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Questions tagged [fragment-shader]

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7 votes
1 answer

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

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

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

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

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

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

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

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

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

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 and messed with the code ...
Jonas's user avatar
  • 31
1 vote
0 answers

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

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

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

Veldrid: Only execute fragment shader

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

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

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

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

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

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

I have a pretty basic widget rendering, largely based upon the "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

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