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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Engine Rendering pipeline : Making shaders generic

I am trying to make a 2D game engine using OpenGL ES 2.0 (iOS for now). I've written Application layer in Objective C and a separate self contained RendererGLES20 in C++. No GL specific call is made ...
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How can I create a “night sky” effect in OpenGL?

I am creating a game using OpenGL and I want to render the effect of a night sky with a few stars in it. I want to have a shiny black effect in the sky so that it looks good. Could some one help in ...
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497 views

In OpenGL, what is “zero state” rendering?

Recently at a job interview, I mentioned that I taught myself modern OpenGL and rendering with vertex buffer objects because my university only taught the fixed function pipeline with immediate mode ...
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223 views

How can I profile the speed of my vertex and fragment shaders separately?

I'd like to know how I can check to see if either my vertex or my fragment shader is a bottleneck in my rendering pipeline. I've read about using glQueryCounter with the GL_TIMESTAMP target to get ...
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971 views

Handle many lights in a scene (with shaders)

I'm curious about how to handle many lights in a scene. Given a very big map in a role playing game, with dungeons (with lights in there) etc. I know about deferred lighting, but that only answers how ...
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OpenGL/GLSL: Render to cube map?

I'm trying to figure out how to render my scene to a cube map. I've been stuck on this for a bit and figured I would ask you guys for some help. I'm new to OpenGL and this is the first time I'm using ...
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Lighting in a Minecraftian World

Minecraft is a game that is largely based on a heightmap and uses that heigtmap information to flood the world with light. From my understanding the highest point in the heightmap is the end of the ...
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Sorting objects before rendering

I'm trying to implement a scene graph and in all the articles i've come across there is talk about object sorting. So you'd sort your objects by "material" for example. Now untill i sat down and ...
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OpenGL get the outline of multiple overlapping objects

I just had an idea for my on-going-game made with opengl in c++: I'd like to have a big outline (5-6 pixel) on multiple overlapping object when the player win something. I thought the best way is to ...
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How does gluLookAt work?

From my understanding, gluLookAt( eye_x, eye_y, eye_z, center_x, center_y, center_z, up_x, up_y, up_z ); is equivalent to: glRotatef(B, 0.0, 0.0, 1.0); ...
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How do I generate a 3D race track from a spline?

I want to generate a 3-dimensional race track around a spline that describes its shape. Here's an illustrative video. The track should be an endless tunnel that sweeps along a 3D spline, with some ...
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OpenGL vs OGRE : Which is the best for beginner? [closed]

I am interested in getting into game development and posses good C/C++ programming skills. I have tried OGRE before, and I am curious whether I should learn either OGRE or OpenGL as a starting point. ...
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Library to load images into textures, Linux, C and OpenGl

I am looking for simple, self-contained C library for Linux to load images from files into OpenGL textures. The licence should be quite liberal: zlib, bsd, mit or something. I have found SOIL, however ...
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900 views

OpenGL vs physics?

I am very new to game programming and I am in my first project. I have come to a point that I need expert advice: Now for the game physics to be able to work on objects, it needs to know each ...
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4answers
714 views

I need help with 3d shading/lighting

How do you guys handle shading in a 3d game? I have a directional light source that shades one side of a tree made of cubes. The remaining 3 sides all get ambient shading only. So the 3d effect is ...
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How do OpenGL's texelFetch and texture differ?

I understand the main differences between texelFetch and texture, but have some questions about the details: Does texelFetch involve a performance penalty? Such as not using a cache or such? Are ...
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3answers
982 views

Why is it possible to encounter a texture coordinate greater than 1 or less than 0

I'm studying a text about texture mapping and in the preparing to draw session, I read: Define the texture wrapping parameters. This will control what happens when a texture coordinate greater than ...
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what is world space and eye space in game development?

I'm reading a book about 3D stuff and OpenGL. The book often talks about world space and eye space. What exactly is the "world space?" Does the "eye space" mean the projection?
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Font outline in OpenGL, FTGL

I'm using FTGL library to render fonts in my game, but I have completely no idea how to create an outline around text. Achieving a shadow could be easy, because I can simply do it like this: (pseudo ...
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3answers
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What is a better abstraction layer for D3D9 and OpenGL vertex data management?

My rendering code has always been OpenGL. I now need to support a platform that does not have OpenGL, so I have to add an abstraction layer that wraps OpenGL and Direct3D 9. I will support Direct3D 11 ...
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3answers
5k views

Draw contour around object in Opengl

I need to draw contour around 2d objects in 3d space. I tried drawing lines around object(+points to fill the gap), but due to line width, some part of it(~50%) was covering object. I tried to use ...
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3answers
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Deferred shading - how to combine multiple lights?

I'm starting out with GLSL and I've implemented simple deferred shading that outputs G-buffer with positions, normals and albedo. I've also written a simple point light shader. Now I draw a sphere ...
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In OpenGL, how can I discover the depth range of a depth buffer?

