1
vote
1answer
80 views

GLSL to Cg: why is the effect different?

With reference to this question, where I was trying to make the shader compile, I am now trying to make an effect appear. The effect can be shown here, through a GLSL shader: But when I use the ...
0
votes
1answer
47 views

What coordinates are we passing to pixel shader from vertex shader?

I have read articles about shader programing and understood the very basic knowledge of shader programing. One thing I always get confused is about the texture mapping. What I pass(output) from VS to ...
1
vote
2answers
88 views

Bad pixels on shader when loading cached binary programs

I have been trying to cache binary shader programs in my game and load them accordingly using "glGetProgramBinaryOES" and "glProgramBinaryOES" respectively. I was successfully able to cache and load ...
1
vote
1answer
48 views

Component-wise GLSL vector branching

I'm aware that it usually is a BAD idea to operate separately on GLSL vec's components separately. For example: //use instrinsic functions, they do the calculation on 4 components at a time. float ...
-2
votes
1answer
57 views

List of GLSL ES built-in variables

I am writing an article on WebGL and three.js, I'm trying to search all the built-in variables available in the vertex and fragment shader. I've found many sites mentioning some, for example: ...
0
votes
1answer
135 views

Optimizations using GLSL shaders

I have written a simple OpenGL application using GLSL shaders. Actually, my program just displays a simple cube with a phong lighting effect like below : Here's a peace of the client code : ...
1
vote
1answer
75 views

Gamma Space and Linear Space with Shader

I am using Unity and I can choose between two color space mode in the settings: Gamma or Linear Space. I am trying to build a Custom Lighting Surface shader but I am facing some problems with those ...
1
vote
1answer
128 views

gl_VertexID values when calling glDrawElements

I am struggling a bit to understand the values that gl_VertexID primitive contains when the vertex shader is executed. I have the standard modern rendering pipeline, in which after setting up ...
-1
votes
1answer
64 views

Unity's pack 4 floats

Linked to: GLSL pack floats into an RGBA texture I found EncodeFloatRGBA/DecodeFloatRGBA shader functions in Unity https://gist.github.com/hecomi/9580605 Now I try to figure out how they work. So I ...
0
votes
2answers
274 views

GLSL: can i use matrix transformation functions in vertex shader?

I have a working OpenGL code where i render a terrain with some trees. I am doing all the matrix mathematics on the client side. Because of which the frame rate of my app is very low, around 25-30 ...
1
vote
1answer
110 views

Blinn, Normal maps & Fresnel?

So something came up today when I was going over my Blinn shader. As I've been taught, the half-angle vector is calculated in the fragment shader, and is equal to normalize(lightDir + viewDir). This ...
2
votes
1answer
239 views

Alpha Blending: use the pixel with the smallest alpha

I'm writing a transparency shader where I need any intersecting textures to, wherever they overlap, take the texture pixel with the smallest alpha value and render only that, discarding the other ...
10
votes
2answers
606 views

Refractive glass shader

I have an infinite hexagonal floor, generated by tessellating a point grid in a tessellation shader pair: Note that this is a flat wireframe - the "shadows" are a lighting trick: Now, I'd like ...
2
votes
2answers
134 views

Does GLSL copy function arguments by value?

My question is about passing variables to GLSL shader. I'm not sure how that works and what are the performance implications. Say I got a function that accepts a "vec4" variable. The question is - is ...
1
vote
0answers
212 views

Normal mapping does not work correctly using GLSL and OpenGL

Hello I wrote a simple OpenGl program using GLSL to render a simple uv mapped plane using the normal mapping technics. Here's the display with a simple phong shading (without normal mapping) : Now ...
2
votes
1answer
117 views

How to work with smaller intermediate textures in OpenGL and GLSL?

I'm working on a project rendering water simulated through smoothed-particle hydrodynamics (SPH) with a non-photorealistic look to use in games. In the actual stage of the project everything about ...
0
votes
2answers
175 views

How to mix pixel colors in Shader?

I have a pixel that have a colour RGB. This color is calculated by the shader and can be anything. How can I override this color by a colour I choose. If my pixel is white it's simple, I can do this: ...
9
votes
3answers
643 views

How can I create a glitter effect?

