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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3answers
85 views

Rendering many similar objects [closed]

I am writing an city builder. The graphics should look pretty simple, there are no fancy models or textures. Something like Synekism. Thus I have only simple models for buildings and splines for ...
0
votes
1answer
114 views

Is there a way to start with OpenGL 3.0+ without need to write my own shaders?

I'm starting with OpenGL and found out that after OpenGL 3.x you must write your own shaders (think it's obligatory). Am I right here? I have made some research but I can't seem to find the answer. ...
2
votes
2answers
90 views

Translating an object in the rotation direction

I am creating a graphical scene with OpenGL and SDL, and I'm running into a problem in regards to translating an object in its rotation direction. Each of the graphical objects in the scene has a ...
1
vote
1answer
76 views

What is the fastest way of reading an atomic counter?

I have an atomic counter in my fragment shader that my application reads after each drawcall. I am currently using glMapBufferRange with GL_MAP_READ_BIT set. This absolutely destroys my applications ...
1
vote
1answer
60 views

Can drawing to an FBO be done purely with a depth input texture, or do I also need a color attachment?

I am trying to implement Exponential Shadow Maps and I've got it almost working. The part I am stuck on is the "optional" separable Gaussian blur of the depth map to give soft-looking shadows. I am ...
1
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0answers
52 views

OpenGL: Avoid geometry shader for cubemap framebuffer

I want to render an environment map into a cubemap framebuffer but I dislike the fact, that I have to use the geometry shader to set gl_Layer because the geometry shader would be a basic passthrough ...
3
votes
1answer
161 views

glBufferData consuming system memory

I am memory profiling my game in Visual Studio and about 60% of memory usage is happening from calls to glBufferData(). I may be missing something but should this consume GPU memory instead of system ...
2
votes
1answer
93 views

OBJ file, face materials and drawing them with OpenGL

I'm implementing a model class which loads OBJ and MTL files, and ran into an issue or question with face materials. Consider the following example: It's a cube with 5 sides Gray and 1 side Green. ...
0
votes
1answer
105 views

Do I necessarily need to write a vertex shader to use geometry instancing?

I've quickly read the GPU gem about geometry instancing, there are many wordings and I'm not sure I understand it well. If I understand it well, when you use instancing, if you want to apply ...
0
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0answers
43 views

Trying to get the fragment shader to output a list

I am trying to figure out a way to get the Fragment Shader to output a list of gl_VertexID-s. I want to use the GPU to get a list of vertices in the viewing frustum. Is there any way I can get a ...
1
vote
1answer
82 views

Averaging normals, or tangents

I am using a library to load an obj but it doest compute the tangets for each vertex, which I need for normal mapping and pom. I computed my tangets, and bitangents, everything appears to be fine, but ...
0
votes
1answer
75 views

OpenGL light calculation

I want to add somebasic point lights to my OpenGL application. I read here that I have to caluclate the light in a pre-projection space: Lighting can be done in any pre-projection space (e.g., ...
7
votes
2answers
674 views

What is the advantage of OpenGL's direct state access mechanism?

I've been reading about OpenGL 4.5 Direct State Access (DSA) at opengl.org and not sure if I'm getting it right. It seems to imply, that the old way is less efficient: glBind(something) glSetA(..) ...
0
votes
0answers
31 views

How to setup States in NIftyGUI and LWJGL

I think this is a simple question but I just cannot figure it out. I have a main menu that is using nifty gui and then my game which is rendered using OpenGL Code (LWJGL) I cannot figure out how to ...
-2
votes
1answer
108 views

How can I get “Good enough” collision for entities? [closed]

I am developing a Pirate ship fighting game. It's a great concept: Ships firing cannonballs, sinking each other, having to work as a team to complete the mission... But.. I've tested it with about ...
1
vote
0answers
74 views

glGetUniformLocation returns 23724032

as the title says, I have a problem using glGetUniformLocation call that returns, for the following code, the value 23724032. I'm writing a little engine and the draw function of my models is: void ...
0
votes
0answers
54 views

Matrix, vector multiplications in OpenTK

I developed a 3d model viewer in c++ with OpenGL, and in c# in OpenTK. Both are using the same shader, but the output from OpenTK is not correct. I read that OpenTK is row major order, and OpenGL is ...
0
votes
0answers
36 views

Lwjgl Textures Overriding true type font

I am making a game in java but I recently came across a problem when I bound my textures, my true type fonts would start copying the texture and i would just see a wall of color where my words had ...
0
votes
0answers
64 views

What limits the number of vertices the GPU can process per clock cycle?

