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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571 views

Using full resolution of depth buffer for 2D rendering

I'm working on a front-to-back renderer for a 2D engine using an orthographic projection. I want to use the depth buffer to avoid overdraw. I have a 16-bit depth buffer, a camera at Z=100 looking at ...
8
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2answers
528 views

stencil shadows - doom 3 engine - precision errors - shadow cracks - why?

I am testing the limits of the Doom 3 engine - in regards to maximum map size. I noticed some stencil shadow precision errors that become more pronounced when objects get further and further away ...
8
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2answers
2k views

How do I apply skeletal animation from a .x (Direct X) file?

Using the .x format to export a model from Blender, I can load a mesh, armature and animation. I have no problems generating the mesh and viewing models in game. Additionally, I have animations and ...
8
votes
2answers
714 views

Does use of simple shaders improve performace/battery life?

I'm making OpenGL game for Android. Till now i've used only fixed function pipeline, but i'm rendering simple things. Fixed function pipeline includes a lot of stuff i don't need. So i'm thinking ...
8
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1answer
2k views

How is animation handled in non-immediate OpenGL?

I'm a newbie to modern OpenGL. I'm comfortable with the immediate OpenGL methodology, but I've never done any serious use of VBOs. My question is about animation. In immediate mode, to achieve ...
8
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1answer
2k views

Creating a glitch effect similar to Watch Dogs

I'm currently working on a LibGDX game. When a user does something wrong, I would like all the graphics on the screen to jitter very similar to the glitch/distort effect seen in the game Watch Dogs ...
8
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2answers
359 views

How to avoid subpixel values in a resolution independent 2D game with orthographic projection?

I'm trying to do resolution independent rendering of moving sprites in a 2D game. My plan is work in a fixed coordinate system in my world (for example 960x540) and use orthographic projection to ...
8
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2answers
2k views

Frustum Culling with VBOs

I have terrain being rendered in my project using VBOs in OpenGL. I would like to apply some Frustum Culling but have no idea how to access each polygon as its drawn to check if it is in view. I think ...
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2answers
1k views

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 ...
8
votes
1answer
539 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 ...
8
votes
1answer
1k views

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 ...
8
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2answers
647 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 ...
7
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1answer
9k views

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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votes
6answers
2k views

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 ...
7
votes
1answer
4k views

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 ...
7
votes
2answers
359 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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3answers
3k views

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, ...
7
votes
2answers
3k views

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 ...
7
votes
1answer
818 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 ...
7
votes
6answers
980 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 ...
7
votes
4answers
1k views

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. ...
7
votes
2answers
414 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 ...
7
votes
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 ...
7
votes
3answers
1k views

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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2answers
3k views

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 ...
7
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1answer
4k views

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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2answers
2k views

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 ...
7
votes
5answers
2k views

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 ...
7
votes
1answer
582 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[]; } ...
7
votes
2answers
5k views

Updating texture memory via shader?

What the title says.Is it possible to update a texture via a glsl shader ? Something like : //Read vec4 Pixel = texture2D(TextureID,gl_TexCoord[TextureIndex].st); //Write to texture memory ? vec4 ...
7
votes
2answers
4k views

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 ...
7
votes
2answers
8k views

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 ...
7
votes
2answers
3k views

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 ...
7
votes
2answers
663 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 ...
7
votes
2answers
4k views

How is the gimbal locked problem solved using accumulative matrix transformations

I am reading the online "Learning Modern 3D Graphics Programming" book by Jason L. McKesson As of now, I am up to the gimbal lock problem and how to solve it using quaternions. However right here, ...
7
votes
2answers
2k views

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. ...
7
votes
1answer
1k views

Efficiently rendering to 3D texture

I have an existing depth texture and some other color textures, and want to process the information in them by rendering to a 3D texture (based on the depth contained in the depth texture, i.e. a ...
7
votes
2answers
871 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 ...
7
votes
3answers
19k views

How to draw 2D images using OpenGL, in SDL?

After everything, I managed to find a simple piece of code that shows how to draw a 2D image with openGL: #include "SDL/SDL.h" #include "SDL/SDL_opengl.h" #include "SDL/SDL_image.h" ...
7
votes
2answers
656 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 ...
7
votes
3answers
2k views

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 ...
7
votes
1answer
3k views

glDrawElements vs glDrawArrays for polygons that do not reuse vertices

Is it better to use glDrawElements or glDrawArrays when not reusing vertices? There must be some difference, otherwise people would always use glDrawElements? I suppose the question could be ...
7
votes
2answers
1k views

How are dynamic blending shadows like this created?

I would like to know, how dynamic shadows, that 'blend' onto other objects, are created.
7
votes
1answer
618 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?
7
votes
1answer
896 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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votes
2answers
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 ...
7
votes
2answers
2k views

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 ...
7
votes
1answer
2k views

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 ...
7
votes
2answers
239 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 ...
7
votes
1answer
4k views

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, ...