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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How to deal with OpenGL and Fullscreen on OS X

I do most of my development on OS X and for my current game project this is my target environment. However when I play games I play on Windows. As a windows gamer I am used to Alt+Tab switching from ...
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399 views

Tone mapping and eye adaptation - pale colors and darker image

I'm trying to implement tone mapping along with eye adaptation and HDR. Actually I implemented this already but I'm not satisfied with result and I think that I made something wrong. My final image ...
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2D Water top surface profile

I am trying to create the effect of the water surface thickness with a vertex-fragment shader. I am in a 3D game environment but It's a scroll view so a "2D" view. Here is a good tutorial of creating ...
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620 views

Need advice for 3D BSP based graphics engine

I have coded myself a OpenGL BSP viewer for an old game format. It is very similar to the Quake 3 file format. Because my interest is developing graphics engines, I want to be developing while looking ...
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Implementing a skybox with GLSL version 330

I am trying to get a skybox working with OpenGL 3.3 and GLSL version 330. I could not find a completely modern OGL skybox tutorial anywhere on the web, so I modernised an older one (using ...
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Correct level of abstraction for a 3d rendering component?

I've seen lots of questions around this area but not this exact question so apologies if this is a duplicate. I'm making a small 3d game. Well to be honest, it's just a little hobby project and ...
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335 views

2-components color model

RGB is the natural color model for OpenGL. But a lot of other color models exist. For example, CMY(K) for printers, YUV for JPEG, the little cousins YCbCr and YCoCg, HSL & HSV from the 70's, and ...
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OpenGL Vertex Attributes - Normalisation

Alas, I have searched, and have found no definitive answer. When would you normalize the vertex data in OpenGL using the following command: glVertexAttribPointer(index, size, type, normalize, ...
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Most efficient way to draw vertex with OpenGL

I am writing an OpenGL 3D game. There will be tons of triangles for terrain and objects in use. I am studying from the OpenGL official guide and the first presented method is to call a function ...
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Using HTML for interface? [closed]

The game I've been working on uses opengl/sfml for graphics. I'm currently working on the interface and I've found determining all the proper offsets/positioning etc. to be a pain. To make it ...
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780 views

How wise is this multithreading architecture?

I'm rewriting a game engine I wrote in an attempt to parallelize as much as possible. I'm considering making properties which may be accessed from multiple threads all use accessors which use boost ...
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6answers
966 views

Does one need normals for a strictly 2d Game?

I'm starting to learn OpenGL by creating a pure 2D game. I have to decide on the format of the Vertices. Do I need a normal component? Or is this for a 2d component not needed? My gut feeling says I ...
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glsl demo suggestions?

In a lot of places I interviewed recently, I have been asked many a times if I have worked with shaders. Even though, I have read and understand the pipeline, the answer to that question has been no. ...
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403 views

Must I worry about quad-based rendering in real world scenarios?

Most of the time in the first chapters of a random book about rasterization and rendering techniques, I find some phrases about a triangle-based rendering system and a quad-based one. I have never ...
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4answers
6k views

Geometry instancing in OpenGL ES 2.0

I am planning to do geometry instancing in OpenGL ES 2.0 Basically I plan to render the same geometry(a chair) maybe 1000 times in my scene. What is the best way to do this in OpenGL ES 2.0? I am ...
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1answer
13k views

How to render a texture partly transparent?

Good Morning StackOverflow, I'm having a bit of a problem right now as I can't seem to find a way to render part of a texture transparently with openGL. Here is my setting : I have a quad, ...
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3answers
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What is the contents of the buffer *after* a call to glSwapBuffers()?

(SDL_GL_SwapBuffers() in particular) When you have drawn a scene, and you call swap-buffers, it is routine to then glClear() the scene before drawing anything; if you don't clear, what is the ...
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How many OpenGL programs should I use to render multiple objects?

My scene has multiple objects in it. (Let's say 3 cubes, 1 cylinder, 8 spheres.) I assume I should create a vertex shader for each. How many programs should I have? Alternatives: One program per ...
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How to invert background pixel's color

I'm writing a game and map editor using Java and jMonkeyEngine. In the map editor, I've got a brush done by wireframed sphere. My problem is: I want to make it visible everywhere, so I want to invert ...
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How do I change a sprite's color?

In my rhythm game, I have a note object which can be of a different color depending on the note chart. I could use a sprite sheet with all the different color variations I use, but I would prefer to ...
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5answers
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Is there a way to blur objects in a 2d game with OpenGL without using shaders?

Is there a nice way in OpenGL to blur objects without using shaders? Currently, I'm accomplishing blur by rendering the object slightly up, down, left, right, and the four diagonals from its original ...
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1answer
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Most efficient way to draw large number of the same objects, but with different transforms

I'd like to draw a large number (multiple thousands) of simple meshes (each maybe... a maximum of 50 triangles, but even that is a very large upper bound), all of which are exactly the same. As a ...
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575 views

Best practices with Vertices in Open GL

What is the best practice in regards to storing vertex data in Open GL? I.e: struct VertexColored { public: GLfloat position[]; GLfloat normal[]; byte colours[]; } ...
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How do multipass shaders work in OpenGL?

In Direct3D, multipass shaders are simple to use because you can literally define passes within a program. In OpenGL, it seems a bit more complex because it is possible to give a shader program as ...
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2answers
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How do you determine which object/surface the user's pointing at with lwjgl?

Title pretty much says it all. I'm working on a simple 'lets get used to lwjgl' project involving manipulation of a rubik's cube, and I can't figure out how to tell which side/square the user's ...
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OpenGL - Stack overflow if I do, Stack underflow if I don't!

