I am working on a 3D simulation program using openGL which uses a render loop with a fixed framerate to keep the screen updated as the world changes. Standard procedure really, and for a typical video game this is certainly the best approach (I originally took this code from an openGL game tutorial). But for me, the 3D scene will not be changing as rapidly and unpredictably as in a computer game. It will be possible for the 3D scene itself to change from time to time but in general it won't change between render calls (it's more of a visualisation tool for geometric problems). The user will be able to control the position/orientation of the camera but in general there will be times when the camera won't move for several seconds/minutes (potentially hundreds of render calls) and since the 3D scene is likely be static for the majority of the time, I wonder if I really need a continuous render loop...?
My thinking is that I will remove the automatic render loop and instead I will explicitly call my update method when either,
The 3D scene changes (very rare)
The camera moves (somewhat rare)
As I will be using this largely for research purposes, the scene/camera is likely to stay in one state for several minutes at a time and it seems silly to be continuously updating the frame buffer when it's not changing.
My question then is, is this a good approach? All the online tutorials for 3D graphics rendering seem to deal with game design but that's not really my requirement. In other words, what are the pros and cons of using a render loop vs. manually calling "update()" whenever something changes?
Thanks
There's no problem with this approach, in fact many 3D apps, like 3DS MAX use explicit rendering. You just pick what is better for your needs, in most games scene changes each frame so it's better to have update loop, but if you were doing some chess game, without animated UI you could also use explicit rendering only when the scene changes.
For apps with rare changes, like 3DS or Blender it would be better to call rendering only on change. This way you save the CPU/GPU but also power and your PC don't heat up so much.
With explicit rendering you can also have some performance tricks, like drawing simplified scene when camera moves, for better performance. Then when camera stops you render the full scene in background once again, and replace the low-quality rendering with the new one.
I have been tearing my hair out for a while over this. I need an OpenGL 3.2 Core (no deprecated stuff!) way to efficiently render many sprites, using batching (no instancing).
I've seen examples that do this with geometry alone, but mine also needs to send textures to it, I don't know how to do this.
I need a well done example of it working in action. And looking at how other libs like monogame and such do it isn't much help, because all I'm interested in is the GL code, and it has to have no deprecated stuff in it.
Basically I want to be able to efficiently render thousands+ of sprites, all having textures. The texture is just a spritesheet, so I just need to tell it to render a region of that spritesheet.
I'm disappointed in the amount of material available for programmable pipeline. To the point where it seems like it'd be so much easier to just say screw it and use fixed pipeline, even though I definitely don't want to do that.
So yeah, any full examples that do what I want? Or could somebody more knowledgable write one up? :)
A lot of the examples are "oh, here's how you render 1 triangle". Well that's great, except nobody needs to render only 1 triangle/quad. And they need to be textured in addition to that!
An example that uses VBOs/VAOs/EBOs
ALSO: this means the code can't use glTexPointer and that stuff, but just in raw VBOs/VAOs...
I saw this question and decided to write a little program that does some "sprite" rendering using points and gl_PointSize. I'm not quite sure what you mean by "batching" as opposed to "instancing," but my program uses the glDrawArraysInstanced() call so that I can render multiple points without needing my VBO to be variable sized. My code also doesn't texture the sprites, but that's easy enough to add in (upload the active texture index (the one that was active during your call to glTexSubImage), to a GLSL sampler2D using glUniform1i).
Anyway, here's the program I wrote: http://litherum.blogspot.com/2013/02/sprites-in-opengl-programmable-pipeline.html Hope you can learn from it!
I am looking for a way to have an animated character in my game. I would like to have a running animation loop when he is running, a jump animation when he jumps etc.
Does the awe6 framework provide anything like this? Maybe using spritesheets, or separate images for each frame.
If I have to use my own system, are there any popular libraries that can help do this, and that work well with awe6? And how would I use it with the framework?
awe6 is not something that works out of the box but rather an architecture for you to build on. It is not designed to fill your requirements without work from you and requires you to have at least a good understanding to integrate another framework/target runtime for what you want. They do have a wiki however you can start with http://code.google.com/p/awe6/wiki/QuickStart
There are many popular frameworks out there that have a lower barrier to entry, such as haxepunk.com, haxeflixel.com, https://github.com/aduros/flambe they all have their own strengths/weaknesses etc for you to decide on and can all easily complete your requests.
