Tagged Questions
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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1answer
11 views
draw two models changing the MVP matrix (android opengl)
I'm newbie with opengl2 in android, and I'm making an app in which I'm testing some things. Now I was trying to duplicate a sphere object with a texture, so I thought it was enough to change my MVP ...
2
votes
0answers
23 views
Spherical Area Lights do not match reference
So I'm adding spherical area lights to my application, and comparing my results with mitsuba, I am getting some differences (left is my approach, right is mitsuba - a pathtraced reference):
What I ...
1
vote
0answers
11 views
Storing and using UV and Normal Data with OpenGL
I'm having trouble mapping UV coordinates to vertices in OpenGL. I'm binding my buffers and enabling all of my attrib arrays perfectly well and things are rendering - but what I'm stuck on is how to ...
0
votes
1answer
23 views
Send OpenGL video flux via UDP [on hold]
It is possible to send the video flux of an OpenGL desktop app via UDP on Linux ? I looked up FBO and off-screen rendering but I still can't figure out how to extract the video flux and send it.
I'm ...
0
votes
1answer
27 views
Solution for Shipping Optimized and Minified GLSL?
I've tried to find a reputable optimizing compiler for GLSL that takes source shaders, performs what optimizations it can statically assume, and outputs a minified GLSL file with optimizations, ...
0
votes
1answer
22 views
OpenGL: Generating a single square with a Quad Strip
I am currently trying to create a terrain generation system (for my 3D game) with OpenGL 2.1.
The way I am doing it requires the creation of a massive 2D square that consists of multiple smaller ...
0
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0answers
17 views
Using CEGUI with SDL2 and openGL4
I am trying to get CEGUI to work on a pc game im making that uses with SDL2 and opengl4 in visual studio.
I tried following this,
http://cegui.org.uk/wiki/Using_CEGUI_with_SDL_and_OpenGL
but it ...
0
votes
0answers
29 views
How to spin a 2D quad in place using only matrices?
In short, I have a textured 2D quad (a sprite). I would like to rotate/spin it about the z-axis (coming out of the screen) using nothing but matrices.
If I do the following to a transform with scale ...
0
votes
1answer
10 views
Translation matrix applyed to the view matrix not working (android opengl2)
I have managed to do an small app using opengl2 in android. It consists on a sphere moving over a rectangle, both with a texture. It's just a test in which I'm testing my first steps in opengl.
Now ...
0
votes
0answers
24 views
Why is glBlendEquation MAX behaving like this?
I'm rendering to a FBO for accumulated lighting in 2D. The plan is to use GL_MAX blend equation to blend all the light sources as a local maximum - I don't want to use the normal "add" blend mode.
...
0
votes
1answer
65 views
How should my engine Identify objects
I'm making a fairly basic openGL 3D engine, at the moment, when you load an object, you would write
manager->LoadObjFile("cube.obj");
manager->AddParent("uvmap.bmp", "cube.obj", "cube", ...
4
votes
0answers
23 views
Irradiance Map ( Irradiance environment map)?
As irradiance map is generated for every possible normal for all the texels in environment map (as every texel act as a light source) so that we can look up irradiance map, based on normal of fragment ...
0
votes
1answer
30 views
OpenGL EBO vs Mesh representation
As an exercise set to myself, I wanted to make a Mesh loader using modern OpenGL.
However, I have to ways of representing the notion of face of a mesh.
Currently, I am using what seems the most ...
0
votes
2answers
38 views
OpenGL strange color issue
I recently made terrain generation for my game, and I created a lighting system (simply diffuse lignting), but there's a strange problem around the edges.
I know, OpenGL interpolates the different ...
-1
votes
1answer
87 views
Create YUV texture for GL_TEXTURE_EXTERNAL_OES format
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favorite
I need to create a yuv texture for GL_TEXTURE_EXTERNAL_OES format.
source : ...
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0answers
76 views
+100
Turning On/Off Vsync no longer working when rendering to an offscreen buffer
I have this reaallly strange issue that as soon as I render to an offscreen framebuffer I am no longer able to toggle VSync while my application is running. I am using OpenTK as the opengl wrapper, ...
