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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10
votes
1answer
736 views

How do I implement 2D shadows cast between layers?

How could I implement 2d shadows that are cast by objects in a different layer? NOT like the dynamic lighting in the well known tutorial from Catalin Zima : But like the shadows of the pipes in this ...
0
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1answer
345 views

Per-fragment lighting system behaves like ambient lighting system

This is the relevant section of my fragment shader ...
6
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1answer
570 views

Why does writing to a D3DFMT_R32F render target clamp to 1?

I'm currently implementing a picking system. I render some objects in a frame buffer, which has a render target, which has the D3DFMT_R32F format. For each mesh, ...
5
votes
1answer
2k views

Better solution for boolean mixing?

Sorry if this question has been asked in the past, but searching Google and here didn't yield relevant results, so here goes. I'm working on a fragment shader that implements both conditional/boolean ...
1
vote
1answer
3k views

Volumetric Fog Shader - Camera Issue

I am trying to build an infinite fog shader. This fog is applied on a 3D plane. For the moment I have a Z-Depth Fog. And I encounter some issues. As you can see in the screenshot, there are two views. ...
4
votes
1answer
616 views

Fog shader camera problem

I have some difficulties with my vertex-fragment fog shader in Unity. I have a good visual result but the problem is that the gradient is based on the camera's position, it moves as the camera moves. ...
1
vote
2answers
77 views

Defining lines from a heightmap

To a pixel shader of a 2D game, I'm passing a 1-row heightmap that holds the height in UV coordinates of evenly distributed points throughout the texture I'm drawing, but as for n points there will ...
0
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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, ...
2
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1answer
699 views

What is the interval of fragment-shader code execution?

Without any intended delay, is the code of a fragment-shader run once per frame? If not, how often will the code be executed? (I'm new to shaders: I'm talking about glsl if it makes any difference)
3
votes
2answers
405 views

Opengl shader questions

I'm currently building a shader that takes a 2D texture sampler and uses UV coordinates to map it. This works fine for all textured objects. However, I'm having a bit of a problem as I'm trying to ...
2
votes
2answers
844 views

3D Distortion Effect

I'm trying to make a distortion effect similar to this: However I'm not making a 2d screen space effect. I'm applying it to a 3d scene and I want it to be placed IN the world, so it can be blocked ...
8
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1answer
2k views

GL ES: Fragment shader optimization

Summary: I get FPS slowdown as soon as I try to tint the sprites (i.e: multiply texture with color in the fragment shader) Details: Hardware: iPod touch 4 I am drawing 700 sprites on the screen ...
0
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1answer
239 views

Shader registers for different graphics card

The title is not very explicative, so i'll try to make myself clear. I have two "working"(on which i work on) PCs : a desktop that runs an NVIDIA GT440 an a laptop with a RADEON HD 4650. I have a ...
2
votes
1answer
130 views

What is a Fragment Pipe?

I remember someone saying "24 fragment pipes on nVidia 7800" in a presentation. Am I correct in saying that a fragment is the data that can generate a pixel in the frame buffer? Or are fragments the ...
9
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1answer
5k views

Optimizing performance of a heavy fragment shader

I need help optimizing the following set of shaders: Vertex: ...
1
vote
1answer
87 views

I have a frag shader, one with an empty s_lightMap, how and why is it effecting the output?

I have an image of concrete rocks of different shades of colors, and I'm applying this shader, but without referencing s_lightMap's uniform in my program: ...
0
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1answer
231 views

Weird rendering issue when applying lightmap through HLSL

I have a weird issue when trying to render the lightmaps in my game. Please see the following screenshots. Note how the scene looks up close with the lightmaps enabled. Note how that same part of ...
3
votes
2answers
5k 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 ...
1
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1answer
819 views

GL_EXT_shadow_samplers killing my shader

I have the following fragment shader for my scene ...
0
votes
1answer
241 views

How to alter the angle of texture projection

I'm currently working on a 3Dish game; it's on a grid, with 3D props and the camera looking down on the grid at about 45º, but I want to use 2D sprites for the player and NPCs. Currently, I'm using a ...
1
vote
1answer
5k views

How to do Triplanar Texturing

Ok maybe i'm missing something because its getting late and i've been programming now for about 72 hours straight (minus a nap or 2) ... I'm trying to write a shader for unity that will apply ...
1
vote
1answer
712 views

Pixel Shader - apply a mask (XNA)

I'd like to apply a simple few masks to few images. The first mask I'd like to implement is mask like: XXXOOO I mean, that on the right everything is masked (to black), and on the left everything ...
2
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0answers
196 views

Best approach to depth streaming via existing codec [closed]

I'm working on a development system (and game) intended for games set mostly in static third-person views. We produce our scenery by CG and photographic techniques. Our background art is rendered ...
5
votes
1answer
2k 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 ...
0
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1answer
1k views

How to create a fog effect in XNA with PixelShaderFunction?

