Questions tagged [opengl]

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 applications like CAD software and computer games. It is also cross-platform. The OpenGL standard is controlled by the Khronos group, which also controls OpenGL ES.

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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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Does multiple downsampling have a benefit?

So i came across this site and you can see these lines on the first and second paragraph: For a crude but easy effect, draw the bright portions of the scene (eg, light sources) into an FBO, then ...
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What are screen space derivatives and when would I use them?

I see the ddx and ddy glsl functions and the hlsl equivalents come up in shader code every now and then. I'm currently using ...
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Large vertex buffer vs multiple draw calls

I'm just getting started with OpenGL, and I'm attempting to use it to create a 2D game. In this game, I have a hexagonal grid made up of a very large variety of differently-colored hexagons. As a ...
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Does the order of vertex buffer data when rendering indexed primitives matter?

I'm building a 3d object's triangles. If I can write them to the buffer in the order they are calculated it will simplify the CPU code. The vertices for the triangles will not be contiguous. Is there ...
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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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How do I implement a quaternion based camera?

UPDATE The error here was a pretty simple one. I have missed a radian to degrees conversion. No need to read the whole thing if you have some other problem. I looked at several tutorials about this ...
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Orthographic unit translation mismatch on grid (e.g. 64 pixels translates incorrectly)

I am looking for some insight into a small problem with unit translations on a grid. Update and Solved I solved my own issue. See below for details. Everything in this part of the post turned out to ...
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Getting a texture from a renderbuffer in OpenGL?

I've got a renderbuffer (DepthStencil) in an FBO and I need to get a texture from it. I can't have both a DepthComponent texture and a DepthStencil renderbuffer in the FBO, it seems, so I need some ...
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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?
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Is GLUT obsolete?

A question was asked about good, up-to date OpenGL resources, one of the answers was a link to a tutorial about modern OpenGL programming. The tutorial in question uses GLUT and GLEW, but I have read ...
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What alternatives to GLUT exist?

I am trying to learn OpenGL, and I just found out that GLUT is obsolete. I already know SDL, and it seems it is a good alternative. Should I use SDL to develop games with OpenGL, or are there any ...
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Why does clip space in OpenGL have 4 dimensions?

I will use this as a generic reference, but the more i browser online docs and books, the less i understand about this. ...
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How to reduce image size without pixelation?

I see lots of games with smooth edges characters and high res images, however when I try to reduce images to say 64x64 for my character I just get a pixelated mess. even if I start with a 64x64 canvas ...
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How to emulate PSX's graphics with OpenGL?

I want to know what options (or shaders) to set so that my OpenGL game looks like Playstation 1 game. I know it probably can not be achieved 100 % because PSX used television and television renders ...
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How do I know if memory isn't being handled right?

My (2D) game's memory footprint seems to increase any time I load a texture, e.g. when I start my game it uses 30 mb private RAM, after transversing a ~367mb background file, so it's all in RAM at ...
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Difference between “buffer” and “array” in OpenGL?

When I read doc on webGL or OpenGL there can be seen some patterns in how names of functions and objects are used. But I can't understand the difference between buffer object and an array. There are ...
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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 ...
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OpenGL - white edges on cubes

In a minecraft-like game I'm making, I get white edges on my cubes: It is much more noticeable in darker textures. The textures are being setup like this: ...
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How to render a texture partly transparent?

Good Morning StackOverflow, I'm having a bit of a problem right now as I can't seem to find a way to render part of a texture transparently with openGL. Here is my setting : I have a quad, ...
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Difference in glDrawArrays and glDrawElements

While refreshing my mind on OpenGL ES, I came across glDrawArrays and glDrawElements. I understand how they are used and sort ...
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Should I distribute shaders in a compiled form or in plain text?

Having an application that uses shaders that have been wrote in GLSL, what is the best strategy for the distribution in the real world and for the desktop and mobile? I'm aiming to distribute this in ...
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Learning OpenGL: Red and Blue book still relevant?

I've recently purchased the Orange book( GLSL ) and am wondering if it is important at all to read through the red and blue books as well? Any thoughts?
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How does UVW texture mapping work?

I'm trying to understand the mathematical theory behind UVW mapping. Can anyone explain me how UVW mapping works? Or at least provide me a pointer?
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Trying to understand light on Opengl, how to simulate a realistic sun light?