1
vote
1answer
36 views
opengl storing multiple indices into indices buffer
After parsing collada files I found out that we have to load two(or more) indices each pointing to say a vertex or normal etc.
like this (<p>3 0 2 0 0 0</p>)
Is there a way to load (and ...
0
votes
0answers
33 views
How to properly use a 3D texture in OpenGL 4?
I working on a student project which consists to make clouds volumetric rendering and implement the feature in an existing engine based on OpenGL 4 and written in C++.
To do so, I have set a compute ...
0
votes
0answers
30 views
Tilemap not rendering properly
I'm making a single-screen scrolling platformer (OpenGL/SDL) and I've made a tilemap out of a 2D array, pre-sized with variables of the LEVEL_HEIGHT and LEVEL_WIDTH. Each element in this 2D array ...
0
votes
1answer
41 views
Strange shadow behavior when light direction is parallel to a plane
i have a strange problem with shadow acne. It occurs when the light direction is parallel to a plane. Here is my code and a few images of the problem:
//this calculates the shadow matrix
...
-1
votes
0answers
27 views
Everything rendering black on new machine
So I've ported my OpenGL project over to my new computer and everything is compiling and linking fine but all of my objects are being rendered without any textures (complete black).
My shaders are ...
0
votes
1answer
30 views
OpenGL perspective matrix far plane
The near plane clips at exactly the value I set just fine but instead of clipping at 1000 the far plane clips at 1.
Here is the code for the projection matrix:
public static Matrix4f ...
0
votes
1answer
54 views
Irrlicht app: Creating STL exception leads to segfault
I'm developing application with C++ language and Irrlicht engine.
When I add std::runtime_error("err") expression into my code, I got segmentation fault at address 0 (before entering to main). If ...
1
vote
1answer
44 views
Opengl occlusion culling huge performance drop
Hello I tried to implement occlusiong culling to my engine in opengl using java & lwjgl. Occlusion works but... performance drop is huge I mean from 60-70 fps to 3-6 fps. Here is my question what ...
5
votes
2answers
559 views
Why would one use a separate alpha mask for sprites?
I've seen tilesets of the game Braid, and for each tileset in the main folder there is an alpha map for it in "alpha" folder.
I wonder, why just not to draw your image as it is (with transparent ...
2
votes
0answers
47 views
GLSL shader with light colors wrong on nvidia optimus
So, I built some code to draw a spinning cube with a red light on the right side, and a blue one on the left.
I run it on my laptop with optimus graphics, and on my desktop with nvidia. On the laptop, ...
0
votes
2answers
81 views
How can I better structure my code to reduce coupling between input and graphics?
I've been working through a few OpenGL tutorials, and decided to give myself the exercise of trying to draw a grid, with the added requirement of being able to press the - and + keys to change the ...
0
votes
1answer
24 views
Reset Opengl multisampling
I start using multisampling by doing
ContextAttribs attribs = new ContextAttribs(3, 3).withForwardCompatible(true).withProfileCore(true);
Display.create(new ...
1
vote
1answer
104 views
Collisions being detected before objects are intersecting
I'm making space invaders (in OpenGL/SDL) and I'm currently having issues with getting the collisions (box collisions) between the bullets and the enemies to be properly detected. In my update() ...
-1
votes
2answers
59 views
How to lock the mouse cursor in the middle in a first person camera?
I want to get a first person camera (like Call of Duty or Minecraft etc.) but I don't know which is the best way to do it.
I have some camera increase rotation methods (camera.increase ...
1
vote
1answer
71 views
How do I structure code with multiple VBOs?
As per my previous question, it seems it would be desirable to use more than a single VBO in my OpenGL program. But I've hit a wall when trying to do this. Currently my main function looks something ...
0
votes
1answer
47 views
Frustum culling only working at certain angles
So how I'm doing this is a little sketchy but I plan on changing it to either AABBs or spheres once I get it working. So the problem I'm having right now is that the frustum culling I've implemented ...
0
votes
0answers
44 views
Black Screen when using High-Performance NVIDIA Processor
I have an issue where my program renders a black screen on other computers. I narrowed it down to when a different graphics card is being used. When I run the program using Integrated Graphics ...
0
votes
2answers
69 views
How to manage VBO geometry for constantly changing data?
