A programming language for OpenGL shaders.

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50 views

ETC1 texture opacity

I'm using the cocos2d-x engine and want to support etc1 on android devices for my game. For ETC1 i'm using the mali compression tool, and GLSL. Everything is working, but I can't change the opacity ...
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0answers
45 views

GLSL lighting shader with model scale

Basically, i'm just trying to find out where to insert the model scale into the lighting calculations. Ive searched the web, but amazingly, couldn't find anything dealing with scale + GLSL. This is ...
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2answers
259 views

GLSL Fragment shader lighting lambert term

Just a simple question: Should I or should i not normalize the SurfaceToLight vector to calculate the lambert term on a GLSL lighting shader? I mean, here: vec3 CalculateLights ( void ) { vec3 ...
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1answer
265 views

ETC1 Support on android alpha problem (GLSL cocos2d-x)

I want to support etc1 in my game, but somehow it doesn't work (I'm using cocos2d-x C++ GLProgram* glp = new GLProgram(); glp->initWithVertexShaderFilename("testv.vsh", "test.fsh"); glp->...
2
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1answer
216 views

GLSL 330 Core Bug? - Uniform variable will not set to value if it is named a certain way

In the code below I have a uniform variable named "vw_matrix" used in the calculation for gl_Position. When I run my program, a rectangle gets printed to the screen. #version 330 core layout (...
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0answers
175 views

Texturing Objects in OpenGL

Using OpenGL tutorials found here, I constructed an .obj file loader as well as a texture file loader using SOIL. I have an issue with drawing a textured object. (Shown here) Assuming I created the ...
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1answer
143 views

How can I blend up to 3 textures on a polygon without blend maps?

For my voxel game I need to blend up to 3 textures in the same polygon. It would be preferable if I could specify a texture id for each vertex, but other solutions are accepted as well. Here's an ...
3
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1answer
6k views

How to compute tangent and bitangent vectors

I have a texture loaded in three.js, then passed to the shaders. In the vertex shader I compute the normal, and I save into a variable the uv vector. <script id="vertexShader" type="x-shader/x-...
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1answer
185 views

Error drawing two VAO, each one using different shader programs (vertex + fragment shader) in OpenGL Core 4.3 / GLSL 430 (SOLVED)

I am trying to draw over a GL_TRIANGLE_FAN one texture to render video frames, using shaderProgram1, and render above it some points (GL_POINTS) using shaderProgram2. By this way: (OpenGL Core 4.3) ...
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2answers
112 views

Problems with Rotation Matrices on Certain Axes

Here is what my rotation matrix looks like: public Matrix4f initRotation(float x, float y, float z) { Matrix4f rx = new Matrix4f(); Matrix4f ry = new Matrix4f(); Matrix4f rz = new ...
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1answer
191 views

WebGL half float equivelant?

I'm trying to find a half float for the purposes of doing math in a fragment shader, not trying to have a half float texture. Is there an equivalent of the half float data type in WebGL? I know you ...
3
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1answer
285 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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1answer
83 views

How to only render fragments with Z from 0 to 1 in OpenGL?

I have been using OpenGL for a year now, but I just recently found out that OpenGL only clips vertices when the absolute value of the x,y or z coordinate is less than the absolute value of w ...
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1answer
97 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 ...
0
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1answer
140 views

Can glsl main() have params or return a value?

I haven't ever seen anyone declare main as anything but void main() or void main(void) but I'm curious, is it possible to have a parameter or return value?
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1answer
126 views

Shader - Color blending

I would like to know how to blend colors in a specific way. Let's imagine that I have a color (A) and an other color (B). I would like to blend them in such a way that if I choose white for the (B) ...
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1answer
59 views

Modern OpenGL Texture Displaying Incorrectly [closed]

I've been working with this code and have simplified it to the most basic form possible, and even then I cannot get a texture to display properly at all. Here is the code: http://pastebin.com/...
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1answer
105 views

Shader - Convert vector into scalar

I am trying to convert a half3 as a simple half but I am facing an issue. As for an example half3(1, 0, 0) give me white but half3(0, 1, 0) gives me black. How can I convert properly a half3 to a ...
2
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1answer
4k views

How to achieve anisotropic filtering

I am loading a texture and using glGenerateMipmap() on it to achieve some level of mipmaping. I get different result on nVidia gt 555m, and on Intel HD 3000. The texture rendered by nVidia is not ...
3
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1answer
1k 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 ...
3
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2answers
220 views

Blending vs Texture Sampling

I don't think this question has been asked before as I couldn't find any information about this on the internet. Lets say I want to blend two textures together: A texture containing the result of ...
2
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2answers
155 views

Rectangular area light illuminance - colour banding

I'm currently working on an implementation of rectangular area lights but I am having some issues with the illuminance calculation, which gives me serious colour banding across the entire lit area. I'...
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0answers
133 views

Is Phong shading supposed to be so camera-angle dependent?

