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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OpenGL Performance Questions

This subject, as with any optimisation problem, gets hit on a lot, but I just couldn't find what I (think) I want. A lot of tutorials, and even SO questions have similar tips; generally covering: ...
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searching for “university kind” free online course about OPENGL [closed]

I know there are a lot of free university courses, but I'm trying to find one about OpenGL. Do you know where can I find one, online?
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Are VBOs only for OpenGL 3.x?

Are VBOs only for OpenGL 3.x? I'm using immediate mode and I know it's bad, slow, and deprecated. But then I looked at display lists but they are deprecated too. I guess the VBO is the only one left ...
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How to handle wildly varying rendering hardware / getting baseline

I've recently started with mobile programming (cross-platform, also with desktop) and am encountering wildly differing hardware performance, in particular with OpenGL and the GPU. I know I'll ...
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3answers
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Is a Single Texture Cube Map Possible?

I'm currently developing a test project to explore OpenGL 3 texturing abilities. I have a simple cube, made of 8 vertices and 36 indices. I want each of the cubes faces to have a different texture, so ...
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OpenGL Insanely Slow [closed]

I'm learning C++, and I'm writing my first OpenGL program. Unfortunately, it seems to be defaulting to Software Rendering (CPU uses bounces, GPU uses stays at 1%). I'm using SDL as the Windowing ...
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Will I have an easier time learning OpenGL in Pygame or Pyglet? (NeHe tutorials downloaded)

I'm looking between PyGame and Pyglet, Pyglet seems to be somewhat newer and more Pythony, but it's last release according to Wikipedia is January '10. PyGame seems to have more documentation, more ...
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3answers
199 views

Is it possible to gain performance by omitting vertex normals in the GPU pipe?

I am working on a rendering problem where I want to render as many raw triangles to the screen as I can with either OpenGL or DirectX with the absolute fastest performance possible. I wondered about ...
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Image loaded from TGA texture isn't displayed correctly

I have a TGA texture containing this image: The texture is 256x256. So I'm trying to load it and map it to a cube: #import <OpenGL/OpenGL.h> #import <GLUT/GLUT.h> #import ...
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576 views

OpenGL are strips/fans faster for rendering or just data bandwidth

When we send data for drawing we can mark it as TRIANGLE_STRIP or TRIANGLE_FAN to reduce the number of vertices we have to specify. Now, does this actually improve the rendering speed on the graphics ...
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2answers
731 views

Rendering (rasterization / ray tracing / others)

I'm completely new to this graphics and game development. I have read about Rendering (drawing a 3D graphic on a display 2D) and there are many ways of rendering, Rasterization, Ray tracing, ...
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OpenGL ES 2.0: Perspective Projection for 2D Games

Prespective Projection has features that could be very well used even in 2D games. At least two very beneficial characteristics that come to my mind are: Using Perspective Projection to substitute ...
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479 views

GL_INVALID_OPERATION in glEnd

I'm having problems drawing a simple sprite. When I draw: void CSprite2D::render() { CHECKGL(glLoadIdentity()); CHECKGL(glEnable(GL_TEXTURE_2D)); ...
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OpenGL Post Processing Introducing Artifacts on Certain Systems

Playing around with God-Rays in my framework, I was greeted with the following artifacts on my laptop: The artifacts themselves act almost like noise, flickering around the image rapidly. They also ...
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3answers
215 views

Rendering order

In this thread Rendering a model with transparent or translucent uv map applied doesn't work , I asked about what was wrong with my model that the transparency wasn't working. I've got an answer ...
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2answers
464 views

I enabled and setup glBlendFunc, but my texture has a white outline. What am I doing wrong?

You can see most of my source code in this question: Instead of the specified Texture, black circles on a green background are getting rendered. Why? Now I have the problem, that my texture has a ...
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1answer
862 views

rotating spheres

I want to continuously rotate 2 spheres, however the rotation does not seem to work. Here is my code: float angle = 0.0f; void light(){ glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); ...
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3answers
616 views

What should I use to handle input? [closed]

What should I use to handle input? I am wanting to use OpenGL so that my games are cross platform. DirectX provides input libraries, and OpenGL does not. Because my games need to be cross platform, I ...
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1answer
93 views

Why are my objects rotating with my camera?

I am working with this C# library that wraps OpenGL. I am trying to understand why my objects in the scene are rotating as I yaw my camera (view matrix). Here is an image where I have 4 separate ...
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2answers
753 views

glGenVertexArrays causes crash

My code keeps crashing at runtime, I have done some creative debugging and determined that it was the glGenVertexArrays that was causing the crash, I've looked around and come across some answers that ...
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1answer
146 views

Does opengl performs Visibilty algorithms based on z-index?

Does OpenGL performs Visibilty algorithms based on z-index? Or we have to write our own algorithms. Mainly I'm referring to z-buffer algorithm. Is it in-built?
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What is the best method to update shader uniforms?

What is the most accepted way for keeping a shader's matrices up to date, and why? For example, at the moment I have a Shader class that stores the handles to the GLSL shader program & uniforms. ...
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2answers
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Calculate object coordinates from window coordinates using inverse projection matrix

What I am trying to to is placing 3D Objects (A Sphere) in the world when I click there. I am using a perspective projection so the first step after calculating the canonical clip coordinates from ...
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3answers
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Set a variable inside a GLSL fragment shader that persists for the render

Is it possible to set a varying variable inside a fragment shader and have it persist? I'd like to use the depth component of the first fragment and use it on all the others, making the fragments all ...
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4answers
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How to pass one float as four unsigned chars to shader by glVertexPointAttrib?

