opengl

Setting ModelView matrix using rotate, translate, etc.. vs setting manual matrix

When setting the ModelView matrix you normally go through several transformations from the identity matrix. for example: glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glRotatef(270.0f, 0.0f, 0.0f, 1.0f); glTranslatef(-rect.size.height / 2, -rect.size.width / 2, 0.0f); Instead of doing those operations one after the other (assume there...

Counting texels using a fragment shader

Hi, I have two textures generated using a fragment shader. I want to be able to count the number of texels in each texture that are above some colour intensity. My question is how can this be done? My initial thought is to count these texels using the fragment shader before generating the texture. However, this would require some sort of...

How to make a 3D UI for an application ?

I'm building an application and I'd like its User Interface to be 3D, most probably a cylinder. The user would see the cylinder[Horizontally laid] and the cylinder's curved surface would have the buttons and any other controls that need to be placed. The cylinder needs to rotate and later, I'd like to add some other effects to the cylin...

texture on cube-side with opengl

hello i want to use a texture on a cube (created by glutsolidcube()), how can i define where the texture is pictured at? (for example on the "frontside" of a cube) glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, texture[0]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filterMode); glTexParameteri(GL_TEXTURE_2...

Object disapear/don't scale in the Z-AXIS of OPENGL.

This code is susposed to have a QUAD orbit around a center point in basically a circle. The problem is while it does the X rotation fine it disapears when it moves in Z axis and doesn't appear to change in size. It feel like it's rendering everything in Orthagraphic view or something. This is my first OpenGL project. OPENGL CODE STAR...

OpenGL Shading Language backwards compatibility

I've noticed that my GLSL shaders are not compilable when the GLSL version is lower than 130. What are the most critical elements for having a backward compatible shader source? I don't want to have a full backward compatibility, but I'd like to understand the main guidelines for having simple (forward compatible) shaders running on GP...

How to show a popup menu using QGLWidget?

Hi, how to show a context menu when you right click within a QGLWidget? ...

How to resize an openGL window created with wglCreateContext?

Is it possible to resize an openGL window (or device context) created with wglCreateContext without disabling it? If so how? Right now I have a function which resizes the DC but the only way I could get it to work was to call DisableOpenGL and then re-enable. This causes any textures and other state changes to be lost. I would like t...

Python: OSX Library for fast full screen jpg/png display

Frustrated by lack of a simple ACDSee equivalent for OS X, I'm looking to hack one up for myself. I'm looking for a gui library that accommodates: Full screen image display High quality image fit-to-screen (for display) Low memory usage Fast display Reasonable learning curve (the simpler the better) Looks like there are several choic...

Fixing LOD gaps, T-junctions

I'm creating a heightmap renderer. One of the examples for solving gaps when doing LOD I found is this: (from Game Programming Gems 2 - Greg Snook - Simplified Terrain using Interlocking Tiles) Wouldn't this still produce a gap, if the three vertices encircled with red were not co-linear? Shouldn't the middle triangle be split into t...

Problem Loading multiple textures using multiple shaders with GLSL

I am trying to use multiple textures in the same scene but no matter what I try the same texture is loaded for each object. So this what I am doing at the moment, I initialise each shader: rightWall.SendShaders("wall.vert","wall.frag","brick3.bmp", "wallTex", 0); demoFloor.SendShaders("floor.vert","floor.frag","dirt1.bmp", "floor...

opengl texture cube c++

hello i create a cube and want on one side an texture. glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, texture[0]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filterMode); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filterMode); glBegin(GL_POLYGON); //Vorderseite glColor4f(1.0f,0.0f,...

Can CUDA results be stored in an OpenGL accessible texture?

Can CUDA be used to generate OpenGL textures? I know it can be done by reading the CUDA results back into system memory, and then loading that into a texture... But I'd like to find a way to save this copy... Can CUDA be used to generate textures? ...

Unwanted SDL_QUIT Event on mouseclick.

I'm having a slight problem with my SDL/Opengl code, specifically, when i try to do something on a mousebuttondown event, the program sends an sdl_quit event to the stack, closing my application. I know this because I can make the program work (sans the ability to quit out of it :| ) by checking for SDL_QUIT during my event loop, and ma...

opengl and mtl parameters

Hi, I am new to opengl. I am trying to parse line items from "mtl" file and use the values as parameters to opengl functions. I could use values of ambience (Ka), specular(Ks) and diffuse(Kd) using glMaterialfv. But I don't know the use for Ni (optical density), d (dissolve), illum (illumination) values given in the mtl file. Which o...

Lighting does not work with gluSphere

This is a simple issue that I'm somewhat ashamed to ask for help on. I'm making a simple call to gluSphere to render a sphere, however, it does not light properly even though I'm pretty sure I added the normals and lighting correctly. If, however, I add a texture, the model lights normally, except it seems to be always SMOOTH, and I can...

Flicker/dead region issues maximizing an MFC window

I'm trying to make an MFC window (a CDialog) go fullscreen whenever the user attempts to maximize it. The window is being used as an OpenGL context. I'm attempting to do everything inside of the CDialog::OnSize callback. Here's the code that I'm using: void MyCDialogSubclass::OnSize(UINT action, int width, int height) { CDialog::OnS...

Problem with JOGL and Framebuffer Render-to-texture: Invalid Framebuffer Operation Error

Okay, so I am trying to render a scene to a small 32x32 texture and ran into problems. I get an "invalid framebuffer operation" error when I try to actually draw anything to the texture. I have simplified the code below so that it simply tries to render a quad to a texture and then bind that quad as a texture for another quad that is ren...

3D Texture mapping

In an .obj, file it is possible to specify 3 values for a vt line. vt 0.769645 0.729072 0.00000000 The .obj spec says its for "depth". What does this actually do and when is it useful? ...

OpenGL Color Interpolation across vertices

Right now, I have more than 25 vertices that form a model. I want to interpolate color linearly between the first and last vertex. The Problem is when I write the following code glColor3f(1.0,0.0,0.0); vertex3f(1.0,1.0,1.0); vertex3f(0.9,1.0,1.0); . .`<more vertices>; glColor3f(0.0,0.0,1.0); vertex3f(0.0,0.0,0.0); All the vertices exc...