I developped a small XNA games in 3D. I would like to add a "fog of war" on my models instantiated with an effect in my (.fx) file. The problem is, I do not know how to change the function "...
0
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1answer
529 views

Incorrect colour blending when using a pixel shader with XNA

I'm using XNA 4.0 to create a 2D game and while implementing a layer tinting pixel shader I noticed that when the texture's alpha value is anything between 1 or 0 the end result is different than ...
3
votes
1answer
654 views

Premultiplied Alpha And Alpha Testing

I have a shader that is supposed to work with either alpha blending or alpha testing, but the color values being passed in are premultiplied alpha values. Is there an easy/standard way to have it ...
2
votes
2answers
1k views

How to set multiple times, in a single spritebatch, the same pixel shader parameter

I make a test with Effect class in XNA and I want to set multiple times the same parameters (MyParameter in below code). My code is : ...
9
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3answers
2k views

Outline sprites

I'm currently working on a 2D game, and my current task is to outline selected object. I basically use a blur shader to do it fully runtime. I first draw my sprite using a vertical gaussian blur ...
0
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2answers
377 views

The saturate function is not working in my pixel shader

I wrote a pixel shader for my game and when I tried to compile it an error occurred: ID3DXEffectCompiler::CompileEffect: There was an error compiling expression ...
2
votes
1answer
212 views

Fragments never falling into spot light's cone

I am using GLSL version 1.20 with OpenGL 2.1 . I am trying to compute when a fragment falls into the area of a spot light. I have already set all the light values with glLightfv and glLightf, also ...
3
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1answer
758 views

Per Instance Textures, and Vertex And Pixel Shaders?

How do you implement per instance textures, vertex shaders, and pixel shaders? Given: 1. Two different model templates in Vertex Buffer, Square & Triangle 2. Instance Buffer with [n] instances of ...
0
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2answers
666 views

How to implement input-texture limited alphablending of 2 textures with HLSL?

I try to implement a HLSL shader the does the normal Alphablend with premultiplied colors (just as XNA4 does) but depending on some existing colors. One can think of adding a glow to a 2D terrain ...
7
votes
1answer
4k views

2D Line drawing with Pixel Shaders

Recently I asked a question, what is the fastest way to render 2D lines using DirectX, and one of the answers mentioned this paper on Fast Prefiltered Lines which uses Pixel Shaders to accomplish ...
1
vote
1answer
2k views

XNA HLSL 2D outline shader

I have gotten into quite a bit of trouble getting my rendering correct in my tile based 2D game. This kind of shader is surprisingly annoying to write, I've heard (we used it in one of our 3D games ...
0
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2answers
2k views

HLSL shader optimization [closed]

The following HLSL shader (without preprocessing) results in 65 arithmetic operations (see below). Can the same effect achieved with <=64 operations? ...
2
votes
1answer
2k views

Apply portion of texture atlas

I'm trying to write a shader that only maps a portion of a large texture to my sprite and I'm getting a strange behaviour with my current code. This is what I have right now: Texture atlas ...
2
votes
1answer
2k views

shader coding: calculate screen coordinates of fragment

Good morning, I'm new to shader coding and trying to implement some visual effects code in shaders using billboards. (Yes, I couldn't have picked anything harder to start with, but I'm lucky that way) ...
15
votes
2answers
4k views

Toon/cel shading with variable line width?

I see a few broad approaches out there to doing cel shading: Duplication & enlargement of model with flipped normals (not an option for me) Sobel filter / fragment shader approaches to edge ...
6
votes
1answer
13k views

In HLSL pixel shader , why is SV_POSITION different to other semantics?

In my HLSL pixel shader, SV_POSITION seems to have different values to any other semantic I use. I don't understand why this is. Can you please explain it? For example, I am using a triangle with the ...
4
votes
3answers
752 views

How to read BC4 texture in GLSL?

I'm supposed to receive a texture in BC4 format. In OpenGL, i guess this format is called GL_COMPRESSED_RED_RGTC1. The texture is not really a "texture", more like a data to handle at fragment shader....
22
votes
2answers
11k views

Do I lose/gain performance for discarding pixels even if I don't use depth testing?

When I first searched for discard instruction, I've found experts saying using discard will result in performance drain. They said discarding pixels will break GPU's ability to use zBuffer properly ...
2
votes
1answer
738 views

How to use Pixel Bender (pbj) in ActionScript3 on large Vectors to make fast calculations?

Remember my old question: 2d game view camera zoom, rotation & offset using 'Filter' / 'Shader' processing? I figured I could use a Pixel Bender Shader to do the computation for ...
8
votes
1answer
7k views

How do I use screen-space derivatives to antialias a parametric shape in a pixel shader?

In Valve's Alpha Tested Magnification paper, it mentions using "per-pixel screen-space derivatives" for doing anti-aliasing. My understanding is that this is the ddx...
1
vote
1answer
3k 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 ...
1
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1answer
1k views

2D Mask antialiasing in xna hlsl

I have two texture2d , one of these is a mask texture and have 2kind color and i use that for mask (filter) second texture2D something like ...
0
votes
1answer
485 views

Instancing pixel shader parameters — pass instance data through vertex shader?

I'm working on a deferred shader, and I want to use instancing to draw point lights. From what I understand, I can send the instance data through the vertex shader and pass it through unchanged to ...
1
vote
1answer
1k views

Need to combine a color, mask, and sprite layer in a shader

My task: to display a sprite using different team colors. I have a sprte graphic, part of which has to be displayed as a team color. The color isn't 'flat', i.e. it shades from brighter to darker. I ...
0
votes
1answer
2k views

Multiple render targets and pixel shader outputs terminology

I'm a little confused on the jargon: does Multiple Render Targets (MRT) refer to outputting from a pixel shader to multiple elements in a struct? That is, when one ...
2
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0answers
794 views

How can I apply an overlay effect to a sprite in XNA?

Suppose I have a character sprite and I want to apply some animating effect that overlays its color, how would I do it? What I desire is something along this line: (From final fantasy tactics) It is ...