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

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4
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1answer
2k views

OpenGL ES 2 shaders for drawing buildings and roads like Google Maps does

I'm trying to create a shader that'll give me an effect similar to what buildings and roads look like on 3D Google Maps. You can see the effect interactively if you enable WebGL at maps.google.com, ...
8
votes
3answers
778 views

What exactly can shaders be used for?

I'm not really a 3D person, and I've only used shaders a little in some Three.js examples, and so far I've got an impression that they are only being used for the graphical part of the equation. ...
5
votes
2answers
2k views

Should the modelview and projection matrices be calculated in the shader or on the CPU?

At minimum I would have a camera with rotation and world position; projections parameters such as angle of view and perspective vs. orthographic; and meshes with scale, angle, and world position. ...
2
votes
1answer
2k views

Drawing simple geometric figures with DrawUserPrimitives?

I'm trying to draw a simple triangle based on an array of vertex. I've been searching for a tutorial and I found a simple example on riemers but I couldn't get it to work. I think it was made for XNA ...
1
vote
1answer
197 views

Blur gets displaced compared to original image

I have implemented a SSAO and I'm using a blur step to smooth it out. The problem is that the blurred texture is slightly displaced compared to the original. I'm blurring using a 4x4 kernel since that ...
2
votes
1answer
652 views

How do you create a cbuffer or global variable that is gpu modifiable?

I'm implementing tonemapping in a pixel shader, for hdr lighting. The vertex shader outputs vertices with colors. I need to find the max color and save it in a global. However when I try and write ...
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 ...
3
votes
1answer
457 views

Complex shading using one single (small) texture

Recently I stumbled upon a demo reel in UDK about how one can attain beautiful results using just one (rather tiny) texture that's being sent to the shader pipeline. The famous link is this one. ...
1
vote
1answer
549 views

OpenGL Tessellation makes point

A little problem with my tessellation shader. I try to implement a simple tessellation shader but it only makes points. Here's my vertex shader : out vec4 ecPosition; out vec3 ecNormal; void ...
1
vote
2answers
252 views

What could cause a pixel shader to paint outside the lines of the vertex shader output?

From what I understand, the pixels that a pixel shader operates on are specified implicitly by the SV_POSITION output (in DirectX) of the vertex shader. What then could cause a pixel shader to render ...
4
votes
1answer
1k views

Bitwise operators in DX9 ps_2_0 shader

I've got the following code in a shader: // v & y are both uints nPixel = v; nPixel << 8; nPixel |= y; and this gives me the following error in compilation: shader.fx(80,10): error ...
8
votes
2answers
697 views

Does use of simple shaders improve performace/battery life?

I'm making OpenGL game for Android. Till now i've used only fixed function pipeline, but i'm rendering simple things. Fixed function pipeline includes a lot of stuff i don't need. So i'm thinking ...
2
votes
1answer
2k views

GLSL compile error when accessing an array with compile-time constant index

I have this shader that works well on my computer (using an ATI HD 5700). I have a loop iterating between two constant values, which is, afaik, acceptable in a glsl shader. I write stuff in two arrays ...
1
vote
1answer
1k views

How can I implement 2D cel shading in XNA?

So I was just wondering on how to give a scene I am rendering a hand drawn look (like say Crayon Physics). I don't really want to preprocess the sprites and was thinking of using a shader. Cel shading ...
9
votes
2answers
971 views

Handle many lights in a scene (with shaders)

I'm curious about how to handle many lights in a scene. Given a very big map in a role playing game, with dungeons (with lights in there) etc. I know about deferred lighting, but that only answers how ...
2
votes
1answer
305 views

Animated light effects in games

I have been wondering now for quite some time, how certain animated texture effects are done, specifically involving light effects. Some good examples of what I mean are the green bridges in ...
4
votes
1answer
695 views

My GLSL shader isn't compiling even though it should. What should I investigate?

I'm porting an iOS game to Android. One of the shaders I'm using wouldn't compile until I reduced the number of uniform variables. Here are the uniform definitions: uniform highp mat4 ...
2
votes
1answer
333 views

Geometry shader questions?

I had some questions on geometry shaders. Do directx geometry shaders offer anything over the opengl ones? What advantages does the official geometry shader implementation on opengl 3.2 have over ...
2
votes
1answer
688 views

Can you store negative numbers with XNA HLSL?

I am trying to make a ripple effect with a HLSL shader, it works so far but I need to output negative numbers and that won't work for the calculations. Is there some way to do this with the ...
10
votes
3answers
2k views

Pixel-perfect rendering to a rendertarget with a fullscreen quad

I have some trouble rendering a bunch of values to a rendertarget. The values never end up in the exact range I want them to. Basically I use a fullscreen quad and a pixel shader to render to my ...
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 ...
1
vote
1answer
150 views

How to mix effects together?

Lets say I have got terrain effect, contains multitexturing, light. Now water effect. It must be different, but must be also affected by light. Other one, player effect, must also be affected by ...
5
votes
2answers
1k views

Detect Mip mapping level in the shader?

