fragment shader) where objects are from uniform texture. Basically, I have my ...
idchlife's user avatar
  • 373
0 votes
2 answers
221 views

Storing array of floats within shader

I am about to implement a framerate histogramm chart for a DirectX Renderer. Ideally I would do this in pure shader code, but for a a histogramm I need to store the timestamps of the last ...
user20154's user avatar
0 votes
0 answers
121 views

Examples of cases where you write depth value in Fragment Shader?

I've very less knowledge when it comes to rasterization and typical rendering in games and other applications. So I was reading up on the rendering pipeline and found that the hardware could do early ...
gallickgunner's user avatar
0 votes
0 answers
23 views

Rendering different array types in the same vertex/fragment shader?

I have a pretty basic widget rendering, largely based upon the learnopengl.com "hello triangle." I'm actually using a tristrip to create two triangles, forming a semi-opaque square over the ...
Sniggerfardimungus's user avatar
0 votes
0 answers
107 views

GPU accelerated 2D graphics library with signed distance functions

I want to create my own 2D graphics library using signed distance functions where everything is drawn on the GPU. Browsing the web I quickly found Inigo Quilez website that describes how to draw basic ...
Nils's user avatar
  • 101