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

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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 this: vec2 uv = fragCoord.xy / ...
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1answer
43 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: uniform sampler2D fbo_texture; uniform float offset; ...
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2answers
3k views

cocos2dx - Custom Fragment Shader and CCRenderTexture

I have a CCRenderTexture that is filled with a sprite when the scene is loaded, as follows, canvas = CCRenderTexture::create(this->getContentSize().width, this->getContentSize().height); ...
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1answer
518 views

GL_EXT_shadow_samplers killing my shader

I have the following fragment shader for my scene #extension GL_EXT_shadow_samplers : require ... vec4 color = texture2D(uTextureUnit0, varTexCoord0); if (colorTransformEnabled != 0) { vec3 ...
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44 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
57 views

How to 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 commands: ...
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3answers
50 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 shader. Is there any way of forcing them ...
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1answer
2k views

Two pass blur shader using libgdx tile map renderer

I am trying to apply the following technique: blur effect using two pass shader to my libgdx game using the OrthogonalTiledMapRenderer. The idea is to blur the background wich is also a tilemap but ...
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86 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
32 views

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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72 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: vec3 scene_normal(vec3 p) { vec3 e = vec3(0.001, 0.0, ...
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31 views

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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60 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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41 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 you can see, the limitations ...
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1answer
1k views

Pixel Shader, YUV-RGB Conversion failing

I am tasked with playing back a video hthat comes in in a YUV format as an overlay in a larger game. I am not a specialist in Direct3d, so I am struggling. I managed to get a shader working and am ...
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1answer
211 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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2answers
148 views

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
145 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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21 views

In HLSL pixel shader, why am I getting [-256.0, 256.0] values in SV_POSITION input?

My question is basically in my DirectX11 pixel shader, why am I getting a range of values from -256.0 to 256.0 in the SV_POSITION input instead of the supposed values from 0.0 to ViewportWidth and 0.0 ...
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68 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
58 views

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: Texture2D NormalGB : register(t0); Texture2D ...
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1answer
366 views

Why i can not load a simple pixel shader effect (. fx) file in xna?

I just want to load a simple *.fx file into my project to make a (pixel shader) effect. But whenever I try to compile my project, I get the following error in visual studio Error List: Errors ...
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48 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: tex2D(TextureHeightSampler, ...
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58 views

Shader to mask image with polygon

I'm new to graphics programming and GLSL in particular. I'm working on a 2D game and the setup is as follows: There is an image on the screen (a sprite in the game engine [Cocos2d-x if it matters]) ...
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1answer
290 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
155 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 ...
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1answer
229 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 ...
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73 views

DirectX My texture does work in my pixelshader

I got a bit of a mystery as I have a problem that should not be a problem. I am working on a fog feature which is similar to other things that I have done. Not very hard at all. The only real ...
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1answer
102 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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92 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: // Include standard headers ...
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1answer
67 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: typedef struct SPos { float x; float y; } SPos; SPos mVertices[6]; SPos mIndicies[6]; GLuint mVao; GLuint ...
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2answers
172 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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52 views

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 frustum. Is there any way I can get a ...
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61 views

OpenGL not rendering to correct target

I have a fbo, with 8 textures in it (g-buffer). What I'm trying to do, is to render all information from opaque objects to first four(color, normal, position, depth), and info from transparent objects ...
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19 views

How to set up lights in Libqglviewer?

I decided to use Libqglviewer and the simple camera example to have a basic camera setup and play with fragment shading. I have not much experience in OpenGL but I have made my way through it. I have ...
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1answer
176 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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115 views

How can I modify my procedural shadows to also show some of the walls?

I'm rendering shadows in Libgdx with the method from this tutorial. I think it's a nice and easy method. I render all my shadows in a framebuffer, then invert it. Before invert: After Invert: ...
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1answer
71 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 involved since I am just using it as a look-up table.
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1answer
206 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 ...
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2answers
1k views

Realtime fisheye to cubic or spherical panorama transformations with OpenGL or pixelshaders

I'd like to transform a sequence of circular fisheye-images to cubic or spherical panorama images to be used in a panorama-viewer based on OpenGL. The viewer-part is nemas problemas but the transform ...
4
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2answers
2k views

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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1answer
281 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 rgb_color(u1, ...
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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
101 views

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 ...
4
votes
1answer
808 views

How do I achieve supersampling / anti-aliasing in pixel shaders?

I am trying to write a couple pixel shaders to apply to images similar to Photoshop effects. For example this effect: But I noticed there is aliasing in my resulting image (the above image is a ...
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2answers
307 views

Water silhouette shader using GLSL

I have this problem to solve using Cocos2d-x 3.x: In my game there is water represented by rectangle texture, modified by the code on the go. I also have a character moving around, rotating etc. I ...
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1answer
647 views

Can't sample texture in HLSL using DX11

Environment: Windows 7 x64 Visual Studo 2012 DirextX11 HLSL Shader Model 5 Ogre 1.9 Okay, so I'm trying to sample a texture in my pixel shader but I'm coming across some strange problems. Here's ...
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294 views

OpenGL shading doesn't work with different projection and view matrices?

I found an online (public-domain) code to do marching cubes, and I am trying to adapt this code to work in my own project. The code uses GLUT and "older-style" OpenGL, whereas I am using GLM and ...
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1answer
169 views

How to fix this existing shadow shader/material with alpha textures?

I hope I could get some help here in finally resolving this problem of mine re: shadow casting with alpha textures. Here's a screenshot on what I am hoping for as a result: A friend of mine just ...
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2answers
16k views

GLSL - one-pass gaussian blur

It is possible to implement fragment shader to do one-pass gaussian blur? I have found lot of implementation of two-pass blur (gaussian and box blur): ...