A programming language for OpenGL shaders.

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GLSL shader compilation

When i'm compiling a shader does it have to be complete? Can i use glCompileShader on a shader without a main() function? The OpenGL reference documentation has a nice writeup on program linking ...
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57 views

How to wrap textures inside shader GLSL

I'm trying out GLSL and one of the problems I'm facing is wrapping a random texture sampler in the shader. Searching for answers on the web first, this leads me to using these commands: ...
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54 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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113 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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81 views

Reconstruct shader vertices in OpenGL

I'm not sure if 'reconstruct' is the correct term for this but essentially what I am trying to do is calculate vertex positions (that are already calculated via shader) on the CPU for the purpose of ...
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248 views

How to mix pixel colors in Shader?

I have a pixel that have a colour RGB. This color is calculated by the shader and can be anything. How can I override this color by a colour I choose. If my pixel is white it's simple, I can do this: ...
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82 views

Arbitrary number of VBO to Vertex Shader

I am currently using standard modern OpenGL way to render a mesh via VBO and attributes glEnableVertexAttribArray(aVertexPosition); glBindBuffer(GL_ARRAY_BUFFER, VBO); ...
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306 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 ...
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111 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: ...
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311 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; ...
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151 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 ...
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Can't render to FBO using a shader

I've added functionality so that I can render to a framebuffer (for post-processing and stuff). I can successfully render to my framebuffer and then render that framebuffer, but anything with a ...
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How does OpenGL-ES 2 assemble primitives?

Two things I'm quite confused about. 1) OpenGL ES 2.0 creates primitives before the vertex shader is invoked. Why, then, does it not automatically provide the vertex shader the position of the ...
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168 views

Java, Crashing with a Shader on Intel HD Graphics

I just got a new computer (Acer Aspire ES1-311) which has an integrated Intel HD Graphics card, and I noticed that this fisheye shader crashes my game (LibGDX game, VM Crash): varying vec2 ...
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243 views

Getting the real fragment depth in GLSL

I am trying to write a simple GLSL shader that just renders the real (not normalized) depth of a fragment as a floating point value. So far, I've figured out how to get the depth of a vertex, and ...
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101 views

Best way to detect if vec3 is between vec3(x) and vec3(y) in glsl

As titled I am sampling from a texture and if the color is somehow gray [vec3(.8), vec3(.9)] and an uniform is 1 I need to substitute that color with another one I am not a glsl veteran but I am ...
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287 views

What coordinates are we passing to pixel shader from vertex shader?

I have read articles about shader programing and understood the very basic knowledge of shader programing. One thing I always get confused is about the texture mapping. What I pass(output) from VS to ...
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379 views

More than 8 lights without deferred shading / lighting [closed]

I want to know if there is any technique (efficient) to use more than 8 lights in a scene made ​​with OpenGL and GLSL. Without making use of deferred shading / lighting. I have not implementadon ...
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69 views

Way to avoid excessively bright objects with specular lighting?

I have a typical Phong shading with specular light. I have all the parameters tuned so to give appropriate highlights from a point light source. Now the problem I have is a new object that has a large ...
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379 views

Optimizations using GLSL shaders

I have written a simple OpenGL application using GLSL shaders. Actually, my program just displays a simple cube with a phong lighting effect like below : Here's a peace of the client code : ...
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187 views

Providing texture coordinates and using indexed drawing at the same time

Please consider the following vertex structure struct vertex { vec3 posL, normalL; }; Using this vertex layout, we can provide the vertex data in an interleaved way, i.e. ...
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145 views

How does OpenGL determine different outputs with shaders?

Lets say I have this GLSL code: #version 330 out vec4 outputColor; void main() { float lerpValue = gl_FragCoord.y / 500.0f; outputColor = mix(vec4(1.0f, 1.0f, 1.0f, 1.0f), ...
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156 views

why is my OpenGL texture transparent?

I have a terrain in OpenGL, and two textures which I am combining using GLSL mix() function. Here are the textures I am using. Now I am able to combine and mix these two textures, but for some ...
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162 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 ...
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105 views

How can I animate a portion of the textures on a model?

