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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2answers
196 views

Resizing a Framebuffer Object (ie: its attachments) on Screen Resize

I have been experimenting with some post-processing effects and I have been using FBOs to store stuff. The problem is, I attempt to resize them when I change resolution. I get no errors, however the ...
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0answers
168 views

OpenGL - Arcball camera rotation

I'm implementing arcball camera rotation, whereby a camera is looking at a coordinate and rotates around it in the x-axis or the y-axis such that the camera is circulating around it; the y-axis will ...
2
votes
2answers
48 views

How do find the right GLxx object for a given function in LWJGL?

I'm just starting to learn the fundamentals of OpenGL via LWJGL. Every OpenGL function is implemented as a method on a GLxx class. The xx corresponds to the version of the spec when that function was ...
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vote
2answers
318 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
54 views

Reasonable texture Formats for VertexTextureFetch in GL

Wich is a reasonable GL version that have support for vertex textures fetchs(VTF) in OpenGL ? (for example GL 3.0, 3.1, 3.3) What textures formats should I expect to be supported in average video ...
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0answers
40 views

Incorrect Texcoords for Bitmap Font? [closed]

I am writing some code to display text using a bitmap font. However, when I run my game to see my results, I am greeted with a blank screen. I changed the texture to pure white to see if it was even ...
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0answers
37 views

opengl fixed function pipeline rendered transparent object with black edge

As you can see from the image,it's a transparent object with a png file,then I render it before call : glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ); glEnable ( GL_BLEND ); glEnable ( ...
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0answers
28 views

Encoding Floats to RGBA and Blending causing artifacts

I am using float packing to encode a float value inside a RGBA texture because I don't have access to float texture unfortunately. Here are the function I am using for encoding and decoding. inline ...
3
votes
2answers
679 views

Do resolution settings have any impact or give any advantage in online FPS games?

There is this crazy theory that has always bothered me. I am not after a technically but more theoretically (although technical knowledge is required to) answer; Two friends are playing the same ...
1
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0answers
69 views

Uniform Buffer Binding-points

I believe Uniform Buffers/Blocks has been the hardest thing to grasp in OpenGL. Hopefully this will be my final issue regarding this. I have created a uniform buffer that contain data of Light ...
0
votes
1answer
97 views

OpenGL Viewport inside of a Viewport

I'm creating a labyrinth in opengl, and I'm trying to create a minimap. For that, I thought of creating a viewport inside of a viewport. I already tried following a tutorial from Lazy Foo, and I can ...
1
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0answers
67 views

How can I do ambient occlusion for simple meshes with few vertices?

I want to do ambient occlusion for some simple buildings. Since simple buildings have very few vertexes, how can I get good results? Is it possible with a per-vertex AO implementation?
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1answer
785 views

Taking advantage of multithreading between game loop and openGL

Talking in context of a game based on openGL renderer : Let's assume there are two threads : Updates the game logic and physics etc. for the in game objects Makes openGL draw calls for each game ...
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1answer
65 views

Reference keyboard keys as “justPressed”, “pressed”, and “justReleased” with SDL in C++

I'm teaching myself 3D graphics with OpenGL and SDL in C++. I'm at a point where I need to be able to query states of individual keys, like so: if (InputManager::justPressed(SDLK_UP)) {} if ...
0
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1answer
54 views

Encoding Float to RG/RGBA and Blending

Encoding a float value inside a RG or RGBA texture is very interesting and useful but it is also become quite useless when you use blending as the result and the values might be altered because of ...
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0answers
55 views

OpenGL Omni-Directional Shadows Debugging

I'm working out making omni-directional point-light shadows for my game engine, and I can't get any of it to work. Here's some relevant code: Here's where I create the depth map, I make a cube map ...
0
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0answers
60 views

Assimp - generate tangents and bitangents

I have started using Assmip 3.1.1 in my OpenGL application. Let's consider a simple example. Here is obj triangle model: mtllib triangle.mtl v -5.0 0.0 0.0 v 0.0 0.0 0.0 v 0.0 5.0 0.0 vn 0.0 0.0 ...
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0answers
51 views

