OpenGL is a graphics standard and API which targets the desktop and workstation markets. It is designed to be easy to accelerate with dedicated computer hardware, and hence most implementations give greatly improved performance over traditional software rendering. Currently, OpenGL is used for ...

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8
votes
0answers
508 views

Variance shadow maps don't want to render properly

I've implemented VSM (and also ESM) in my engine but results are for me not as I expected and saw in many examples published on network. I set filtering of shadow maps to GL_LINEAR but when I compare ...
5
votes
0answers
90 views

OpenGL: Frame partially jumps back and forth

I'm working on a project with SDL and OpenGL. The game works great on Windows, Linux, OS X and iOS. However, the Android version is showing a problem on my phone in particular. I have tested another ...
4
votes
0answers
135 views

How to correctly implement 'layered lighting' with Box2D-Lights

How does one only allow Box2D-Lights to affect one and only one OrthographicCamera. After researching, I found the following answer. This answer goes into detail about how to prevent one camera from ...
4
votes
0answers
51 views

Environment mapping without cubemap (need coordinates projection)

I'm working on a project with C++ and glsl (4.1). I have implemented a mirror object which is a plane at height 0 that works as follow: I render the scene with a MVP computed such that the camera ...
4
votes
0answers
55 views

Spherical Area Lights do not match reference

So I'm adding spherical area lights to my application, and comparing my results with mitsuba, I am getting some differences (left is my approach, right is mitsuba - a pathtraced reference): What I ...
4
votes
0answers
73 views

Irradiance Map ( Irradiance environment map)?

As irradiance map is generated for every possible normal for all the texels in environment map (as every texel act as a light source) so that we can look up irradiance map, based on normal of fragment ...
4
votes
0answers
69 views

How do I align the cube in which shadows are computed with the view frustrum? (“View Space aligned frustum”)

Short and concise: Given 8 world space positions that form a cube of arbitrary size, position and orientation and given an arbitrary light direction. How do I compute the View and Projection matrix ...
4
votes
0answers
83 views

Draw Edges in OpenGL

I use blender game engine, and blender use openGL for graphics. How can I draw lines around all 3D objects? Would this be a job for a filter? Mainly, I want my end result to look drawn. I found this: ...
4
votes
0answers
96 views

How to draw Shadow Volumes in one draw call?

I've got a simple app that draws 3D cubes using instance rendering and I'm implementing Shadow Volume. Each cube's vertex, uv, normal and index data are statically stored in 4 vertex array buffers. On ...
4
votes
0answers
281 views

How much is atomicAdd slower than an atomic counter?

I am considering replacing an atomic counter in my shader code with a SSBO an atomicAdd operation. What I need to know is the difference in performance of these two. I know the atomic counter executes ...
3
votes
0answers
19 views

LibGDX: Shader files in assets - Access is Denied

I stored the glsl files in android -> assets -> shaders directory, but when I run the app, an error is displayed: Error:Gradle: Execution failed for task ':android:mergeDebugAssets'. Error: ...
3
votes
0answers
67 views

Geometry Shader crashing

I keep getting some strange errors in my Geometry shader and when I search for the cause of the errors, it returns nothing substantial. Here is the code. Shader #version 450 core layout(triangles) ...
3
votes
0answers
45 views

Rotation of a ball moving on a surface

I have a ball that moves along a platform. The ball is characterized as a sphere that has a radius and a position. The platform basically is a rectangle consisting of two vertex triangles. Its class ...
3
votes
0answers
57 views

I get weird perspective using GLM where the depth is flipped. Please help

The depth is rendered wrong and I can't figure out why. using namespace std; using namespace glm; int width = 640; int height = 480; float aspect = (float)width/height; int fps = 60; void start(){ ...
3
votes
0answers
94 views

Is it possible to use OpenCL in libgdx?

