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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153 views

Understanding implementation of glu.PickMatrix()

I am working on an OpenGL project which requires object selection feature. I use OpenTK framework to do this; however OpenTK doesn't support glu.PickMatrix() method to define the picking region. I ...
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0answers
12 views

Barycentric vertex coordinates in GLES 2.0

I have a certain set of polygons, which are stored in a vertex buffer and an index buffer. The polygons are textureless and normalless. The polygons are dynamic, their buffers get constantly emptied ...
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18 views

Ping Poing and blending

I have to render a scene, once per light, and blend the result of the various passes. I heard and read that one way to increase performances and Render Targets to use would be Ping Poing. Since I am ...
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2answers
118 views

Application of classes with critical non-static fields in LWJGL

I'm going to be as specific about this question as I can. Ultimately, how is it that I apply a class that uses non-static fields in LWJGL? More specifically, I know that OpenGL is quite nearly more a ...
0
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1answer
48 views

Planet terrain not connecting properly

I'm trying to generate some simple planets in OpenGL using libnoise (including noiseutils), but the terrain is not correctly connecting where the sphere "completes itself" and I was wondering if ...
4
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1answer
83 views

cost of texture change vs color change

How would I go about determining the difference in cost between changing the render color of an object every frame vice changing the texture (same sheet, just changing the source rectangle) every ...
1
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1answer
82 views

What types of matrices are needed for game and graphics programming?

I am writing a 3D math library for general game development and want to know what type of Matrix classes I should include. Is just a 4x4 matrix enough, or must I provide 3x4 and dedicated rotational ...
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1answer
167 views

Is there a standard way to track 2D tile positions both locally and on screen?

I'm building a 2D engine based on 32x32 tiles with OpenGL. OpenGL draws from the top left, so Y coordinates go down the screen as they increase. Obviously this is different than a standard graph ...
2
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1answer
161 views

How do I use unpackHalf2x16?

I'm trying to use (un)packHalf2x16, without success so far. I'm drawing with: glVertexAttribIPointer(0, 2, GL_UNSIGNED_INT, 0, 0); glEnableVertexAttribArray(0); glBindBuffer(GL_ARRAY_BUFFER, vbo); ...
2
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1answer
44 views

Indexed Drawing in OpenGL not working

I am trying to render 2 types of primitives- - points ( a Point Cloud ) - triangles ( a Mesh ) I am rendering points simply without any index arrays and they are getting rendered fine. To render ...
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1answer
40 views

Taking fixed direction on hemisphere and project to normal (openGL)

I am trying to perform sampling using hemisphere around a surface normal. I want to experiment with fixed directions (and maybe jitter slightly between frames). So I have those directions: vec3 ...
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1answer
67 views

OpenGL render to texture causing edge artifacts

This is my first post here so any help would be massively appreciated :) I'm using C++ with SDL and OpenGL 3.3 When rendering directly to screen I get the following result And when I render to ...
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0answers
61 views

i want to be a game developres please help [on hold]

bare with my English ok so we have done this semester C language but i didn't like much of C so i just prepared as much as a needed for my exam and i learned C++ coz its much better and advance than ...
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2answers
2k views

Changing the color of some fragment of a texture using shaders

Declarative programming language QML allows to connect the elements, their properties with universal variables in shader programs description. For these purposes there is such elements as ...
1
vote
1answer
104 views

Assimp skeletal animation matrices

I startded to make an assimp only opengl skeletal animation demo. For that I used this: http://sourceforge.net/p/assimp/discussion/817654/thread/5462cbf5 And something is not correct in bone matrices. ...
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1answer
37 views

Can I directly pass a Boost ptr_vector list to glBufferData?

I have a data structure like this: typedef struct vertex_ { float x; float y; float z; float s; float t; }vertex; Then I add to a list called: boost::ptr_vector<vector> vertices; Is there a ...
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0answers
33 views

lodepng “undefined reference” (MinGW)? [on hold]

I'm trying to use the library lodepng (lodev.org) in a C++ project. The actual library is a header and a C++ source file so the error I'm getting is confusing me. When I try reference a function or ...
0
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3answers
91 views

Using same buffer for vertex and index data?

