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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848 views

Multithreaded Game Loop

I'm trying to implement a multithreaded game loop. I already did that but had to use a few locks for that, which ruined the performance. After researching a bit I came up with this idea: Instead of ...
6
votes
1answer
5k views

Interleaving Arrays in OpenGL

In my pursuit to write code that matches todays OpenGL standards I have found that I am completely clueless about interleaving arrays. I've tried and debugged just about everywhere I can think of but ...
6
votes
1answer
334 views

Get SFML to report the version of OpenGL that is being used

How can I get SFML to report the version of OpenGL that is being used by the render window?
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1answer
1k views

VBO and gl*Pointer management practises?

I'm aware it's not a simple yes/no question and for the moment I can't tell if it can be simply answered, or is it a topic for a long discussion which is not suitable for our Q&A format. I want ...
6
votes
1answer
3k views

Bones Animation - Matrices and calculations

We are 'on final' when it comes to finishing the project, but just before implementing the animation system. Our Client decided to choose "Bones Animation" - which is that I should export each ...
6
votes
3answers
2k views

Direct3D and OpenGL Matrix representation

As I read in OpenGL matrices are column major. It means that if I create a 16 element array first four elements are the first column in matrix. Is it the same for Direct3D or any transformation's ...
6
votes
1answer
5k views

Help understanding gluLookAt()

I am fairly new to openGL( 3 months ) and am asking for assistance in understanding the fundamentals behind gluLookAt(). Currently I have spent most of my time with openGL modeling scenes with fixed ...
6
votes
1answer
474 views

Spherical harmonics lighting interpolation

I want to use hardware filtering to smooth out colors in texels of a texture when I'm accessing texels at coordinates that are not directly at the center of the texel, the catch being that the texels ...
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votes
2answers
6k views

How to rotate camera centered around the camera's position?

Currently I am using gluLook at like so: gluLookAt(position.x, position.y, position.z, viewPoint.x, viewPoint.y, viewPoint.z, upVector.x, upVector.y, upVector.z); with the above,...
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votes
2answers
2k views

Geometry shader for multiple primitives

How can I create a geometry shader that can handle multiple primitives? For example when creating a geometry shader for triangles, I define a layout like so: layout(triangles) in; layout(...
6
votes
1answer
755 views

GLSL subroutine not being used

I'm using a gaussian blur fragment shader. In it, I thought it would be concise to include 2 subroutines: one for selecting the horizontal texture coordinate offsets, and another for the vertical ...
6
votes
1answer
2k views

Problem with Assimp 3D model loader

In my game I have model loading functions for Assimp model loading library. I can load the model and render it, but the model displays incorrectly. The models load in as if they were using a seperate ...
6
votes
2answers
2k views

How can I make the switch from immediate mode to VBOs?

I've been using OpenGL for a short time now- and I'd like some clarification on VBOs. As I understand it, a VBO is an object stored on VRAM. In immediate mode, to apply a texture we simply bind it and ...
6
votes
1answer
1k views

Rendering 2D grass

My current project, using Java and OpenGL, has a fairly standard overhead tilemap in the style of the Zelda games. I'd really like to add "real" grass to the grass tiles so that there are actually ...
6
votes
2answers
372 views

Changing player color without multiple player bitmaps [duplicate]

Possible Duplicate: How to colorize certain parts of a model - like RTS games have those team colors? Ok, so here is my current situation. I have a player model, fully UV mapped, and textured. ...
6
votes
1answer
167 views

How to find out at runtime if Vulkan and/or OpenGL support is available?