I am trying to create a glittering effect for my realtime shader but I don't know how. Here is one example, and another example. What technique can I use to implement this?
10
votes
1answer
933 views

How do Raymarch shaders work?

I have been looking at shaders found here shadertoy.com and most of the cool ones have noise and raymarch in common. I do not understand the source code at all but I really want to. How do these ...
-1
votes
1answer
196 views

is instanced rendering faster? [closed]

Is instanced rendering used in GLSL faster than doing something like this.. for(int i=0; i<10; i++) { glDrawArrays(GL_POINTS, 0, 3000); } Suppose I want to render 'grass', which is the best ...
0
votes
0answers
31 views

Strauss model : no specular component [duplicate]

I implemented the Strauss model with the metalness, transparency and smoothness parameters, taking the formulas from the book "Programming vertex geometry and pixel shaders", this is how I implemented ...
0
votes
1answer
86 views

How can I avoid applying textures to a fragment in a shader when the surface normal is (0, 1, 0)?

I have a small GLSL shader with a vertex shader and a fragment shader. I want to avoid applying textures to faces that have a normal equal to (0, 1, 0). Is this possible? These are my shaders: ...
1
vote
1answer
138 views

Separate shader programs or branch in shader? [duplicate]

I have a bunch of point lights and directional lights. Instead of checking the light type in the fragment shader and then branch for either point light calculation or directional light calculation, is ...
0
votes
0answers
96 views

How can I compute spotlight attenuation when I only have a spotlight cutoff angle?

I am trying to compute the spot light attenuation, though I don't have a spotCosCutoff (cosine of the spotlight cutoff angle) predefined variable in the shader so I have to compute it myself. This is ...
2
votes
0answers
227 views

Ashikhmin-Shirley model implementation: ugly result

I am trying to implement the Ashikhmin-Shirley model using these formulas: This is the GLSL 1.2 fragment shader code: uniform vec4 materialAmbient, materialDiffuse, materialSpecular; uniform ...
3
votes
2answers
310 views

When is the Z coordinate normalized in GLSL?

I thought that whenever you transform an object to world space, then view space and finally screen space, the last matrix you apply(the projection matrix) normalizes the z values between 0 and 1. ...
2
votes
1answer
279 views

Is this GLSL equivalent to this HLSL?

I was wondering if the both shader codes are equivalent. So the question is, is this GLSL vNormal = mat3(FUSEE_ITMV[0].xyz, FUSEE_ITMV[1].xyz, FUSEE_ITMV[2].xyz) * fuNormal; Equivalent to this ...
1
vote
1answer
144 views

Fragment shader seems to floor() imprecisely

I'm trying to interpolate coordinates in my fragment shader. Unfortunately if close to the upper edge the interpolated value of fVertexInteger seems to be rounded up instead of beeing floored. This ...
1
vote
0answers
158 views

GLSL, Internal error: assembly compile error for fragment shader at offset 513

My vertex and fragment shaders link correctly. When I try and link my shader program I get the error: "Internal error: assembly compile error for fragment shader at offset 513". Pastebin of fragment ...
1
vote
1answer
611 views

GLSL 2d Per Pixel Lighting

First time writing shaders, and having a bit of an issue getting per-pixel lighting to work. The problem is pretty simple, but I'm afraid am doing something wrong here. Vertex Shader: #version 150 ...
1
vote
1answer
210 views

Bump mapping Problem GLSL

I am having a slight problem with my Bump Mapping project. Although everything works OK (at least from what I know) there is a slight mistake somewhere and I get incorrect shading on the brick wall ...
3
votes
1answer
673 views

Shadow mapping does not work correctly using GLSL shaders

I'm a beginner in shadow mapping. I have in my scene two meshes : a cube and a floor. The scene is lighted by a single point light. Here's for the following display the light properties : ...
0
votes
2answers
246 views

HLSL's Tex2D for GLSL?

