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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-2
votes
2answers
185 views

Rendering structure [closed]

my question is "What is the best way to structure rendering code". Is it better to make a class with a render function that iterates through all game objects based on there name or type and have no ...
0
votes
1answer
206 views

Get world-position in Vertex shader

I'm wondering how I can get the final position of a vertex. I use glTranslate in my render code, and I'm not getting the world-coordinates correct. My world is devided in chunks and my position get's ...
0
votes
1answer
273 views

GLSL Shaders-> How to manage?

As your game get's bigger and bigger, you will use more and more different shader effects. Let's take an easy example: I have clouds in my voxel-based world, and I want to give it a blue-ish tint ...
0
votes
1answer
332 views

Drawing the same scene with perspective then orthographic projections

I have a scene that I'm rendering first with a perspective matrix. I then want to rerender it in a different viewport using an orthographic matrix for a top-down 2D view of the scene. I think I may be ...
1
vote
1answer
228 views

OpenGL / Assimp oddity or error?

A friend and I are working on developing a game engine in C++. He doesn't live anywhere near me, so we use Dropbox to sync our files. I opened his project to test his code, and I kept getting errors ...
3
votes
2answers
300 views

Using a programmable pipeline in a game engine

As a learning experience, I'm developing my own 3D game engine using OpenGL. I'm a little confused as to how to implement my rendering engine such that it uses a programmable pipeline while still ...
0
votes
2answers
834 views

Screen or World Coordinates to tile Coordinates

I have Plane made of tiles in opengl. I start drawing them at (0, 0, -20) after that i do my translations so that the view is rotated somewhat similar to an isometric (kind of) perspective. I'd now ...
3
votes
2answers
207 views

Extract smaller frustum from camera frustum?

Background: I was thinking of implementing multiselection by performing a frustum culling on a sub-part of the screen. Problem: Given total screensize, a rectangle on the screen (pos, size), and ...
2
votes
1answer
952 views

smooth shading vs flat shading, what's the difference in the models?

I'm loading the exact same model with Assimp, except one is exported from Blender, shaded smoothly, and the other was exported from Blender, shaded flatly. Here is my results from loading both into my ...
1
vote
1answer
81 views

Get the address of a matrix in GLM library

Is there a way to get the address of a matrix from a GLM matrix? I'm using opengl 4 and glm library though I can't seem to find anything, which might help.
-1
votes
2answers
638 views

Need help drawing obj file! [closed]

I'm using GLFW and I want to draw a obj file. How are they drawn? I know how to draw 3D in OpenGL but when I open the obj file I see "v"s, "vn"s, "f"s, "vt"s, what are these? I don't know how to read ...
2
votes
1answer
177 views

How to rotate camera around some point?

I have screen with dimensions: 800x600. The object that I want to rotate around is located at (400,300, -50) - center of the screen. Orthogonal projection: Near plan - 0.1f, far plane - 1000.0f left - ...
13
votes
1answer
2k views

Which is the best LOD method for planet rendering?

I'm currently working on my thesis, it is an engine to render terrains of planetary size. I'm still finishing my research and I have encountered a lot of stuff about this subject, the problem is that ...
1
vote
0answers
263 views

Separating rendering and logic thread in GLFW? [closed]

I want to separate my rendering thread (the main thread) and my logic thread in my GLFW game. I'm new to the concept of threading inside games. How would this be done? GLFW isn't thread safe so it ...
0
votes
0answers
139 views

Correct way to calculate Perspective Matrix [duplicate]

I have seen at least 3 different ways to calculate the perspective matrix and I'm confused as to which one I should be using and what the differences are? OpenGL says to do it this way: f = ...
1
vote
1answer
427 views

Can't get Depth testing to work (cube faces shine through)

I'm making my first steps with OpenGL with LWJGL. I am currenlty constructing a... wait for it... CUBE. Quite creative... Up to now i made it to three of its faces and thats where the Problems began. ...
4
votes
3answers
314 views

How to skip the sky in lighting shaders?

