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 would I setup fog to follow a players coordinates?

I'm wondering if its possible to setup a fog to a player's coordinates (where there is fog around the player to make it more third-person) the main reason I ask this is because I have my player more ...
7
votes
0answers
428 views

Variance shadow maps don't want to render properly

I've implemented VSM (and also ESM) in my engine but results are for me not as I expected and saw in many examples published on network. I set filtering of shadow maps to GL_LINEAR but when I compare ...
7
votes
2answers
349 views

Why does accessing a uniform float make my shader more than twice as slow?

My fragment shader was significantly slowed down by a recent change, and I've been trying to understand why. I isolated the main slow-down to accessing a single particular uniform float. If I include ...
7
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4answers
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OpenGL 2D Rasterization Sub-Pixel Translations

I have a tile based 2D engine where the projection matrix is an orthographic view of the world without any scaling applied. Thus: one pixel texture is drawn on the screen in the same size. That all ...
6
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3answers
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What features does D3D have that OpenGL does not (and vice versa)?

Are there any feature comparisons on Direct3D 11 and the newest OpenGL versions? Well, simply put, Direct3D 11 introduced three main features (taken from Wikipedia): Tessellation Multithreaded ...
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2answers
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What does changing GL_TEXTURE_WRAP)_(S/T) do?

I am working through some beginner OpenGL tutorials, and the current one teaches how to apply a texture to a simple rectangle. The tutorial states tells me to set the texture parameters ...
6
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4answers
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2D Platformer Collision Handling

I am trying to create a 2D platformer (Mario-type) game and I am some having some issues with handling collisions properly. I am writing this game in C++, using SDL for input, image loading, font ...
6
votes
2answers
777 views

How to use OpenGL functions from multiples thread?

I'm writing a small game using OpenGL. I'm implementing basic networking in this game and I'm facing a problem. I have a thread in my client socket class that check for available data, when there ...
6
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2answers
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Where to start learning OpenGL with C++? [duplicate]

Possible Duplicate: What are some good learning resources for OpenGL? I have learnt C++ and made some cool text based games and such but I would love to start graphical programming. I'm a ...
6
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3answers
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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 ...
6
votes
2answers
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OpenGL ES 2.0: Using VBOs?

OpenGL VBOs (vertex buffer objects) have been developed to improve performance of OpenGL (OpenGL ES 2.0 in my case). The logic is that with the help of VBOs, the data does not need to be copied from ...
6
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2answers
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How detect which OpenGL texture formats are natively supported?

For example, how detect if my videocard doesn’t support "bgr8" and convert it to another format, such as "rgba8" in software mode. UPDATE: Sorry for the confusion. This question more about situation ...
6
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1answer
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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 ...
6
votes
3answers
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glTranslate, how exactly does it work?

I have some trouble understanding how does glTranslate work. At first I thought it would just simply add values to axis to do the transformation. However then I have created two objects that would ...
6
votes
3answers
615 views

shadowing billboards

I have a lot of billboarded 3D spheres (they have a heightmap so work properly with depth and penetration; although each is made of just a quad (with slight distortion), they look and feel and are ...
6
votes
2answers
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2D games and modern OpenGL

Preconcepts Ok, so what I've gathered so far is this: don't use fixed pipeline (deprecated or going to be deprecated) vbos store "object models" (n vertex data, mostly) vaos describe how data is ...
6
votes
4answers
2k views

How can I generate a view or projection matrix for OpenGL 3.+

I'm transitioning from OpenGL 2 to OpenGL 3.+ and to GLSL 1.5. I'm trying to avoid using the deprecated features. My question how do we now generate the view or projection matrix. I was using the ...
6
votes
1answer
340 views

GLSL vertex shaders with movements vs vertex off the screen

If i have a vertex shader that manage some movements and variations about the position of some vertex in my OpenGL context, OpenGL is smart enough to just run this shader on only the vertex visible on ...
6
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2answers
4k 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 ...
6
votes
4answers
2k views

Spell Effects/Shaders

I want to be able to achieve spell effects that cause a fragmenting/discoloring effect on the sprite. The first couple seconds of this video http://www.youtube.com/watch?v=HNCFh7mkvuc shows what I ...
6
votes
2answers
358 views

Know if you're fully utilizing the GPU

I render ~17.000 VAOs each frame. 2.840.386 triangles. Only applying texture, nothing else. I have three computers and the performance across them is not as expected. Cheap laptop(i3-4010U & ...
6
votes
1answer
1k views

How would one draw many objects using the same VBO

I'm kind of stuck with this question for some time now, maybe because I don't know exactly what to search for, it might be a term I have not heard of yet as most tutorials ends after drawing one ...
6
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2answers
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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, ...
6
votes
4answers
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Generating triangles from a square grid

I have a 2D square grid of values representing terrain elevations, and I want to generate triangles from that grid to make a 3D view of the terrain. My first thought was to split each square ...
6
votes
2answers
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Toggle Fullscreen at Runtime

Using the library GLFW, I can create a fullscreen window using this line of code. glfwOpenWindow(Width, Height, 8, 8, 8, 8, 24, 0, GLFW_FULLSCREEN); The line for creating a standard window looks ...
6
votes
2answers
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Disadvantages of using multiple versions of OpenGL in LWJGL?