I am trying to port a HLSL shader to GLSL. I'm just not quite sure how to convert this line: outA += Input.Color.a * tex2D(s, Input.TexCoord.xy + float2(-4.0 * pxSz.x * blurSize,0)).a * 0.05; ...
0
votes
2answers
818 views

Draw wireframe overlay of model in GLSL

I have a 3D model that has a GLSL script, and I want to draw a line on each border of its polygons in the fragment shader. What should I do? Note: I am using Ogre3D, so I can't use OpenGL's ...
3
votes
0answers
360 views

Jet engine exhaust shader [closed]

How would I create a jet engine exhaust effect, as shown in the image from Fzero GX below. GLSL and OpenGL examples/solutions are prefered, though other resources are also welcome. Requirements ...
0
votes
0answers
276 views

Fragment shader not applying intended color to output

I started working with OpenGL recently, having previously worked on mods. I'm using GLFW3, GLEW, and whatever tutorials I can find. So far I've come up with this code: //Headers #include ...
3
votes
2answers
67 views

Local shape color blending

I am trying to implement this in Unity 4 Pro. But I am stuck in the blending part. I don't understand how you could blend multiples textures/colors using multiples volumes on an object. How could you ...
0
votes
1answer
192 views

Creating a fragment shader to darken a white texture over time - OpenGL GLSL

So as a part of learning OpenGL, I've now decided to try and be a bit more creative with shaders, as part of a practice game I'm making using C/OpenGL. I'm completely new when it comes to working ...
3
votes
1answer
218 views

Directional light shader not behaving as expected

I coded my first glsl shader which manage diffuse and specular effects of a directional light. This is the fragment shader. #version 120 //matrix uniform mat4 model_matrix; //directional light ...
7
votes
2answers
4k views

GLSL Shader - Change Hue/Saturation/Brightness

I'm trying to change the hue of an image using a GLSL fragment shader. I want to achieve something similar to Photoshop's Hue/Saturation Adjustment layer. In the following image you can see what I've ...
1
vote
0answers
129 views

Matrix array doesn't seem to get populated

I'm trying to stream an array of matrices to a vertex shader, but it seems that only the first matrix works. What could be the problem? I suspect that I upload the matrices in a wrong way. C# ...
0
votes
1answer
73 views

Vertex and Fragment Shader worldNormal

How to access/calculate worldNormal in a Vertex and Fragment shader ? Thanks a lot !
2
votes
1answer
129 views

Shader Variable Types

I have a simple question. what are the meaning of : half4 myHalf; myHalf.yyyy; myHalf.xxzz; // or myHalf.yw Thanks a lot !
1
vote
1answer
952 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. ...
0
votes
0answers
259 views

GLSL gl_ModelViewMatrix breaks my code?

So I have the following shaders which work (to the extent that they are completed anyway). //Vertex Shader uniform float offset; void main() { gl_TexCoord[0].t = gl_MultiTexCoord0.t; ...
0
votes
1answer
186 views

Shader program compiles fine on Ati, fails on other vendors

Got a real annoying problem here. My shader program compiles fine on my Ati Radeon HD card, but on Nvidia and Intel it failes to compile. Vertex shader: #version 120 attribute vec3 in_position; ...
0
votes
2answers
1k views

What is the best method to update shader uniforms?

What is the most accepted way for keeping a shader's matrices up to date, and why? For example, at the moment I have a Shader class that stores the handles to the GLSL shader program & uniforms. ...
2
votes
1answer
224 views

GLSL Multiple Uniform Structs

I'm developing a lighting system for my voxel game, and I have to send multiple (alot, say up to 200) lights to my shader program. Those lights contain the following data: Position (vec3) Color ...
2
votes
1answer
532 views

Simple Optimized Blur Shader

I have a vertex-fragment shader that use the Unity3D GrabPass functionality (it grabs the screen). And I apply my GrabPass to have a transparent effect. GrabPass { "_GrabTex" } sampler2D ...
2
votes
1answer
148 views

OpenGL Calculate Matrices

Im trying to switch from the glTranslate etc to my own Matrices, but for some reason it does not work. Here are my 2 functions to create the view- and projection matrix: public Matrix4f ...