I recently implemented a sky in my deferred rendered game. It is a procedurally calculated sphere with a texture applied to it. Unfortunately all lighting shaders (light sources, ambient occlusion) ...
5
votes
1answer
691 views

Slow glReadPixels

I have implemented a lense flare for my game, and it looks great. The first draft used individual sprites each with its own draw call. This was very slow, so I reengineered it to use a single draw ...
0
votes
1answer
155 views

Framebuffer formats with enhanced Alpha precision

I render some lines with alpha values into an FBO. Because I play a lot with alpha, I need the alpha channel to have more detail than RGBA8. For example, RGBA32F works like a charm. As I have only a ...
0
votes
0answers
284 views

Specular Light not working Phong shading

I want to implement Phong-Shading using GLSL. I also want to calulate all values using uniforms in the shaders. Nearly everything works fine, but there is an error with the specular term of the ...
0
votes
1answer
96 views

Direction from the camera to the light source

I'm currently writing a game using OpenGL and GLSL. For the shader I need the direction from the current camera to the light source. The lightsource is given by lightSource.position as a uniform as ...
-1
votes
1answer
2k views

OpenGL noob: Using VBO to draw a colored triangle [closed]

I tried using straight vertex arrays to draw a triangle with different colors for each vertex and it works fine, but when I use VBO it won't work, so I'm doing something wrong. // point 1 ...
2
votes
1answer
197 views

How to implement a multi-platform Java 2D game engine's graphics?

I'm not sure whether this question should be posted here. I'm trying to make a basic generic game engine in Java. Here's what I have so far. public abstract class Device { public abstract void ...
4
votes
2answers
454 views

OpenGL: Filtering/antialising textures in a 2D game

I'm working on a 2D game using OpenGL 1.5 that uses rather large textures. I'm seeing aliasing effects and am wondering how to tackle those. I'm finding lots of material about antialiasing in 3D ...
0
votes
2answers
858 views

Texture mapping issue in my Wavefront *.obj parser

I wrote a simple *.obj parser reading read vertices, texcoords and normals. But when I draw a model the texture isn't mapped correctly. I have already tried uv.y = 1.0f - uv.y to get inverted Y axis ...
2
votes
2answers
171 views

State propagation in modern OpenGL

When last I dabbled in game development, I managed my geometry in a tree. Every node would call the render method on it's children, prior to resetting it's transformations, thus allowing the ...
3
votes
1answer
118 views

Do I need Texture Units when NOT using shaders?

Does calling glActiveTexture() even make sense when not using shaders? I only have to switch the textures before drawing a buffer with glBindTexture(), right?
8
votes
1answer
2k views

Modern shadow rendering techniques?

What is the state of the art in terms of shadow rendering? My target is OpenGL 3.2, using a deferred rendering pipeline, if that matters. It's been years since I looked into shadow rendering, and at ...
0
votes
1answer
480 views

VBO GL_STREAM_DRAW double buffer or new buffer?

There is some conflicting information on the STREAM usage specifier. Apple's documentation states you should use double buffering and update the stream buffer that is not being read by the GPU. ...
10
votes
1answer
876 views

How to reduce image size without pixelation?

I see lots of games with smooth edges characters and high res images, however when I try to reduce images to say 64x64 for my character I just get a pixelated mess. even if I start with a 64x64 canvas ...
0
votes
1answer
84 views

Freeglut: Functions missing

I'm currently learning OpenGL (in class) and we're using freeglut 2.8.2, which works just fine (using Visual Studio 2012). As an additional learning resource I'm reading the "OpenGL Superbible, 5h ...
1
vote
1answer
1k views

glBufferSubData and offset alignment?

I'm having trouble rendering some of my meshes; some display just fine, some are drawn wrong or not at all. While troubleshooting I was looking at the openGL docs ...
2
votes
2answers
161 views

How scanline rendering finds an intersection with an object

I'm a newbie with graphics and after I read many articles on the web I still don't understand how in rasterizing from a pixel coordinate like (0;0) on the screen the intersection with an object (let's ...
1
vote
3answers
984 views

Set a variable inside a GLSL fragment shader that persists for the render

Is it possible to set a varying variable inside a fragment shader and have it persist? I'd like to use the depth component of the first fragment and use it on all the others, making the fragments all ...
21
votes
1answer
602 views

My game seems to be incompatible with recording software. What could be causing this?

