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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3
votes
1answer
312 views

Odd blending result (semi-transparent 2d quad over 3D scene)

I'm working on a GUI library for my game, and I'm having problems with my blending. I have a 3D scene, which I render with glDrawArrays. In the fragment shader the alpha color is hardcoded 1.0f ...
2
votes
2answers
1k 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 ...
1
vote
1answer
562 views

Voxel Performance

So Im trying to make a minecraft style voxel game to learn OpenGL, but Im running into performance issues. I found this thread : http://stackoverflow.com/questions/4995652/3d-occlusion-culling where ...
5
votes
1answer
10k views

Why is Minecraft's default resolution (seemingly) non-standard?

Background: I'm writing some articles on Minecraft in an attempt to introduce 10-year olds to development through modding. I know very little about the game itself, though :) I'm trying to understand ...
0
votes
1answer
132 views

Per-fragment lighting system behaves like ambient lighting system

This is the relevant section of my fragment shader varying vec3 normal; varying vec3 halfv; ... vec4 color = ambient * gl_LightSource[0].ambient; vec3 n = normalize(normal); float ...
1
vote
1answer
228 views

How to deal with lot of textures in one draw call?

I'am currently developing text rendering & some kind of tile based texturing for simple landscape with textures blending. e.g. something like this but in 3D. In first realization I have been used ...
0
votes
3answers
429 views

Using different shaders on the same model at runtime

I've already asked similar but a bit unclear question here but this time I will be very specific and to the point. Suppose I have an actor which grabs a power up. He starts to glow using bloom shader ...
9
votes
1answer
1k views

Engine Rendering pipeline : Making shaders generic

I am trying to make a 2D game engine using OpenGL ES 2.0 (iOS for now). I've written Application layer in Objective C and a separate self contained RendererGLES20 in C++. No GL specific call is made ...
0
votes
1answer
322 views

GLSL: Strange light reflections

According to this tutorial I'm trying to make a normal mapping using GLSL, but something is wrong and I can't find the solution. The output render is in this image: Image1 in this image is a plane ...
2
votes
1answer
618 views

How to tell what part of a 3D cube was touched

I am writing a rather simple android game and I am implementing Open GL to draw a 3D cube that spins upon the X, Y and Z axis and I need to know where the user has clicked on the texture of the cube. ...
2
votes
1answer
194 views

Shader Variable Types

I have a simple question. what are the meaning of : half4 myHalf; myHalf.yyyy; myHalf.xxzz; // or myHalf.yw Thanks a lot !
2
votes
1answer
756 views

How to modify VBO data

I am learning LWJGL so i can start working on my game. In order to learn LWJGL I got the idea to implement the map builder so I can get comfortable with graphics programming. Now, for the map ...
16
votes
1answer
3k views

How would you implement chromatic aberration?

How would you implement the effect of chromatic aberration with shaders? Would rendering of the world with different focus distances for each color solve the problem (maybe with the usage of only one ...
1
vote
1answer
166 views

GL_GENERATE_MIPMAP vs. GL_MAX_TEXTURE_SIZE

If we generate mipmaps for a texture using GL_GENERATE_MIPMAP (or glGenerateMipmap), how big can the original texture be? Is it the size returned by GL_MAX_TEXTURE_SIZE, or half of it?
2
votes
1answer
550 views

How to do directional per fragment lighting in world space?

I am attempting to create a GLSL shader for simple, per-fragment directional light. So far, after following many tutorials, I have continually ran into the issue: my light is specified in world ...
0
votes
1answer
292 views

What's the equivalent of wglShareLists for Mac OS?

I'm trying to share lists between two contexts on Mac OS but despite my research I couldn't come up with an answer so far. I've found that NSOpenGLContext was able to initialize a context with a ...
2
votes
1answer
912 views

Problem using glm::lookat

I am trying to rotate a sprite so it is always facing a 3D camera. Object GLfloat vertexData[] = { // X Y Z U V 0.0f, 0.8f, 0.0f, 0.5f, 1.0f, -0.8f,-0.8f, 0.0f, ...
0
votes
1answer
813 views

Why won't my vertex buffer render in GLFW3?