I don't know if I'm doing something wrong or missing anything but I want to simulate sun light, like in a sunny day. When the object is facing the directional light, it's well lit and there's no ...
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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).
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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, ...
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How do multipass shaders work in OpenGL?

In Direct3D, multipass shaders are simple to use because you can literally define passes within a program. In OpenGL, it seems a bit more complex because it is possible to give a shader program as ...
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Best (Most Popular?) Image Format For Texturing [closed]

Okay, so I am using C++ with OpenGL, and I am going to create a loader to load in textures for my 3D game. (But the textures are 2D). I want the option of transparency, even if I decide not to use it. ...
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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 ...
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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 ...
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Am I allowed to make my Minecraft clone open source?

I'm developing in my spare time a game like Minecraft. In fact, it isn't "like Minecraft", because I'm trying to make it a close as possible copy of it (meant as exercise for myself at the age of 16 ...
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Fastest way to create a simple particle effect

I am looking to the fastest way to create really simple particle effect that will be spammed like hell on the game... Basically, my game looks like a vectrex game, made mostly of lines... I want to ...
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How can I use the graphics pipeline to render volumetric data based on a density function?

Both graphics APIs (OpenGL and DirectX) devise a well defined pipeline in which several stages are programmable. These programmable stages require to take a fixed minimum amount of data and are ...
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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 ...
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API agnostic bridges (ie. OpenGL/D3D/Whatever). Do you use them, how you make them. Pro's and Con's [closed]

You are making a 3d engine. You want best of multiplatform worlds. Suddenly you realize that if you want to use Direct3D on Windows machines and OpenGL on OSX/Linux, you'll have to sacrifice supported ...
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Should unbind buffers?

I'm making some tests with OpenGL ES 2 and got some questions, my current program is like that: ...
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Most common 3D model format for opengl

I'm a novice that is starting to play with OpenGL ES on Android devices. To practice OpenGL I wanted to create a small game engine and so I was wondering what the best 3D model file format would be. ...
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differences between opengl 3 and opengl 4

I'm just getting started with game programming and I want to start learning opengl. I found a very great tutorial from scratch to get started with opengl 3 and I'm wondering if there is a big ...
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How does Halo draw projectiles?

I am trying to draw projectiles and doing billboarding. A projectile consists of a bill-boarded "particle" and a "tracer". When I billboard a projectile, it cannot be seen when the player's viewing ...
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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 ...
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Deferred tiled shading, tile frusta calculation in OpenGL

I'm trying to do deferred tiled shading in OpenGL using the compute shader but I have hit a snag when trying to create the frustum for each tile. I'm using AMD's Forward+ demo (written in D3D) as a ...
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Object-Oriented OpenGL

I have been using OpenGL for a while and have read a large number of tutorials. Aside from the fact that a lot of them still use the fixed pipeline, they usually throw all the initialisation, state ...
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Skybox texture artifact on edge

I have strange problem with drawing skybox texture on Mac. On iPhone everything is going fine. I have tried to change near and far planes value with no success. It is a skybox of six textures, and ...
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How do I use depth testing and texture transparency together in my 2.5D world?

Note: I've already found an answer (which I will post after this question) - I was just wondering if I was doing it right, or if there is a better way. I'm making a "2.5D" isometric game using OpenGL ...
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OpenGL binding and relations among entities

This is mostly a documentation question. I hope this is the proper place to ask and not, for example, programmers or stackoverflow. I did not read the OpenGL specification, but from books (Red Book) ...
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Rotate object around fixed axis

I am trying to let the user of my app rotate a 3D object drawn in the center of the screen by dragging their finger on screen. A horizontal movement on screen means rotation around a fixed Y axis, and ...
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Is it a good option to simultaneously work on a game and a game engine? [closed]

I'm considering this, now I work on 3d game but I want also to make in slow tempo, iteratively a game engine is it a good choice? The game what I working on is with non custom engine (Unity, Unreal ...
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What is the purpose of indices in 3D rendering?

Suppose you were creating a 3D cube in OpenGL. You implement the necessary vertex data for the object (cube). What would be the point of using indices? ...
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How can I bend an object in OpenGL?

Is there a way one could bend an object, like a cylinder or a plane using OpenGL? I'm an OpenGL beginner (I'm using OpenGL ES 2.0, if that matters, although I suspect, math matters most in this case, ...

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