I am doing a GL multi-pass rendering app for iOS. The first pass renders to a depth buffer texture. The second pass uses the values in the depth buffer to control the application of a fragment shader. ...
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2answers
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What is the advantage of OpenGL's direct state access mechanism?

I've been reading about OpenGL 4.5 Direct State Access (DSA) at opengl.org and not sure if I'm getting it right. It seems to imply, that the old way is less efficient: glBind(something) glSetA(..) ...
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631 views

What is the primary use of Vertex Buffer Objects?

From what I've read, it seems VBOs are purely for performance. I'm working on a very rudimentary learning project in lwjgl and I'm just trying to figure out what more advanced features of the library ...
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Trapping mouse inside window in OpenGL with GLUT?

I perfectly understand that GLUT is limited and the following problem can't probably be solved with OpenGL/GLUT, but since I don't know exactly if it can or not, I better just ask. Maybe I'm doing ...
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Sprite sheets with buffer objects and shaders

What is the "best" way to handle sprite sheets with shaders and buffers? In immediate mode it is easy to modify a sprite's texcoords when it is drawn, but I don't know how to do this with modern ...
8
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1answer
3k views

Taking advantage of multithreading between game loop and openGL

Talking in context of a game based on openGL renderer : Let's assume there are two threads : Updates the game logic and physics etc. for the in game objects Makes openGL draw calls for each game ...
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2answers
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Fastest way to draw small particles in opengl?

Quick question : Which is the fastest method to render a large array of 4x4/8x8 particles in opengl ? Currently i spend 2triangles for each one but i think that its slow so i would really like to know ...
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4answers
523 views

Why nearby triangles tend to disappear?

I've just enabled back face culling and I'm noticing a weird behavior: when all vertices of my triangle is outside the view and 2 of them is behind me (I think) the triangle disappears. So to see it, ...
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4answers
512 views

What types of effects or shaders would you teach in a rendering class? [closed]

I am looking for a list of topics that would be fun to learn and not too complicated to implement with a prototyping tool like FX Composer or Rendermonkey for an intermediate class of real-time ...
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2answers
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How do games handle rendering Asian unicode text?

I'm currently in the process of implementing text rendering in my game engine, and I decided to utilize AngelCode's BMfont to generate font textures, and then have OpenGL render textured quads for ...
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1answer
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How to efficiently render a large terrain mesh?

Recently I've been stuck on a problem thinking about the best way to generate a terrain into my game. In another projects I normally used heightmaps, so all the core-work was based on the engine used, ...
8
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1answer
445 views

OpenGL: Light at end of tunnel effect

Anyone knows any implementation of the "light at the end of tunnel" effect? where the outside is entirely bright and gradually becomes more visible? The reverse could also be true, where the inside ...
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3answers
822 views

I would like to know how an OpenGL driver will be implemented to learn opengl internals?

I'm learning OpenGL and really like to know how the interaction with the Graphics card will be. I feel understanding how it was implemented in the Graphics driver, will let me know complete internals ...
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4answers
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Geometric Transformations on the CPU vs GPU

I've noticed that many 3d programs normally do vector/matrix calculations as well as geometric transformations on the CPU. Has anyone found an advantage in moving these calculations into vertex ...
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1answer
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Rendering 8 bit graphics

I have a strong programming background just not from game development. I only made some pong and snake in high school and I did some OpenGL in college. I want to make my own game engine. Nothing ...
8
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1answer
3k views

SDL2 with OpenGL — weird results, what's wrong?

I'm porting an app to iOS, and therefore need to upgrade it to SDL2 from SDL1.2 (so far I'm testing it as an on OS X desktop app only). However, when running the code with SDL2, I'm getting weird ...
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1answer
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Getting OpenGL hardware acceleration with SDL on Linux

I'm trying to use SDL + OpenGL but I don't believe hardware acceleration is working because the framerate for around 18000 polys is about 24fps on a quad core machine but is a hopeless 1-2fps on an ...
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4answers
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How to improve batching performance

I am developing a sprite based 2D game for mobile platform(s) and I'm using OpenGL (well, actually Irrlicht) to render graphics. First I implemented sprite rendering in a simple way: every game object ...
8
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1answer
3k views

Which c/c++ model animation library for OpenGL [closed]

I'm fairly new to game development, played around with xna before and just learning OpenGL & c now and I'm interested to know which c/c++ based model animation libraries are out there and which ...
8
votes
3answers
363 views

How do I play a video file in OpenGL?

Is there a library that will let me load a movie file and play it in an OpenGL application? Or maybe just a code sample that someone has lying around? I'm also using GLUT, if that makes a ...
8
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3answers
465 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 ...
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2answers
491 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 ...
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2answers
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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 ...
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698 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 ...
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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 ...
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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 ...
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320 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 ...
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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 ...