Questions tagged [fragment-shader]
The fragment-shader tag has no usage guidance.
1
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0answers
34 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 ...
2
votes
0answers
59 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 ...
2
votes
0answers
49 views
Show the edges between the clipping plane and clipped objects [closed]
I want to utilize shaders to not only discard fragments if they are on one side of a predefined plane but also render a contour along the intersection.
My fragment shader currently does something ...
2
votes
1answer
43 views
Alpha component in color buffer affects RGB components?
I'm looking for a way to make my surface semitransparent, and for now i ended up using this configuration:
...
2
votes
2answers
57 views
Writing data to a shader resource at runtime in DX12
I'm hoping to port my existing toy raytracer to a window so that I can see samples accumulate over time. And then port over to Pixar's pmj02:
https://graphics.pixar.com/library/...
1
vote
1answer
146 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 ...
1
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0answers
60 views
1
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1answer
180 views
Curve rotation in GLSL fragment shader
I'm trying to figure out the correct math to rotate and translate a curve displayed in a fragment shader.
What I try to accomplish is to define a curve, for example a sine curve, in a local ...
4
votes
1answer
259 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 ...
2
votes
2answers
89 views
Shader cannot move texture x, y location
Crossposted https://forum.openframeworks.cc/t/shader-cannot-move-texture-x-y-location/29395
Hello I am trying to move the x y location of the texture using this code but it doest not work.
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-2
votes
1answer
49 views
gaussFactorForOffset cannot call a non-function how to fixed this code?
Crossposted here http://forum.lwjgl.org/index.php?topic=6724
Hello guys I am trying to blur image using fragment shader but it is not smooth.. I search the internet and I found similar problem... ...
1
vote
1answer
361 views
Is it possible to override or disable blending per pixel
I'm rendering transparent objects in separate framebuffer then compositing it with opaque one to get final image.
The transparent pass has additive blending:
...
6
votes
1answer
365 views
Ray tracing - partial derivatives for texture lookup
I'm doing some ray tracing on GPU using a fragment shader...
How can I calculate texture coordinates partial derivatives with respect to screen coordinates so I could perform filtered texture lookup ...
3
votes
0answers
50 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 ...
4
votes
1answer
264 views
Z buffer working in OpenGL
After Z-Buffer Testing does the fragment shader run on the discarded fragments?
Does the Z-Test happen after the fragment shader runs?
Please, tell me the step by step events that occur in the Z-Test....
7
votes
2answers
3k views
Advice on how to create GLSL 2D soft smoke/cloud shader
I want to recreate this smoke/cloud effect which is used in the Arrival (2016) movie end credits.
I uploaded a sped up version of the credits to see the smoke dynamics.
http://streamable.com/n3309 ...
6
votes
1answer
2k views
Fragment shader's output variables
EDIT: This is a duplicate of a question from stack overflow:
https://stackoverflow.com/questions/9222217/how-does-the-fragment-shader-know-what-variable-to-use-for-the-color-of-a-pixel
If you want to ...
7
votes
0answers
525 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. ...
4
votes
1answer
179 views
OpenGL ES Frag Shader - Branching
Working on optimizing a fragment shader which is slowing down my OpenGL ES 2.0 shader based game. This is used with a shadow buffer to determine if the fragment/pixel is inside a shadow volume.
The ...
5
votes
2answers
118 views
Will the gaussian kernels in this fragment shader be computed for every fragment?
I am running this fragment shader on every pixel on screen. I am trying to make it as efficient as possible. BTW I am running open gl es 2.0.
The code segment below is only a sample from the code, ...
11
votes
1answer
590 views
Using a LUT to speed up a trig heavy shader for mobile devices
I am trying to get this shader to run on a really old iDevice, as well as eventually Androids.
Even when I reduce the code down to 2 sine functions per fragment the shader runs at about 20fps.
I ...
5
votes
1answer
427 views
How to correctly implement Lambertian BRDF with point light
I'm implementing a simple Lamberitan BRDF in GLSL, using a point light source. My fragment shader simply returns light_colour * 1.0/PI * cosine, which should model ...
1
vote
1answer
107 views
How to ensure a fragment shader only runs once
I am trying to programmatically figure out how many "texture2d " calls the gpu can make before the fps drops below 60fps.
My current way of doing this is to have a fragment shader with a for loop ...
1
vote
1answer
353 views
Why does substracting -1 in shader fail for a float data type?
I am loading a texture in a WebGL fragment shader (GLSL version 1.00).
This is my working code:
...
6
votes
2answers
221 views
In a shader, how to store fragment coordinates in a spatial partitioning from one pass to the next?
I have a post-effect camera-shader in which I want to implement a simple spatial partitioning of the screen between two passes of the fragment shader.
The first pass should divide the screen into ...
4
votes
1answer
135 views
Count number of green fragments that are within a given distance from each screen fragment
First of all, let me explain what I am really trying to achieve. In a post-effect shader acting on a camera-renderer, I want to change the color of each fragment depending on how many green (RGBA = 0,...
4
votes
1answer
393 views
Shader won't work
I have managed to implement a garoud shader with specular lighting efects in Processing 3.0 . Now I am trying with a fragment Phong shader but cannot make it work. I can´t find where is the error. It ...
9
votes
1answer
5k views
Why is accessing textures much slower when calculating the texture coordinate in the fragment shader?
When using textures in GLSL, it is best to calculate the final texture coordinates in the vertex shader and hand them over to the fragment shader using varyings. ...
