Questions tagged [fragment-shader]

A program that runs on the GPU to determine output colors for pixels. Also known as a fragment shader.

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How can I use an HLSL pixel shader to peek at other pixels?

I think this is like a pixilation shader but I had a hard time trying to find one online, and one that I could manipulate specifically. I want to create a pixel shader for my monogame project that ...
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1answer
651 views

GLSL - Only draw arond point / flashlight effect

I'm currently trying to achieve a sort of flashlight effect in GLSL. I only want to draw textures within a certain distance of a specified point (the mouse position, for example). Here's a quick ...
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48 views

Choosing between multiple shaders based on uniform variable

I want to choose from 2 fragment shaders based on the value of an uniform variable. I want to know how to do that. I have onSurfaceCreated function which does compile and link to create program1 and ...
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1answer
159 views

Luminance 'y' value of surface texture

For my opengl video player app, I am using surface texture bound to GL_TEXTURE_EXTERNAL_OES source : https://github.com/crossle/MediaPlayerSurface/blob/master/src/me/crossle/demo/surfacetexture/...
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1answer
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Schlick Fresnel Shader

I hope you are all doing ok. I have an issue with my Fresnel shader that doesn't allow the Fresnel to change as my camera moves around. I'm not sure what i'm doing wrong. I'm using glsl with the ...
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2answers
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How do I draw individual pixels in the distance?

Hello everyone I am working with unity3d and I am faced with a task. I have a list of 3D points and I want to draw a pixel for every point on the list that exists after my cameras frustums far-plane. ...
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1answer
135 views

Super formula on shader

I'm using Shader-toy to experiment and try to learn a bit the shader science. As exercise I wan to replicate some of the wikipedia math plots. I've started with a Super Formula. What I want to ...
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1answer
810 views

Fragment shader, tint color problem

I am new to shaders, and I am trying to tint a texture to mark status of a enemy. I am implementing shaders on OpenGL ES 2.0 (Mobile) The problem is that with this shaders, I see the enemy without ...
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1answer
132 views

FXAA Parameter Confusion

I have a question about the popular FXAA shaders that are out there written using HLSL or GLSL, and they all mainly feature these three parameters: ...
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Create overlapping transparent images [duplicate]

I want to achieve this effect in the image. To make this I don't think a single pass to a stencil buffer would be enough because stencil buffers can't mask out the actual alpha inside of the ...
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145 views

Shader - Directional Lights Depth

Is there a way to retrieve the deph from directional lights ? I can access the _ShadowMapTexture but this is not the depth. I found how to access the shadow map of, I think, every light type by using ...
2
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1answer
329 views

Libgdx - GLSL shader which uses mod doesn't seem to work properly on android

Through trial and error I've managed to come up with a scanline-ish shader I'm satisfied with. On my desktop testbed it looks like this: Basically, every 2nd(vertical) pixel is darkened. However, ...
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807 views

Unity - reconstruct position from depth

I am using Unity and I want to reconstruct position from depth and frustum corners in pixel shader. I am doing this: In my App, I calculate view-space corners of the far frustum plane and pass them ...
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1answer
385 views

Getting rid of texture bleeding

Edit: I figured out what problem I was facing, it's called Texture/Pixel bleeding, which I was not aware of yet. I posted an answer below consisting of a small description of the problem and a link to ...
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3answers
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Is there a way to get what pixel is being processed within the fragment shader?

In OpenGL, a fragment shader goes through each pixel, right? So is it possible (within the shader itself) to get what pixel it is processing and color each specific pixel?
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1answer
41 views

Is it necessary to use texture filtering if I use texture coordinate system?

I have one question about using texture filtering. It's clear when I used normalized texuture coordinates (in any API) for example from (0,0) to (1,1) it is necessary to use texture filtering because ...
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3answers
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How do I write a shader that lights up when objects are near a surface?

In this Overwatch gameplay video, the character's shield lights up white in areas that are near other objects' geometry. Note the white edges on the blue shield, near the floor, walls and pillar. I ...
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1answer
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Pixelation shader explanation?

I was looking for a pixelation shader for my postprocessing and came across this shader snippet - Works pretty well! - Not a whole lot of explanations on how it works except for "Pixelation is process ...
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1answer
2k views

Shadertoy getting help moving to glsl

I spent some time writing a shader on shadertoy but now, when I try to translate my code to opengl I don't know how to calculate the uv that they describe as like ...
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1answer
519 views

Underwater Shader Animation Help

I found an underwater (distort) effect and I got it to work but somehow I cannot make it animate given the offset here: Fragment Shader code: ...
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2answers
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How do I wrap textures inside shader GLSL?

I'm trying out GLSL and one of the problems I'm facing is wrapping a random texture sampler in the shader. Searching for answers on the web first, this leads me to using these: glTexParameter() ...
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3answers
2k views

OpenGL, GLSL, Modify Background Fill via Fragment Shader

I have noticed that fragments rendered by the glClearColor() method do not pass through shaders. However, I'd like to modify these fragments using my fragment ...
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1answer
2k views

equirectangular panorama rendering?

I want to render my scenes as equirectangular panorama frames. I can get the angular fisheye which is what I actually need by applying the rendered frame as a texture to a correctly UV mapped circle. ...
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1answer
588 views

How to pass a big (60+) amount of variables to an HLSL pixel shader?