I have started to try to learn OpenGL, and I decided to use GLFW to assist in window creation. The problem is, since GLFW3 is so new, there are no tutorials on it or how to use it with modern OpenGL ...
3
votes
3answers
472 views

What is the practical use of IBOs / degenerate vertex in OpenGL?

Vertices in 3D models CAN get cut in the process of optimizing 3D geometry, (degenerate vertices) by 3D graphics software (Blender, ...) when exporting because they aren't needed when reusing a vertex ...
3
votes
1answer
449 views

The most efficent ways for drawing lines all day long with OpenGL

I'd like to put a computer screen that is running an OpenGL programs in a room. It has to run all day long (not in the night). I'd like to draw lines that are slowly fading in the background. The ...
1
vote
1answer
571 views

does glBindAttribLocation silently ignore names not found in a shader?

Does glBindAttribLocation silently ignore names that are not found? For example, in a shader: // Some vertex shader in vec3 position; in vec3 normal; // ... And in some set up code: // While ...
1
vote
1answer
227 views

How can I use OpenGL and D3D to render to the same window at the same time?

I have main render loop in which initial drawing is done via OpenGL to an SDL window, and after that the same window handle is passed to a Direct3D device, which does subsequent rendering. Once I ...
0
votes
0answers
354 views

Convert OpenGL code to DirectX

First of all, this is kind of a follow up question on @byte56 excellent anwser on this question concerning picking algorithms. I'm trying to convert one of his code examples to directX 11 however I ...
2
votes
0answers
320 views

OpenGL: Attempt to allocate a texture too big for the current hardware [closed]

I'm getting the following error: java.io.IOException: Attempt to allocate a texture to big for the current hardware at ...
1
vote
1answer
99 views

What is the purpose of bitdepth for the several components of the framebuffer in glfwWindowHint function of GLFW3?

I would like to know what are the following "framebuffer related hints" of GLFW3 function glfwWindowHint : GLFW_RED_BITS GLFW_GREEN_BITS GLFW_BLUE_BITS GLFW_ALPHA_BITS GLFW_DEPTH_BITS ...
2
votes
1answer
121 views

How to obtain touch events from a GL Viewport, not the whole screen?

Background I'm implementing viewport resizing in order for my game to maintain the same display ratio on all devices. However, I've found an issue with getting touch events. Basically, if my ...
0
votes
1answer
318 views

Basic shadow mapping fails on NVIDIA card?

Recently I switched from an AMD Radeon HD 6870 card to an (MSI) NVIDIA GTX 670 for performance reasons. I found however that my implementation of shadow mapping in all my applications failed. In a ...
0
votes
1answer
1k views

OpenGL + SDL Linking Problem [closed]

So I'm trying to write a simple application with SDL 1.2 and OpenGL. This a stripped down version of the code containing the one problem I'm having. //The headers #include "SDL.h" #include ...
3
votes
2answers
701 views

Rendering artifacts at a large scale

I'm a new to OpenGL or graphics in general. Trying to write a game with realistic scale. I had a perfectly fine rendering of earth at a small scale, but when I try to scale it up to 1:1 I get this ...
9
votes
1answer
3k views

Game Engine Design – Ubershader - Shader management design

I want to implement a flexible Ubershader system (with deferred shading). My current idea is to create shaders out of modules, which deal with certain features (FlatTexture, BumpTexture, Displacement ...
6
votes
3answers
528 views

State of the art Culling and Batching techniques in rendering [closed]

I'm currently working with upgrading and restructuring an OpenGL render engine. The engine is used for visualising large scenes of architectural data (buildings with interior), and the amount of ...
0
votes
0answers
142 views

Handling 3D perspective for different aspect ratio

I have problem for supporting different aspect ratio in developing Mobile Game. I was developing on 2:3 screen which is iPhone 4 (Retina). When I use width and height for screen size and use fixed ...
0
votes
1answer
103 views

Which is the right way to build a OpenGL Projection Matrix

This time I'm trying to learn the core of matrix transformations. I dont like the idea to using a Math library and dont understand what is hapening on background, because this I'm having some ...
1
vote
1answer
677 views

Playing movies with OpenGL in Java

I am trying to play a movie file into an OpenGL texture in a Java application. I am using JOGL and have a basic OpenGL scene, but I have no idea how to play a movie into a texture. The only thing I ...
1
vote
0answers
443 views

How to implement OpenGL triple buffering

I'm trying to implement the triple buffering described here ...
6
votes
1answer
482 views

How can I debug _why_ glDrawArrays is very slow?

