a computer program that runs on graphics hardware and provides a high degree of control over how scenes are rendered

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7
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4answers
1k views

glsl demo suggestions?

In a lot of places I interviewed recently, I have been asked many a times if I have worked with shaders. Even though, I have read and understand the pipeline, the answer to that question has been no. ...
7
votes
2answers
3k views

How many OpenGL programs should I use to render multiple objects?

My scene has multiple objects in it. (Let's say 3 cubes, 1 cylinder, 8 spheres.) I assume I should create a vertex shader for each. How many programs should I have? Alternatives: One program per ...
7
votes
1answer
347 views

Should the Oj lobe of a Lafortune shader cause the light to be displaced?

I implemented the Lafortune shader in WebGL, and my biggest concern is about this formula: Explanation Kd/Ks is the material diffuse/specular color, ρd/ρs is the light diffuse/specular ...
7
votes
1answer
4k views

How to invert background pixel's color

I'm writing a game and map editor using Java and jMonkeyEngine. In the map editor, I've got a brush done by wireframed sphere. My problem is: I want to make it visible everywhere, so I want to invert ...
7
votes
4answers
9k views

How do multipass shaders work in OpenGL?

In Direct3D, multipass shaders are simple to use because you can literally define passes within a program. In OpenGL, it seems a bit more complex because it is possible to give a shader program as ...
7
votes
1answer
2k views

How to implement this kind of ripples with a GLSL fragment shader?

So I have already implemented the reflection part: uniform sampler2D texture; uniform vec2 resolution; uniform vec3 overlayColor; void main() { vec2 uv = gl_FragCoord.xy / resolution.xy; if (uv.y ...
7
votes
1answer
1k views

XNA Sprite Flash Effect

I'm looking for a way to render every non-transparent pixel in a sprite solid white (to 'flash' the sprite white when the player takes damage etc). This is on Windows Phone 7. I was using a very ...
7
votes
1answer
2k views

Custom shadow mapping in Unity 3D Free Edition

Since real time hard and soft shadows are Unity 3D Pro only features I thought I will learn Cg programming and create my own shadow mapping shader. But after some digging I found that the shadow ...
7
votes
2answers
823 views

Geometry Shader not generating geometry for some Vertices

I am playing with a geometry shader and I am wondering why it doesn't generate geometry for each vertex in all meshes? I don't think this is a Cull problem because the same vertices generate ...
7
votes
1answer
1k views

Adding a simple mix() destroys the framerate

I have a very simple shader and added linear fog via mix like this: finalColor = mix(finalColor, vec3(0.5, 0.8, 0.95), vUVoutAndViewZ.z); Note that the view Z distance is in the variable that also ...
7
votes
3answers
4k views

Rotating a vector by another vector in shader

I have a terrain surface with a normal for each point on the terrain. I have a second detail normal map to be applied to the terrain. These normals are in 3-space. The Y value of both normals is ...
7
votes
1answer
235 views

Slow uniform array in shader causing FPS drop

I'm trying to use an uniform array of matrices in my compute shader. However, it's really slow. I've narrowed it down to this lines of code: uniform mat4 someMatrixArray[64]; ... vec4 result = ...
6
votes
2answers
763 views

What is this Super Mario shading technique (the edge glow) called?

What is this Super Mario shading technique (the edge glow) called? It can best be seen at the legs.
6
votes
3answers
2k views

What are the big advantages of shaders ? What is doable with them, and what can't be done without them?

I don't really know when vertex and/or pixel shaders became available for consoles and computers, but what could we do without them ? I don't really understand what is achievable with shaders and what ...
6
votes
3answers
7k views

What happened to .fx files in D3D11?

It seems they completely ruined .fx file loading / parsing in D3D11. In D3D9, loading an entire effect file was D3DXCreateEffectFromFile( .. ), and you got a ID3DXEffect9, which had great methods ...
6
votes
1answer
606 views

Changing water color based on depth

I'm looking to make a water shader that colors the water based on its depth. Up until now my water shader that I've used has basically been extremely reflective and only looked somewhat blue because ...
6
votes
1answer
5k views

GLSL if-else statement unexpected behaviour

This question is related to this other one I asked a few days ago. Because I have finally get to the bottom of the issue, I have rather preferred to open a new question with a more detailed ...
6
votes
2answers
121 views

Shading Languages vs Materials in 3D editors

There are many 3d packages which are able to construct materials. Autodesk Maya, 3ds max, Houdini, etc. There are languages which are able to construct materials as well, like GLSL and Cg. How does ...
6
votes
2answers
4k views

Updating texture memory via shader?

