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
votes
3answers
5k views

Animation in OpenGL using 3D Models

I have created a model in Blender. Now i want to read that 3D model in my c++ program. I figured that a model can be exported to various file formats e.g. .obj, .3ds or COLLADA and then can be read in ...
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 ...
9
votes
2answers
5k views

OpenGL: Is it possible to use VAO's without specifying a VBO

On all the tutorials I can find about VAO's (Vertex Array Objects), they show on how to use them by configuring vertex attributes and binding a VBO (Vertex Buffer Object). But I want to create a VAO ...
9
votes
1answer
18k views

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); ...
8
votes
3answers
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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 ...
8
votes
3answers
3k views

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 ...
8
votes
3answers
2k views

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 ...
7
votes
4answers
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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. ...
5
votes
1answer
592 views

How to insert and remove blocks quickly in a Minecraftian world?

I currently have volume data for the world stored as an array of booleans. I then check each empty block and if it has non-empty neighbors the faces get drawn. This prevents me from sending a bunch ...
2
votes
2answers
6k views

What is the best method to update shader uniforms?

What is the most accepted way for keeping a shader's matrices up to date, and why? For example, at the moment I have a Shader class that stores the handles to the GLSL shader program & uniforms. ...
12
votes
12answers
13k views

Is it a waste to learn OpenGL?

What I've gathered around the internet and various sources is that DirectX has pretty much taken a stronghold grip onto the graphics API domain. And to be honest, I gave learning DirectX10 a chance, ...
12
votes
1answer
6k views

How can I tell how much video card memory I'm using?

I want to programmatically determine at runtime how much video card memory is being used by my program. Specifically I'm wondering about how to do it on a Windows machine using OpenGL, but am ...
11
votes
8answers
20k views

Getting Started with 2d Game Dev (C++): DirectX or OpenGL? [closed]

So, i'm a student looking to get my foot in the door of game development and im looking to do something 2D, maybe a tetris/space invaders/something-with-a-little-mouse-interaction clone. I pointed ...
10
votes
1answer
2k views

Should I give each character its own VBO or should I batch them into a single VBO?

I'm making a 3D first person game. Should I give each character its own VBO or should I batch all characters into a single VBO? What are the pros/cons?
7
votes
1answer
2k views

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 ...
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. ...
6
votes
1answer
1k views

How to implement translation, scale, rotation gizmos for manipulating 3D object's transforms?

I am in the process of developing a basic 3D editor. It uses OpenGL for rendering a 3D world. Right now my scene is just a few boxes of different sizes and I am at the stage where I want to be able to ...
6
votes
1answer
412 views

With what projection matrix should I render a portal to a texture?

I'm using OpenGL. I have problem with my engine's portal implementation. To create the first portal I do: create a virtual camera with the position of the second portal and the correct orientation ...
6
votes
1answer
5k views

Interleaving Arrays in OpenGL

In my pursuit to write code that matches todays OpenGL standards I have found that I am completely clueless about interleaving arrays. I've tried and debugged just about everywhere I can think of but ...
6
votes
1answer
6k views

GLSL if-else statement unexpected behaviour

This question is related to this other one I asked a few days ago. Because I have finally get to the bottom of the issue, I have rather preferred to open a new question with a more detailed ...
5
votes
3answers
7k views

Open Source Engine for RTS [closed]

I must write a cross-platform real-time-strategy game within 2-3 months. I want use C++ and OpenGL and am looking for an engine. The engine must be open source and work under both Linux and Windows. ...
4
votes
1answer
5k views

Combining rotation,scaling around a pivot with translation into a matrix

In short: I need to combine rotation (in the form of a quaternion), scaling around a pivot point along with translation into a transformation matrix. The long: I am trying to implement a proprietary ...
4
votes
2answers
8k views

How to draw a smooth circle in Android using OpenGL?

I am learning about OpenGL API on Android. I just drew a circle. Below is the code I used. public class MyGLBall { private int points=360; private float vertices[]={0.0f,0.0f,0.0f}; private ...
4
votes
2answers
4k views

How does one write to another process's OpenGL/DirectX context?

I want to write a short of chat client that display the messages in-game (OpenGL/DirectX), but I really don't know how to handle this. It is easy to write my client in my graphic context... but what ...
4
votes
2answers
7k views

View matrix in opengl

Sorry for my clumsy question. But I don't know where I am wrong at creating view matrix. I have the following code: createMatrix(vec4f(xAxis.x, xAxis.y, xAxis.z, dot(xAxis,eye)), vec4f( ...
3
votes
2answers
1k views

Checking if an object is inside bounds of an isometric chunk

How would I check if an object is inside the bounds of an isometric chunk? for example I have a player and I want to check if its inside the bounds of this isometric chunk. I draw the isometric ...
7
votes
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 ...
6
votes
1answer
6k views

GLSL - Rewriting shaders from #330 to #130

I recently created a game (LD21) that uses a geometry shader to convert points into textured triangles/culling. Since I was under the impression that the support for #330 was widespread I only wrote ...
5
votes
2answers
1k views

OpenGL behaviour depending on the graphics card?

