Questions tagged [opengl]

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 applications like CAD software and computer games. It is also cross-platform. The OpenGL standard is controlled by the Khronos group, which also controls OpenGL ES.

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2answers
738 views

glUniformMatrix4fv OpenTK equivalent

Very simple and quick question which surprisingly I couldn't find an answer to over the internet: what is the equivalent of glUniformMatrixfv for opentk? I've browsed all the 7 overloads of GL....
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1answer
24 views

How does re-glBufferData()'ing interact with glVertexAttribPointer?

I understand the basic sequence: glGenBuffers() creates a "buffer object name," glBindBuffer() creates the actual buffer object (as well as binding the name), glBufferData() "creates ...
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2answers
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Calculating vertex normals in OpenGL C++

Does anyone knows a simple solution for calculating vertex normals? I've been looking for this on the internet but i cant find a simple solution, for example, if I have some vertices like this: ...
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1answer
172 views

TBN matrix for normal and parallax mapping

I'd like to refer to this question because I didn't completely answer to my problem. I've implemented normal and parallax mapping but because of some assumptions I have to use two different TBN ...
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0answers
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How do I make the 3rd person camera follow the space ship in my Space Shooter game?

https://youtu.be/13HgaeZWlIA I am making a 3D space shooter game using OpenGL and Bullet Physics. I am having a hard time with the 3rd person Camera though. If you take a look at the video above you ...
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Speeding up map rendering

My map loading and rendering process is slow when using very large maps, so I'm looking for ways to make it more efficient. My current solution works like this: My map loader uses for loops for ...
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2answers
48 views

What rotation needs to be applied to align mesh with expected axis of target?

I'm using LWJGL and JOML to create a 3D view of hexagons whose positions lie on a torus. I have a number (NxM) hexagons, whose centres and normals I have calculated to be placed on the torus to ...
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0answers
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Having problems with making a button class (checkIfClick) opengl

Just basing how sfml does it, I get the globalbound of the object and then check if the mouseposition is within the object. I ...
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1answer
29 views

Get black bars with framebuffer and glViewport

I have read several tutorials and answers regarding framebuffers and glViewport, but I can't seem to resolve this issue I have. I want to take a low resolution framebuffer (400x225) and place it in a ...
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1answer
131 views

I can't make the cube map to use shadow mapping - or it seems so

Basically, I'm following tutorials as I'm very new to OpenGL. I managed to perform shadow mapping towards just one direction, meaning I created 2D texture depth map. Now with omnidirectional shadow ...
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0answers
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Having trouble with 2d projection (Opengl)

I need to change the normalize coords from -1 to 1 to the width and height of my application. The reason why I want to change the normalize coords is because i think it would be a easier set position ...
0
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1answer
54 views

Attempt to fix sprite sheet pixel bleeding in OpenGL 2D causing sprite distortion

While working on a project, I encountered the common problem of pixel bleeding when trying to draw subregions of my sprite sheet. This caused sort of "seams" to appear at the edges of my ...
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1answer
60 views

Parts of OpenGL rendering area missing/transparent until resize

I am having a weird transparency issue when running my game in windowed mode. Parts of the window, left and top parts in normal window mode, right and bottom when in maximised window, become ...
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3answers
667 views

What resources are available to read and share pyglet code? [closed]

I am a Python programmer (I know the ins and outs decently well), and I have dabbled with Pygame. I want to make 3D applications and games, and so naturally I've been looking at OpenGL. pyglet uses ...
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1answer
2k views

OpenGL - white edges on cubes

In a minecraft-like game I'm making, I get white edges on my cubes: It is much more noticeable in darker textures. The textures are being setup like this: ...
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0answers
31 views

Direct State Access (DSA) is Failing, but pre 4.3 OpenGL works [closed]

I currently have an OpenGL project in which I am using GLFW for the window and context creation, and GLAD for loading OpenGL functions. The GLAD version I am using is OpenGL 4.6, compatibility profile,...
6
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1answer
805 views

How to make Volume Heat Distortion effect in OpenGL?

I'm working on adding volume effects to an existent, open-source game engine. At the moment, the engine only supports two dimensional "thruster" bitmaps with a planar heat distortion drawn over the ...
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1answer
67 views
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1answer
183 views

Animate some tiles of tile map

I have a game where each "tile" of the terrain is a triangle (Settlers 2). Those are placed next to each other and in way creating an infinite world (right/bottom jumps back to left/top). There is a ...
0
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1answer
34 views

how to move a 2d shape in opengl 4.6 (glfw)

Class Button So from my understanding in order to move a 2d shape you need manipulate the vertices and then update???? If i do need to update the buffer how i would go by doing that? float xpos = 150 ...
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1answer
66 views

OpenGL approach to depth-testing-like combination of a large buffer of fragments

I have a depth buffer and color buffer created by another effect. The buffer is more than double my screen size. It is not rendered from geometry, but as a whole it resembles a rendered scene with an ...
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1answer
113 views

How to update indices for dynamic mesh in OpenGL?

So I am making a 3D batchrenderer for my engine, and the basic concept is that we make large enough VBO and IBO to accompany all the vertex data(positions, normals, uv etc.) and update the VBO using <...
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1answer
306 views

Show only some parts of a point cloud. OpenGl4

I am developing an opengl 4.0 app which is showing a point cloud. In the other hand, I have an array "pos" where I have some x,y,z positions: ...
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3answers
874 views

How to hide a post-processed mesh outline when/where the mesh is hidden

I'm working on setting up an active outline in my 3d engine, a highlight effect for selected 3d characters or scenery in the screen. After working with the stencil buffer and getting some ...
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4answers
28k views

How to draw 2D images using OpenGL, in SDL?