I'm building an engine, which has Vulkan for its primary rendering engine. But to have at least some backwards compatibility with devices that don't get drivers for (Mainly mobile) it I want to ...
6
votes
1answer
201 views

Dual paraboloid shadows on GLSL

I'm trying to port an XNA example to OpenTK + OpenGL, I found it here http://graphicsrunner.blogspot.com.es/2008/07/dual-paraboloid-shadow-maps.html But I'm having a really hard time, I think my maps ...
6
votes
1answer
906 views

Sprite with alpha Blending in 3D world

I'm working on a game in a 3D world with elements 2D only (Like Don't starve game) for Android and IOS. Currently, I've managed "Sprite" without alpha blending, I've just put a condition in the pixel ...
6
votes
2answers
2k views

Square game map rendered as sphere

For a hobby project of mine I have created a finite voxel world (similar to Minecraft), but as I said, mine is finite. When you reach the edge of it, you are sent to the other side. That is all ...
6
votes
1answer
1k views

Difference between the terms Material & Effect

I'm making an effect system right now (I think, because it may be a material system... or both!). The effects system follows the common (e.g. COLLADA, DirectX) effect framework abstraction of Effects ...
6
votes
1answer
1k views

Can I use the default depth buffer when drawing to FBO?

How to attach default depth buffer to FBO? How to use depth renderbuffer buffer attached to FBO (after drawing to it) as a default depth buffer? Basically I want to use the same depth buffer for both ...
6
votes
1answer
6k views

GLSL - Rewriting shaders from #330 to #130

I recently created a game (LD21) that uses a geometry shader to convert points into textured triangles/culling. Since I was under the impression that the support for #330 was widespread I only wrote #...
6
votes
1answer
7k views

OpenGL ES 2.0: Understanding Perspective Projection Matrix

Setting the Perspective projection matrix in Open GL (including OpenGL ES 2.0) has the following general format: glm::mat4 perspective(float fovy, float aspect, float zNear, float zFar); Notice the ...
6
votes
1answer
179 views

OpenGL flat shading of non-planar polygons using TBOs

I'm trying to implement flat shading for non-planar polygons (using a single normal vector per polygon) based on buffer textures, but I can't seem to figure out how to set up things correctly. The ...
6
votes
1answer
438 views

With what projection matrix should I render a portal to a texture?

I'm using OpenGL. I have problem with my engine's portal implementation. To create the first portal I do: create a virtual camera with the position of the second portal and the correct orientation ...
6
votes
1answer
3k views

Exponential Variance Shadow Mapping - implementation

I use a variance shadow mapping with a "standard" light bleeding fix in my graphics engine which is based on deferred rendering.. I have a single shadow map for a directional light beacause a test ...
6
votes
1answer
1k views

Octree implementation for fustrum culling

I'm learning modern (>=3.1) OpenGL by coding a 3D turn based strategy game, using C++. The maps are composed of 100x90 3D hexagon tiles that range from 50 to 600 tris (20 different types) + any ...
6
votes
1answer
884 views

How to flip a BC6/BC7 texture?

I have some code to load DDS image files into OpenGL textures, and I'd like to extend it to support the BC6 and BC7 compressed formats introduced in D3D11. Since DirectX and OpenGL disagree about ...
6
votes
2answers
731 views

An odd performance problem rendering a simple scene (less than 14k vertices) in OpenGL using two vbos with LWJGL

Problem I have been having a strange degrading performance issue rendering a simple scene containing two "chunks" of 4x4x4 cubes each. Video of problem This is a screen capture showing my console ...
6
votes
1answer
5k views

Making a camera in a 2D game (glOrtho)

I'm trying to make a camera that follows my character and it seems I've managed. However, I don't know how to limit that my camera don't follow me when my character reachs the boundaries of the ...
6
votes
2answers
890 views

Textures for an underwater environment?

I'm trying to build an underwater scene. I'm including my scene in a large cube, which I'm going to texture with images that resemble an underwater environment. Where can I get textures for something ...
6
votes
3answers
1k views

How can I get into opensource game development? [closed]

The short and sweet question I'm new to game programming in general, so how do I go about making GOOD QUALITY opensource games? What I have come across There are a multitude of games that I have ...
6
votes
1answer
2k views

How to implement translation, scale, rotation gizmos for manipulating 3D object's transforms?

