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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15
votes
2answers
2k views

Do I lose/gain performance for discarding pixels even if I don't use depth testing?

When I first searched for discard instruction, I've found experts saying using discard will result in performance drain. They said discarding pixels will break GPU's ability to use zBuffer properly ...
4
votes
2answers
1k views

interpolating frames in a vertex shader

My models are stored as a set of meshes, each with a vertex list and normal list per key-frame, and indices for GL_TRIANGLES which is shared for all frames. Each frame I lerp between two adjacent ...
7
votes
1answer
10k views

How to render a texture partly transparent?

Good Morning StackOverflow, I'm having a bit of a problem right now as I can't seem to find a way to render part of a texture transparently with openGL. Here is my setting : I have a quad, ...
7
votes
2answers
1k views

How do I change a sprite's color?

In my rhythm game, I have a note object which can be of a different color depending on the note chart. I could use a sprite sheet with all the different color variations I use, but I would prefer to ...
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
4answers
3k views

2D Platformer Collision Handling

I am trying to create a 2D platformer (Mario-type) game and I am some having some issues with handling collisions properly. I am writing this game in C++, using SDL for input, image loading, font ...
4
votes
1answer
192 views

Can you help me solve the paradox that has confused me about the glViewport and glOrtho functions?

suppose that I have an image that I want to apply as a texture on a geometry (at time we don't consider texture mapping but this image has a certain width and height here it is a 512x512 image) I want ...
4
votes
1answer
547 views

How to do perspective projection “parallax” but without changing the scale or offset of objects?

Hello everyone I have this problem that I have tried everything I could think of. The problem: I am making a 2D game with parallax effect but I am using 3d space so am not simulating the parallax but ...
3
votes
1answer
1k views

Rotating To Face a Point

I am trying to rotate a line to point to the mouse's world coordinates (rather where the mouse lies on the plane where y=0). I am running into a couple of problems though: Whilst it follows the ...
2
votes
2answers
781 views

SAT, How Do I Find The Penetration Vector?

I've just successfully implemented Separating Axis Theorem (SAT) in my game but I was wondering how do I find the penetration vector? I heard it can be useful for collision response. e.g. The harder ...
1
vote
1answer
971 views

Are interleaved vertex data formats better than non-interleaved formats?

I have been reading up on data formatting for 3D objects so that I can render my meshes as fast as possible in OpenGL. I am quite new to OpenGL so bear with me. The format for interleaving your ...
1
vote
1answer
424 views

lighting for landscape

I've got a landscape(created in Photoshop .raw file) and a .tga texture for it. I read .raw file and read .tga file like this LoadRawFile("landscape.Raw", MapSize * MapSize, &HeightMap[0][0]); ...
1
vote
2answers
1k views

First person camera with Bullet Physics

Before integrating the Bullet Physics, the camera worked fine. But instead of using my own simple struct for transform data, I use rigid body structs provided by the physics library now. There are ...
1
vote
1answer
384 views

Using two FBOs results in the second FBO having nothing drawn to [closed]

I'm writing a deferred renderer, and I use two FBOs: the first one for G-buffer (color, normal, depth) and the second one for lighting (light output), so the first one has three textures bound and the ...
1
vote
1answer
261 views

Selection of a mesh with arbitrary region

Considering example: I have a mesh(es) on the OpenGL screen and would like to select a part of it (say for delete purpose). There is a clear way to do the selction via Ray Tracing, or via Selection ...
0
votes
1answer
1k views

Transparency in opengl - texture with alpha, color from background [duplicate]

I have to draw texture with transparent areas on square. But I don't want this transparencies to take color from this polygon, but from the background. Do you have any good tutorial to achieve it? ...
0
votes
4answers
2k views

Opengl lighting not working

I have rendered a spinning model in LWJGL. I have calculated normals and enabled lighting. Now I make a light: float lightpos[] = {0, 0, 0, 0}; FloatBuffer lightposb = ...
0
votes
4answers
673 views

Missing triangles in model

I am having an issue where triangles in a model aren't being shown. The left is wireframe, the right is the finished image. For some reason a bunch of the triangles aren't being shown. The project ...
0
votes
3answers
373 views

How to deal with VBOs when rendering mesh's that may or may not be displayed?