Trackball Rotation using Quaternions

I am trying to figure out rotations using quaternions. I am using a trackball that tracks the mouse when I click. So when I click on the right and drag to the left, the cube rotates around the y ...
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1answer
70 views

Render model with meshes with materials and/or textures

I'm making a model class that is using Assimp in the background. I want my models' meshes to be able to have a material and an optional texture on top of that. Right now I'm doing it like this: for ...
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2answers
145 views

Problems with rendering a SkyBox

At the moment I'm writing an Android OpenGL ES 2.0 game but now I get stuck on rendering a SkyBox. Here is my (a bit simplified) code for the SkyBox: float vertices [] = ...
3
votes
1answer
102 views

what is the very last element of a 4x4 transformation matrix for? [duplicate]

while its a similar value to its neighbour - Z translation (and I wont say if thats above or to the left for fear of sparking a religious war!) and it only seems to change when the Z translation value ...
0
votes
1answer
111 views

Looking for Bezier curve OpenGL open source implemention [closed]

well in short im looking for something like this as open source. https://www.youtube.com/watch?v=Cut3_A0Xm3Y i need to implement especially the Bezier curve editing in my app in open gl . any ideas ...
0
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1answer
61 views

Cubemap faces rotation in GS shader

I Can't get correct rotations for cubemap faces. Thats should come to geometry shader, from camera "view" matrix I want make 6 faces for my cubemap, but seems I can't get it correctly... My first ...
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2answers
89 views

Rendering objects with either normal maps, either specular maps, or with both, or with neither?

My hobby engine has a deferred renderer that supports normal maps and specular maps. Now, some objects may have normal maps, and some may have specular maps. In some cases, an object has both maps, ...
0
votes
1answer
77 views

glVertexAttribPointer stride ambiguity

As a hobbyist junior game programmer, I have done multiple small OpenGL projects just to have fun with 3D. I've tested VBOs in C++ and in Java and I found something or rather understood Java tutorials ...
2
votes
1answer
70 views

How can I deal with vertex precision errors between terrain chunks?

I am using OpenGL to render the following scene, using vertex data from one of the map files of a popular MMORPG. The data is chunked and the pictured scene is made up of 256 (16x16) chunks. However ...
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2answers
49 views

How can I chain together Stencil tests from the same re-occurring routine, but keep the tests separate?

Sorry for the bad title; I don't know how else to explain this. I have a class called a Container. An instance of Container has other elements "inside" it. These elements have independent positions ...
2
votes
1answer
320 views

How do I build Assimp with MinGW?

How can I build Assimp with cMake and MinGW? I tried, but I don't get a functioning library... Details of my attempt: I am trying to build the Open Asset Import Library (Assimp) but I have been ...
4
votes
1answer
187 views

Should unbind buffers?

I'm making some tests with OpenGL ES 2 and got some questions, my current program is like that: Init ------- -> create index buffer -> fill index buffer glBufferData … -> create vertex ...
1
vote
2answers
60 views

Rendering order of shadowing point lights?

I'm implementing shadow mapping in my deferred rendering engine. I've got spot lights working, and now I'm working on point lights. Currently, I do it like this: // Loop through the point lights for ...
0
votes
0answers
45 views

Ray casting: need to find start and end vectors

So I have a 3D object and I'm trying to implement Maximum Intensity Projection on it. I already started of using a default vector to show per pixel, namely: pixelCoord[0] = uVec[0] * (i - ...
0
votes
1answer
41 views

Is it possible to store diffuse and normal maps in the same texture area and preserve SRGB/linear space?