Before going into specifics, I'm mostly interested in making simple 2D games with some 3D elements, not fancy AAA.
Based on what I've gathered, everyone seems to suggest to use OpenGL 3+ with ...
1
vote
4answers
246 views
How to draw a Minecraft-like world with Open GL
I recently completed the this Open GL tutorial. The tutorial shows how to set up a window and shaders, and teaches you how to draw a single cube in the middle of the screen, which all makes sense to ...
1
vote
1answer
56 views
Libgdx, TiledMap, and tearing
My TiledMap tears when the window is specific sizes, resized, or the camera moves.
The tileset is padded by 2px and have tried as high as 10px. Each tile is 70x70.
Here are the pack.json ...
0
votes
0answers
16 views
In Cocos-2d-x, is there a way to get a shared OpenGL context for use with background loading
We are using parts of the Cocos-2D-X engine and we have a background loading thread which loads textures in the background. Is there a way to get a ShareGroup so we can safely bind an OpenGL context ...
0
votes
0answers
30 views
OpenGL ES 2.0 how to access LUT
I've created a look up table for my fragment shader and I'm passing it in as a uniform float array.
uniform float hueLut[360];
My program works fine on most devices but I ran across one device ...
0
votes
1answer
49 views
One framebuffer for each light vs unique framebuffer per light
Currently I have two ideas how to implement my lighting system:
1) Use one framebuffer per light source
no need to switch texture attachments of framebuffer
may be faster
bigger memory usage
2) ...
0
votes
4answers
77 views
Issue translating objects by one unit in the y direction
I'm currently making space invaders (in OpenGL/SDL) and I'm running into an issue with the movement of the aliens. I have a 2-d vector of aliens (5 rows of 11) and I'm translating each in the x ...
2
votes
2answers
183 views
What happens if I don't call glNormal for some vertices?
Let's say I have an object where some vertices will have the same normal and some won't. Are these two equivalent? Note I'm working with an old OpenGL version (2.3 I think).
Option 1
...
1
vote
0answers
59 views
Memory leak with glfwSetWindowTitle? [closed]
I am using GLFW for a game, and I have a function which allows me to set the window title.
// PROBLEM WITH INCREASING MEMORY USAGE
void WindowSystem::setTitle( const string & title )
...
0
votes
1answer
73 views
Sprite quickly disappears after rendering
I'm currently making space invaders and I'm using the game loop pattern as described here. I have an entity class from which there is a spaceship derived class. The base entity class contains all of ...
0
votes
0answers
34 views
Unprojecting a 2D triangle
I am looking to describe triangle in world space, given that the following are known:
Two of its vertices in screen space (or rays in the world)
One of its vertices in world space (the right angle ...
0
votes
1answer
48 views
Sprite Sheet Texture not being rendered
I'm making space invaders (in OpenGL/SDL) and I've run into a problem
when trying to draw the sprite for the spaceship from the spritesheet.
In my entity class, I have a pointer for the sprite that ...
1
vote
1answer
33 views
Android Opengl: Alternate values for gl_FragColor
I'm writing an Android application that utilizes opengl to perform some changes to the camera output. I've written my code in such a way that I finally figured out what is causing the performance ...
0
votes
0answers
34 views
Multithread OpenGL to Upload Meshes
My game is rendered in dynamically generated chunks, each of which has its own mesh.
Every time I generate a chunk and upload its mesh, there is a huge lag spike.
Is there a good way of eliminating ...
0
votes
1answer
32 views
GlViewport-code doesn't work in one specific screen?
I am currently working on a small game using LibGDX and Java.
However, I have found one oddly specific problem. I want the game to resize so that it never has to be cropped and so it never has to cut ...
0
votes
2answers
126 views
Optimising Voxel World Rendering
There are a couple of questions like this already. This one is different because it is specifically about rendering, as opposed to navigation and generation. I've implemented suggestions from here ...
0
votes
2answers
134 views
SDL or SFML: which is the best option if I only want to use OpenGL for my graphics? [closed]
I've read a lot about creating graphics with OpenGL in SDL and SFML over the past few days, and I want to know which one I should pick. As mentioned in most of the things that I've read, both allow ...
