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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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
227 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
427 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
321 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
617 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
193 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
751 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
165 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
549 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
909 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
808 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
467 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
446 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
566 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
226 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
319 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
697 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
524 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
140 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
674 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
440 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
368 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
180 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
238 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
143 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
295 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
709 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
202 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
360 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
341 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
524 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 ...
3
votes
1answer
261 views

small independent game development on a virtual machine

I've been learning about OpenGL and SFML with c++ now for about 6-8 months, and would like to work on a small little personal game to put some of my skills to the test. Now I want to kill two birds ...
1
vote
1answer
128 views

OpenGL light not shining quad

I've constructed a scene using OpenGL/GLUT with a spot light but I'm getting troubles with light shining some of the walls what is going on and how to solve?
0
votes
1answer
192 views

Shader program compiles fine on Ati, fails on other vendors

Got a real annoying problem here. My shader program compiles fine on my Ati Radeon HD card, but on Nvidia and Intel it failes to compile. Vertex shader: #version 120 attribute vec3 in_position; ...
7
votes
3answers
3k views

How do I implement occluded lighting in a block-based 2D game?

I want to have 2D lighting that can be blocked by in-game objects. My game has a top-down view and all game objects are described by rectangles. Let's say I have a 10x10 world and I place a light at ...