What the title says.Is it possible to update a texture via a glsl shader ? Something like : //Read vec4 Pixel = texture2D(TextureID,gl_TexCoord[TextureIndex].st); //Write to texture memory ? vec4 ...
6
votes
4answers
2k views

Spell Effects/Shaders

I want to be able to achieve spell effects that cause a fragmenting/discoloring effect on the sprite. The first couple seconds of this video http://www.youtube.com/watch?v=HNCFh7mkvuc shows what I ...
6
votes
2answers
933 views

Rendering collections of light sources

I have a small test environment where small point lights are scattered. Players should able to collect them. The collectible lights are rendered using a simple billboard technique where two triangles ...
6
votes
3answers
1k views

Is it possible to load shader files from a DLL?

I have a few HLSL files that I'd like to add into a DLL project so that I don't have to keep adding these same shader files into a new Content project every time I want to use them. Is this possible, ...
6
votes
1answer
419 views

OpenGL 2.0 - Texture animation with 'pixelated' effect

I'm looking for a way to reproduce the effect I've tried to sketch in the image below with OpenGL ES 2.0. The idea is to let a drop of color fall over a cube which get filled with a kind of ...
6
votes
1answer
158 views

How can I speed up this HLSL shader?

I have written a lighting shader file that is used as the fragment shader part of a deferred lighting pipeline. Unfortunately, each iteration seems to be adding 0.5ms to my frame time, so any more ...
6
votes
2answers
366 views

Improving the efficiency of my bloom/glow shader

I'm making a neon style game where everything is glowing but the glow I have is kinda small and I want to know if there's an efficient way to increase the size of it other than increasing the pixel ...
6
votes
1answer
722 views

GLSL subroutine not being used

I'm using a gaussian blur fragment shader. In it, I thought it would be concise to include 2 subroutines: one for selecting the horizontal texture coordinate offsets, and another for the vertical ...
6
votes
1answer
473 views

Huge 2d pixelized world

I would like to make a game field in a indie-strategic 2d game to be some a-like this popular picture. So every "pixel"(blocks) changes it's color slowly, sometimes a bright color wave happens, etc, ...
6
votes
3answers
1k views

XNA shader compiler error in release mode

I'm having a hard time figuring out if I'm doing something wrong, or if there is a bug with Visual Studio. I want to pass a float into my pixel shader, clamp it to a value, and then return it as part ...
6
votes
1answer
1k views

Can I use the default depth buffer when drawing to FBO?

How to attach default depth buffer to FBO? How to use depth renderbuffer buffer attached to FBO (after drawing to it) as a default depth buffer? Basically I want to use the same depth buffer for both ...
6
votes
2answers
630 views

What is a good alternative to Unified Shader for Shadows?

Most shadow systems I have seen use a unified shader system for shadowing techniques, resulting in an uber shader for the projects. What alternatives do you find work well or is the unified shader ...
6
votes
2answers
399 views

How can I optimize a parallax effect consisting of multiple transparent layers?

I have a parallax effect in MonoGame consisting of multiple semi-transparent layers of textures. The effect is simple, but rendering multiple transparent layers on top of each other is rather slow. ...
6
votes
1answer
932 views

Partial Shader Signatures HLSL D3D11 C++

I had been debugging a problem I was having in a single shader file with 2 functions in it. I'm using DirectX 11, vs_5_0 and ps_5_0. I have stripped it down to its basic components to understand what ...
6
votes
2answers
3k views

Using a GLSL fragment shader to draw a texture in the middle of a quad

I'm not sure how possible this is, but I'm trying to use a fragment shader to draw a portion of a texture in the middle of a quad. This is all 2D. The quads consist of four vertices from (0, 0) to ...
6
votes
1answer
2k views

How to manage shaders?

