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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0answers
105 views

Which will be better for a beginner, SDL, SFML or OpenGL? [closed]

I want to make games.For now simple 2D games, but I don't know from where to start. I "know" C++, but i havent worked with classes.I want to begin with game development and I searched in the internet ...
2
votes
4answers
229 views

OpenGL setup on Windows

I have been trying to use OpenGL for two days now. First on Mac, then on Windows. The problem with Mac is that it doesn't support the newer versions of OpenGL. I ran a tutorial that actually did get ...
5
votes
2answers
169 views

How to use OpenGL functions from multiples thread?

I'm writing a small game using OpenGL. I'm implementing basic networking in this game and I'm facing a problem. I have a thread in my client socket class that check for available data, when there ...
0
votes
1answer
71 views

OpenGL ES 1 Pixel Error?

I am developing a game on android using OpenGL ES 1.0 for Android OS. It is a 2d game using a simple Orthographic projection and textures for the sprites. One of these textures has a small line (it ...
-1
votes
1answer
76 views

How do I put different textures on different walls? LWJGL

So far I have it so you are running around in a box, but all of the walls are the same texture! I've loaded up other textures for the walls (I want the walls a different texture than the floor) but it ...
1
vote
1answer
211 views

OpenGL - Calculating camera view matrix

Problem I am calculating the model, view and projection matrices independently to be used in my shader as follows: gl_Position = projection * view * model * vec4(in_Position, 1.0); When I try to ...
2
votes
1answer
270 views

OpenGL 4D textures with bilinear interpolation

I want to use and interpolated 4D texture in OpenGL, i.e. a texture that is accessed with a texture coordinate vector (s, t, p, q) and interpolated linearly in every texture coordinate. The extension ...
1
vote
0answers
60 views

Different way to pass uniforms to seperate draws in glMultiDrawElementsIndirect

Given OpenGL version 4.3 and GLSL 430, what would be the best way to pass a matrix to each model in a draw call to glMultiDrawElementsIndirect? I am thinking of going the way of a TBO and indexing it ...
1
vote
0answers
58 views

Android: Hardware Scaler

I was reading through this: using-hardware-scaler-for-performance and am a little confused by it. It says all you need to do to invoke the scaler is to set it like so: surfaceView = new ...
1
vote
1answer
121 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 ...
0
votes
0answers
47 views

Issue with turntable rotation openGL

I am trying to implement turn table like rotation in my openGL app. In turn-table like rotation, z-axis is not supposed to roll. But in my app z-axis rolls like anything when I try to rotate the ...
0
votes
0answers
69 views

Help with instancing: seg fault with glVertexAttribDivisor

I'm trying to get the basics of instancing in OpenGL 3.3 and failing miserably. I'm starting with the Jason McKesson's Depth Buffering tutorial, then modifying it so that only the ...
1
vote
1answer
80 views

Why are my objects rotating with my camera?

I am working with this C# library that wraps OpenGL. I am trying to understand why my objects in the scene are rotating as I yaw my camera (view matrix). Here is an image where I have 4 separate ...
0
votes
1answer
128 views

Create 2D sprites with libGdx using a shape and a texture separately

I am creating a 2D game with LibGdx that will have creatures that are generated from dozens of characteristics with potentially millions of unique combinations. For each segment of each creature, I ...
0
votes
1answer
96 views

Making particles accelerate toward a mouse point

I'm currently working on a particle simulation program that makes pixels move towards a mouse point continually accelerating, but i'm running into some math issues. Currently my particle will ...
0
votes
2answers
68 views

Trouble getting shadow maps working

I am trying to implement shadow maps in my game following this tutorial. For some reason, the light is not being occluded. In the above screenshot, the big white sprite in the foreground is a ...
0
votes
1answer
109 views

Calculating Per Vertex Normal in Geometry Shader

I am able to calculate normals per face in my Geometry Shader but i want to calculate per vertex normal for smooth shading. My Geometry shader is #version 430 core layout ( triangles ) in; layout ( ...
1
vote
0answers
109 views

How can I reduce draw calls when using glBufferSubData and DYNAMIC_DRAW?