I am in the process of developing a basic 3D editor. It uses OpenGL for rendering a 3D world. Right now my scene is just a few boxes of different sizes and I am at the stage where I want to be able to ...
6
votes
3answers
9k views

Confusion over GLViewport

I'm hoping someone can help me understand the GLViewport and what happens when we resize it This will illustrate my confusion.... So, here I have a quad stuck in the middle of the screen. If I ...
6
votes
1answer
884 views

Texture coordinate discontinuity with mipmaps creates seams

I just started learning openGL and I am getting this artifact when texturing a sphere with mipmaps. Basically when the fragment samples the edge of my texture, it detects the discontinuity (say from 1 ...
6
votes
2answers
3k views

Using a GLSL fragment shader to draw a texture in the middle of a quad

I'm not sure how possible this is, but I'm trying to use a fragment shader to draw a portion of a texture in the middle of a quad. This is all 2D. The quads consist of four vertices from (0, 0) to (...
6
votes
1answer
2k views

How to manage shaders?

I've done some shader programming some time ago but only simple stuff. I'm especially interested in how do you manage shaders? Do you just write one of each kind, or do you need more of them? If so, ...
6
votes
1answer
91 views

OpenGL 3.3 Core Compatibility with OpenGL 4.x

Are all OpenGL calls in 3.3 Core and GLSL 330 core shaders valid and functionally equivalent in OpenGL 4.0 through 4.5 core? I can't seem to find a clear and definitive answer; both in specification ...
6
votes
4answers
312 views

Is index drawing faster than non-index drawing

I need to draw a lot of polygons consisting of 6 vertices's (two triangles). Without any texture coordinates, normals etc., both approaches result in 72 bytes. In the future I would definitely also ...
6
votes
1answer
2k views

TBN Matrix : Eye vs. World Space Conflict

I am tired of misleading and insufficient articles making me more confused each time I read, I need a clarification that will solve my TBN matrix problem forever. Each article I read informs me ...
6
votes
1answer
697 views

Library for generating primitive shapes? [closed]

I'm looking for a library to generate the data for primitive shapes for opengl. I have lights, and I simply wants to draw a sphere to represent the lights transform in the world I do not want a ...
6
votes
2answers
3k views

FBX Importer - Texture Name

I have a problem with the FBX SDK. I read in the data for the vertex position and the uv coordinates. It works fine, but now I want to read for each polygon to which texture it belongs, so that I can ...
6
votes
2answers
1k views

Vertex data split into separate buffers or one one structure?

Is it better to have all vertex data in one structure like this: class MyVertex { int x,y,z; int u,v; int normalx, normaly, normalz; } Or to have each component (location, normal, texture ...
6
votes
1answer
3k views

Weird error with opengl in Android using Libgdx : “EGL_BAD_ATTRIBUTE”

I am having a weird error when uploading my game in the phones. E/Adreno200-EGL(5128): qeglDrvAPI_eglGetConfigAttrib:484>: EGL_BAD_ATTRIBUTE I am uploading the textures with AssetManager. I am ...
6
votes
1answer
186 views

Excluding Background from Color Picking

I've implemented picking based on color coding, but I don't want the background color to be pickable. Is there any way in openGL (2.x) to exclude the background color? For some reason, doing glClear(...
6
votes
1answer
243 views

How can I extrude a regular, grid-based 2D shape to 3D?

I have a list of vertex coordinates which encircle several 2D areas. Orthogonal lines only, but not necessarily convex areas... similar to PCB traces of conductive copper areas. I want to draw them ...
6
votes
1answer
200 views

In a shader, why does substituting a variable with the expression producing it cause different behaviour?

I have this correctly-working OpenGL shader producing Perlin noise: float left = lerp(fade(v), downleft, topleft); float right = lerp(fade(v), downright, topright); float result = lerp(fade(u), ...
6
votes
1answer
1k views

OpenGL ES object rotation around z axis

I have an object on my screen which is presented rotated and panned, But i have 2 problems regarding the z axis rotations. It's a bit tricky to explain so i uploaded 2 videos to describe each problem. ...
6
votes
1answer
461 views

How to debug framerate drops with VBOs, OpenGL

I'm working on an experimental app to test how VBOs perform when rendering a minecraft-like world. If the performance is better than what I use now I'll update my actual game. Based on what everyone ...
6
votes
3answers
1k views

State of the art Culling and Batching techniques in rendering [closed]

I'm currently working with upgrading and restructuring an OpenGL render engine. The engine is used for visualising large scenes of architectural data (buildings with interior), and the amount of ...