I've been studying 3D graphics on my own for a while now and I want to get a greater understanding of just how everything works. What I would like to do is to create a simple game without using DirectX or OpenGL. I understand most of the math I believe, but the problem I am running up against is I do not know how to get control of the pixels being displayed in a window.
How do I specify what color I want each pixel in my window to be?
I understand I will probably run into issues with buffers and image shearing and probably terrible efficiency problems, but I want to create my own program so that I could see from the very lowest level, of the high level language, how the rendering process works. I really have no idea where to start though. I've figured out how to output BMPs, but I would like to have a running program spitting out 20+ frames per second. How do I accomplish this?
You could pick a environment that allows you to fill an array with values for pixels and display it as a bitmap. This way you come closest to poking RGB values in video memory. WPF, Silverlight, HTML5/Javascript can do this. If you do not make it full screen these technologies should suffice for now.
In WPF and Silverlight, use the WriteableBitmap.
In HTML5, use the canvas
Then it is up to you to implement the logic to draw lines, circles, bezier curves, 3D projections.
This is a lot of fun and you will learn a lot.
I'm reading between the lines that you're more interested in having full control over the rendering process from a low level, rather than having a specific interest in how to achieve that on one specific platform.
If that's the case then you will probably get a good bang for your buck looking at a library like SDL which provides you with a frame buffer that you can render to directly but abstracts away a lot of the platform specifics issues. It has been around for quite a while and there are some good tutorials to give you an idea of whether it's the kind of thing you're looking for - see this tutorial and the subsequent one in the same series, which should be enough to get you up and running.
You say you want to create some kind of a rendering engine, meaning desinging you own Pipeline and matrice classes. Which you are to use to transform 3D coordinates to 2D points.
When you have got the 2D points you've been looking for. You can use say for instance on windows, you can select a brush and draw you triangle values while coloring them at the same time.
I do not know why you would need Bitmaps, but if you want to practice say Texturing you can also do that yourself although off course on a weak computer this might take your frames per second significantly.
If you aim is to understand how rendering works on the lowest level. This is with no doubt a good practice.
Jt Schwinschwiga
I am in the process of developping a game, and after two months of work (not full time mind you), I have come to realise that our specs for the game are lacking a lot of details. I am not a professional game developper, this is only a hobby.
What I would like to receive help or advices for is this: What are the major components that you find in games, that have to be developped or already exists as librairies? The objective of this question is for me to be able to specify more game aspects.
Currently, we had specified pretty much only how we would work on the visual, completely forgetting everything about game logic (AI, Entities interactions, Quest logic (how do we decide whether or not a quest is completed)).
So far, I have found those points:
Physics (collision detection, actual forces, etc.)
AI (pathfinding, objectives, etc.)
Model management
Animation management
Scene management
Combat management
Inventory management
Camera (make sure not to render everything that is in the scene)
Heightmaps
Entities communication (Player with NPC, enemy, other players, etc)
Game state
Game state save system
In order to reduce the scope of this queston, I'd like it if you could specifically discuss aspects related to developping an RPG type of game. I will also point out that I am using XNA to develop this game, but I have almost no grasp of all the classes available yet (pretty much only using the Game component with some classes that are related to it such as GameTime, SpriteBatch, GraphicDeviceManager) but not much more.
You have a decent list, but you are missing storage (save load), text (text is important in RPGs : Unicode, font rendering), probably a macro system for text (something that replaces tokens like {player} with the player characters name), and most important of all content generation tools (map editor, chara editor, dialog editor) because RPGs need content (or auto generation tools if you need ). By the way have links to your work?
I do this exact stuff for a living so if you need more pointers perhaps I can help.
I don't know if this is any help, but I have been reading articles from http://www.gamasutra.com/ for many years.
I don't have a perfect set of tools from the beginning, but your list covers most of the usual trouble for RUNNING the game. But have you found out what each one of the items stands for? How much have you made already? "Inventory Management" sounds very heavy, but some games just need a simple "array" of objects. Takes an hour to program + some graphical integration (if you have your GUI Management done already).
