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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6
votes
1answer
334 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
2answers
372 views

Changing player color without multiple player bitmaps [duplicate]

Possible Duplicate: How to colorize certain parts of a model - like RTS games have those team colors? Ok, so here is my current situation. I have a player model, fully UV mapped, and textured. ...
6
votes
1answer
3k views

gl_PointCoord always zero

I am trying to draw point sprites in OpenGL with a shader but gl_PointCoord is always zero. Here is my code Setup: //Shader creation..(includes glBindAttribLocation(program, ATTRIB_P, "p");) ...
5
votes
1answer
323 views

Can I leverage the fact that my scene is often static to improve OpenGL (JOGL) performance?

My scene is drawn based on the location of several (often several million) vertices (kept in VBO's) and a camera. I can easily tell in my code when my scene has changed and when it hasn't. There are ...
5
votes
1answer
156 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 ...
5
votes
1answer
3k views

What is the recommended way to output values to FBO targets? (OpenGL 3.3 + GLSL 330)

I'll begin by apologizing for any dumb assumptions you might find in the code below since I'm still pretty much green when it comes to OpenGL programming. I'm currently trying to implement deferred ...
4
votes
1answer
4k views

OpenGL ES 2.0: Moving Camera in Orthogonal (2D) Projection

I have quite large 2D game scene. The scene is much larger than the screen of the LCD. Therefore, I have to move the camera (view) in desired directions, to display particular parts of the scene. ...
4
votes
2answers
376 views

How does a general Renderer::drawRect(0, 0, 100, 100) handle VBO's?

Lots of game engines and GUI systems have a general Renderer class with functions like: renderer.drawRect(0, 0, 100, 100); renderer.drawText(204, 452, "Hello, world!"); I understand how this could ...
4
votes
3answers
2k views

Is “pure” OpenGL productive enough?

I know that this is a difficult question and I hope I can convey my meaning. Over time I've used many different engines from XNA over Unity to Panda3d and even tried native directX once. My final ...
3
votes
1answer
160 views

what is the very last element of a 4x4 transformation matrix for? [duplicate]

while its a similar value to its neighbour - Z translation (and I wont say if thats above or to the left for fear of sparking a religious war!) and it only seems to change when the Z translation value ...
3
votes
1answer
689 views

How can I implement beam effects like these?

I am interested in the techniques I could use to create the following effects: Can I accomplish this with a particle system or a series of texture quads, or what? You can see this effects in ...
3
votes
2answers
296 views

Instead of the specified Texture, black circles on a green background are getting rendered. Why?

I'm trying to render a Texture via OpenGL. But instead of the texture black circles on a green background are rendered. (They scale, depending what the rotation of the texture is) Example: The ...
3
votes
4answers
2k views

Multiplatform GLSL shader validator?

Im working on a multiplatform (Pc,Mac,Linux) game that uses shaders quite extensively. Since we do not have any funding, it is pretty hard to test our game on all possible hardware configurations. ...
3
votes
1answer
893 views

Architecture to draw many different objects in OpenGL

I have some objects that I want to draw. I am not sure how I can create my architecture in a way where I can draw everything as fast as possible. As example: class MyObject { float[] vertices; ...
3
votes
1answer
2k views

OpenGL ES Basic Fragment Shader help with transparency

I have just spent my first half hour playing with the shader language. I have modified the basic program I have which renders the texture, to allow me to colour the texture. varying vec2 texCoord; ...
3
votes
1answer
3k views

smooth shading vs flat shading, what's the difference in the models?

I'm loading the exact same model with Assimp, except one is exported from Blender, shaded smoothly, and the other was exported from Blender, shaded flatly. Here is my results from loading both into my ...
2
votes
1answer
832 views

What happens when a texture is too large for a device

The question is two fold: What happens on a device when a texture is too large for it to handle? Will it crash or simply downsize it? In Unity if I use texture atlases of size 4k and then set ...
2
votes
1answer
750 views

How can I improve the performance of texture switching without resorting to atlasing?