I'm working on a game that uses CEGUI and Ogre. Recently, we've discovered that some of our customers with GeForce4 MX 4000's, performance is terrible. After a night spent debugging, I've tracked ...
0
votes
0answers
200 views

Problem adding texture to VBO with png texmap in OpenGL

I was doing a VBO and able to load all the data of OBJ file but now I have problem adding texture to it. what i did is that I use the slick library to get the texture file and bind it to the VBO ...
0
votes
2answers
369 views

Is this Rotation Matrix correct?

I'm having heavly troubles with setting up a View Matrix and a Projection Matrix. It simply doesnt work. So I think my problem is related to my rotationMatrix function. I'm using this tutorial to ...
0
votes
0answers
181 views

Using shaders with GLFW3

i've setup the newest version of glfw & glew on mingw (i'm using windows 7). I've previously used freeglut & glew but i switched to glfw because i've heard it was better for games. So my ...
5
votes
1answer
239 views

How to pass depth buffer from OGRE to CUDA?

I am using OGRE for rendering some objects. At every frame, I would like to pass the resulting depth buffer to CUDA for running some kernels on it and computing a result. How can I achieve this? How ...
1
vote
0answers
144 views

Aiming with a crosshair with a lot of polygons/triangles

I'm working on a 3d kindof game where I'll eventually be able to modify the shapes present in the environment by pulling their faces with a crosshair. The thing is that I don't know how to achieve ...
-1
votes
1answer
84 views

How do I use Opengl 3.2? [closed]

My computer is using OpenGL 3.1 and I want to develop in OpenGL 3.2 but I don't know how. Thanks in advance all help is appreciated.
1
vote
1answer
298 views

Workaround for reading and writing same texture?

To apply post effects, it is often needed to read the preliminary image, perform computations on its pixels and store the result in the same texture again. For example, think of a tone mapping or ...
3
votes
1answer
714 views

TBN Matrix : Eye vs. World Space Conflict

I am tired of misleading and insufficient articles making me more confused each time I read, I need a clarification that will solve my TBN matrix problem forever. Each article I read informs me ...
1
vote
1answer
203 views

How can I find the location of OpenGL object after rotation?

I have a rotating object, a cube, which I rotate in OpenGL as follows: gl.glPushMatrix(); gl.glTranslatef(400.0f, 300.0f, 1300.0f); gl.glRotatef(m_x, 4.0f, 0.0f, 0.0f); gl.glRotatef(m_y, 0.0f, 4.0f, ...
2
votes
1answer
361 views

Fog shader camera problem

I have some difficulties with my vertex-fragment fog shader in Unity. I have a good visual result but the problem is that the gradient is based on the camera's position, it moves as the camera moves. ...
-1
votes
1answer
125 views

Ray picking gives inversed results

I'm trying to do a simple ray picking implementation to allow a user to select a cell in a grid rendered in 3D. I'm almost there, but I've ran into an issue which I can't seem to solve. Consider the ...
-3
votes
1answer
280 views

Opentk: Move Bones model 3d [closed]

I have a model in 3ds max and have exported to obj file using tutorials and I managed to load my model and apply a texture. My problem is that I have to move a part of this model and to move while ...
0
votes
0answers
346 views

GLSL gl_ModelViewMatrix breaks my code?

So I have the following shaders which work (to the extent that they are completed anyway). //Vertex Shader uniform float offset; void main() { gl_TexCoord[0].t = gl_MultiTexCoord0.t; ...
0
votes
1answer
525 views

Simplest way to render image over top of another with another image used as mask in OpenGL?

The effect I'm looking for is to have a single large background image that is always visible (at full alpha) and then show a second image (what I call a light map or specular map) that is partially ...