At first I had the problem where I had about 150 rectangles rendered every tick. I only used STATIC_DRAW and glBufferData. I added support for DYNAMIC_DRAW and glBufferSubData and now I have a very ...
1
vote
0answers
140 views

Point light shadowmapping woes [closed]

I'm doing point light shadow mapping and I'm tearing my hair out trying to iron out a bug. The problem is shadows are basically "inverted" somehow, or wierdly placed. Here's five screenshots; you ...
0
votes
1answer
83 views

Deferred lighting and point light volumes

I'm doing deferred point light shadow mapping and I am drawing my point lights using light volumes. Normally I access the position/diffuse texture/normals using this in the fragment shaders: vec2 ...
3
votes
1answer
156 views

What is the maximum number of shaders I can have in OpenGL 4?

What is the maximum limit of shaders I can have on the GPU? With 1000 different objects, I might have 1000 * 5 shaders (vertex, tcs, tes, geo, frag) on the GPU at a time. Though only one will be ...
0
votes
1answer
87 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 ...
2
votes
1answer
113 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 ...
1
vote
1answer
86 views

Techniques for managing vertex buffer memory

I'm learning OpenGL and I haven't seen any advice on managing vertex buffers in all of the tutorials I've read. The basic problem is that I have some memory allocated as a buffer B in which I'm going ...
4
votes
1answer
88 views

OpenGL - What steps to take to correctly set up an Uniform Block Array

I have managed to get uniform blocks to work, but I seem to make something wrong when trying to setup an array of uniform blocks. Assume this glsl: layout(std140, binding=1) uniform LightingBlock ...
2
votes
2answers
83 views

OpenGL - How to draw each nth triangle using glVertexAttribPointer

I have a vertex buffer. There are situations when I don't want to render the whole mesh, but let's say each nth triangle of the mesh. I am using VAOs and VBOs. My data in the buffer is like this: ...
0
votes
2answers
88 views

Achieving a fixed frame-rate with varying scenes

I am working on an OpenGL 3D model viewer app for iOS. I have to load, view and navigate extra detailled 3D models on an iPad. I hardly achieve 2 fps, if i load and navigate a very complex model. I ...
0
votes
1answer
109 views

Pixel Buffer Object (PBO) does not work correctly

I've written a very simple OpenGL application. Its goal is to load a texture and draw it on a plane using a PBO. If I use the function 'glTexSubImage2D' the plane is not textured and the function ...
2
votes
1answer
107 views

How I reuse the same vertex data, but have different colors, for my sphere objects?

I'm using OpenGL to display a 3D network, with nodes represented as spheres (I haven't gotten to edges yet). I'm a total novice, and having a bit of trouble wrapping my head around OpenGL. These ...
3
votes
1answer
144 views

How to achieve cavalier projection using OpenGL fixed pipeline?

I want to make a quick demo program showing a cube, or a user loaded model, rotating in screen rendered with one of three projections: perspective, isometric and cavalier. Using the fixed pipeline, ...
-1
votes
2answers
111 views

How to translate along Z axis in OpenTK

I am playing around with an OpenGL sample application I downloaded for Xamarin-Android. The sample application produces a rotating colored cube I would simply like to edit it so that the rotating cube ...
0
votes
3answers
92 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 ...
0
votes
1answer
229 views

openGL Camera setup for Zoom in/out centered at point under cursor

I am trying to implement a zoom in/out navigation mode in a openGL 3dViewer. I was able to implement zoom functionality centered at screen center just by moving eye towards the center in perspective ...
0
votes
0answers
24 views

opengl output to texture with 4 levels of depth

i'm building a game where transparency is important. I can live with being restricted to four levels of depth and my current plan is to do two passes: 1. render everything to a texture using ...
0
votes
1answer
153 views

Optimizations using GLSL shaders

I have written a simple OpenGL application using GLSL shaders. Actually, my program just displays a simple cube with a phong lighting effect like below : Here's a peace of the client code : ...
1
vote
4answers
223 views

Are VBOs only for OpenGL 3.x?