I'd like to use texture images that are not a sprite sheet or other form of texture atlas, mainly because I'll be consistently adding and swapping textures while I figure out the direction my game ...
2
votes
2answers
650 views

OpenGL Camera causes spatial distortion

I'm trying to implement a 3D camera of the "Orbit around the origin" variety in a game engine I'm developing in order to learn about 3D graphics and game programming. I have a basic handle on the ...
2
votes
2answers
2k views

LWJGL multiple keyboard/mouse input checks

As in many game libraries such as LWJGL, you can check mouse/keyboard events with Mouse.isButtonDown or Keyboard.IsKeyDown. I want to check for button/key presses, not if it's currently pressed down (...
2
votes
1answer
3k views

Zooming to point of interest

I have the following variables: Point of interest which is the position(x,y) in pixels of the place to focus. Screen width,height which are the dimensions of the window. Zoom level which sets the ...
2
votes
2answers
1k views

How should I do 3D games through Java on a mac? [closed]

I have been self-teaching myself Java on the mac mostly because the language is cross-platform. Recently, I have been only able to develop 2D games using the Graphics2D class. Now, I want to learn ...
2
votes
1answer
449 views

OpenGL: What are the adoption rates of the various versions (And what's a reasonable version to use)

This question is looking for updated answers for this question, which was made 1.5 years ago - as well as seeking more information. Given that OpenGL 3.0 was released just over 5 years ago, what ...
2
votes
1answer
2k views

Restoring projection matrix

I am learning to use FBOs and one of the things that I need to do when rendering something onto user defined FBO, I have to setup the projection, modelview and viewport for it. Once I am done ...
2
votes
1answer
811 views

Checking Collisions In 2D Platformer With Tiles

My team and I are developing a 2D platformer with C++/SDL/OpenGL, and we already defined a collision system, but we have a problem checking collisions with the tilemap. The tiles of the tilemap are ...
1
vote
2answers
2k views

First person camera with Bullet Physics

Before integrating the Bullet Physics, the camera worked fine. But instead of using my own simple struct for transform data, I use rigid body structs provided by the physics library now. There are ...
1
vote
1answer
1k views

Multiple buffering in OpenGL on Windows

What is the most common way modern games perform triple buffering ? What does the SwapBuffers exactly do in terms of OpenGL states ? Is it possible to perform double and triple buffering independently ...
1
vote
2answers
147 views

Modern opengl for direct3d programmers [duplicate]

I don't think this is quite the same questions as this one but if you disagree feel free to close this :) With SteamOS being announced yesterday I can see that it's entirely possible that opengl will ...
1
vote
0answers
41 views

Cell height with heightmap for collision detection

Hello everyone I'm programming a game with c++ and openGL. My world is generated from a heightmap (100x100 matrix with values 0-255) and now I need a function that returns the actual height based on ...
1
vote
1answer
3k views

How to use mipmap in OpenGL-ES

I have recently entered in the OpenGL world. I am very pleased with the performance that I got with opengl compared to those obtained with a SurfaceView and its canvas. At the same time because of the ...
1
vote
1answer
1k views

How can I calculate a terrain's normals?

Im trying to implement basic lighting in Opengl 3+ (a sun) with this tutorial : http://www.mbsoftworks.sk/index.php?page=tutorials&series=1&tutorial=11 Im building a basic terrain and its ...
1
vote
2answers
610 views

3D picking for mouse move event

I implemented color picking recently and I would like to use it as kind of highlight when mouse is over an object but I am concerned about performance. Color picking requires whole frame to be drawn, ...
1
vote
1answer
490 views

Using two FBOs results in the second FBO having nothing drawn to [closed]

I'm writing a deferred renderer, and I use two FBOs: the first one for G-buffer (color, normal, depth) and the second one for lighting (light output), so the first one has three textures bound and the ...
1
vote
1answer
3k views

Basic Car Movement, Converting 2D Vectors to 3D problems

I'm trying to follow this guys method for steering a basic car. Link. It's the first example I can sort of get my head around and I'm trying to convert it to a working 3D version. To get some scope, ...
1
vote
1answer
1k views

Translating local to global coordinates in ARToolkit / OpenGL

Ok, so I've tried reading over the other questions and something's just not clicking for me. I am working on an augmented reality application using ARToolkit, however it should just be straight ...
1
vote
2answers
1k views