I've just finished a little Game-Dev project for university and I need to record a video to accompany my submission (just in case they can't get my source to work). Basically my game doesn't work at ...
4
votes
1answer
736 views

Picking 3D with OpenGL ES 2

I'm trying to implement picking in my framework but I don't understand how I can do this. I'm working with: OpenGL ES 2. GLM mathematic library. What I have understand, picking can be made with ...
2
votes
2answers
588 views

Realtime fisheye to cubic or spherical panorama transformations with OpenGL or pixelshaders

I'd like to transform a sequence of circular fisheye-images to cubic or spherical panorama images to be used in a panorama-viewer based on OpenGL. The viewer-part is nemas problemas but the transform ...
3
votes
2answers
3k views

2D water shader similar to Limbo's effect

I'm wondering how I would go about creating a 2D water shader that is seen in this video http://www.youtube.com/watch?v=phChFfi4GOs The water effect that limbo uses is pretty awesome. I'm not so ...
0
votes
1answer
273 views

How to seamlessly texture a cube in OpenGL

I have been following this site as an intro to OpenGL. After going through the model obj loading tutorial, I wanted to create my own .obj (a cube) as well as my own texture. Following this blender ...
1
vote
1answer
170 views

Size of an image imported with FreeImage

I'm having abit of a brainfart and I can't quite grasp what I'm doing wrong. It's quite simple, I am importing an image with FreeImage (http://freeimage.sourceforge.net/) which has a method ...
1
vote
2answers
430 views

Calling glGetError() in release builds?

Currently, I'm calling glGetError() after each OpenGL function call in order to be able to detect and report bugs. I've been reading that glGetError() calls should be reduced to once per frame in ...
2
votes
0answers
69 views

uniform z slices in clip-space

1) Context I'm using a regular OpenGL perspective projection matrix created with GLM (glm::perspective) and taking the inverse (glm::inverse) to transform clip-space back into view space (and world ...
1
vote
0answers
128 views

Posible to export f-curves in blender?

I work with some friends on a rail shooter game in openGL. For creating our world we are using Blender. Since we want our Tank to follow a path I have started to work with creating bezier curves and ...
1
vote
2answers
139 views

Calling opengl32.DLL from java?

I don't like LWJGL in some cases, so I prefer to use Swing. The thing is that Swing doesn't have OpenGL. I have tried JOGL and it's a mess to install, needs external jars, and I have yet to get it ...
1
vote
0answers
239 views

textures and bouncing balls inside a cube [closed]

i have a cube with texture but when i add 3 balls so that they bounce on the walls of the cubes everything seemed to be wrong,the balls are not bouncing in the right directions, i want them to bounce ...
1
vote
0answers
102 views

How to put OpenGL in a state for drawing blended, colored, nontextured polys?

Using OpenGL1.1 (sadly) I'm trying to draw a cube, which is colored and alpha blended. It is instead showing up as opaque black. Even without including alpha in the color it still shows up as opaque ...
0
votes
1answer
327 views

gluLookAt strange behavior implementing camera

I'm having a super tough time trying to implement what I thought would be a very straightforward problem. I'm trying to demonstrate a free camera that can move forward/back, strafe left/right, fly ...
3
votes
2answers
1k 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 ...
-1
votes
1answer
449 views

OpenGL/SDL2 window stopped rendering [closed]

I have been working on a game engine for a couple of days now and I've had it rendering a colourful cube and playing sounds in OGG format, but, after refactoring my code-base to make things easier; it ...
2
votes
1answer
184 views

Translating Viewmatrix is inverted, why?

So I've defined a Projectionmatrix, Viewmatrix and a Modelmatrix using OpenGL (LWJGL). But when I translate my Viewmatrix to +X it moves my object to the right (hence my camera is moving to the ...