A programming language for OpenGL shaders.

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1answer
349 views

Multisampled Texture

i have some doubts with multisampled textures. In fragment shader, how to pass multiple samples? We use glTexImage2DMultisample instead of glTeximage2D. so, how to upload texture data? I want to ...
5
votes
1answer
199 views

Blend multiple regions from same texture atlas

I'm representing terrain in my game as a grid with at each node a composition, for example 100% rock, or 50% grass, 50% soil. I'd like to use this composition vector to blend textures together. I'm ...
3
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1answer
489 views

how to organize rendering

I use a deferred rendering. During g-buffer stage my rendering loop for a sponza model (obj format) looks like this: int i = 0; int sum = 0; map<string, mtlItem *>::const_iterator itrEnd = ...
2
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1answer
174 views

Shadow cubemapping?

I am working on a game with C++ and OpenGL 3.2. I have successfully implemented directional shadow maps and now I'd like to upgrade them to shadow cube maps (for point lights). I've done some Googling ...
3
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1answer
2k views

How are vertex shader outs sent as inputs to the fragment shader?

I'm learning some OpenGL 3.2 way of doing things and I think it's quite great, I'm actually understanding more of shaders and non-fixed pipeline in 1 week rather than those 2 years I tried to learn ...
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1answer
291 views

fragment shader with SNORM textures

I want to apply SNORM texture by using GL_TEXTURE_3D as a target, what will be the fragment shader for the same? Also, what should be the data type of texture data?
4
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0answers
1k views

OpenGL problem with FBO integer texture and color attachment [closed]

In my simple renderer, I have 2 FBOs one that contains diffuse, normals, instance ID and depth in that order and one that I use store the ssao result. The textures I use for the first FBO are RGB8, ...
2
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1answer
748 views

Low-level GPU code and Shader Compilation

Bear with me, because I will raise several questions at once. I still feel, though, that overall this can be treated as one question that may be answered succinctly. I recently dove into solidifying ...
13
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1answer
1k 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 ...
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2answers
289 views

Deferred rendering order?

There are some effects for which I must do multi-pass rendering. I've got the basics set up (FBO rendering etc.), but I'm trying to get my head around the most suitable setup. Here's what I'm ...
5
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1answer
471 views

Cheap ways to do scaling ops in shader?

I've got an extensive world terrain that uses vec3 for the vertex position attribute. That's good, because the terrain has endless gradations due to the use of floating point. But I'm thinking about ...
2
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0answers
345 views

Per fragment lighting with OpenGL 4.x tessellated model

I'm experienced with OpenGL 3+. I'm dabbling with tessellation shaders and have now got to a point where I have a nicely tessellated teapot/plane demo (quick look here) As can be seen from the ...
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1answer
328 views

how to use a mask texture?

A texture pack for a sponza model contains mask textures (black and white). I guess that I should read only a red channel from that texture, right ? I use deferred rendering and for shading ...
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1answer
1k views

What is the difference between Constant Vertex Attributes and Uniforms?

According to the OpenGL ES 2.0 Programming Guide: A constant vertex attribute is the same for all vertices of a primitive, and therefore only one value needs to be specified for all the vertices of ...
3
votes
1answer
624 views

GLSL per pixel lighting with custom light type

Ok, I am having a big problem here. I just got into GLSL yesterday, so the code will be terrible, I'm sure. Basically, I am attempting to make a light that can be passed into the fragment shader (for ...
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vote
2answers
265 views

Low complexity shader to indicate the sides of a polyline

I have a bunch of polylines that I draw using GL_LINES. They can have thousands of points. They actually represent the separation of land and water on a map. I don't have complete polygons, just the ...
3
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1answer
883 views

GLSL custom interpolation filter

I'm currently building a fragment shader which is using several textures to render the final pixel color. The textures are not really textures, they are in fact "input data" to be used in the formula ...
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0answers
1k views

ssao implementation

I try to implement a ssao based on this tutorial: link I use a deferred rendering and world coordinates for shading calculations. When saving gbuffer a vertex shader output looks like this: ...
5
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1answer
2k views

Morph a sphere to a cube and a cube to a sphere with GLSL

I'm getting started with GLSL with quartz composer. I have a patch with a particle system in which each particle is mapped into a sphere with a blend value. With blend=0 particles are in random ...
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1answer
377 views

OpenGL ES 2. How do I Create a Basic Fading Streak Effect?

