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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“Unable to create OpenGL 3.3 context (flags 0, profile 1)”

Trying to run any of the well-known McKesson's tutorials on a friend's laptop results in the aforementioned exception. I read that in order to run applications which use OpenGL 3.3 you must at least ...
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430 views

Erasing part of lines in libgdx with ImmediateModeRenderer

Hi i'm using the ImmediateModeRenderer renderer = new ImmediateModeRenderer10(); to render a line with the next block renderer.begin(matrix, GL10.GL_LINES); renderer.color(color.r, color.g, ...
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1k views

Back-face culling in 2d openGL game

I have a 2d game I've made using openGL ES. The game contains a large quad that fills the entire screen (as a background image) and many smaller quads that make up a number of balls that bounce across ...
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FBO Depth Buffer not working

I'm trying to get the depth buffer for my 2D game working by offsetting the z value of the rectangles. For some reason, my depth buffer is coming back empty. The value is always 0. I'm assuiming there ...
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778 views

glsl applying shader

I want to use a shader just for learning purposes. But i have a few questions about it. I have the following code: Vertext shader: const float Eta = 0.66; // Ratio of indices of refraction ...
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OpenGL relative 2D camera

Some days ago, I've felt a need to add a camera to my game, it's a puzzle. That would let me move the board, zoom in and etc. This gave me control to do boards muuuch larger, soon, more complex ...
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196 views

Why is texturing interfering with my ID-based picking implementation?

Today I came across a tutorial about color picking and I implemented it on my machine. But there is a problem: when I disable the texture and draw the object I want to pick with its picking color, it ...
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Detect two specific objects collision with bullet physics

I have got some problem with defining collision between objects in my game using bullet physics. I know that objects are colliding with each other simultaneously and I don't have to do anything more. ...
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3D picking lwjgl

I have written some code to preform 3D picking that for some reason dosn't work entirely correct! (Im using LWJGL just so you know.) I posted this at stackoverflow at first but after researching some ...
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3k views

Picking objects with mouse ray

I simply want to pick a few spheres in my scene using the mouse-ray. I have implemented(copied most of it but with little understanding) a ray-sphere collision code. Also I have implemented the code ...
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678 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 ...
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246 views

Frame Buffer Objects vs calling TexCoord2f?

I'm learning the basics of OpenGL with lwjgl currently, and following a guide I've got textured quads that can move around a scene. I've been reading about Frame Buffer Objects, and I'm not really ...
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375 views

Time calculation between openGL update calls

In XNA, the system calls update and draw function with the time information. This contains information such as how much time has passed since last update was called. This makes easy to integrate time ...
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Tips for writing 3D Collision detection with opengl

I would like to any tips/articles/tutorials on how to write collision detection using OpenGL and C++ in 3D mainly just simple box collisions etc but also if there are any advanced resources that would ...
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522 views

2d game tools , what to work on first?

My friend and I would like to program a 2D game. We were discussing about tools needed, so while I am working on the tools, he will work on game logic and stuff. Probably I will put our tools into the ...
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why specular light is not running?

i'm on JOGL this is my method for lighting: private void lights(GL gl) { float[] LightPos = {0.0f, 0.0f, -1.0f, 1.0f}; float[] LightAmb = {0.2f, 0.2f, 0.2f, 1.0f}; float[] LightDif = ...
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843 views

OpenGL FBO Rendering

I'm getting some artifacts when I try to use a colour attachment on an FBO. I'm saving my first pass as a texture, then passing it as an input to an anti-aliasing shader. The result is, as below, some ...
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53 views

Vertex shader in OpenGL/GLSL - transformation of the interior of a textured quad

I have a LWJGL project and ran into a problem with a vertex shader I wrote. In my scene I am rendering a map whose ground consists of rectangular tiles. On top of that there are other objects (I used ...
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64 views

Geometry Shader only creates one primitive

I am currently trying to use the geometry shader. My input is a set of points, for which multiple triangle should be created This is the geometry shader #version 330 layout(points) in; ...
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121 views

Should all primitives be GL_TRIANGLES in order to create large, unified batches?

Optimizing modern OpenGL relies on aggressive batching, which is done by calls like glMultiDrawElementsIndirect. Although glMultiDrawElementsIndirect can render a large number of different meshes, it ...
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94 views

How to create a regular grid of triangles correctly?

I am trying to create an terrain using opentk/opengl. I have a problem with the VBO/IBO. I think a picture of the problem is the best way to show it: I dont understand why the last triangle of a ...
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2answers
88 views

Keeping ratio the same across devices on fixed screen game

My game is an Android game using OpenGL ES 2.0 (But this question could apply to any platform). I have read many questions on here regarding ratio management, and also read many tutorials outside of ...
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32 views

How should I handle a modelview stack with multiple shader programs involved?

I'm building a framework where each object has an associated program and each object has a 'draw' method. What is the best choice, to have a single modelview stack handled by a Renderer class or to ...
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39 views

vertex is bending inwards

I am trying to draw a picket fence, but the center of the picket vertex looks bent in the middle, why is the picket bending inwards to the left? // draw fence pickets float a; for (a=-25; a<=25; ...
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83 views

Gamma Space and Linear Space with Shader

I am using Unity and I can choose between two color space mode in the settings: Gamma or Linear Space. I am trying to build a Custom Lighting Surface shader but I am facing some problems with those ...
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266 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 ...
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156 views

How to save am image of a screen using JOGL

Hope this is a better place to ask things like this. I have a 2D scene with some sprites drawn in Swing frame. I need them to be saved as an image. The problem is every tutorial I found seem to be ...
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41 views

Having trouble setting color in fragment shader

For some reason, the color isn't applying to the object. Here's my fragment shader code. There's probably something obvious wrong with it that i'm not seeing. #version 330 core out vec3 Color; ...
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92 views

DirectX Bullet Tracer Effect

I'm wondering if anyone knows some common and efficient ways to do a fast tracer for an instant bullet. I've seen people speak on forums of using primitive lines with DirectX, but I doubt this ...
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1answer
85 views

Is there a way to use other fonts, besides the default ones in OpenGLUT?