Is it possible to use the same buffer for both GL_ARRAY_BUFFER and GL_ELEMENT_ARRAY_BUFFER? I load both vertex data and index data into a big slab of memory, so it would be easier for me to just load ...
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1answer
48 views

Sources to learn OpenGL [on hold]

I really wish to learn OpenGL, but all I have is a very old laptop. It supports OpenGL 1.2 version only. I tried learning through books but trying out the programs are next to impossible, since none ...
2
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2answers
82 views

Render with multiple lights (one pass per light)

Hi I'm new here so sorry if I make some mistakes writing this question. I have already a system that at the moment handle multiple lights just passing an array of light struct and loop through it. I ...
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2answers
90 views

c++ OpenGL framerate question

I am writing a simple 3D pacman using c++ and OpenGL. I'm new in OpenGL development, I wanted to make a small project before learning next concepts. For now I can't have more than 55fps when ...
0
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0answers
15 views

Qt OpenGL shader errors [closed]

I get the following error after compiling a Qt-OpenGL project: bool QGLShaderPrivate::create(): Could not create shader of type 1. Vertex shader for simpleShaderProg (MainVertexShader & ...
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3answers
86 views

Is OpenGl still supported in C?

I'm reading the OpenGl superbible 3th edition (well I plan to) and it's all in C. Since this book was written in 2004 and all the other later versions are written in C++, i was wondering whether or ...
1
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1answer
42 views

Obtain linear depth values on FBO and deal with small differences

I've a render target on which I have both a color and a depth attachment. In a second pass I need to run a filter whose width depends on the derivative and values of the depth. Now, if I try, in the ...
1
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1answer
80 views

GLSL to Cg: why is the effect different?

With reference to this question, where I was trying to make the shader compile, I am now trying to make an effect appear. The effect can be shown here, through a GLSL shader: But when I use the ...
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0answers
30 views

how decal projection works in opengl?

I want to draw a quad that fit on another mesh,how to setup projection matrix of this quad?I need an orthoprojection matrix right? At first I thought I only need to do some ray test of each vertex of ...
1
vote
1answer
119 views

Render 2 images that uses different shaders

Based on the giawa/nehe tutorials, how can I render 2 images with different shaders. I'm pretty new to OpenGl and shaders so I'm not completely sure whats happening in my code, but I think the shaders ...
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0answers
20 views

Good books on Android OpenGL game development [closed]

I don't know if opinion based questions will get down voted here. But anyways , I wanted to know some good books on Android game development with OpenGL. I have some intermediate knowledge on Java ...
1
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2answers
47 views

Palette reduction to pre-defined palette

I'm writing a bunch of GLSL effects for fun, but I can't wrap my head around this. Basically, I want to reduce a texture's palette into a pre-defined set of colors. For example, a post-processing ...
0
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1answer
317 views

Using Shader causes triangle to disappear

The following is my rendering code. Private Sub GameRender() GL.Clear(ClearBufferMask.ColorBufferBit + ClearBufferMask.DepthBufferBit) GL.ClearColor(Color.SkyBlue) ...
10
votes
2answers
8k views

OpenGL ES 2.0 Point Sprites Size

I am trying to draw point sprites in OpenGL ES 2.0, but all my points end up with a size of 1 pixel...even when I set gl_PointSize to a high value in my vertex shader. How can I make my point sprites ...
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votes
0answers
28 views

How to get 3D objects using Visual C++ | OpenGL | SDL | Blender [closed]

How to get 3D objects using Visual C++ | OpenGL | SDL | Blender Hi, I have been searching for a tutorial(s) witch corresponds or my specific desire but I had no luck, any suggestions? Thanks.
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0answers
22 views

changing camera's reference point position by a keyboard event

I would like to change the camera's reference point position using gluLookAt. I would like that it changes when I press for exemle 'a'. I tried with: void VueOpenGL::Paint(wxPaintEvent&){ ...
2
votes
1answer
126 views

Mouse Speed in GLUT and OpenGL?