I have a model to which I have attached multiple textures. Both textures are currently static, but if I want to move (or slide) the texture which is on the top (in UV space), is that possible? Maybe ...
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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 * ...
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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 ...
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92 views

Vertex and Fragment Shader worldNormal

How to access/calculate worldNormal in a Vertex and Fragment shader ? Thanks a lot !
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351 views

GLSL Shaders-> How to manage?

As your game get's bigger and bigger, you will use more and more different shader effects. Let's take an easy example: I have clouds in my voxel-based world, and I want to give it a blue-ish tint ...
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202 views

texture movement stutters

Hey I at the moment I have got my texture to move however it stutters as I increment by 0.001 every second. My animation is done via FPS if that make sense and here is some code FrameCount++; ...
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568 views

How to get a smooth dimming with SSAO?

I implemented SSAO in my game based on the tutorial at gamerendering.com. But the results I get are disappointing. Instead of a smooth effect as seen in the nvidia demos, my implementation causes ...
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2answers
384 views

LWJGL Game crashes on some other machines [closed]

I just tried running my game on a friend's laptop, but for some reason it crashes. The exported .jar runs fine on my machine, and some others too. I can see that is has something to do with the ...
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732 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: ...
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269 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 ( ...
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676 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 ...
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681 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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26 views

Processing through multiple shaders (LWJGL/Java/OpenGL)

Very simple question: Is it possible to process a vbo through different shaders? If so, how? What I want is sth like this: reflectionShader.bind(); //starts shader reflectionShader.load(some_values); ...
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66 views

How do I start and stop a GLSL shader?

Is there a way to start and stop a shader?. I want to use this shader to sweep once over my texture and then stop. Does anybody know how to do that? void mainImage( out vec4 fragColor, in vec2 ...
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83 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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229 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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84 views

Cubemap faces rotation in GS shader

I Can't get correct rotations for cubemap faces. Thats should come to geometry shader, from camera "view" matrix I want make 6 faces for my cubemap, but seems I can't get it correctly... My first ...
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176 views

Fragment Shader output type error

StackExchange! I've been working with opengl for a bit and I'm trying to finally load the shaders instead of having them inline. I'm having a ton of issues, though. As soon as I solve one, another ...
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58 views

Overload how an object instance of a class is treated when used

So I've made this struct that encapsulates a glm::vec4. This is because vec3s are treated as 16-byte in GLSL, but I don't want to assign a vec4 if I only really need 3 components. Anyway, my question ...
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122 views

Ray casting problem using JOGL

I'm trying to port an old perfectly functioning ray casting implementation from my lwjgl project (FF pipeline) to a new project using JOGL and shaders. My problem is that my ray no longer intersects ...
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1answer
155 views

Uniform Block solve padding/alignment for vec3 in CPU struct

I have a struct on the CPU which I'm sending to a uniform block in my shader. After a bit frustration I finally got it to work. The problem I had was that vec3s are actually treated as 16-bytes, or in ...
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1answer
166 views

GLSL: Vertex attribute to int

I'm trying to write a shader which renders a multitextured geometry wihout rerendering the geometry with each texture. In my test I'm not using textures, I just convert the texture index to a color ...
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280 views

3D position of an arbitrary UV coordinate

I have a UV map for a 3D mesh that encodes "links" between pairs of UV coordinates. I have previously defined this links (or pairs), one to one. The links are enconded using the function rgb_color(u1, ...
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117 views

Blurring part of the screen - optimisation

I develop 3d menu and sometimes I need to blur only part of the screen. I use a forward rendering. I create a frame buffer object with 3 color attachments. Rendering looks like this: bind fbo ...
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98 views

Proper way to encapsulate a Shader into different modules

I am planning to build a Shader system which can be accessed through different components/modules in C++. Each component has its own functionality like transform-relevated stuff (handle the MVP ...
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224 views

GLSL to Cg fragment shader

I have found very useful resource on the Swiftless website on OpenGL. Unfortunately, I cannot manage to adapt a GLSL fragment shader to my project, which uses Cg. Here it is: uniform sampler2D ...