So, I'm trying to figure out LWJGL, and my goal is to use OpenGL 3.2 (because pretty shaders are pretty). But in every tutorial I can find for LWJGL, they import a bunch of different OpenGL versions ...
6
votes
1answer
392 views

Why would I support multiple rendering engines simultaneously?

I've seen some games from the early 2000s that had a launcher where you could select the rendering engine you wanted to use: DirectX or OpenGL. Maybe I haven't looked hard enough, but I haven't seen ...
6
votes
2answers
643 views

GL_EXT_draw_instanced vs VBO's

I'm having trouble understanding the benefit of the newer GL_EXT_draw_instanced over traditional VBO's. Don't both keep geometry cached on the gpu for faster redrawing? VBO's seem much more ...
6
votes
1answer
8k views

How to use modern OpenGL for 2D games?

I've found a plethora of "modern" OpenGL (3.0+) tutorials for 3D, but I have found next to nothing when looking for information on how to use it for 2D game development. How can I get started using ...
6
votes
3answers
17k 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" ...
6
votes
2answers
1k views

Best way to do buttons for an OpenGL ES iPhone game

I'm making a simple 2d game in OpenGL ES and I want to add movement buttons to it. What's the best way of going about this? In previous projects I've simply added UIButtons to the view but I hear ...
6
votes
1answer
498 views

Display Lists in OpenGL

I heard that there was a faster method of displaying vertices, rather than recreating the GL_TRIANGLES, each time the scene is drawn. I thought I read somewhere that this method was obselete. Why ...
6
votes
4answers
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Can't understand these UV texture coordinates (range is NOT 0.0 to 1.0)

I am trying to draw a simple 3D object generated by Google SketchUp 8 Pro onto my WebGL app, the model is a simple cylinder. I opened the exported file and copied the vertices positions, indices, ...
6
votes
1answer
262 views

Why do I see spaces between polygons in OpenGL, only on an Nvidia 720M?

I'm developing an OpenGL application that renders .obj 3D models. I use VBOs to render the polygons. Using the same code, the loaded models appear fine on all PCs, except on my Nvidia 720M. My ...
6
votes
1answer
575 views

Multithreaded Game Loop

I'm trying to implement a multithreaded game loop. I already did that but had to use a few locks for that, which ruined the performance. After researching a bit I came up with this idea: Instead of ...
6
votes
2answers
1k views

Fixed Function vs Programmable Pipeline performance with many batches

In OpenGL 2.0 I can easily make 10,000 draw calls per frame (with state changes in between each call). However, if i try to do this in either OpenGL ES 2.0 or DirectX9 with shaders, my peformance is ...
6
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 ...
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
297 views

Get SFML to report the version of OpenGL that is being used

How can I get SFML to report the version of OpenGL that is being used by the render window?
6
votes
1answer
1k views

VBO and gl*Pointer management practises?

I'm aware it's not a simple yes/no question and for the moment I can't tell if it can be simply answered, or is it a topic for a long discussion which is not suitable for our Q&A format. I want ...
6
votes
1answer
3k views

Bones Animation - Matrices and calculations

We are 'on final' when it comes to finishing the project, but just before implementing the animation system. Our Client decided to choose "Bones Animation" - which is that I should export each ...
6
votes
3answers
2k views

Direct3D and OpenGL Matrix representation

As I read in OpenGL matrices are column major. It means that if I create a 16 element array first four elements are the first column in matrix. Is it the same for Direct3D or any transformation's ...
6
votes
4answers
12k views

Wavefront *.obj loader in C++

I'm creating a game using OpenGL (via SDL) and C++ (via Visual Studios 2010 Professional). During the game, I will be using 3D character animation. I'd like to use wavefront *.obj files for all the 3D ...
6
votes
1answer
5k views

Help understanding gluLookAt()

I am fairly new to openGL( 3 months ) and am asking for assistance in understanding the fundamentals behind gluLookAt(). Currently I have spent most of my time with openGL modeling scenes with fixed ...
6
votes
1answer
2k 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 ...
6
votes
1answer
409 views

Spherical harmonics lighting interpolation

I want to use hardware filtering to smooth out colors in texels of a texture when I'm accessing texels at coordinates that are not directly at the center of the texel, the catch being that the texels ...
6
votes
1answer
722 views

GLSL subroutine not being used

I'm using a gaussian blur fragment shader. In it, I thought it would be concise to include 2 subroutines: one for selecting the horizontal texture coordinate offsets, and another for the vertical ...
6
votes
1answer
2k views

Problem with Assimp 3D model loader

In my game I have model loading functions for Assimp model loading library. I can load the model and render it, but the model displays incorrectly. The models load in as if they were using a seperate ...
6
votes
1answer
2k views

How do engines like Unreal relate to OpenGL or D3D?

Well I'm completely completely new to computer graphics and even more to game development. I am searching info and all that stuff to have the basics quickly. But there's a big question mark in my ...
6
votes
1answer
1k views

Rendering 2D grass

My current project, using Java and OpenGL, has a fairly standard overhead tilemap in the style of the Zelda games. I'd really like to add "real" grass to the grass tiles so that there are actually ...