Is there a way to do this in pixel shader 2.0/3.0? I've got on or off transparency so when the mipmapping level is different the transparency can take up too much of the texture and make it ...
0
votes
3answers
1k views

Can't render to FBO using a shader

I've added functionality so that I can render to a framebuffer (for post-processing and stuff). I can successfully render to my framebuffer and then render that framebuffer, but anything with a ...
1
vote
2answers
553 views

openGL managing images, VBOs and shaders

I'm working on a game where I use shaders with vertex attributes (so not immediate mode). I'm drawing lots of images and changing the width/height of the quads I use to draw them a lot. To optimize ...
3
votes
2answers
1k views

Optimizing gaussian blur with linear filtering

There's a few (here, and here) gaussian blur tutorials out there suggesting that you can essentially cut the number of texture lookups in a gaussian blur shader in half by exploiting the GPU's ...
2
votes
2answers
2k views

Dealing with 2D pixel shaders and SpriteBatches in XNA 4.0 component-object game engine?

I've got a bit of experience with shaders in general, having implemented a couple, very simple, 3D fragment and vertex shaders in OpenGL/WebGL in the past. Currently, I'm working on a 2D game engine ...
4
votes
1answer
9k views

How do I pass vertex and color positions to OpenGL shaders?

I've been trying to get this to work for the past two days, telling myself I wouldn't ask for help. I think you can see where that got me... I thought I'd try my hand at a little OpenGL, because ...
2
votes
1answer
149 views

How do I read the an environment map CPU side? (Similar to texCube function on GPU)

I need to extract the one pixel from a environment mapping (I already have the 6 textures) using the normal vector. How can I achieve this ? I want something very similar to what texCUBE(link) does ...
5
votes
1answer
3k views

GLSL Editor and Debugger for MacOSX with ES2 support

is there a GLSL editor for the mac? I need it for iOS OpenGLES2 shader. How do you best debug shader? Regards
0
votes
1answer
747 views

Help understand GLSL directional light on iOS (left handed coord system)

I now have changed from GLKBaseEffect to a own shader implementation. I have a shader management, which compiles and applies a shader to the right time and does some shader setup like lights. Please ...
8
votes
2answers
2k views

Billboard rendering without distortion?

I use the standard approach to billboarding within Unity that is OK, but not ideal: transform.LookAt(camera) The problem is that this introduces distortion toward the edges of the viewport, ...
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 ...
0
votes
1answer
324 views

Error X3650 when compiling shader in XNA

I'm attempting to convert the XBDEV.NET Mosaic Shader for use in my XNA project and having trouble. The compiler errors out because of the half globals. At first I tried replacing the globals and ...
1
vote
1answer
2k views

Early Z culling - Ogre

For Ogre experienced people, but also experts in the field: Early Z culling is sometimes quite desirable, and that's what I tried to do in Ogre by using a two pass material. The first one is writing ...
4
votes
1answer
5k views

Simple GLSL example to render a 2d textured quad?

I would really love to add shader support in my game , although i can't seem to find a SIMPLE example on how to setup opengl for using shaders. So i would like to ask : Does anyone knows if there are ...
1
vote
1answer
317 views

Why can't a blendShader sample anything but the current coordinate of the background image?

In Flash, you can set a DisplayObject's blendShader property to a pixel shader (flash.shaders.Shader class). The mechanism is nice, because Flash automatically provides your Shader with two input ...
2
votes
1answer
1k views

Shader optimization - Cg/HLSL pseudo and via multiplication

HLSL/Cg do not allow texture fetching inside conditional blocks. To get around this I am first checking a variable and performing some computations, afterwards I set a float flag to 0.0 or 1.0, ...
41
votes
2answers
5k views

How to render realistic ice?

I am trying to write an ice shader in Unity that looks good and at least semi-realistic. If the following shot (found on Google) was CG, what would its shader include? (the foreground cave). I might ...
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, ...
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 ...
3
votes
1answer
725 views

Shadow-mapping xna

I've been trying to implement shadows in my game and I've been following quite a few tutorials online, mainly Riemers, but I'm always getting the same 2 errors when I'm drawing my models and setting ...
1
vote
0answers
508 views

Unity surf shader not rendering [closed]

I have created a default surface shader in unity and added a texture but it is not rendering. If i switch to a diffuse shader i see the texture but my shader is just black. Shader "TestShader" { ...
1
vote
2answers
1k views

How to achieve this particular screen filter with GLSL?

I know this may be a "short" question, but still here it goes. I would like to know how to achieve a post rendering effect, that looks like the following image from walking dead series: I will ...
0
votes
1answer
895 views

Custom made depth bias (vertex) shader

As most of intermediate graphics programmers know, z-fighting can be a problem. That's why most game engines prevent this from happening by using a slope depth bias algorithm. As there's no direct ...
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 ...
2
votes
0answers
380 views

Normal maps in 3dsMax - OgreMax - how to view associated tangent vectors?

Reading this post I found out that 3dsMax might not use the same tangents when rendering normal mapped objects. In my case, I was using Ogre and OgreMax to analyze results and they were very ...
8
votes
3answers
2k views

Deferred shading - how to combine multiple lights?

I'm starting out with GLSL and I've implemented simple deferred shading that outputs G-buffer with positions, normals and albedo. I've also written a simple point light shader. Now I draw a sphere ...
4
votes
2answers
7k views

Basics of drawing in 2d with OpenGL 3 shaders

I am new to OpenGL 3 and graphics programming, and want to create some basic 2d graphics. I have the following scenario of how I might go about drawing a basic (but general) 2d rectangle. I'm not ...
0
votes
4answers
2k views

Render 3D torus shape entirely in GLSL

I was wondering, is it possible to render a (3D) torus shape entirely in GLSL, i.e. without using vertex/index arrays? Suggestions are welcome, thanks.