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2d engine design philosophy

fireking · 2002-09-13T11:33:20

well ive come to a point where my 2d engine will almost do anything i want it to, but i need to organize it, maybe give it a little re design as far as how the interface to the designer looks and operates. at the current moment, i have the following classes: engine bitmap map tile camera everything starts with the camera, which could probably just be put into the engine, since it only contains some variables, but i left it out incase you wanted to create multiple cameras, then when rendering, the camera can shift all around the map, depening on which camera you pass in the render function. The render function takes the variables from the cameras, and renders the 2d scene according to their values. For instance, you could create a camera class, CurrentCamera, then create several cameras. Then pass CurrentCamera in the render function, but the current camera could be any of the other cameras you have created. I think this makes the system extremely flexible in that aspect. Next the engine is initialized, passing an initial camera. This is where one of my problems lie. The engine uses data from the camera to create a back buffer (virtual bitmap in system memory). The camera has variables like viewx, viewy, x, y, and vhalf. Viewx specifies the number of tiles going across on the render surface. For instance, 11x11 would be viewx = 11, viewy=11. This would make it so that rendering will render a 11x11 display. Vhalf is used to specify the middle of that. the middle of 11x11 is 5. Ok, so what if you create a camera that has a bigger view size? well the engine doesnt like it, thats for sure... Next we have the bitmap class. This is used to load two bitmaps, a regular bitmap, and a bitmap used for masking. These are loaded into two dc's, DC and MaskDc. When you need to draw something, you must use a dc that contains the graphics, thats what the bitmap class is for. You can obviously created multiple ones, and pass any of the bitmap classes you want in the rendering function. You can only have one bitmap class per render pass. I know this is limited, but so is GDI and its memory resources. After about 5 fairly good size bitmaps are loaded into DC's, GDI starts to slow down... Next we have the Map. The map is nothing but an array of tiles. So lets talk about a tile. A tile contains srcx, srcy, width, and height, and a render function. Srcx tells where the x position should start in the Bitmap DC for rendering. Srcy tells where the y position should start in the bitmap dc for rendering. Width and height tells how far right, or down, it should go from the x,y position when it renders. The render function of a tile takes an engine, a camera, and a bitmap. The reason is that it blits the part of the bitmap specified by the tile, using information from the camera, into the dc of the engine(which is a back buffer). Then the engine can render to any dc you want it to, cuz its just blitting from a back buffer to the dc you specify. The formula i used to render a tile, is the following map(x,y) is a two dimensional array of tile class we use c.x (Camera x) plus the current ix in the for loop, minus half of the view size ix as long iy as long for ix = 0 to (c.viewx-1)//we start with 0, so subtract one for iy = 0 to (c.viewy-1)//11x11 would be 0 - 10 x 0 - 10 map(c.x + ix - c.vhalf,c.y + iy - c.vhalf).Render next next Some parameters are passed into the render function of course, but i am just using this as an example Anyways, what can be done to possible improve my system, and possibly fix some of the problems i have addressed? Thanks, --Fireking Owner/Leader Genetics 3rd Dimension Development [edited by - fireking on September 7, 2002 8:34:16 PM]

General and Gameplay Programming Programming

Started by fireking September 07, 2002 07:32 PM

13 comments, last by fireking 21 years, 7 months ago

Anonymous

September 11, 2002 02:54 PM

Consider using Allegro. Relatively speedy, easy to use, and relatively portable.

www.talula.demon.co.uk/allegro/

LessBread

1,415

September 11, 2002 03:06 PM

DX in C isn''t that horrible, but I can appreciate your fondness for GDI. In fact, I''d be interested in checking out your code if you''re up for sharing it, fireking. Drop me an email if so.

"I thought what I'd do was, I'd pretend I was one of those deaf-mutes." - the Laughing Man

Dreddnafious Maelstrom

586

September 11, 2002 05:40 PM

Whats up FireKingX,? still playing around with the GDI I see.
Drop by Truevision and ruffle those rats up a bit, everyone has grown complacent without you messing around with them a bit. Ever finish the editor that you built that great GUI for?

Dreddnafious Maelstrom

"If i saw farther, it was because I stood on the shoulders of giants."

Sir Isaac Newton

"Let Us Now Try Liberty"-- Frederick Bastiat

fireking

122

Author

September 11, 2002 09:15 PM

quote:Original post by Dreddnafious Maelstrom
Whats up FireKingX,? still playing around with the GDI I see.
Drop by Truevision and ruffle those rats up a bit, everyone has grown complacent without you messing around with them a bit. Ever finish the editor that you built that great GUI for?

Dreddnafious Maelstrom

"If i saw farther, it was because I stood on the shoulders of giants."

Sir Isaac Newton

lol!

actually, i did not finish Gen3dEdit. Mainly due to the fact that Truevision was missing a lot of features I was needing at the time. I could resume the project eventually, but expect at least a 2 week period as I look at all of my code and understand it all again (it was an insanely complicated program, keeping all of the gui in order with the dynamic object oriented design of the world).

Yeah, Im still messing with the GDI. Kind of a self education type of deal. It''s like a new years resolution or something, a promise made to my self, that I can accomplish a 2d tile engine with the GDI in great speeds with tons of features. I am using C++ to do it now, mainly because I just need to move on, and VB is really a peice of junk (depending on the app you are making).

Good to hear from ya!

--Fireking

Owner/Leader
Genetics 3rd Dimension Development

--FirekingOwner/LeaderFiregames Development &Blackdragon Studios

angagon

122

September 13, 2002 11:33 AM

Nah, SDL is the way to go and it''s cross-platform compatible.

Matt

2d engine design philosophy

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