I am in trouble at trying to pass a big amount of variables needed for my pixel shader computations. After trying and failing to link my struct to a cbuffer (data alignement mismatch) I tried passing ...
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1answer
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Stencil buffer VS conditional discard in fragment shader

I have a continuous height-mapped mesh to represent landscape. I also have 1 to let's say 10 wells on this landscape represented by additional models. What I want to achieve is to create an illusion ...
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138 views

Raymarching tangents

I've recently started to experiment with raymarching over on shadertoy.com. It seems common to find the normal for a distance field like so: ...
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How do I sample a cubic shadow map in DirectX 11?

I've implemented a cubic shadow map for dealing with omni-directional light sources in my scene. By defualt it produces hard shadows Obviously a shadow map with higher resolution (currently using ...
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1answer
752 views

Unity: cg fragment shader processing array of points

I need to write a fragment shader which would somehow be aware of N points that are in the scene and darken pixels based on their world coord distance to the points. I'm looking for a method that ...
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0answers
299 views

Issues with 2D raycasting lighting under limitations of HLSL 3.0 pixel shader

I've been writing my own HLSL pixel shader for dynamic lighting using raycasting. Unfortunately, since I'm using this out of XNA, I can only use up to ps_3_0. As ...
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2answers
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Best way of writing pixel manipuliting-intensive applications with OpenGL/Direct3D

Recently I have been making little experiments with engines similar to old Wolfenstein 3D, Doom and Build, engines where the 3D rendering is entirely done in software and therefore you need full ...
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1answer
832 views

2D day night mapping

I'm looking for this kind of effect MINUS the lights and snow (Another problem). It needs to change depending on the time of year. Doesn't need snow or city lights. Now I'm pretty new to shaders (...
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1answer
1k views

how change branching logic to math equivalent glsl? [closed]

im totally newbie and this just for fun afaik lot of best practice suggest to minimize usage of branching. can you help me optimize below glsl especially on branch part? ( target 120 ) the bgcolor ...
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1answer
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Sample() returns (0, 0, 0) for normal map 90% of frames

I'm having some trouble reading the values from my Normal map in my lighting fragment shader. The relevant part of the shader code is as follows: ...
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234 views

How to sample png heightmap in HLSL

I am working on simple parallax shader and I have problem with sampling height texture for value. My aproach amples texture and give me RGB values of picture: ...
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1answer
2k views

Tile Map Shader?

I'm trying to write a shader in unity that will take tiles from a sprite sheet and draw them onto a tile map. I'm new to shaders so this might be totally wrong, I think it might just be a math error ...
3
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1answer
4k views

How to generate a RGB * a texture for a glow effect in GLSL?

I would like to create a glow effect in GLSL, there is a tutorial that explains how we multiply RGB * a : I have some questions : is it an operation that is in a fragment shader, where RGBa is ...
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1answer
3k views

How to use a buffer in GLSL to do a LUT-lookup?

I am currently on a medical application which needs different kinds (up to totally individual) lookup tables (LUT) for image display. And this done with 10bit finish. So it is most of the time ...
3
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1answer
1k views

Calling Shader Functions Inside Other Shaders

I'm new to OpenGL and GLSL, and bit confused about calling conventions of shader functions. I'm trying to implement various procedural noise algorithms in GLSL. I'd like to have separate files for ...
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503 views

opengl shaders getting started problem

I'm following this tutorial for shading in opengl. However I wanted to start with another shader to make things more interesting So this gives me the following code: ...
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1answer
133 views

How to combine VAO and shader language?

I'm new and trying to draw a very simple quad with VAO and GLSL. My definitions: ...
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3answers
3k views

How to prevent intepolated texture in fragment shader (Unity CG)

Think about minecraft - all the textures in minecraft have a very nice crisp pixelated look. Well, I'm trying to write a shader that will do this but it appears "sampler2d" returns some sort of ...
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0answers
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Trying to get the fragment shader to output a list

I am trying to figure out a way to get the Fragment Shader to output a list of gl_VertexID-s. I want to use the GPU to get a list of vertices in the viewing ...
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1answer
562 views

Fragment Shader output type error

StackExchange! I've been working with opengl for a bit and I'm trying to finally load the shaders instead of having them inline. I'm having a ton of issues, though. As soon as I solve one, another ...
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1answer
151 views

Is it possible to look up a texel from a texture in GLES2 GLSL framgent shader without using sampler?

Is there some way I can directly access texture memory from fragment shader in GLES2 GLSL? I don't need the sampler to be ...
3
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1answer
571 views

Shadow mapping. I don't understand what to do after creating the depth texture

I'm taking an intro to computer graphics course, so this is something we haven't touched on. I am reading this tutorial http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-16-shadow-...
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2answers
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How to implement color changing fragment shader?

I have a background of a given size and filled with a given color. I want to change it with an animation effect, starting from the center and spread out until it extends the whole background. The new ...
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2answers
2k views

3D position of an arbitrary UV coordinate

I have a UV map for a 3D mesh that encodes "links" between pairs of UV coordinates. I have previously defined this links (or pairs), one to one. The links are enconded using the function ...
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1answer
866 views

2D RGBA texture is gray in GLSL shader

I have a shader to perform LUT coloring of a texture and a c++/c# programs that call it which work perfectly when i use a 1D texture. Since i need to support computers that don't support the 1D ...
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3answers
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Why is H (blinn) used instead of R (phong) in specular shading?

I can't find a good reason for this anywhere. The reflection vector used in phong has a simple basis in physics. But the half vector used in blinn seemingly has no rational basis, and does not ...
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2answers
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Best way to detect if vec3 is between vec3(x) and vec3(y) in glsl

As titled I am sampling from a texture and if the color is somehow gray [vec3(.8), vec3(.9)] and an uniform is 1 I need to substitute that color with another one I am not a glsl veteran but I am ...