For each vertex I use two floats as position and four unsigned bytes as color. I want to store all of them in one table, so I tried casting those four unsigned bytes to one float, but I am unable to ...
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2answers
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How to implement explosion in OpenGL with a particle effect?

I'm relatively new to OpenGL and I'm clueless how to implement explosion. So could anyone give me some ideas how to start? Suppose the explosion occurs at location $(x, y, z)$, then I'm thinking of ...
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Shaders not linking correctly

I'm writing a rather simple "ShaderManager" which aids me with loading shaders in Open GL, altough I am having a few issues: The shaders don't link correctly The the attributes don't bind Here's ...
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529 views

What is the better approach to redraw a static background scene for game?

Take for an example I have the background scene of a game which should remain static for an interval.Then for every time redrawing the scene,is it better for me to store the color buffer for every ...
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2answers
393 views

Should SIMD be used by people who are new to game development?

I have been learning game development, using C++ and OpenGL, for about 4-5 months. Before that I used to program in C# and the .NET platform(about a year). So, I consider myself new to game ...
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377 views

Does Blitz3D use its own 3D engine or does it wrap OpenGL?

How does Blitz3D work? I mean internally, does it use OpenGL with basic wrappers or it using some open source 3D engine that itself wraps OpenGL?
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565 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 ...
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2answers
6k views

OpenGL ES 2.0: Controlling Transparency in Fragment Shader

The following is the OpenGL ES 2.0 simple GLSL Fragment Shader, I use to place textures on polygons, to render 2D sprites. varying mediump vec2 TextureCoordOut; uniform sampler2D Sampler; void ...
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687 views

Collision Problems

I'm having some troubles with a 2D platformer type game (there's more to it, but that's all that matters for this question). I had collision with the platforms working fine, but if the character hit ...
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3answers
82 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 ...
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Difference between Spherical Harmonics and Spherical Harmonics Lighting

What is the difference between Spherical Harmonics and Spherical Harmonics Lighting in OpenGL?
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2answers
319 views

C++, OpenGL: Building a polyhedron via geometry shader

I'm stuck with geometry shaders in OpenGL - c++ programming. I want to create simple cube by repeating 6 times drawing one rotated wall. Here is my vertex shader (everyting has #version 330 core in ...
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1answer
104 views

It possible to render a true quad (without triangles) using OpenGL?

Is it possible to render a "true" quad in OpenGL? By that I mean a square which is not made out of two triangles.
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2answers
300 views

How can rotate a 2D textured quad in legacy OpenGL immediate mode?

I have a texture of a tank, and I want to it appearance on the screen depends on its current direction, so I decided to use rotating texture functions of OpenGL. I followed some advices through Google ...
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1answer
87 views

OpenGL - Buffer Usage

I am currently working on a little OpenGL project. At the moment I am trying to find a good solution for rendering multiple objects. I have set up a terrain with its own buffers, which works just ...
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1answer
465 views

Shadow map: depth texture always returns 0

I'm implementing a shadow map for the sun light in my voxel engine using a depth texture attached to a framebuffer. But when I sample the depth texture during the normal pass, the value returned is ...
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2answers
381 views

What dimensions should you use for a perspective projection frustum?

What dimensions should you use for a perspective projection frustum? Initially I created a perspective matrix based on the width and height of the screen, with a calculated zNear value based on a ...
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1answer
325 views

Infinite / Treadmilling Hexagonal Grid

So, I can happily render an infinite square grid by moving said grid whenever the camera moves out of a grid square, auto diff = (cameraTranslation - gridTranslation); bool moveGrid = false; if ...
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1answer
964 views

Marching Cubes Terrain [closed]

For the past week I've been researching the Marching Cubes algorithm. I hope to use this for Terrain as it would allow the creation of destruction of terrain. After looking at source code and reading ...
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2answers
275 views

LWJGL - If I use VBOs what can I do about separate textures?

So basically this is my problem: I am creating a game that needs a texture for each object. Now I would use a sprite sheet but the textures are different sizes. I am using VBOs and I need to some how ...
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1answer
569 views

Obj Blender Export Recommendation for OpenGL C++

I have been modelling some objects inside blender, like a light bulb. I finished the light bulb, and I got a question at the time of export it. I want to export the light bulb in the wavefront format ...
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2answers
855 views

LWJGL MouseY Coordinates are flipped

So I'm very new to using OpenGL and LWJGL, although I am proficient in Java itself. One of the first things I read in the documentation of the Display class was that it maps the origin to the bottom ...
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1answer
311 views

Using OpenGL GLEW within Unity

Edit:- How do I implement GLEW (or OpenGL extension libraries) within Unity? Original Question:- I've recently been looking into some really nice features of OpenGL 3.2 that I want to take ...
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1answer
2k views

GLSL - rewriting (geometry) shader from #330 to #130 version

I'm having trouble running example from: https://raw.github.com/progschj/OpenGL-Examples/master/07geometry_shader_blending.cpp My graphics card supports only #130 shaders version so I have to rewrite ...
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2answers
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Transparent parts of texture are opaque black instead

I render a sprite twice, one on top of the other. The sprites have transparent parts, so I should be able to see the bottom sprite under the top sprite. The transparent parts are black (the clear ...
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2answers
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SDL for 3D game programming?

I have been studying SDL for a few weeks and I have succeeded in making a 2D Ping-Pong game, but I want to get started in 3D development, and I'd like to know if SDL is capable (and suitable) for 3D ...