After everything, I managed to find a simple piece of code that shows how to draw a 2D image with openGL: ...
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1answer
200 views

How to deal with VBO and obj files for physics simulation?

I'm having a hard time struggling with obj files and clothing simulations. I first made the obj file processor class that deals with the typical obj file problem: having multiple indices for vertex ...
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1answer
780 views

LibGDX - Draw multiple textures with different positions with one shader?

currently I'm optimizing my render calls by drawing multiple textures with one shader. The background textures who all share the same position are no problem. But now I want to draw some Textures with ...
3
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1answer
717 views

Specular Light not working (Phong Lighting)

There seems to be a problem with my current Phong Shading implementation. I have been using the per fragment approach. The specular highlight aspect of the technique is not rendering as it should, as ...
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1answer
255 views

How can I access an OpenGl buffer from within a GLSL 330 shader?

I am currently attempting to create a simulation using OpenGl's GPU acceleration for both the simulation computations and rendering. The rendering portion of my simulation is complete and working, but ...
0
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1answer
42 views

Memory Usage Issue with declared variables (when swapping between states)

So my problem is that When I make a Shader variable and I swap between mainmenustate and gamestate really fast I notice my memory usage increase alot but as soon I switch my Shader varaible into a ...
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1answer
3k views

Drawing fonts with LWJGL3 with OpenGL

I'm very sorry if this question has already been answered, but since I've been struggling with this for many days I thought I'd give it a shot here. My goal is to somehow render some text on the ...
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3answers
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What does a perspective projection matrix look like in OpenGL?

I've been trying to construct a perspective projection matrix myself and finding it extremely difficult. I realize that a perspective projection matrix is by default a frustum in OpenGL 3.3+ that is ...
0
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1answer
199 views

OpenGL Parallax Displacement Mapping Not Working

I am attempting to implement parallax displacement mapping into my OpenGL code but it is not working as it should. https://imgur.com/a/9yIQL As I move around, double-lines moves around and if I am ...
4
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1answer
2k views

Why is my model rotating opposite direction around the Y axis?

I have a simple scenario. I have a simple scene, and in it I'm drawing a grid and a model, with some axis for orientation. I noticed when I rotate the model about it's local Y axis, if I rotate the ...
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1answer
417 views

Help with dual quaternion skinning

I'm trying to convert my code to use dual quaternion skinning instead of matrix skinning because i just can't get the skinning matrix created correctly from bones+weights using matrices. Edit: just ...
0
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1answer
217 views

Offset on camera following object that accelerates

I have camera a that is actively following an object (a plane) from behind. This object can accelerate or decelerate. I would like to have a camera offset when I move the plane, so it doesn't look so ...
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3answers
331 views

Where did I lose vertex binding?

I make OpenGL render framework for my bachelor graduate work. I created simple Model and Shader classes. But when I tried to render some vertices, they do not render. I saw with an OpenGL profiler, ...
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0answers
473 views

How to change mac opengl version back to mesa

A while ago I wanted to use the functionality of opengl 4.5+ on my mac, so I installed mesa with macports, and it worked. Recently, however, I tried to use my code again and it said that these ...
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2answers
177 views

How to keep same aspect ratio in different devices with cocos2dx?

I have been making a board game and I am using cocos2dx. There are two scenes for now, One is main menu and the other is gameplay scene. When I run the apk on tablet with EXACT_FIT resolution policy ...
0
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1answer
82 views

How to correctly reset vertex attributes after modification

I am trying to use the same vertex shader for two different use cases to preserve memory, but I am having issues where the modifications of one shader run are passed on to the next run, even after ...
1
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1answer
328 views

Frame Buffer Object (FBO) is not working. What is the right way to use?

I am trying to use FBO but i am living some problems. I will show you my steps but first i will show my running screen ,so we can compare them. Like before fbo after fbo. My running screen and Draw() ...
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1answer
73 views

What is the best way to approach a multi pass rendering system?

I am trying to code a new feature in my engine but I can't find a way to implement my idea, which is the next one. I am trying to get multi pass rendering with more than two passes. I know how to do a ...
0
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1answer
699 views

Adjusting view matrix when glViewPort & resizing

I have an issue when my window resizes. I have a simple MVP shader like this gl_Position = projection * view * model * vec4(in_Position, 1.0); to render a map ...
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0answers
45 views

Problem with bullet movement

I'm trying to draw "bullets" in my game, but I think something is wrong with velocity computation. Sometimes the "bullets" are going in the right way, but sometimes they won't. The ...
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2answers
3k views

Using an array of 3d points to construct point cloud or surface in OpenGL

I have an array of 3 dimensional point objects, I can manipulate the input into this array into any configuration I want, for example, it could be a vector of floating point numbers, a vector of ints, ...
4
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2answers
5k views

Where and how to smooth a voxel-based terrain surface?

I want to smooth the blocky terrain in a Minecraft-like world. The smoothing affects visual appearance and physics but not the logic of placing and picking blocks. I have my mathematical formula to ...
4
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2answers
1k views

OpenGL GLSL using projection,view and transformation

I have been trying to get a simple triangle to render on the screen. I am using Projection, View and Transformation matrices but am unable to get anything to the screen. Main loop ...
0
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1answer
154 views

Replacement for glDrawElementsBaseVertex in OpenGL ES?

I am porting my game engine(c++) to Emscripten, which unfortunately only supports OpenGL ES 3.(Not 3.2) Therefore I don't have access to glDrawElementsBaseVertex, which is needed by my renderer(...

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