A programming language for OpenGL shaders.

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1answer
112 views

Telling my shader when to use which Texture

So I've just managed to get Texturing via GLSL shaders to work and i can pass a sampler2d textureHandler + my uv coordinates into my shader to specify the texture to be displayed on my Tiles. Now im ...
2
votes
1answer
126 views

Fragments never falling into spot light's cone

I am using GLSL version 1.20 with OpenGL 2.1 . I am trying to compute when a fragment falls into the area of a spot light. I have already set all the light values with glLightfv and glLightf, also ...
8
votes
1answer
424 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 ...
7
votes
3answers
3k views

First time shadow mapping problems

I have implemented basic shadow mapping for the first time in OpenGL using shaders and I'm facing some problems. Below you can see an example of my rendered scene: The process of the shadow mapping ...
4
votes
1answer
248 views

Creating Seamless Perlin Noise Across Faces of Cube

I am writing a planet renderer and have stumbled into a problem that I cannot solve. I am generating heightmaps in a glsl pixel shader. These heightmaps are generated for every quad in the quadtree ...
0
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1answer
105 views

Why are some of my normals facing away from the camera?

I'm trying to use WebGL to render some simple models, and I'm running into issues where pixels near the edge of my model are passing normals to my fragment shader that point away from the camera. This ...
0
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2answers
146 views

Models are not rendered correctly. OpenGL

I'm working on my university OpenGL project and as a base of it I'm trying to combine several OpenGL tutorials, mainly tutorials from http://ogldev.atspace.co.uk/. The problem I have is that models ...
7
votes
2answers
400 views

Deferred tiled shading, tile frusta calculation in OpenGL

I'm trying to do deferred tiled shading in OpenGL using the compute shader but I have hit a snag when trying to create the frustum for each tile. I'm using AMD's Forward+ demo (written in D3D) as a ...
0
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1answer
105 views

Linking error at tessellation shaders in GLSL

I'm testing the triangle tessellation from the link http://prideout.net/blog/?p=48#shaders . All the shader are compiled correctly, but when I try to link the program using the command: ...
1
vote
1answer
217 views

Can you have shader variables that vary per primitive?

A shader normally has values that vary per-vertex and values that vary per-fragment. Can you have values that vary only per primitive, such as per-triangle or per-quad?
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2answers
159 views

Ward model implementation: specular component too weak

I'm trying to implement the Ward shading model, the anisotropic, computationally efficient version: This is how I made it: float alphaX=0.5, alphaY=0.5; // asinotropic roughness float ...
-1
votes
1answer
170 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 ...
1
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0answers
71 views

Texture not visible on particles

This is the first time I am working with particles (GL_POINTS) I am using kinematic equations and controlling their movement in vertex shader. I am following an example given in OpenGL 4.0 Cookbook ...
2
votes
1answer
133 views

Color bleed on voxel edges when using anti-aliasing

My Minecraft-like game uses a texture containing four block IDs in each pixel (RGBA). These IDs are used in the shader to determine what color each whole block should be. I'm having an issue with ...
1
vote
1answer
184 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 ...
0
votes
0answers
30 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 ...
1
vote
1answer
120 views

How can I extract the RGB color data from a TGA image?

I am working in OpenGL, and I am trying to create terrains using height maps. I am using my own functions to load a TGA image, and in order to pass data to heightmap vertex shader I need to retrieve ...
6
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, ...
2
votes
0answers
180 views

Help with 2D sprite instancing [closed]

Alright, so I'm pretty new to OpenGL programming. I've been writing my own engine, initially using the fixed function pipeline. I then did a 1:1 replacement of the fixed-function methods with shaders ...
0
votes
1answer
82 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
118 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
2answers
687 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 ...
4
votes
3answers
830 views

Implementing skeletal animation and GPU skinning (DOOM MD5)

DISCLAIMER This question has been completely rewritten to narrow the scope of the question in light of previous suggestions and answers, but the same problem still persists. Currently I'm trying to ...
0
votes
0answers
56 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
183 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
221 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. ...
1
vote
1answer
136 views

How does HLSL handle clip(vector)?

My goal is to convert clip() to GLSL, version 1.5. I'm currently doing a basic: if (x < 0) discard; But if x is not a scalar, obviously I can't use the "<" operator. So I'm wanting to ...
1
vote
1answer
452 views

Light following me around the room. Something is wrong with my shader!