For the iPad app I am writing using OpenGL ES 2 I have a single quad - shaded using GLSL - that is dragged around the screen. Very basic. This works fine. But is rather boring. I want to increase ...
0
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1answer
509 views

OpenGLES GLSL Shader attributes always bound to 0

So I have a very simple vertex shader as follows #version 120 attribute vec3 position; attribute vec3 inColor; uniform mat4 mvp; varying vec3 fragColor; void main(void){ fragColor = inColor; ...
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2answers
3k views

Passing multiple Vertex Attributes in GLSL 130

(note this question is closely related to this one however I didn't fully understand the accepted answer) To support videocards in laptops I have to rewrite my GLSL 330 shaders to GLSL 130. I'm ...
4
votes
3answers
195 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 ...
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1answer
792 views

How to convert Maya shaders and Renderman shaders to GLSL?

I know this 2 products but i have never used them for production, since I have a bunch of cool shaders i would like to use them under OpenGL with GLSL but i don't know where to start. If it's not ...
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1answer
603 views

samplerCubeShadow and texture offset

I use sampler2DShadow when accessing a single shadow map. I create PCF in this way: result += textureProjOffset(ShadowSampler, ShadowCoord, ivec2(-1,-1)); result += textureProjOffset(ShadowSampler, ...
2
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1answer
453 views

Billboarding restricted to an axis (cylindrical)

I have succesfully created a GLSL shader for a billboarding effect. I want to tweak this to restrict the billboarding to an arbitrary axis, i.e. a billboarded quad only rotates itself about the ...
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2answers
1k views

Learning OpenGL GLSL - VAO buffer problems?

I've just started digging through OpenGL and GLSL, and now stumbled on something I can't get my head around this one!? I've stepped back to loading a simple cube and using a simple shader on it, but ...
4
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2answers
616 views

How Do I Raycast for a Spherical Harmonic Shader Using the iOS GPU?

I am beginning an Spherical Harmonics shader project for an iOS app I am writing. I have begun by reading this excellent in-depth paper on the subject (PDF) - http://bit.ly/aQmax3. The paper ...
2
votes
2answers
630 views

Is this a reliable method of parsing glGetShaderInfoLog()?

I want to get a list of errors and their line numbers so I can display the error information differently from how it's formatted in the error string and also to show the line in the output. It looks ...
5
votes
2answers
866 views

Geometry shader for multiple primitives

How can I create a geometry shader that can handle multiple primitives? For example when creating a geometry shader for triangles, I define a layout like so: layout(triangles) in; ...
2
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1answer
133 views

Uniform not being applied to proper mesh [closed]

Ok, I got some code, and you select blocks on a grid. The selection works. I can modify the blocks to be raised when selected and the correct one shows. I set a color which I use in the shader. ...
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vote
2answers
277 views

Depth buffer values reset on change shader?

I have 2 different shaders, and when I change the shader (glUseProgram), it seems that the depth information is lost, because everything drawn with the 2nd shader appears completely on top of anything ...
3
votes
2answers
749 views

OpenGL sprites and point size limitation

I'm developing a simple particle system that should be able to perform on mobile devices (iOS, Andorid). My plan was to use GL_POINT_SPRITE/GL_PROGRAM_POINT_SIZE method because of it's efficiency ...
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4answers
554 views

What is a right datatype in C++ for OpenGL scene representation with use of GLSL

I am programming in C++ OpenGl with GLSL. Until now I have been using a data structure that is composed of std::vector filled with structures of vertexes and with their parameters (position , normal, ...
9
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2answers
2k views

Sorting objects before rendering

I'm trying to implement a scene graph and in all the articles i've come across there is talk about object sorting. So you'd sort your objects by "material" for example. Now untill i sat down and ...
10
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1answer
2k views

GLSL, all in one or many shader programs?

