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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10
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3answers
2k views

Missing features from WebGL and OpenGL ES

I've started using WebGL and am pleased with how easy it is to leverage my OpenGL (and by extension OpenGL ES) experience. However, my understanding is as follows: OpenGL ES is a subset of OpenGL ...
2
votes
1answer
3k views

Using gluLookAt to move camera in 2D iPhone game?

I'm trying to use gluLookAt to move the camera in my iPhone game, but every time I've tried to use gluLookAt my screen just goes "blank" ( grey in this case ) I'm trying to render a simple triangle ...
10
votes
2answers
5k views

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. ...
34
votes
4answers
23k views

Vertex Array Object (OpenGL)

I've just started out with OpenGL I still haven't really understood what Vertex Array Objects are and how they can be employed. If Vertex Buffer Object are used to store vertex data (such as their ...
31
votes
5answers
19k views

Should I use textures not sized to a power of 2?

In the early days of OpenGL and DirectX, texture sizes were required to be powers of two. This meant interpolation of float values could be done very quickly, using shifting and such. Since OpenGL 2....
10
votes
2answers
4k views

Efficient skeletal animation

I am looking at adopting a skeletal animation format (as prompted here) for an RTS game. The individual representation of each model on-screen will be small but there will be lots of them! In ...
3
votes
2answers
2k views

Implementing camera for 2d side scroller game?

I'm implementing a 2D side scroller for iOS (using C/C++ with OpenGL) (beat'em up style like double dragon/final fight ). My scenes are composed of one cyclical background image ( the end of the ...
8
votes
1answer
2k views

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 ...
3
votes
2answers
560 views

WinAPI window taking 50% of CPU when idle

I'm currently working on a game that creates a window using WindowsAPI. However, at the moment the process is taking up 50% of my CPU. All I am doing is creating the window and looping using the ...
7
votes
2answers
667 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 ...
6
votes
3answers
2k views

Common light map practices

My scene consists of individual meshes. At the moment each mesh has its associated light map texture, I was able to implement the light mapping using these many small textures. 1) Of course, I want ...
11
votes
3answers
5k views

What is the difference between OpenGL 1.x and 2.x?

Is there a good tutorial that shows the difference between OpenGL 1.* and 2.*? It would be very helpful to know which functions I should not be calling (like glBegin(), I assume).
3
votes
1answer
2k views

Why does glGetUniformLocation report some of my uniform locations as -1?

I have been writing GLSL shaders for over a year but this is the first time I have run into this problem. I am on the iOS platform - if that matters. In a vertex shader I have this: uniform mediump ...
0
votes
2answers
1k views

opengl memory issue - quite strange

I have heard that textures consumes lot of memory but I am surprised how much.... I have 7 textures 1024 16 bit each. And while I will run my app it consumes 57MB of memory. I think that this is "a ...
3
votes
1answer
987 views

Is there a global “low resolution” filter for OpenGL?

I'm trying to learn a little about OpenGL, so I'm making a simple 2D game (with OpenTK), and so far it's coming along well. I thought it would be fun to give it that, for lack of a better word, ...
-1
votes
1answer
215 views

Retrieve the coordinates of the *occluding* (closest/drawn) pixels during 3D overlap, using OpenGL?

Sorry if the question is not worded well, I'm a new to both 3D and OpenGL. How could I go about obtaining the 3D coordinates of the occluding object, at the point where occlusion is happening (i.e. ...
1
vote
1answer
534 views

GL_INVALID_OPERATION in glEnd

I'm having problems drawing a simple sprite. When I draw: void CSprite2D::render() { CHECKGL(glLoadIdentity()); CHECKGL(glEnable(GL_TEXTURE_2D)); CHECKGL(glEnable(GL_BLEND)...
3
votes
1answer
2k views

Why does OpenGL seem to ignore my glBindTexture call?

I'm having problems making a simple sprite rendering. I load 2 different textures. Then, I bind these textures and draw 2 squares, one with each texture. But only the texture of the first rendered ...
1
vote
1answer
378 views

OpenGL 3 and the Radeon HD 4850x2

A while ago, I picked up a copy of the OpenGL SuperBible fifth edition and slowly and painfully started teaching myself OpenGL the 3.3 way, after having been used to the 1.0 way from school way back ...
9
votes
5answers
4k views

OpenGL's matrix stack vs Hand multiplying

Which is more efficient using OpenGL's transformation stack or applying the transformations by hand. I've often heard that you should minimize the number of state transitions in your graphics ...
3
votes
2answers
359 views

What happens to allocated video memory when the program terminates?

Using OpenGL it is possible to load textures, buffer arrays, compiled shaders and more to the video memory. When a C++ program exits, heap memory that was allocated by it is cleaned. What happens to ...
2
votes
1answer
719 views

Beginner question about vertex arrays in OpenGL

Is there a special order in which vertices are entered into a vertex array? Currently I'm drawing single textures like this: glBindTexture(GL_TEXTURE_2D, texName); glVertexPointer(2, GL_FLOAT, 0, ...
4
votes
4answers
3k views

how to do partial updates in OpenGL?

It is general wisdom that you redraw the entire viewport on each frame. I would like to use partial updates; what are the various ways can do that, and what are their pros, cons and relative ...
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 ...
3
votes
1answer
2k views

OpenGL ES Basic Fragment Shader help with transparency

I have just spent my first half hour playing with the shader language. I have modified the basic program I have which renders the texture, to allow me to colour the texture. varying vec2 texCoord; ...
1
vote
2answers
3k views

why specular light is not running?

i'm on JOGL this is my method for lighting: private void lights(GL gl) { float[] LightPos = {0.0f, 0.0f, -1.0f, 1.0f}; float[] LightAmb = {0.2f, 0.2f, 0.2f, 1.0f}; float[] LightDif = {0....
0
votes
5answers
2k views

OpenGL vs DirectX? [closed]

I saw the articles that were going on about OpenGL being better than DirectX and that Microsoft are really just trying to get everyone to use DirectX even though it's inferior so that gaming is almost ...
8
votes
4answers
717 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 ...
-3
votes
1answer
645 views

Why is this .obj loader not drawing anything but the included .obj?