I'm trying to do a spot (Blinn) light, with falloff and attenuation. It seems to be working OK except I have a bit of a space problem. That is, whenever I move the camera the light moves to maintain ...
0
votes
1answer
94 views

Why do the ALPHA channel in TGA is not visible?

Good morning GDSE, I am loading a TGA using loadTGA function found in superbible 4th edition source code. Here is how the image looks in Gimp You can see I have enabled alpha channel in Gimp, I ...
2
votes
1answer
237 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 ...
0
votes
0answers
76 views

OpenGL moving a texture

I am working on a game, i have a model to which i have attached multiple textures. Both the textures are static, but If i want to move the texture which is at the top, is it possible? By top i mean, ...
1
vote
1answer
115 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 ...
2
votes
2answers
282 views

GLM Velocity Vectors - Basic Maths to Simulate Steering

UPDATE - Code updated below but still need help adjusting my math. I have a cube rendered on the screen which represents a car (or similar). Using Projection/Model matrices and Glm I am able to ...
3
votes
2answers
541 views

scaling point sprites with distance

How can you scale a point sprite by its distance from the camera? GLSL fragment shader: gl_PointSize = size / gl_Position.w; seems along the right tracks; for any given scene all sprites seem nicely ...
0
votes
1answer
121 views

fragment shader directional light positioning with camera

Im trying to set up directional lighting in the fragment shader. So the direction of my light moves with the camera position. #version 150 core uniform sampler2D diffuseTex; ...
2
votes
1answer
46 views

Accessing 3D texture data without normalized coordinates directly, but with filtering

texelFetch() exists to access texture data with texture coordinates in "image dimensions", but texelFetch skips filtering. In case of 2D textures, it's possible to use a rectangle texture sampler to ...
1
vote
2answers
753 views

Developing GLSL Shaders? [closed]

I want to create shaders but I need a tool to create and see the visual result before I put them into my game. As to determine if there is something wrong with my game or if it's something with the ...
1
vote
2answers
488 views

In GLSL is it possible to offset vertices based on height map colour?

I am attempting to generate some terrain based upon a heightmap. I have generated a 32 x 32 grid and a corresponding height map -> In my vertex shader I am trying to offset the position of the Y ...
1
vote
2answers
216 views

OpenGL position from depth is wrong

My engine is currently implemented using a deferred rendering technique, and today I decided to change it up a bit. First I was storing 5 textures as so: DEPTH24_STENCIL8 - Depth and stencil ...
0
votes
1answer
142 views

Problems when rendering code on Nvidia GPU

I am following OpenGL GLSL cookbook 4.0, I have rendered a tesselated quad, as you see in the screenshot below, and i am moving Y coordinate of every vertex using a time based sin function as given in ...
1
vote
0answers
117 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 ...
2
votes
1answer
179 views

Incorrect lighting results with deferred rendering

I am trying to render a light-pass to a texture which I will later apply on the scene. But I seem to calculate the light position wrong. I am working on view-space. In the image above, I am ...
1
vote
0answers
105 views

Bad texture on model with different GPU [closed]

I have some kind of distortion on the texture of my 3D model. It works perfectly well on an AMD GPU, but when testing on a integrated Intel HD graphics card it has a weird issue. I don't have a ...
3
votes
4answers
421 views

How many times fragment shader is executed?

I have an OpenGL code, with 3 different shader programs. I have a simple question, I know fragment shaders are executed for every every fragment in the scene. But is there a way using which we can ...
5
votes
1answer
987 views

How does one get adjacency information in a geometry shader?

If you use triangle_adjacency as the input type of a geometry shader, do you need to do something on the client side besides make the primitive mode triangle_adjacency? Basically what I'm asking do ...
0
votes
1answer
309 views

GLSL billboard move center of rotation

I have successfully set up a billboard shader that works, it can take in a quad and rotate it so it always points toward the screen. I am using this vertex-shader: void main(){ vec4 tmpPos = (MVP * ...
0
votes
0answers
71 views

Triangle Clipping

I want to determine which part of a triangle is visible in a frustum in OpenGL, is there a way to get visible coordinates of triangle in the viewing frustum?
0
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1answer
53 views

Working with floats in OpenGL ES 2

Are there any reasons or situations one would use in their shader float(1) over just 1.0 ?
1
vote
1answer
488 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 ...
7
votes
1answer
793 views

Optimizing performance of a heavy fragment shader

I need help optimizing the following set of shaders: Vertex: precision mediump float; uniform vec2 rubyTextureSize; attribute vec4 vPosition; attribute vec2 a_TexCoordinate; varying vec2 tc; ...