I've done some shader programming some time ago but only simple stuff. I'm especially interested in how do you manage shaders? Do you just write one of each kind, or do you need more of them? If so, ...
6
votes
2answers
1k views

Looking for an example of glass with XNA or DirectX 9

Any good pointers on how to get the refractive look of glass? I'm looking to create a think piece of glass type of look, sort of the type that you'd have on bathroom shower doors.
6
votes
1answer
522 views

Performance of pixel shaders vs. SpriteBatch: XNA

Precondition: I read this question/answer about using shaders, or spritebatch, to render and mark a sprite. I need to do something like that. I also have a 2D lighting PoC which I need to write. The ...
6
votes
3answers
1k views

How to handle multiple effect files in XNA

So I'm using ModelMesh and it's built in Effects parameter to draw a mesh with some shaders I'm playing with. I have a simple GUI that lets me change these parameters to my heart's desire. My question ...
6
votes
1answer
198 views

In a shader, why does substituting a variable with the expression producing it cause different behaviour?

I have this correctly-working OpenGL shader producing Perlin noise: float left = lerp(fade(v), downleft, topleft); float right = lerp(fade(v), downright, topright); float result = lerp(fade(u), ...
6
votes
2answers
979 views

Casting a shadow over a whole scene with GLSL in 2D?

I'm making a (non-isometric) side scrolling 2D game and I want each fragment that I draw to cast a small drop shadow when it is near another object. What sort of algorithms are used in fragment ...
6
votes
1answer
3k views

gl_PointCoord always zero

I am trying to draw point sprites in OpenGL with a shader but gl_PointCoord is always zero. Here is my code Setup: //Shader creation..(includes glBindAttribLocation(program, ATTRIB_P, "p");) ...
6
votes
1answer
3k views

Atmospheric Scattering

I'm trying to implement atmospheric scattering based on Sean O`Neil algorithm that was published in GPU Gems 2. But I have some trouble getting the shader to work. I've downloaded sample code of ...
6
votes
1answer
150 views

How is Signed Distance Field Ray Marching implemented for a dynamic world?

I think I understand the basics of Signed Distance Field Ray Marching. You model your scene with a bunch of distance fields (such as these: ...
5
votes
2answers
1k views

Different number of lights => different shader

I have a shader that computes lighting for each light. PointLight PointLights[10]; uniform const float NumPointLights; for(int i = 0; i < NumPointLights; i++) { lightVec = ...
5
votes
2answers
803 views

What does the term 'photorealistic' really mean?

I was wondering about the term 'photorealistic' in regards to rendering and was wondering how this is used. Is it used to describe a shader (or set of) that have certain quantifiable features? Or any ...
5
votes
3answers
773 views

What Shading/Rendering techniques are being used in this image?

My previous question wasn't clear enough. From a rendering point of view what kind of techniques are used in this image as I would like to apply a similar style (I'm using OpenGL if that matters): ...
5
votes
1answer
573 views

What is the point of this hard-coded vector when calculating luminance in glow/bloom effects?

I have looked at two different vertex shaders that calculate luminance and both use a "magic" vector that I'm not sure the meaning of the the actual values. For instance: const mediump vec3 ...
5
votes
1answer
1k views

How is this glowing with colors radiating outward 2D effect accomplished?

I'm currently totally at a loss as to how this effect is done: http://www.youtube.com/watch?v=zp8MHUNp7Cg The glowing on the ship and the changing color. I want to do this effect in XNA 4.0 any ...
5
votes
3answers
895 views

Finding out what pixel on the screen the fragment falls on

In my 2D game, I render tiles. I want to do lighting without needing an extra buffer the size of the screen. Either in glsl or hlsl, what could I feed to the shader each time I render a bitmap so ...
5
votes
1answer
341 views

Where to store shaders

I have an OpenGL renderer which has a Scene member variable. The Scene object can contain N SceneObjects. I use these SceneObjects for storing the vertex position and any transforms. My question is, ...
5
votes
1answer
805 views

What is the maximum number of shaders I can have in OpenGL 4?

What is the maximum limit of shaders I can have on the GPU? With 1000 different objects, I might have 1000 * 5 shaders (vertex, tcs, tes, geo, frag) on the GPU at a time. Though only one will be ...