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 ...

learn more… | top users | synonyms

4
votes
1answer
90 views

Textures “don't work” when I don't specify any texture parameters. Is this a driver bug or intended behavior?

Whenever I try to use textures, I have to at least specify the sample filtering parameters (GL_TEXTURE_MAG_FILTER, GL_TEXTURE_MIN_FILTER) for textures to work at all. If I don't, sampling the textures ...
0
votes
1answer
71 views

OpenGL rendering to multiple windows, having 1 main loop for each window

I have written a little OpenGL framework in the past year that i would like to extend to support multiple windows in the near future. I have an idea about what I would like to do but I am not sure if ...
9
votes
2answers
2k views

How to make natural looking voxel

I'm developing a voxel game, but I think I use the wrong technique. I currently use flat tiles, to make blocks, and I think theres a better and more efficient way. I have seen a voxel game, which ...
1
vote
1answer
54 views

Handle vertex indicies in a vbo batch drawing call

I'm new in the OpenGL 2 world and want to render a lot of cubes (> 150.000). How can I render such kind of cubes in practise? My idea is to split the cubes to a set of vbo's (Maybe 2000 cubes per ...
2
votes
1answer
166 views

Signed Distance Fields: How are different colour channels used to improve output of sharp corners?

The naive approach to implementing signed distance field font rendering suffers quality issues where sharp corners get softened (either outward- or inward-facing corners, i.e. convex or concave ...
0
votes
1answer
47 views

Compress 16 bit raw data in webgl

I have a 3D volume where every voxel is 16 bits. Is there anyway I can use some kind of compression to store the data so I can use less video ram? Webgl supported different compressiosn if you enable ...
0
votes
0answers
28 views

Does the on-screen size of object change with the direction of camera?

I'm reading the following document, and on page 3 it says: The first thing to notice is that the desired projection on the screen does not change with view direction. That is, whether the screen is ...
1
vote
2answers
106 views

Difference between Spherical Harmonics and Spherical Harmonics Lighting

What is the difference between Spherical Harmonics and Spherical Harmonics Lighting in OpenGL?
2
votes
3answers
223 views

Generating 3D-like effect

I'm making a 2D sidescroller game and want to give the blocks a 3D like effect. This way it looks like the player is walking on 3D blocks while walking on a 2D plane (thus having only x,y ...
1
vote
1answer
79 views

Shader - Realtime texture masking

The first thing that comes in mind is masking using RGBA values. With this you can obtain this kind of textures and this kind of results. But with this, you can only store up to 4 masks inside a ...
0
votes
1answer
78 views

GLSL: Incompatible Types at Initialisation (and no available implicit conversion)

I'm recieving the following error when compiling my GLSL shader: Incompatible types in initialization (and no available implicit conversion) It occurs on line 94: int shadowMap = ...
0
votes
1answer
77 views

Intersperse 2D with 3D opengl

I want to be able to draw 3D objects as well as 2D objects in an openGL environment. Normally, I would draw my 3D stuff, disable the depth buffer and depth mask, then draw my 2D stuff. However, this ...
0
votes
1answer
51 views

Edit VBO data or create a new one?

I have a question: if I have a VBO, and I have to change all the data inside it (because of resizing, ...), would it be more efficient to delete the old one and create a new one (and reallocate the ...
0
votes
2answers
304 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 ...
0
votes
0answers
200 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
50 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 ...
1
vote
2answers
332 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 ...
0
votes
1answer
58 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 ...
1
vote
0answers
44 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 ...
0
votes
0answers
39 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 ( ...
0
votes
0answers
31 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
732 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
vote
0answers
84 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
114 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
vote
0answers
69 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?
8
votes
1answer
947 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 ...
1
vote
1answer
78 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
votes
1answer
62 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 ...
0
votes
0answers
64 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
votes
0answers
74 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 ...
0
votes
0answers
67 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 ...
0
votes
1answer
83 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 ...
1
vote
2answers
160 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
132 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
votes
1answer
68 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 ...
1
vote
2answers
96 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
94 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
74 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 ...
0
votes
2answers
55 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 ...
1
vote
1answer
417 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
252 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
61 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
47 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
45 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
votes
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
64 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
138 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
176 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 ...