I'm using OpenGLUT functions like glutBitmapString to render sentences and words in a game. However, there is a limited set of fonts to use and I need some bigger size fonts. Is there a way to add new ...
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118 views

Why is the light following my camera around?

I have implemented a simple Phong shader without specular highlights for now (just ambient + diffuse components) The problem however, is that the calculations seem to be done in camera space; as I ...
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1answer
93 views

In glsl, how do indices work?

I have made a vertex shader and fragment shader and kind of know how they work, and I know that you specify what index you want your vertices to be in inside the shader program. So if the vertex was ...
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272 views

Decoupling rendering pipeline (for UI responsiveness): Multithreading and multiple contexts?

Warning! Wall of text (see <TL;DR> paragraphs below for short version) I have been noticing something in quite many games (most recently in cutting-edge RTS games such as Uber Entertainment's ...
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136 views

Efficient way of loading wavefront models in openGL game

In my game, a RTS game, the units are all wavefront obj. all their animation frames are each seperate wavefront obj file. ie. without any skeletal animation; fully rigid models. So when many units are ...
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369 views

SSAO looks wrong

I'm trying to implement SSAO based on this tutorial. My setup: OpenGL 3.2 Forward renderer View-space depth and normal in a single 16-bit floating point texture. The result I get is this: The ...
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166 views

How can I compute the orbit of one body around another?

I'm attempting to have a planet (with a known mass and radius) orbit it's sun (also with a known mass and radius). It doesn't have to be 100% realistic, but it should be possible that the sun have ...
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2answers
200 views

gl_FrontFacing - is there perfomance cost?

If I use gl_FrontFacing in my PS, is there any performance cost during vertex transformation (like cross product from triangle vertices), or is this value computed any time ?
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1answer
233 views

How to achieve anisotropic filtering

I am loading a texture and using glGenerateMipmap() on it to achieve some level of mipmaping. I get different result on nVidia gt 555m, and on Intel HD 3000. The texture rendered by nVidia is not ...
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1answer
91 views

Run OpenGL shader on part of a texture

How do I run an OpenGL shader on just a portion of an off screen texture and leave the rest of the texture unmodified? Are there any calls that restrict the sampled pixels to just a rectangle or do I ...
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1answer
138 views

How to enable geometry shader in OpenGL 4.2?

I'm porting my Direct3D-based engine to OpenGL and I'm using geometry shaders for rendering text characters (basically, textured billboards). D3D version works fine, but in OpenGL mode it gives only ...
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423 views

glGenerateMipmap confusion

I'm trying to get a grip on mipmaps with OpenGL. I believe I understand the concept, but when trying to have OpenGL generate them I wonder how it determines how many mipmaps to generate? Here's what ...
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202 views

How can I handle errors when there is no valid OpenGL context?

I'm writing cross-platform (iOS, Android, OSX, Windows) library code that draws its output using OpenGL. I expect my users will often try to call my library's rendering functions without a valid ...
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1answer
41 views

Drawing behavior when a fragment is written to multiple times in a single pass

This seems really basic, but I'm confused and can't find a clear answer anywhere. What happens to a target fragment of a rendertarget if the fragment is written to multiple times within one pass ...
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1answer
157 views

How can I extract the RGB color data from a TGA image?

I am working in OpenGL, and I am trying to create terrains using height maps. I am using my own functions to load a TGA image, and in order to pass data to heightmap vertex shader I need to retrieve ...
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1answer
63 views

Models not rendering when far away

I am making a game where objects are represented by colored cubes. I have files that mark the location and rotation of the cubes. I've been using Processing's 3D library and the cubes disappear within ...
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2answers
404 views

OpenGL position from depth is wrong

My engine is currently implemented using a deferred rendering technique, and today I decided to change it up a bit. First I was storing 5 textures as so: DEPTH24_STENCIL8 - Depth and stencil ...
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2answers
836 views

In GLSL is it possible to offset vertices based on height map colour?

I am attempting to generate some terrain based upon a heightmap. I have generated a 32 x 32 grid and a corresponding height map -> In my vertex shader I am trying to offset the position of the Y ...
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2answers
815 views

Drawing multiple objects from one Vertex Buffer Object in OpenGL/OpenTK

I am trying to experimenting drawing method using VBO in OpenGL. Many people normally use 1 vbo to store one object data array. I was trying to do something quite opposite which is storing multiple ...
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192 views

How to only render part of an image in lwjgl/openGL

I'm making a mining/building game in java using slick2D and I want to make it so you can only see a few blocks in any direction while you are underground. The best example I could find of what I want ...
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489 views

Uncharted 2 tone mapping and an eye adaptation

I found an example of uncharted 2 tone mapping on this site. Here is the code: float A = 0.15; float B = 0.50; float C = 0.10; float D = 0.20; float E = 0.02; float F = 0.30; float W = 11.2; float3 ...