Usually, one would want to upload texture data to OpenGL with GL_SRGB* for the internalformat of a texture, and GL_RGB* (or some other linear format) for normal data or specular highlight maps. We can ...
0
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0answers
33 views

Deforming meshes in OpenGL [closed]

I'm learning about OpenGL, specifically OpenGL-ES 2.0 on Android. The question I've posed to myself this evening is: how can I deform a mesh? I think I have some answers. So my questions for SE ...
1
vote
1answer
58 views

render with const depth value

This is a question that may have an answer that differs for vanilla desktop GL and GL ES 2.0 (and wishful thinking is that ES 3.0 would have the same answer as vanilla GL). What I'm doing is ...
0
votes
1answer
127 views

Trying to implement Camera

I'm trying to implement a Camera class in order to walk and look on the world as follow: #ifndef _CAMERA_H_ #define _CAMERA_H_ #include <glm\glm.hpp> class Camera { public: Camera(); ...
1
vote
1answer
173 views

How can I render a JBox2D ParticleGroup?

I want to render a ParticleGroup from JBox2d using OpenGL. I've managed to define a particle group area, but I'm unsure how to draw the individual particles. Here's how I create the ParticleGroup: ...
0
votes
0answers
48 views

Why Reducing fragments by increasing geometry vertices turn out to be slow?

I am developing a ray-casting program by OpenGL. At first I made a large bounding box including the whole volume and render this box, which triggers the ray-casting. I'm trying to optimize this ...
8
votes
1answer
401 views

Creating a glitch effect similar to Watch Dogs

I'm currently working on a LibGDX game. When a user does something wrong, I would like all the graphics on the screen to jitter very similar to the glitch/distort effect seen in the game Watch Dogs ...
5
votes
2answers
595 views

2D games and modern OpenGL

Preconcepts Ok, so what I've gathered so far is this: don't use fixed pipeline (deprecated or going to be deprecated) vbos store "object models" (n vertex data, mostly) vaos describe how data is ...
1
vote
1answer
126 views

How can I load raw Bayer images using OpenGL?

I want to load a raw Bayer format image and convert it to RGB using OpenGL. So far I have played around with glTexImage2D() and loaded a Bayer image as a monochrome texture. My question is: how can I ...
0
votes
1answer
106 views

Fragment Shader output type error

StackExchange! I've been working with opengl for a bit and I'm trying to finally load the shaders instead of having them inline. I'm having a ton of issues, though. As soon as I solve one, another ...
1
vote
1answer
103 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.
-1
votes
1answer
47 views

How would I go about merging two models together in-game to create a new model? [closed]

Let's say I have two models: model 1 is hilt and model 2 is blade. How would I merge these to models together to create a sword?
0
votes
2answers
92 views

How to draw a textured 2D square using OpenGL

I am attempting to get started using OpenGL, and have learned how to open a window and draw basic shapes. However, I do not know how to texture them and have been unable to find any tutorials on how ...
2
votes
1answer
213 views

OpenGL light appears to move with camera and changes with object rotation

I have a working open gl es 2.0 3d engine (my own) that I've used in several iOS apps. I recently noticed that on a mutli-symmetrical object the lighting didn't look the same at each rotation. For ...
1
vote
1answer
90 views

model view projection multiplication order

I'm debugging a lighting problem where the camera position is effecting the diffused lighting component on my 3d model. In researching my problem I went back and am reading over all the how to ...
4
votes
2answers
410 views

Is there an alternative to VBOs or deprecated functions to draw many small quads?

I was thinking about how to program a user interface in a 3D game. The problem is, immediate mode (glBegin and glEnd) is deprecated for a long time but I don't think vertex buffer objects (or arrays) ...
1
vote
1answer
87 views

Why would OpenGL ignore GL_DEPTH_TEST setting?

I cannot figure out why some of my objects are being rendered on top of each other. I have Depth testing on. glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); Do I need to draw by order of what is ...
0
votes
1answer
89 views

How can I draw a ray from the camera in world space?

How can I construct a ray from the camera position to where it looks at, in world space. My previous method is draw a line by using two points. The first point is the camera position, and the other is ...
3
votes
2answers
81 views

How can I draw curves above a mesh surface?

I am making an animation of a deformed sphere that represents some aspects of the wave function in a hydrogen atom. I am starting with an octahedron that i push through a tessellation shader. The ...