I am doing some 3D demos using OpenGL and I noticed that GLSL is somewhat "limited" (or is it just me?). Anyway I have many different types of materials. Some materials have ambient and diffuse color, ...
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1answer
134 views

running GL ES 2.0 code under Linux ( no Android no iOS )

I need to code OpenGL ES 2.0 bits and i would like to do this and run the programs on my desktop for practical reasons. Now, i already have tried the official GLES SDK from ATI for my videocard but ...
2
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2answers
873 views

Simple OpenGL program major slow down at high resolution

I have created a small OpenGL 3.3 (Core) program using freeglut. The whole geometry is two boxes and one plane with some textures. I can move around like in an FPS and that's it. The problem is I face ...
2
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0answers
424 views

GLSL Bokeh using Quads and Textures [closed]

I'm trying to create a depth of field effect with bokeh sprites in GLSL. Specifically, what i would like to do is, for each pixel: See if the pixel is out of the focal range If it is, draw a quad ...
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6answers
12k views

OpenGL ES 2.0: Repository of Quality Shaders

Could I kindly ask, to suggest me a repository of high quality OpenGL (OpenGL ES 2.0) vertex and fragment shaders, please? I am looking for pixel based ligting shaders (such as phong) and simmilar. ...
0
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1answer
317 views

What are the steps taken by this GLSL code?

1 void main(void) 2 { 3 vec2 pos = mod(gl_FragCoord.xy, vec2(50.0)) - vec2(25.0); 4 float dist_squared = dot(pos, pos); 5 6 gl_FragColor = (dist_squared < 400.0) 7 ? ...
0
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1answer
475 views

Correct Rotation and Translation with a 4x4 matrix

I am using a 4x4 matrix to transform verts in a shader. I multiply an identity matrix by a rotation matrix by a translation matrix. I am trying to first rotate the verts and then translate them, ...
6
votes
1answer
273 views

GLSL vertex shaders with movements vs vertex off the screen

If i have a vertex shader that manage some movements and variations about the position of some vertex in my OpenGL context, OpenGL is smart enough to just run this shader on only the vertex visible on ...
13
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1answer
2k views

Should I distribute shaders in a compiled form or in plain text?

Having an application that uses shaders that have been wrote in GLSL, what is the best strategy for the distribution in the real world and for the desktop and mobile? I'm aiming to distribute this in ...
6
votes
4answers
978 views

Impact of variable-length loops on GPU shaders

Its popular to render procedural content inside the GPU e.g. in the demoscene (drawing a single quad to fill the screen and letting the GPU compute the pixels). Ray marching is popular: This means ...
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vote
3answers
1k views

iOS - pass UIImage to shader as texture

I am trying to pass UIImage to GLSL shader. The fragment shader is: varying highp vec2 textureCoordinate; uniform sampler2D inputImageTexture; uniform sampler2D inputImageTexture2; void main() { ...
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3answers
686 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 ...
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0answers
263 views

Full screen shader causes performance hit

I basically want to have a shader run that can do something like toon shading, or grayscale the whole screen, or radial lighting. To do this, I create a new bitmap each time the display resizes that ...
3
votes
1answer
2k views

Deferred Rendering and Normal Mapping

I'm working on a deferred renderer and need a bit of help getting normal maps working. What I've been doing with them so far is just multiplying the normal texture with the object normals ...
9
votes
4answers
5k views

Debugging Shader Code?

I'm writing a game engine, and when I use a perspective camera I get a black screen. I am not going to ask exactly why this is because there would be a lot of code to share and, frankly, I think ...