I am currently experimenting with OpenGL to make my own game. I wrote some test code to see what are the limits of my GPU. I own a Geforce 840m. This essentially consists of a draw command ...
0
votes
1answer
45 views

glPush/PopMatrix on projection Matrix?

I am trying to simulate a camera which is always at same distance behind my player, my plan is, to transform the projection matrix correctly with glPush/PopMatrix, as i do it with the modelview ...
0
votes
0answers
24 views

How to create freeglut/openGL template in codeblocks?

After the installation of gcc, codeblocks and freeglut-dev on my Kubuntu 14.04, i was trying to create a project based on openGL and freeglut, but i don't know where is located the freeglut ...
0
votes
2answers
77 views

Z-Value of clip-space position is always 1.0

I render a lot of quads on the screen into z direction (20 x 2000). I want to get the depth value in a final render target. But it looks like z is always 1.0f. I checked the result with the OpenGL ...
0
votes
0answers
59 views

Transformation order for augmented reality game using OpenCV and OpenGL

I'm trying to create a simple AR application where I'm augmenting the camera image of a Kinect with virtual objects that are tracked using an optical tracking system. The following picture ...
0
votes
2answers
69 views

How animate objets seperately?

I've set up a simple scene with some triangle and quads. With glPushMatrix() and glPopMatrix() i achieved to move an object to a new position, relative to another object in my render scene, but what ...
0
votes
1answer
77 views

Getting the real fragment depth in GLSL

I am trying to write a simple GLSL shader that just renders the real (not normalized) depth of a fragment as a floating point value. So far, I've figured out how to get the depth of a vertex, and ...
0
votes
1answer
98 views

Distortion problem with perspective projection

For various reasons – partly educational, partly technical – I'm writing a 3D game engine from scratch, using OpenGL 3.0; aiming for Core Profile, eventually, so of course I'm using a custom matrix ...
0
votes
0answers
29 views

Perspective Projection Far Plane Not Clipping?

I've just discovered that far away objects in my world don't seem to clip like they should with a perspective projection matrix. When I fly far away from my main landscape, so that I am much more ...
0
votes
0answers
47 views

How to create custom cubemap images?

I managed to use cube maps in OpenGL to get reflection and refraction effects. So far I used images from this site, however, I want to create my own set of images to use in a cubemap, the idea is just ...
0
votes
1answer
171 views

OpenGL 4.3 in C++ : Drawing static Triangle (“Hello Triangle”). Color does not appear (Triangle is just completely white)

I am going through an OpenGL book trying to get the examples to work. I am using Glew, Glfw, and that's it beyond Opengl 4.3, which my I know my graphics card supports completely via the OpenGL ...
0
votes
1answer
85 views

Java LWJGL - Monster follow script not working properly

I have written a script to be set off whenever a player is within a distance of the monster. The script checks if the x position is greater than or less than the players x, and same for the z. (y is ...
1
vote
2answers
111 views

How does rendering with Swing compare to rendering with openGL?

[summary: Is the performance of Swing at least in the same dimension as openGL [through LWJGL]? If yes, what percentage would you give it? What possible other problems can I expect from Swing in the ...
2
votes
1answer
125 views

What are some ways of making a game engine centered around the idea of drawing vector lines and polygons only? [closed]

I've always loved the look of games that just use simple lines and polygons for graphics. Rez is one of my favorite games, visually. I'm a programmer and designer first and foremost, and I'm horrible ...
39
votes
3answers
4k views

Why do tutorials use different approaches to OpenGL rendering?

http://www.sdltutorials.com/sdl-opengl-tutorial-basics http://www.opengl-tutorial.org/beginners-tutorials/tutorial-2-the-first-triangle/ These two tutorials use completely different approaches to ...
0
votes
3answers
243 views

In OpenGL what's quicker, lots of smaller VAOs, or one large one updated each frame?