I'm working on a multiplayer game and will be displaying other players near the player. At most 16 players could be near the gamer however there could also be 0. What I'm thinking of doing is ...
0
votes
3answers
829 views

OpenGL 2D Depth Perception

I have a 2D RPG game written in Java using LWJGL. All works fine, but at the moment I'm having trouble deciding what the best way to do depth perception is. So , for example, if the player goes in ...
0
votes
2answers
525 views

CubeRealm OpenGL rotation problems, need help. :\

I'm totally new to OpenGL and I'm working on a Sandbox game called CubeRealm. My problem you see is rotation. I've got it in my head that to rotate the 'camera' I just rotate all the scene by the ...
-9
votes
2answers
1k views

Creating a Game Engine with a C++ Compiler?

I'm thinking of creating a Game Engine with a C++ Compiler using OpenGL but I don't know how to create a compiler in an application. Do I have to write the compiler? or could I use (for example) the ...
33
votes
10answers
4k views

What makes a game look “good”? [closed]

I am working on a 3D space game using OpenGL and C++ and I am planning to focus on giving the game modern, eye-catching graphics, but the more I think of it the more I realise I don't really know what ...
17
votes
6answers
4k views

Separating game data/logic from rendering

I'm writing a game using C++ and OpenGL 2.1. I was thinking how could I separate the data/logic from rendering. At the moment I use a base class 'Renderable' that gives a pure virtual method to ...
17
votes
4answers
4k views

Procedural Planets, Heightmaps and Textures

I am currently working on an OpenGL procedural planet generator. I hope to use it for a space RPG, that will not allow players to go down to the surface of a planet so I have ignored anything ROAM ...
27
votes
6answers
12k views

How can I improve rendering speeds of a Voxel/Minecraft type game?

I'm writing my own clone of Minecraft (also written in Java). It works great right now. With a viewing distance of 40 meters I can easily hit 60 FPS on my MacBook Pro 8,1. (Intel i5 + Intel HD ...
19
votes
1answer
6k views

File format for static and animated 3D models

I'm currently writing a 3D game in C++ with OpenGL and I'm coming to the part where to load 3D models in. Therefore I'm looking for popular file formats and techniques to display static meshs and ...
24
votes
2answers
5k views

After a succesful glLinkProgram, should I delete / detach my shaders?

After I have a linked program, and thinking about defensive programming, should I delete and detach the shaders used to link this program? If yes, is that going to free any resources? Or do these ...
17
votes
1answer
4k views

How would you implement chromatic aberration?

How would you implement the effect of chromatic aberration with shaders? Would rendering of the world with different focus distances for each color solve the problem (maybe with the usage of only one ...
8
votes
5answers
11k views

What alternatives to GLUT exist?

I am trying to learn OpenGL, and I just found out that GLUT is obsolete. I already know SDL, and it seems it is a good alternative. Should I use SDL to develop games with OpenGL, or are there any ...
21
votes
3answers
8k views

For voxel rendering, what is more efficient: pre-made VBO or a geometry shader?

Given a fairly static voxel array, what is more efficient: using the CPU to pre-generate a VBO to render the voxel faces (ignoring more advanced forms of rendering like marching cubes for now) or ...
13
votes
3answers
7k views

Why does OpenGL >= 3 only allow VBOs?

I see that OpenGL versions 3 and up eliminate the use of client-side rendering. Immediate mode has been eliminated, and vertex arrays seem to be deprecated. Instead, if I understand correctly, VBOs ...
22
votes
4answers
7k views

Why is programmable pipeline( GLSL ) faster than fixed pipeline?

So I'm teaching myself GLSL and am trying to figure out why it's suppose to be faster than the fixed function pipeline. The reason I am having a problem is that from my understanding , the shaders ...
14
votes
6answers
5k views

What is the purpose of the canonical view volume?