I've been adapting a tutorial on .obj file loading on the windows system to glut. The thing's not drawing a thing except the "Foot.obj" file that the tutorial included and I'm going kinda nuts trying ...
5
votes
2answers
1k views

interpolating frames in a vertex shader

My models are stored as a set of meshes, each with a vertex list and normal list per key-frame, and indices for GL_TRIANGLES which is shared for all frames. Each frame I lerp between two adjacent key-...
5
votes
3answers
754 views

game models that stand in grass

The open source game Glest has models that feel detached from the ground that they sit on because of the hard edges. In real life, grass is not flat! What are the options and recommendations for ...
3
votes
3answers
1k views

Can you sync screen update on vertical retrace with OpenGL?

In OpenGL, is there a way to ensure I get exactly, no more nor less, 60 (or whatever rate my monitor is set for) frames per second? Of course given that the new frame can be calculated in less than 1/...
2
votes
2answers
6k views

Is there any opengl cel shading tutorial out there (without GLAUX)?

I want to implement cel shading into my opengl game. I have only found a nehe tutorial that uses glaux (old as hell). I'm looking into it, but I wanna avoid the pain of learning how to translate those ...
3
votes
1answer
159 views

Chess engine on which to apply a custom-made OpenGL skin

Is there any opensource chess engine that I can use to practice my OpenGL skillset? I think it would be a neat exercise.
1
vote
0answers
4k views

How can I get and install glaux.h in Visual Studio 2008? [closed]

I would rather NOT use glaux.h, but I need to make it run some code from gametutorials.com. How can I find it and install it? I've followed the instructions of a couple of google results, but I'm ...
1
vote
3answers
2k views

Correct order of rotation and translation

Trying to get this right in openGL: 1) glRotate( cameraRotation ) 2) glTranslate( -cameraPosition ) 3) glRotate( objectRotation ) 4) glTranslate( objectPosition ) 5) Draw Object is that right?
10
votes
3answers
3k views

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 ...
3
votes
1answer
2k views

Loading and drawing materials using Lib3ds

Hey all, i'm currently using Lib3ds to load models into my C++/OpenGL project. So far, i've been follow the model loading tutorial found here. The tutorial gives a good example of how to draw the ...
3
votes
3answers
4k views

OpenGL and 3ds model loading: Path of least resistance?

Hey guys, im working on a final class project for a graphics class, and me and a teammate are making a simple 3d tower defense game. We're currently planning on using 3ds models and drawing them ...
15
votes
6answers
6k views

What is the purpose of the canonical view volume?

I'm currently learning OpenGL and haven't been able to find an answer to this question. After the projection matrix is applied to the view space, the view space is "normalized" so that all the points ...
16
votes
7answers
5k views

Modern Shader Book? [closed]

I'm interested in learning about Shaders: What are they, when/for what would I use them, and how to use them. (Specifically I'm interested in Water and Bloom effects, but I know close to 0 about ...
4
votes
3answers
2k views

BlitzMax - generating 2D neon glowing line effect to png file

Originally asked on StackOverflow, but it became tumbleweed. I'm looking to create a glowing line effect in BlitzMax, something like a Star Wars lightsaber or laserbeam. Doesn't have to be realtime, ...
14
votes
1answer
941 views

Is there any performance benefit to sharing shaders between programs?

OpenGL allows you to share the same shader between multiple programs. Aside from saving small amounts of memory and a shader handle, are there any GPU-side performance benefits to doing this?
4
votes
2answers
2k views

Lost on OpenGL versions, which to start?

I was reading about OpenGL, and found out the Red Book is a great book for me to read to learn. I then read that even though they have 3.x and 4.x versions, I should still stick to 2.x so I don't ...
1
vote
3answers
4k views

Will I have an easier time learning OpenGL in Pygame or Pyglet? (NeHe tutorials downloaded) [closed]

I'm looking between PyGame and Pyglet, Pyglet seems to be somewhat newer and more Pythony, but it's last release according to Wikipedia is January '10. PyGame seems to have more documentation, more ...
5
votes
2answers
3k views

Rendering 2d sprites into a 3d world?

In opengl how do I render 2d sprites in opengl given that I have a png of the sprite? See images as an example of the effect I'd like to achieve. Also I would like to overlay weapons on the screen ...
4
votes
3answers
558 views

What resources are available to read and share pyglet code?

I am a Python programmer (I know the ins and outs decently well), and I have dabbled with Pygame. I want to make 3D applications and games, and so naturally I've been looking at OpenGL. pyglet uses ...
3
votes
3answers
7k views

Camera Rotation using angles

I currently try to rotate a camera (using gluLookAt()) around a point , i successfully do it for rotating around one global axis. But when i want to use more than one axis , I'm stuck . I've ...
4
votes
3answers
2k views

Java and Eclipse setup properly, how do I install JOGL or LWJGL? [closed]

I have my Java environment installed alongside Eclipse, and I was successfully able to create and run a new project (simple System.out.println("Yay I work!"); I have the OpenGL SuperBible, and I ...
4
votes
1answer
2k views

OpenGL clipping plane

I need to move clipping plane of OpenGL and begin the clipping from that position. The default location of clipping plane is (0,0,0), so if my model is far enough from the center of coordinate system ...