A programming language for OpenGL shaders.

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4
votes
2answers
979 views

Jagged transparency when rendering translucent textures (OpenGL 3.2 + GLSL)

Like most others, I'll start off mentioning that I'm still a beginner when it comes to OpenGL and GLSL programming. So bear with me on any dumb mistakes you may spot in the code ahead. I'm basically ...
-1
votes
1answer
546 views

GLSL code is very slow…why? [closed]

I know this is a very difficult thing to simply modify without the full project code, but I am having a massive performance problem with GLSL code that seems to be very efficient to me. I am stuck at ...
1
vote
1answer
306 views

My game works on the emulator and the PSVita, but crashes on Android

I made a game on PSM, ported from a previous iOS/Android game. I test it on the emulator and PSVita and runs fine. However, as I test it on a PlayStation Certified Android device, it crashes on load. ...
1
vote
1answer
421 views

How to have qt5 work on desktop like on mobile devices (es2, correct glsl version)?

I am looking for help/information concerning this issue : My work: I have an opengl es2 render engine that works on an iOS app. I almost managed to make it work by calling the same openGL rendering ...
3
votes
1answer
1k views

Cook Torrance model implementation : black specular light

I am trying to implement the Cook-Torrance model, and this is how I calculate the parameter Rs: float Rs(float m,float F,vec3 N, vec3 L,vec3 V, vec3 H) { float result; float NdotV= ...
1
vote
1answer
802 views

How to rotate a direction

I'm working a spotlight for my deferred renderer and I'm having trouble with matching the mesh to the visual representation of the light. Right now my mesh is a cone, the apex of the cone is at ...
2
votes
1answer
654 views

Gaussian blur filter and “shimmering”

I have a fairly bog-standard Gaussian blur filter (seperable) I'm using to make a glow effect in my pipeline. At the moment I'm rendering it only to 256x256 texture and then doing a very simple ...
0
votes
3answers
419 views

Phong lighting model unrealistic result

I am using OpenGL 2.1 and GLSL 1.20 . I am trying to compute the fragment color applying the Phong lighting model. This is the formula I have (the original formula has a summation, but since the ...
1
vote
1answer
515 views

What book/guide should I follow for GLSL [closed]

I searched a lot on the web without coming to a real solution and if I ask this it's because I really have difficulties getting an answer. I need to learn well GLSL 1.20 with OpenGL 2.1. I have ...
0
votes
1answer
610 views

vec4 for vec3 multiplication while calculating the specular value

I'm following this tutorial to calculate the specular color of a vertex. I use OpenGL 2.1 with GLSL version 120. This is the formula that I apply: spec= (R*eye)^s * Ls * Lm With: ...
0
votes
1answer
150 views

deferred rendering and a few shading functions

How to use a few shading functions together with deferred rendering (for example some objects are shaded based on a lighting equation, other get a fixed color) ? I draw a full screen quad when ...
2
votes
0answers
573 views

Shader Maker version 130 is not supported [closed]

I am trying to compile a vertex shader with Shader Maker and if I try to use the version 130 it says: Compiling Vertex Shader ERROR: 0:3: '' : version '130' is not supported Compiling ...
0
votes
1answer
1k views

Formula for replicating glTexGen in OpenGL ES 2.0 GLSL

I also posted this on the main StackExchange, but this seems like a better place, but for give me for the double post if it shows up twice. I have been trying for several hours to implement a GLSL ...
0
votes
1answer
239 views

OpenGL RTT FrameBuffer question and Rendering to texture while sampling it

What i need to do: Blur the selected texture and pass the texture to another effect for postprocessing. Notice that i want one texture passed all over. How do i want to do this: Bind the FBO ( ...
2
votes
1answer
303 views

Would I perform one pass per effect in Deferred Shading?

I'm implementing deferred shading the first time. Doing so I came up with a conceptual question. First I render the geometry in a framebuffer with muptiple rendering targets for depth, normals, and ...
2
votes
1answer
371 views

mat3x4 in webGL shaders

I am porting the IQM bone animation format to Javascript and have run into a problem... The vertex shader is failing to compile and the only error message I get out is 'mat3x4' : syntax error on the ...
3
votes
1answer
229 views

Texture prefetching in GLSL

I have a fragment shader which needs lots of semi-random access to 32x32 texture patch. Fortunately, the patch is constant for each poly, so there should be no issue storing the whole thing to the ...
5
votes
2answers
1k views

Rain drops on screen

I am trying to make simple rain drop effect on screen.Something like this http://fc00.deviantart.net/fs20/f/2007/302/5/6/Rain_drops_by_rockraikar.png My idea is to: Create small drop shaped normal ...
3
votes
1answer
170 views

Queries regarding Geometry Shaders

I am dealing with geometry shaders using GL_ARB_geometry_shader4 extension. My code goes like : GLfloat vertices[] = { 0.5,0.25,1.0, 0.5,0.75,1.0, -0.5,0.75,1.0, ...
0
votes
2answers
630 views

GLSL light coloring blocked surfaces

I have created a very simple lighting shader. It currently only supports point lights, but it lights up surfaces that are completely blocked from the light. I know why, but I want to know how I can ...
4
votes
1answer
156 views

Forcing early-z with raytracing

I'm working on a GLSL raytracer, and I need to be able to edit gl_FragDepth in the FS. However, doing so disables early-z culling. The scene is rendered front-to-back and the FS can only push points ...
1
vote
0answers
542 views

shader-based particle systems [closed]

I have a classic particle system where each particle is represented by a quad and, each time step, I move each particle. My target is webGL which means I don't have instancing, attribute divisors nor ...
1
vote
1answer
437 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
233 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
votes
1answer
621 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
votes
1answer
175 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
votes
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 ...
1
vote
1answer
320 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?
5
votes
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, ...
3
votes
1answer
982 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 ...
14
votes
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 ...
1
vote
2answers
321 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
votes
1answer
586 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
votes
0answers
430 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 ...
1
vote
1answer
337 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 ...
4
votes
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
700 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 ...
1
vote
2answers
277 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
votes
1answer
1k 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 ...
5
votes
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 ...
0
votes
1answer
410 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
votes
1answer
640 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; ...
1
vote
2answers
4k 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
227 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 ...
0
votes
1answer
919 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 ...
1
vote
1answer
731 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
votes
1answer
601 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 ...
3
votes
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
votes
2answers
723 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
703 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 ...