This is something that never happened to me before. I have an OpenGL code that uses GLSL shaders to texture a 3D model. The code involves a lot of GPU texture processing, blending, etc... I wanted to ...
5
votes
2answers
2k views

Should the modelview and projection matrices be calculated in the shader or on the CPU?

At minimum I would have a camera with rotation and world position; projections parameters such as angle of view and perspective vs. orthographic; and meshes with scale, angle, and world position. ...
5
votes
1answer
843 views

How do particle systems work?

I want to implement a particle system in my game, but I've never programmed a particle system and don't know where to start. I only want to display pixels (GL_POINTs) with different sizes in ...
4
votes
2answers
234 views

How do I separate physics from framerate?

Skyrim (Creation Engine / Gamebryo) is a prime example of a game that has its physics tied to the framerate for which it has been heavily criticized, because if you disable vsync / have a > 60 HZ ...
4
votes
2answers
9k views

OpenGL - Understanding the relationship between Model, View and World Matrix

I am having a bit of trouble understanding how these matrixes work and how to set them up in relation to one another to get a proper system running. In my understanding the Model Matrix is the matrix ...
4
votes
3answers
3k views

What method replaces GL_SELECT for box selection?

Last 2 weeks I started working on a box selection that selects shapes using GL_SELECT and I just got it working finally. When looking up resources online, there is a significant number of posts that ...
4
votes
1answer
3k views

Access vertex data stored in VBO in the shader

If I wanted to store extra data in a VBO for skinning (indices for indexing into an array of matrices of bones and floats for applying weights to those bones) How would I go about accessing that data ...
4
votes
2answers
6k views

Texture antialiasing?

In my Minecraft-clone style game, blocks are textured with a border that is lighter then the block color. See picture below: To achieve this effect without the textures being blurry I use this ...
4
votes
3answers
2k views

Question About An Implementation Of Parallax Scrolling In C++/SDL/OpenGL

I been working in a project with a team for a Software Engineering class and we think that using the parallax scrolling will help our game to look really nice but we are not really sure if our idea ...
4
votes
1answer
801 views

In an artillery game how do I mask out the part of the terrain that was hit

Let's say I want to make a really simple artillery game, something like Gorillas. I don't have any experience in games, just some basic understanding of OpenGL. I want to do this for fun and to learn ...
3
votes
1answer
2k views

How do I fit the camera frustum inside directional light space?

I'm trying to improve the coverage of a shadow map for a directional light. Currently, it works great if the camera is looking straight down. However, if the camera is close to the ground and looking ...
3
votes
1answer
6k views

How to implement a basic arcball camera in OpenGL with GLM

I only just started learning OpenGL and even things like vector maths etc a couple of days ago, so I am having a bit of trouble figuring out exactly what to do to implement an arcball camera system. ...
3
votes
1answer
1k views

OpenGL ES drop shadows for 2D sprites

I've got a an OpenGL scene rendered with a bunch of sprites, and I'd like to automagically add drop shadows to all of them. Here's a picture showing what I mean: The scene uses orthographic ...
2
votes
1answer
2k views

Pygame water ripple effect

I have Googled for it but there are no ready scripts - as opposed to the same effect on Flash. I have checked the algorithm on The Water Effect Explained and also tested an implementation of the ...
-1
votes
1answer
474 views

Detailed Modern Opengl Tutorial? [duplicate]

I am asking for a specific modern opengl tutorial. I need a tutorial that does not skip to explain any lines of code. It should also include different independent objects moving/rotating (most ...
-2
votes
1answer
463 views

What are some good resources for learning OpenGL on Android? [closed]

Mainly I learned how to develop Android applications, but now I want to know how to make high resolution games, so does someone have a good book or a video that teaches OpenGL?
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).
8
votes
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 ...
7
votes
2answers
238 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
2answers
2k views

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 ...
6
votes
1answer
1k views

exporting bind and keyframe bone poses from blender to use in OpenGL

EDIT: I decided to reformulate the question in much simpler terms to see if someone can give me a hand with this. Basically, I'm exporting meshes, skeletons and actions from blender into an engine ...
6
votes
3answers
1k views

Understanding how to create/use textures for games when limited by power of two sizes

I have some questions about the creating graphics for a game. As an example. I want to create a motorbike. (1pixel = 1centimeter) So my motorbike will have 200 width and 150 height. (200x150) But the ...