I'm currently learning OpenGL and haven't been able to find an answer to this question. After the projection matrix is applied to the view space, the view space is "normalized" so that all the points ...
15
votes
2answers
691 views

OpenGL: Where shoud I place shaders?

I'm trying to learn OpenGL ES 2.0 and I'm wondering what is the most common practice to "manage" shaders. I'm asking this question because in the examples I've found (like the one included in the API ...
9
votes
3answers
3k views

Lighting in a Minecraftian World

Minecraft is a game that is largely based on a heightmap and uses that heigtmap information to flood the world with light. From my understanding the highest point in the heightmap is the end of the ...
8
votes
3answers
2k views

What is a better abstraction layer for D3D9 and OpenGL vertex data management?

My rendering code has always been OpenGL. I now need to support a platform that does not have OpenGL, so I have to add an abstraction layer that wraps OpenGL and Direct3D 9. I will support Direct3D 11 ...
7
votes
3answers
4k views

Draw contour around object in Opengl

I need to draw contour around 2d objects in 3d space. I tried drawing lines around object(+points to fill the gap), but due to line width, some part of it(~50%) was covering object. I tried to use ...
4
votes
5answers
6k views

openGL book recommendation [closed]

I wanna start learning OpenGL especially for android game programming but I would eventually want to be able to use this knowledge for windows\linux as well. I'm having difficulty choosing between ...
15
votes
7answers
2k views

For 2D games, is there any reason NOT to use a 3D API like Direct3D or OpenGL?

I've been out of hobby Game Development for quite a while now. Back when I did it, most people used Direct Draw to create 2D games. By the time I stopped people were saying OpenGL or Direct3D with ...
13
votes
4answers
5k views

Fixed-Function vs Shaders: Which for beginner?

I'm currently going to college for computer science. Although I do plan on utilizing an existing engine at some point to create a small game, my aim right now is towards learning the fundamentals: ...
10
votes
3answers
4k views

Animation in OpenGL using 3D Models

I have created a model in Blender. Now i want to read that 3D model in my c++ program. I figured that a model can be exported to various file formats e.g. .obj, .3ds or COLLADA and then can be read in ...
10
votes
2answers
4k views

Efficient skeletal animation

I am looking at adopting a skeletal animation format (as prompted here) for an RTS game. The individual representation of each model on-screen will be small but there will be lots of them! In ...
9
votes
2answers
4k views

OpenGL: Is it possible to use VAO's without specifying a VBO

On all the tutorials I can find about VAO's (Vertex Array Objects), they show on how to use them by configuring vertex attributes and binding a VBO (Vertex Buffer Object). But I want to create a VAO ...
9
votes
1answer
13k views

How does gluLookAt work?

From my understanding, gluLookAt( eye_x, eye_y, eye_z, center_x, center_y, center_z, up_x, up_y, up_z ); is equivalent to: glRotatef(B, 0.0, 0.0, 1.0); ...
8
votes
3answers
3k views

Font outline in OpenGL, FTGL

I'm using FTGL library to render fonts in my game, but I have completely no idea how to create an outline around text. Achieving a shadow could be easy, because I can simply do it like this: (pseudo ...
8
votes
3answers
2k views

Deferred shading - how to combine multiple lights?

I'm starting out with GLSL and I've implemented simple deferred shading that outputs G-buffer with positions, normals and albedo. I've also written a simple point light shader. Now I draw a sphere ...
7
votes
4answers
1k views

glsl demo suggestions?

In a lot of places I interviewed recently, I have been asked many a times if I have worked with shaders. Even though, I have read and understand the pipeline, the answer to that question has been no. ...
5
votes
1answer
568 views

How to insert and remove blocks quickly in a Minecraftian world?

I currently have volume data for the world stored as an array of booleans. I then check each empty block and if it has non-empty neighbors the faces get drawn. This prevents me from sending a bunch ...
12
votes
12answers
11k views

Is it a waste to learn OpenGL?

What I've gathered around the internet and various sources is that DirectX has pretty much taken a stronghold grip onto the graphics API domain. And to be honest, I gave learning DirectX10 a chance, ...