Been looking for a way to implement some OpenCL stuff in my libgdx project. It's possible via LWJGL which libgdx is based on, but it's only for the Desktop environment. Would like to have it cross ...
3
votes
0answers
128 views

Shadow mapping - Can't get the right texture coordinates

I'm trying to implement shadow maps for Spotlight's, but alas I can't get them to work. I have verified that my fragment shader is getting the shadow map texture. I can sample from it in the ...
3
votes
0answers
271 views

OpenGL Depth Cubemap with Geometry Shader Not Rendering Correctly

I was having some trouble with cubemaps in OpenGL, and was hoping to get some help. I've been following a tutorial about point light shadow mapping using cubemaps, where a geometry shader is used to ...
3
votes
0answers
95 views

OpenGL enabled Java game not detected by Fraps

Recently I found out that I could enable OpenGL hardware acceleration in my java game with the line System.setProperty("sun.java2d.opengl", "True"); Initial tests showed a big boost in performance. ...
3
votes
0answers
114 views

OpenGL Planet Generation - Simple Matrix Issue (Planet “Spins” With Mouse)

I originally asked this question on StackOverflow & was directed here by a commenter. Im currently working on a OpenGL planet rendering. I'm using the Tessellation pipeline. So far things are ...
3
votes
0answers
67 views

Tangents face the same direction on opposite sides of mesh

I have noticed that the tangent vectors that I am calculating are not always facing the correct direction. The tangents on the left and right of the mesh both face the same direction. Here is a ...
3
votes
0answers
121 views

Render on texture with alpha 0 for the background colour

Sorry if the question is stupid but I am very new to opengl. I render on a target a scene with a couple of object on a background that is nothing more than the clear colour (which is 0.0,0.0,0.0,0.0)...
3
votes
0answers
725 views

AlphaToCoverage + Alpha Blending = Artifacts

I'm experiencing a strange problem using OpenGL SampleAlphaToCoverage mode. There are rendering artifacts when using alpha-blending on pixels that have been rendered using alpha-to-coverage - and I ...
2
votes
0answers
129 views

How to “hot-reload” a glsl shader

I am wondering if its possible to dynamically change shaders while the code is running. In my game, I want to have a development mode in which users can change the shader source and dynamically see ...
2
votes
0answers
26 views

OpenGL cubemap binding

I'm experimenting a strange behaviour of textures inside my shaders. Basically I need and bind two cubemap textures inside my shader but only one gets actually bound. I've tried swapping the two ...
2
votes
0answers
52 views

What happens to Buffer data that isn't used?

I have a vertex struct that has 5 glm::vec3 but some of my objects only use 2 or 3 of those members. So I have two questions : 1.) What happens to the large buffer I create, even though I don't use ...
2
votes
0answers
103 views

Texture Mapping to procedurally generated geometry

How can I calculate texture coordinates of such geometry? The angle shown in the image (89.90 degree) may vary, therefore the geometry figure is changing and is not always such uniform.(maybe like ...
2
votes
0answers
47 views

How to store sprite data in a VBO?

I'm planning on rendering many sprites in my games, but I am not sure which method of storing their data to use. I haven't tried all of them yet, but I want to see if I also have anything important ...
2
votes
0answers
33 views

Applying different materials to an object

I'm currently implementing an Object Loader for the Wavefront File Format (*.obj). When exporting a model (with associated materials) from blender, a material for a group of faces is specified like ...
2
votes
0answers
46 views

How to calculate specular contribution in PBR?

I'm trying to implement PBR in our project (we started a small game engine for academic and learning purposes) and I cannot understand what is the right way to calculate specular and diffuse ...
2
votes
0answers
65 views

GLSL shader with light colors wrong on nvidia optimus

So, I built some code to draw a spinning cube with a red light on the right side, and a blue one on the left. I run it on my laptop with optimus graphics, and on my desktop with nvidia. On the laptop, ...
2
votes
0answers
222 views

OpenGL Render Queue Design

I am currently designing the rendering system for a 2D game built in C++ and OpenGL, and am unsure about how to go about implementing a sorting procedure to maximise efficiency and minimize OpenGL ...
2
votes
0answers
110 views

Subsurface Scattering - Transmittance

I have a question related to SSS and especially transmittance. I've looked at several papers about that topic, most of them from Jorge Jimenez, which are very interesting and, I admit, a bit hard for ...
2
votes
0answers
30 views

GL.Scissor not working as expected

I have some code for rendering a button in an application and I want to clip the text if it's wider than the button itself. Here a bit of code to describe what I'm doing: GL.Enable(EnableCap....
2
votes
0answers
106 views