I would like to simulate a point that moves in 2D. The input should be the speed of the mouse, so the new position will be computed as following new_position = old_position + ...
0
votes
2answers
62 views

Passing variables down the pipeline glsl

I am sorry to post a question that may be easily tested, but I don't have an OGL4+ hardware at the moment and I have to make some design decision beforehand so I wanted a clear scenario. Looking at ...
0
votes
1answer
75 views

WebGL wrong scaling of rectangle

I'm working with this tutorial http://www.html5rocks.com/en/tutorials/webgl/webgl_transforms/ and my result is, that the rectangle moves in the direction of it's scaling values, and also scales at ...
3
votes
1answer
706 views

exporting bind and keyframe bone poses from blender to use in OpenGL

EDIT: I decided to reformulate the question in much simpler terms to see if someone can give me a hand with this. Basically, I'm exporting meshes, skeletons and actions from blender into an engine ...
5
votes
2answers
655 views

atmospheric scattering and sky geometry

I'm trying to implement an atmospheric scattering in my graphics (game) engine based on the gpu gems article: link. An example implementation from that article uses a skydome. My scene is different - ...
0
votes
1answer
31 views

When and how to apply affine translations to vertices of a mesh with LWJGL

So, I have a rigid body class, containing a list of vertices and a 4x4 transformation matrix. At the moment, I'm applying the transformation matrix to each vertex individually, and am unable to revert ...
1
vote
1answer
141 views

Random lines away from images in java2d opengl game

Working on a java game that uses some pngs images for icons/textures. A few images ( fewer than 5, out of dozens ) are showing some odd parallel "artifact" lines. They move with the image, are ...
4
votes
3answers
565 views

How portable are OpenGL versions, really?

If I write a game engine that uses OpenGL 1.5 (not assuming what else I do), is it portable now and is it still portable five years from now or are/will support for OpenGL by hardware and drivers (be) ...
15
votes
2answers
9k views

I can't figure out how to animate my loaded model with Assimp

I have loaded in a model to my C++ OpenGL game. It is a COLLADA file type that I have loaded, and I setup an animation under blender for the file. The problem is I don't know how to animate the model. ...
0
votes
1answer
364 views

LWJGL font not rendering, even with depth test and texture_2D

I'm running into an odd little problem here. I'm attempting to render a basic console over my LWJGL-based application, which should be easy enough through a decorator pattern of renderers (as in, one ...
1
vote
1answer
189 views

Calculating shadowmap coordinates for cubemap in shading pass?

I'm trying to implement shadow mapping with cube maps. I believe I've done the first stage by filling the cube map, but for the final shading pass I am unsure how to exactly calculate the cubemap ...
2
votes
1answer
97 views

Use different values for Depth Test and Depth Write in OpenGL

Is there a way to use something similar to PolygonOffset to make a depth test more permissive (move fragment depth towards eye) but still write the original depth value to the depth buffer? The only ...
0
votes
1answer
138 views

translate-scroll repeated 2d texture using opengl shader

I managed to implement an infinite 2d texture scrolling using the following shader. btw I'm using cocos2d-x 2.2.1. The vertex shader: attribute vec4 a_position; attribute vec2 a_texCoord; #ifdef ...
1
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1answer
95 views

glOrtho setting view

I am duplicating this thread from stackoverflow, please remove it if that is not allowed. I'm completely new in OpenGL. I have this problem: I have quite a complicated scene, and I am looking at it ...
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0answers
25 views

Get light positions from an environment map

As the title says, I was wondering if there's a way, in a preprocessing step, to infer the position of a some light sources starting from an environment map. I think I saw lights inferred from an ...
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3answers
65 views

Most efficient way to do 2d tiles (VBO vs Instancing)

Ok so I am looking at building a game that uses 16*16 tiles, and renders anywhere from 400,000 to 1,000,000 tiles onto the screen at any given time. The tiles will be destroyable . What is the most ...
5
votes
1answer
196 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 ...