Multipule VBO in Opengl [closed]

I have currently in my application 2 VBO one which is a streamed buffer and for the moment the other is a static buffer. However even when the steam buffer is not bound and the static buffer is bound ...
1
vote
1answer
96 views

Greedy Mesh generation for a voxel-based game

EDIT: I have already found my problem and fixed it (but I cant accept my own answer for another 2 days) I'm currently making a 3D voxel-based game and now that I have started optimising some aspects ...
1
vote
0answers
266 views

Strange rendering issue with monogame/WinGL with HD7670M

I'm having some strange rendering issues with latest monogame/winGL code as seen below; As you can see the xna and tomspilmans WinDX port seems just okay. I'm having this problem on my laptop ...
0
votes
1answer
139 views

glDrawElements Crash

This is the "init" code of the Renderer class: glGenBuffers(1,&_idVBO); glGenBuffers(1,&_idEBO); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,_idEBO); glBindBuffer(GL_VERTEX_ARRAY,_idVBO); GLint lUV ...
0
votes
1answer
351 views

GLSL to Cg fragment shader

I have found very useful resource on the Swiftless website on OpenGL. Unfortunately, I cannot manage to adapt a GLSL fragment shader to my project, which uses Cg. Here it is: uniform sampler2D ...
0
votes
1answer
390 views

OpenGL How to render a voxel based world scene with many objects

I am working on a voxel game engine using OpenGL binding for JVM languages (scala is my case) - LWJGL 3 for OpenGL version 4.5 . Currently I'm stuck with chunk rendering (32*32*32 blocks). To render ...
0
votes
1answer
141 views

Getting ray using gluUnProject or inverted MVP matrix

I've read a lot of topics here, on SO, opengl.org etc. Example how gluUnProject should work (from NeHe tutorial): winX = (float)x; winY = (float)viewport[3] - (float)y; glReadPixels( x, int(winY), 1, ...
0
votes
2answers
143 views

Switched from immediate mode to VBOs, game runs slower

trying to improve draw performance on my c++, OpenGL, SDL game. Back in school we mostly learned immediate mode, so thats how my drawing was originally implemented. When I started reading up online ...
0
votes
1answer
135 views

Is it possible to display no white images/sprites when using the latest Android OS?

Was it okay to use Texture.setEnforcePotImages(false) in order to disable conditional width and height pixel size that requires power of 2? I'm planning to sell the game app at Google Play. I want to ...
0
votes
1answer
305 views

How does OpenGL determine different outputs with shaders?

Lets say I have this GLSL code: #version 330 out vec4 outputColor; void main() { float lerpValue = gl_FragCoord.y / 500.0f; outputColor = mix(vec4(1.0f, 1.0f, 1.0f, 1.0f), vec4(0....
0
votes
0answers
106 views

Rendering a model with transparent or translucent uv map applied doesn't work

Before I try to make anything transparent, the model renders nicely. When I change the uv layout so that one piece of the model will be transparent, it renders horribly. This is the result with a ...
0
votes
1answer
123 views

How can texture packing improve performance?

Let's say I let a user give my library (a GUI system) multiple textures for rendering elements. What would be the performance impact of rendering with each of those textures separately versus, say, ...
0
votes
1answer
298 views

Where to store OpenGL object id:s

When working with OpenGL, you often recieve integer id:s to keep track of OpenGL objects. For example, representing a simple mesh, you may have a number of references to objects like so: GLuint ...
-1
votes
1answer
225 views

Create YUV texture for GL_TEXTURE_EXTERNAL_OES format

0 down vote favorite I need to create a yuv texture for GL_TEXTURE_EXTERNAL_OES format. source : https://github.com/crossle/MediaPlayerSurface/blob/master/src/me/crossle/demo/surfacetexture/...
-2
votes
1answer
483 views

Incorrect rotations using openGL GLM and shaders [closed]

The goal of my program is to display a simple colored triangle rotating on the Y axis without any translation. I'm using the GLM library. The problem is that the transformations of my triangle are not ...