I'm not sure if I have a bug in my code or not. It seems like it's a bug, or at least a major shortfall. Here's two images of the same model at slightly different angles (by moving the camera): As ...
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0answers
378 views

Confused About My Code Suggesting The Normal Matrix Is Equivalent To The ModelView Matrix

I'm learning environment mapping in OpenGL by following this page. In his vertex shader, the author calculates the vertex normal in eye space with the following code: nEye = vec3(viewMatrix * ...
2
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1answer
2k views

2D water shader in SFML

I want to implement the algorithm for a 2D water surface described here and here. Before somebody finds out, beats me up and deletes this, I'm gonna say it myself. I posted this question over at ...
3
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0answers
114 views

OpenGL Planet Generation - Simple Matrix Issue (Planet “Spins” With Mouse)

I originally asked this question on StackOverflow & was directed here by a commenter. Im currently working on a OpenGL planet rendering. I'm using the Tessellation pipeline. So far things are ...
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3answers
552 views

Combine flat and smooth shading with a single model geometry

I need to be able to switch between smooth and flat shading interactively. Is there a way to do this efficiently with a single geometry? For example, smooth shading does not require duplicate ...
4
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1answer
453 views

Skybox rendering

I am sorry if this is trivial, but I got into OpenGL just very very recently. I am trying to render skybox (with cubemaps) and this is what I have done: Created a VBO with vertices positions (36 ...
3
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1answer
348 views

What are the advantages of tangent space shading/lighting, and what about attenuation?

In several topics here it was suggested by people that doing lighting in tangent space is better than doing it in world space. Right now I am doing it in camera space, but it's really similar to world ...
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1answer
691 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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1answer
246 views

How to optimize my lighting shader?

I want to create a lighting effect on a gray-scaled world using cocos2d-x. What I've done is creating a layer which runs a shader program that receives light positions and radiuses as input and ...
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0answers
34 views

converting HSLS gives error

I'm using the following parser: https://github.com/unknownworlds/hlslparser I also have the following code: /* * Bo Sun, Columbia University, All rights reserved * --------------------------------...
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1answer
312 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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1answer
322 views

Dot based light mask with shader on sprites

So I have a scene, completely based on 2D sprites. I want to render "light sources" into a seperate frame buffer (so mostly dots around, for example, the centre of a flame) and then render that frame ...
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0answers
150 views

Invalid operation (1282) in GLSL vertex shader

My GLSL vertex shader works fine, but you if put a for loop inside or rename the uniform xxx to something else, it says the follwoing: Exception in thread "main" org.lwjgl.opengl.OpenGLException: ...
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0answers
38 views

Strange result, when changing variable name

I have no idea, what is going on. The mat4 xxx is the cause. Renaming it to "bones"/"bone_transfromations" etc. won't work it gives me an error. Renaming it to "test" works perfectly fine... This is ...
0
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1answer
432 views

why is glVertexAttribDivisor crashing?

I am trying to render some trees with instancing. This is rather weird, but before sleeping yesterday night, I checked the code, and it was in a running state, when I got up this morning, it is ...
4
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0answers
269 views

How much is atomicAdd slower than an atomic counter?

I am considering replacing an atomic counter in my shader code with a SSBO an atomicAdd operation. What I need to know is the difference in performance of these two. I know the atomic counter executes ...
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2answers
464 views

glsl uniform int as index of const array

I have a const array that define a few materials for directionnal light. I'd like to change the material using an uniform int as index of that array. Doing that leads to severe framerate drop. I know ...
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1answer
205 views

Can drawing to an FBO be done purely with a depth input texture, or do I also need a color attachment?

I am trying to implement Exponential Shadow Maps and I've got it almost working. The part I am stuck on is the "optional" separable Gaussian blur of the depth map to give soft-looking shadows. I am ...
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2answers
481 views

How can I optimize these GLSL bitwise operations?

I need the following part of my vertex shader simplified. Sb=Sb|((gl_VertexID&(128+1))<<9); Sb=Sb|((gl_VertexID&(512+4))<<6); Sb=Sb|((gl_VertexID&(2048+16))<<3); Sb=...
1
vote
1answer
146 views

OpenGL Post Processing Introducing Artifacts on Certain Systems

Playing around with God-Rays in my framework, I was greeted with the following artifacts on my laptop: The artifacts themselves act almost like noise, flickering around the image rapidly. They also ...
3
votes
1answer
144 views

If-clause in GLSL

I read a few thing about, that in GLSL both sides of the if-clause is executed, so do you have any idea for a workaround for this one: uniform int uses_bones; uniform mat4[] bone_transformations; ...
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1answer
282 views

OpenGL/GLSL/LWJGL return value from shader

I'm trying to do some bone animation. I don't want the whole skeleton to be loaded to the GLSL shader every time, even tough it's not needed, because one vertex is parented to one bone, not more. My ...
1
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2answers
132 views

Vertex Skinning Looks Messy on Real Android Device using Monodroid

I have no problem doing the "vertex skinning" for three-dimensional animation. All goes well when using the emulator (and genymotion). However, when run on a real device (such as Samsung and Lenovo) ...
1
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1answer
423 views

How does an energy-conservative Blinn-Phong-Fresnel model work?

What is a plausible, basic equation/pseudo-code for energy-conservative Blinn-Phong shading, including Fresnel with a coloured light-source? The net gives so many alternatives that it's hard to ...
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0answers
62 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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1answer
150 views

Averaging normals, or tangents

I am using a library to load an obj but it doest compute the tangets for each vertex, which I need for normal mapping and pom. I computed my tangets, and bitangents, everything appears to be fine, but ...
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0answers
182 views

glGetUniformLocation returns 23724032

as the title says, I have a problem using glGetUniformLocation call that returns, for the following code, the value 23724032. I'm writing a little engine and the draw function of my models is: void ...
2
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1answer
86 views

What will happen if the argument of mix() or clamp() is above 1 or below 0?

There's two magnificent intrisincs: mix() in GLSL and clamp() in HLSL, which are used to implement linear interpolation. Let's say we have a variable: float v = ?; // where ? can be [-FLOAT_MAX, +...