I'm in a multimedia class in college, and we're "learning" OpenGL as part of the class. I'm trying to figure out how the OpenGL camera vs. modelview works, and so I found this example. I'm trying to ...
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660 views

OpenGL or OpenGL ES

What should I learn? OpenGL 4.1 or OpenGL ES 2.0? I will be developing desktop applications using Qt but I may start developing mobile applications in a few months, too. I don't know anything about ...
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How long does it take for OpenGL to actually update the screen?

I have a simple OpenGL test app in C which draws different things in response to key input. (Mesa 8.0.4, tried with Mesa-EGL and with GLFW, Ubuntu 12.04LTS on a PC with NVIDIA GTX650). The draws are ...
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Why should I not use glTools/glut when developing complete applications?

I've started learning how to use OpenGL a while back, using the OpenGL SuperBible, Fifth Edition, and I've had people arguing about the fact that the book doesn't really teach how to use OpenGL but ...
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OpenGL 2 and back vs 3 and forward: What are the key differences for 2D graphics?

OpenGL contexts before and after OpenGL 3.0 are rather different. So far I've really only worked with buffers on either side anyway, I do know the most notable difference is lack of Immediate Mode. ...
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803 views

How can I debug _why_ glDrawArrays is very slow?

I'm working on a game that uses CEGUI and Ogre. Recently, we've discovered that some of our customers with GeForce4 MX 4000's, performance is terrible. After a night spent debugging, I've tracked ...
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613 views

Should I batch up debug primitives for rendering in modern OpenGL?

I've recently started porting some old rendering demos I did to modern OpenGL. I had a debug drawing class in my old code which used immediate mode glBegin(), glEnd() etc. for rendering debug objects ...
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Optimizing Octree Rendering

Say I have an octree and at a certain level I store VBOs in that octree. I know the dimensions of of the nodes that own the vbo so I can do basic frustum culling. That works nicely because everything ...
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What state is stored in an OpenGL Vertex Array Object (VAO) and how do I use the VAO correctly?

I was wondering what state is stored in an OpenGL VAO. I've understood that a VAO contains state related to the vertex specifications of buffered vertices (what attributes are in the buffers, and what ...
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How are dynamic blending shadows like this created?

I would like to know, how dynamic shadows, that 'blend' onto other objects, are created.
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529 views

How to render portals in OpenGL?

I am making RPG in OpenGl and I need to make some portals. How should I render it if I want to see through the portal on the other side?
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864 views

Do I really have to write my own optimized model format?

So I'm a brand new noob to the world of game dev and I'm starting off by trying to write my own game using C++ and openGL. I'm getting into loading models etc and while searching around for "the best ...
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2k views

Enabling multisampling in Irrlicht?

I'm working on a little game that uses Irrlicht. I'm pretty new to Irrlicht and I was wondering how I could enable multisampling. The device driver is EDT_OPENGL initiated as such: IrrlichtDevice ...
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What causes some computers to have no or slow OpenGL, and how to fix it?

I am using Java with JOGL to create OpenGL enhanced 2D graphics. The graphics operations I use are nothing fancy, and should be supported by almost any recent graphics card. For example, my game ...
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Do I need to rewrite my HLSL shaders when porting from XNA to MonoGame?

I'm looking at porting an XNA project I have to monogame, but I have a fair number of HLSL shaders. It seems that Monogame for PC uses OpenGL as the rendering backend, and I'd rather not have to ...
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235 views

Can applications using old versions of Opengl still run on newer cards?

OpenGl 3.0 and up has a quite big difference from the older versions like OpenGl 2.x and opengl 1.x in terms of implementation, does that mean applications which are written with the old versions of ...
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1answer
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Using glReadBuffer/glReadPixels returns black image instead of the actual image only on Intel cards

I have this piece of code glReadBuffer( GL_FRONT ); glReadPixels( 0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, buffer ); Which works just perfectly in all the Nvidia and AMD GPUs I have tried, ...
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4answers
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Impact of variable-length loops on GPU shaders

Its popular to render procedural content inside the GPU e.g. in the demoscene (drawing a single quad to fill the screen and letting the GPU compute the pixels). Ray marching is popular: This means ...
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1answer
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How can I organize render and transformation data in a scalable fashion?

I am writing for OpenGL 2.0 and in the future porting to OpenGL ES 2.0. I only use VBOs and shaders (no immediate mode, no vertex arrays). I already have working solutions, they just... feel wrong. ...
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1answer
151 views

What is the optimal texture size?

I recently added a texture packager to my project that will pack a certain amount of textures into a single one, like this: So for example this one is 582x1023 pixels in size. The goal of adding ...
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234 views

Slow uniform array in shader causing FPS drop

I'm trying to use an uniform array of matrices in my compute shader. However, it's really slow. I've narrowed it down to this lines of code: uniform mat4 someMatrixArray[64]; ... vec4 result = ...
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Terrain & Multi-Texturing

I'm using OpenGL (Version 4.4) (and C++ if that matters). I've created a terrain renderer, the terrain is stored as a 3D scalar field (isosurface/voxels). It uses a slightly modified version of ...
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2answers
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Atmospheric scattering and sky geometry

I'm trying to implement an atmospheric scattering in my graphics (game) engine based on the GPU Gems article: link. An example implementation from that article uses a skydome. My scene is different - ...
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1answer
437 views

Weird problem with advect program in fluid simulator

I implemented 2d fluid simulator. Solver runs entirely on GPU. All works fine... on my work PC. But on home PC I have some awful glitches, and I can`t understand how to fix them. Empirically I ...
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2answers
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Getting the number of fragments which passed the depth test

In "modern" environments, the "NV Occlusion Query" extension provides a method to get the number of fragments which passed the depth test. However, on the iPad / iPhone using OpenGL ES, the extension ...