How to start planning
When I develop games in my spare time, I usually get an idea because another game lacks this function/option. Then I start up what ever development tool I am currently using and try to see if I can make a prototype showing this idea. It's not always about fancy graphics, but most often it's more about finding out how to solve a certain problem. Green and red boxes will help you most of the way, but otherwise, use Google Images and do a quick search for prototype graphics. But remember that these images are probably copyrighted, so only use them for internal test purposes and to explain to your graphic artists what type of game/graphic you want to make.
Secondly, you'll find that you need to find/build tools to create the "maps/missions/quests" too. Today many develop their own "object script" where they can easily add new content/path to a game.
Many of the ideas we (my friends and I) have been testing started with a certain prototype of the interface, to see if its possible to generate that sort of screen output first. Then we build a quick'n'dirty map/level-editor that can supply us with test maps.
No game logic at this point, still figuring out if the game-engine in general is running.
My first game-algorithm problem
Back when I was in my teens I had a Commodore 64 and I was wondering, how do they sort 10 numbers in order for a Highscore? It took me quite a while to find a "scalable" way of doing this, but I learned a lot about programming too.
The second problem I found
How do I make a tank/cannon fire a bullet in the correct direction when I fly my helicopter around the screen?
I sat down and drew quick sketches of the actual problem, looked at the bullet lines, tried some theories of my own and found something that seemed to be working (by dividing and multiplying positions etc.) later on in school I discovered this to be more or less Pythagoras. LOL!
Years and many game attempts later
I played "Dune" and the later C&C + the new game Warcraft (v1/v2) - I remember it started to annoyed me how the lame AI worked. The path finding algorithms were frustrating for the player, I thought. They moved in direction of target position and then found a wall, but if the way was to complex, the object just stopped. Argh!
So I first sat with large amounts of paper, then I tried to draw certain scenarios where an "object" (tank/ork/soldier) would go from A to B and then suddenly there was a "structure" (building/other object) in the pathway - what then?
I learned about A-star pathfinding (after solving it first on my own in a similar way, then later reading about the reason for this working). A very "cpu heavy" way of finding a path, but I learned a lot from the process of "cracking this nut". These thoughts have helped me a lot developing other game algortimes over time.
So what I am saying is: I think you'll have to think more of:
How is the game to be played?
What does the user experience look like?
Why would the user want to come back to the game?
What requirements are needed? Broadband? 19" monitor with 1280x1024?
An RPG, yes - but will it be multi-user or single?
Do we need a fast network/server setup or do we need to develop a strong AI for the NPCs?
And much more...
I am not sure this is what you asked for, but I hope you can use it somehow?
There are hundreds of components needed to make a game, from time management to audio. You'll probably need to roll your own GUI, as native OS controls are very non-gamey. You will probably also need all kinds of tools to generate your worlds, exporters to convert models and textures into something suitable for your game etc.
I would strongly recommend that you start with one of the many free or cheap game engines that are out there. Loads of them come with the source code, so you can learn how they have been put together as you go.
When you think you are ready, you can start to replace parts of the engine you are using to better suit your needs.
I agree with Robert Gould's post , especially about tools and I'd also add
Scripting
Memory Management
Network - especially replication of game object states and match-making
oh and don't forget Localisation - particularly for text strings
Effects and effect timers (could be magical effects, could just be stuff like being stunned.)
Character professions, skills, spells (if that kind of game).
World creation tools, to make it easy for non-programmer builders.
Think about whether or not you want PvP. If so, you need to really think about how you're going to do your combat system and any limits you want on who can attack whom.
Equipment, "treasure", values of things and how you want to do the economy.
This is an older question, but IMHO now there is a better answer: use Unity (or something akin to it). It gives you 90% of what you need to make a game up front, so you can jump in and focus directly on the part you care about, which is the gameplay. When you run aground because there's something it doesn't do out of the box, you can usually find a resource in the Asset Store for free or cheap that will save you a lot of work.
I would also add that if you're not working on your game full-time, be mindful of the complexity and the time-frame of the task. If you'll try to integrate so many different frameworks into your RPG game, you can easily end up with several years worth of work; maybe it would be more advisable to start small and only develop the "core" of your game first and not bother about physics, for example. You could still add it in the second version.