Texture coordinates for custom geometry in SceneKit ios9

I am trying to texture the a custom plane shape I created in scenekit on iOS9. I need the texture to spread out and stretch over the entire surface. I have a vertex and fragment shader on an ...
2
votes
0answers
48 views

Consistent Shadow Map Filtering

I want to filter my shadow map generated by PSSM, but the problem is that I have a inconsistent filter size. The problem is that the shadow map sources rotate to find the best fit for the camera ...
2
votes
0answers
46 views

Formula for model matrix with mouse coordinates

I'm trying to create a simple OpenGL app where I can drag objects with the mouse. The code below is based on a raycasting algorithm covered here. I'm using the diff between the current mouse coord ...
2
votes
0answers
79 views

Instancing meshes messing up scene lighting

I've been rendering a scene (some objects over a large field of grass) to test shadow mapping which is working fine. But when I use instancing to "gain" performance, I not only get a decrease in ...
2
votes
0answers
127 views

Bringing over OpenGL code to unreal engine?

So I've been developing games and apps in C++/OpenGL for a while, and am thinking of starting to use Unreal Engine for many things. I've built up quite the huge libarry for UI / rendering related ...
2
votes
0answers
72 views

How do you fix wobbling shadow edges?

I've implemented an omni-directional shadow map and I've noticed a rather unwanted behaviour on the shadows. It seems like when the angle between the occluded points and the light source is really ...
2
votes
0answers
175 views

Texturing Objects in OpenGL

Using OpenGL tutorials found here, I constructed an .obj file loader as well as a texture file loader using SOIL. I have an issue with drawing a textured object. (Shown here) Assuming I created the ...
2
votes
0answers
58 views

Opengl Skybox Texturing Error

I'm using cubemaps to render a skybox in my game. Thinking this would be a simple task I threw some stuff together using the tutorials I found online, particularly this. Taking all of this together, ...
2
votes
0answers
425 views

Confused About My Code Suggesting The Normal Matrix Is Equivalent To The ModelView Matrix

I'm learning environment mapping in OpenGL by following this page. In his vertex shader, the author calculates the vertex normal in eye space with the following code: nEye = vec3(viewMatrix * ...
2
votes
0answers
149 views

OpenGL: Avoid geometry shader for cubemap framebuffer

I want to render an environment map into a cubemap framebuffer but I dislike the fact, that I have to use the geometry shader to set gl_Layer because the geometry shader would be a basic passthrough ...
2
votes
0answers
356 views

Uniform Buffer Binding-points

I believe Uniform Buffers/Blocks has been the hardest thing to grasp in OpenGL. Hopefully this will be my final issue regarding this. I have created a uniform buffer that contain data of Light ...
2
votes
0answers
268 views

Shadow map shimmering, indexing outside the shadow map

I have tried to reduce shadow shimmering/flickering using technique described here: http://msdn.microsoft.com/en-us/library/windows/desktop/ee416324%28v=vs.85%29.aspx I works as I want and shimmering ...
2
votes
0answers
572 views

Easy way to set face colors with indexed VBOs?

I'm loading OBJs, which lend themselves well to setting up as indexed VBOs, since each vertex is only defined once and then a face definition will reference the same vertex more than once when they ...
2
votes
0answers
706 views

Is it reasonable to use a 2D texture as a lookup table in GLSL

I need a lookup table in a shader. The input values would be color values and the output other color values. Something like: uniform float lut[256]; color = vec3(lut[int(color.r*255.)], lut[int(...
2
votes
0answers
585 views

implementing shadows into my 2D GLSL-based lighting system

I'm writing a lighting system in OPENGL using GLSL shaders, and I'm pretty happy with the light casting I have so far, but I'm totally stuck on casting shadows. Everything I've found online on this ...
2
votes
0answers
546 views

Android: Hardware Scaler

I was reading through this: using-hardware-scaler-for-performance and am a little confused by it. It says all you need to do to invoke the scaler is to set it like so: surfaceView = new ...
2
votes
0answers
257 views

Text alignment in OpenGL with FreeType2

I'm trying to implement font rendering and have got into some trouble with glyph metrics. Here's the code where I get the metrics: Glyph gl; gl.width = face->glyph->metrics.width / 64; gl....