A programming language for OpenGL shaders.

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1answer
90 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
154 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
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2answers
952 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
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3answers
1k 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
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0answers
130 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
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0answers
253 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
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2answers
391 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
243 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
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1answer
575 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
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1answer
140 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
313 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
174 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 ...
3
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2answers
377 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
1k 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
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1answer
242 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
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1answer
67 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 ...
3
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2answers
1k 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 ...
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vote
2answers
1k 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 ...
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2answers
526 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
255 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
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0answers
202 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
241 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
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0answers
121 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
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4answers
709 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
1k 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
627 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
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0answers
84 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
55 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
690 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
1k 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; ...
1
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0answers
375 views

Geometry shader and triangle adjacency

I'm currently trying to change my project to use GL_TRIANGLE_ADJACENCY instead of GL_TRIANGLES. Following this question, I have managed to construct my index buffer fine, but when it comes to the ...
4
votes
1answer
406 views

OpenGL FBO not being drawn to

In my project I'm trying to implement a deferred rendering system, problem is, I can't seem to get a second FBO to work. UPDATE 1 Here is the FBO initialization code: /// G-Buffer FBO GLuint ...
0
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2answers
329 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
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1answer
1k views

GLSL - Declaring global variables outside of the main function scope

Does it help to declare variables outside of your main function scope in GLSL? Do these variables actually get reused and is it more efficient? Here is the code in question: varying vec2 vposition; ...
3
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0answers
412 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 ...
1
vote
2answers
213 views

GLSL: define a constant for both vertex and fragment shader

I have a constant for defining an array in the vertex shader. I want to use this constant also in the fragment shader to define another array of the same size. Naive attempts fail (simply use the ...
6
votes
1answer
706 views

How would one draw many objects using the same VBO

I'm kind of stuck with this question for some time now, maybe because I don't know exactly what to search for, it might be a term I have not heard of yet as most tutorials ends after drawing one ...
0
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0answers
163 views

Shadow-casting through time acting in “reverse” before next notciable shadowmap update

question was re-written to better explain the problem I have a scene of big thin parallelepiped, small cube, and a light source, all aligned on Y axis, like so: _ | | | |----[ ]----Light |_| Both ...
7
votes
2answers
257 views

Diffuse Reflection confusion

From what I've read, with a simple directional light, the color of a point, if you only take diffuse reflection into account (intensity = 1), should be color = color_of_point * color_of_light * ...
3
votes
2answers
72 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
211 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 ...
5
votes
1answer
2k views

GLSL default shaders

I've been arming my engine with error checking code. I'll try to describe this situation to my best abilities. Whenever i load a shader and there's an error (file doesn't exist, compilation error, ...
0
votes
3answers
1k views

OpenGL tile rendering

Currently I'm trying to render a TileMap using OpenGL 2.1, GLSL 1.2. I would like to draw every tile in just one draw call. I use a single texture with all tiles, identifying each one by an index. ...
0
votes
1answer
202 views

VBO in a class doesn't draw when The class has a destructor

I am making this class QuadTemplate class QuadTemplate { public: QuadTemplate() { vbo=0; uvbuffer=0; vao=0; TextureID=0; vboType=0; ...
7
votes
2answers
5k 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 ...
3
votes
2answers
3k views

Rotating an object when the center in not the origin - opengl

I'm beginning with GLSL and I learning the basic, I am using glm to do the matrix calculations at this point everthing ok,the problem is how I can move the origin to the center of my object, not the ...
3
votes
1answer
263 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 ...
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0answers
135 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# ...
3
votes
1answer
744 views

Incorrect GPU skinning

I'm having some problems with implementing skinning and skeletal animation. It seems that the skeleton and the mesh are loaded correctly, but the mesh gets funky when the bone transformations are ...
4
votes
2answers
1k views

Using two shaders instead of one with IF statements

I've been working on porting a relatively large opengl ES 1.1 source to ES 2.0. In OpenGL ES 2.0 (which means, everything uses shaders), I want to draw a teapot three times. The first one, with a ...