In my game engine, a mesh can be made of many submeshes. These submeshes may or may not share vertex data with the rest of the mesh, if they don't they have their own vertex data array. I've noticed ...
1
vote
2answers
187 views

Tiled Rendering - Projection matrix

I'm trying to figure out how to perform tiled rendering of my 3d scene (OpenGL). The motivation is to cut the scene up into several textures, combining them into a single image for saving at a very ...
0
votes
0answers
44 views

OpenGL not rendering to correct target

I have a fbo, with 8 textures in it (g-buffer). What I'm trying to do, is to render all information from opaque objects to first four(color, normal, position, depth), and info from transparent objects ...
0
votes
0answers
58 views

A simple “beam tracing” simulation

I am trying to implement a simple beam tracing simulation. Basically it models the path of a beam within a pipe: In the picture, the beam starts emitting from p1, hitting the boundary at p2 and ...
0
votes
2answers
61 views

GL_SPOT_CUTOFF not working properly

I'm new to OpenGL. I'm studying OpenGL 2.1 and I'm trying to make a little program to test the GL_SPOT_CUTOFF property, but when I set a value between 0.0-90.0, the light doesn't work and everything ...
0
votes
1answer
86 views

Java LWJGL - How can I click to interact with objects?

I want to be able to click on a monster to walk to him and start attacking him. The part that doesnt make sense to me is the conversion between the mouse position, and the actual terrain position. ...
3
votes
1answer
118 views

Where can I find OpenGL state changes profiling?

Is there any benchmark that actually measure state changes cost in OpenGL 3.x/4.x and gather an average statics for all graphics cards? (I don't want to optimize only for my old AMD card, I'm not even ...
0
votes
2answers
49 views

How to render apart blocks of a cone [closed]

in OpenGL I want to render a cone in parts like on the image. My problem is to calculate the arc of each block in 3D space. has someone an idea how to handle this?
0
votes
1answer
89 views

Normal Mapping issue

The first image shows a spotlight shining correctly on the floor. The second image shows the same spotlight but rotated 180 degrees. The first is correct, the second is not. The third image ...
0
votes
1answer
67 views

Textures not rendering on part of Cube [closed]

Hello all I have been trying learning opengl and have rendered a colorful cube and decided to texture it, now when I run the program the textures render on all of the faces except for the back face ...
0
votes
1answer
104 views

OpenGL 4.4 LWJGL - How can i render text to the screen

I have been told that you need to create a texture atlas for the font, and individually assign each character to a texture and add them up to create the string you want to produce. This seems a little ...
1
vote
1answer
79 views

Problem with SLD/OpenGL

I've started to do sth. with SDL/openGL, but I haven't managed to get this tutorial running yet (http://www.sdltutorials.com/sdl-opengl-tutorial-basics). Since this tutorial, or most tutorials at ...
0
votes
0answers
57 views

Maximum tile and texture size for tiled maps

I'm currently making a game using libGDX and Tiled. Everything was running fine until I changed the tile size from 96x96 to 300x300. Most layers are still displayed correctly but the tiles of a ...
0
votes
1answer
67 views

Manipulating vertices after multiplication with MVP matrix (OpenGL)

I'm making a collage of lots 16x16 renders on a 512x512 texture, of the same scene, from various viewing positions and angles, preferably lots of times per second. I've profiled my program (which ...
2
votes
2answers
169 views

What are my options other than game engines? [closed]

I'm a programmer. I've experience in Java, python, and c++. I see that some big games are built using game engines (Crysis uses Cryengine). However, other don't (Bayonetta for example). what's their ...
4
votes
1answer
90 views

Textures “don't work” when I don't specify any texture parameters. Is this a driver bug or intended behavior?

Whenever I try to use textures, I have to at least specify the sample filtering parameters (GL_TEXTURE_MAG_FILTER, GL_TEXTURE_MIN_FILTER) for textures to work at all. If I don't, sampling the textures ...
0
votes
1answer
71 views

OpenGL rendering to multiple windows, having 1 main loop for each window

I have written a little OpenGL framework in the past year that i would like to extend to support multiple windows in the near future. I have an idea about what I would like to do but I am not sure if ...