Are VBOs only for OpenGL 3.x? I'm using immediate mode and I know it's bad, slow, and deprecated. But then I looked at display lists but they are deprecated too. I guess the VBO is the only one left ...
0
votes
1answer
59 views

Jagged text + additive blend in openGL

I am having some trouble understanding how openGL blend modes work. At first I was using glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) and it all looked fine except that I couldn't use any ...
1
vote
1answer
135 views

What should I do when a VBO becomes too large in OpenGL?

Currently I have one buffer for my vertex data and one buffer for normals data. I fill them and then pass them to OpenGL for rendering. The problem is when I load too large mesh file like "Lucy" from ...
3
votes
1answer
225 views

OpenGL glDisable(GL_TEXTURE_2D) vs glBindTexture(GL_TEXTURE_2D,0)

I would like to ask which one of the glDisable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D,0) is better to use after I finished my texture rendering. Is there any difference performance-wise?
1
vote
1answer
335 views

Deferred Rendering With Diffuse,Specular, and Normal maps

I have been reading up on deferred rendering and I am trying to implement a renderer using the Sponza atrium model, which can be found here, as my sandbox.Note I am also using OpenGL 3.3 and GLSL. I ...
0
votes
0answers
57 views

How to create a 2D overlay over a 3D game? (LWJGL/OpenGL) [duplicate]

GameDev! I would like to create a 2D overlay over a 3D world, using LWJGL (Java version of OpenGL), to show information to the player, for example, a chat box, health bar, selected cannonball type, ...
1
vote
1answer
172 views

Shadow map: depth texture always returns 0

I'm implementing a shadow map for the sun light in my voxel engine using a depth texture attached to a framebuffer. But when I sample the depth texture during the normal pass, the value returned is ...
0
votes
0answers
57 views

Diffuse Mapping in a Game

I want to figure out the diffuse maps of some rusted objects that I plan to render in my game arena. I have taken the images of some sample objects and have also scanned them for a model of the ...
0
votes
1answer
84 views

why is glVertexAttribDivisor crashing?

I am trying to render some trees with instancing. This is rather weird, but before sleeping yesterday night, I checked the code, and it was in a running state, when I got up this morning, it is ...
1
vote
1answer
39 views

vertex is bending inwards

I am trying to draw a picket fence, but the center of the picket vertex looks bent in the middle, why is the picket bending inwards to the left? // draw fence pickets float a; for (a=-25; a<=25; ...
12
votes
6answers
618 views

Seamless tilemap rendering (borderless adjacent images)

I have a 2D game engine that draws tilemaps by drawing tiles from a tileset image. Because by default OpenGL can only wrap the entire texture (GL_REPEAT), and not just part of it, each tile is split ...
1
vote
0answers
65 views

Text alignment in OpenGL with FreeType2

I'm trying to implement font rendering and have got into some trouble with glyph metrics. Here's the code where I get the metrics: Glyph gl; gl.width = face->glyph->metrics.width / 64; ...
2
votes
1answer
107 views

How do I check why is no output on screen?

I'm using OpenGL 3.3+, and I'm trying to create an orthographic projection to draw on screen. I have the model data in a buffer: X Y 0, 0 50, 100 100, 0 And I create my Model-View-Projection ...
1
vote
0answers
95 views

What's the best way to set up an OpenGL draw loop in windows?

On mac os x, there's a way to pass the system a function pointer that is triggered at an ideal time to start your drawing code. These are the CVDisplayLink tools. I'd like to understand how to do ...
1
vote
1answer
79 views

Gamma Space and Linear Space with Shader

I am using Unity and I can choose between two color space mode in the settings: Gamma or Linear Space. I am trying to build a Custom Lighting Surface shader but I am facing some problems with those ...