Jo Engine: 2D game engine for the Sega Saturn

[Team Andromeda]

Looks really nice . Would have loved to see both a 2D Sonic and Streets Of Rage III on the Saturn.

[Johannes Fetz]

I agree. I hope that my engine will motivate people to make more homebrew games on the SS.

[Johannes Fetz]

Hi,

A new version is now available with mode7 support and better performance

Everything is here : http://www.jo-engine.org/download/

[tryphon]

How do you debug/test your homebrew ? I suppose using an emulator (SSF ?) for debugging, but for testing ? Are you forced to burn a CD every time, or is there another way (like Everdrives for Megadrive) ?

[Johannes Fetz]

I use Yabause and SSF most of the time, but my sega saturn has a Mod-Chip that plays any Sega Saturn CD and an usb interface.

http://www.gamingenterprisesinc.com/DataLink/

[tryphon]

I think I'll buy a Saturn

[Johannes Fetz]

Good choice

[Johannes Fetz]

Hi,

New update available with a fast malloc implementation which also supports multiple memory zone

Everything is here : http://www.jo-engine.org/download/

[mo68K]

Hi,

New update available with a fast malloc implementation which also supports multiple memory zone

Everything is here : http://www.jo-engine.org/download/

First of all, this is a nice project. Well I'm on vacation right now, but I took a look in your docs and unfortunately I couldn't find one type of function:

1) Imagine that I have a tile like 16x16, It's possible to draw only part of this tile using offsets? For example:

0,0------------
|              |
|   8,8--      |
|   |   |      |
|   |___|      |
|        12,12 |
|              |
|______________|16,16

So from a tile with 16x16 it it would draw from positions: 8x8 to 12,12.

2) If the first question is positive, would it be possible to scale this new rect up/down?

Thanks.

[Johannes Fetz]

Hi mo68K,

Yes you can, but it works like this:

1) You have to create a table which contains offset and size of each tile :

/*{x, y, width, height}*/

static jo_tile MyTiles[] =
{
{0, 0, 32, 32},
{128, 128, 32, 32},
{0, 96, 32, 32},
};

Restriction: width and height must be a multiple of 8 (temporary)

2) You load the tileset using the previous defined table. Example with a big TGA image:

int first_tile_sprite_id = jo_sprite_add_tga_tileset(JO_ROOT_DIR, "FULL.TGA", JO_COLOR_Green, MyTiles, 3);

So each tile is a sprite (mandatory for hardware operation & optimization)

3) Now to draw the second tile for example:

jo_sprite_draw3D(first_tile_sprite_id + 1, 0, 0, 500);

4) I haven't finished the scale abstraction but the following method works:

jo_sprite_set_scale(__jo_sprite_pos, 2.0); /* x2 */
jo_sprite_draw3D(first_tile_sprite_id , 0, 0, 500);
jo_sprite_set_scale(__jo_sprite_pos, 1.0); /* restore scale*/

For more details, you can check the "demo - tileset" folder.

I hope this will help you

[mo68K]

Hi mo68K,

...

I hope this will help you

I understood everything, but I think this is not what I'm looking for, because in my case, I would need to set the offset dynamically, while for what I see, you set an array where every value is a multiple of 8.

But before going too far on this, I need to sit down and try your engine first and see what I can do, but currently I am bit far from my computer for development because I'm in vacation.

Soon I take a look I'll come back to talk about.

Finally 2 things:

1) There is a video about the mode 7 example? I'd like to see it!

2) Now for the Admin of the Forum: I don't want to violate any rules of this forum, but I have a source-code of what I think was a famous game of Saturn. I'll talk with the programmer, if he agree, could I share in here? But I don't know how to deal with the Publisher.

[mo68K]

...
I hope this will help you

Thanks and I understood everything, but I think this is not what I'm looking for, because in my case, I would need to set the offset dynamically, while for what I see, you set an array where every value is a multiple of 8.

But before going too far on this, I need to sit down and try your engine first and see what I can do, but currently I am bit far from my computer for development because I'm in vacation.

Soon I take a look I'll come back to talk about.

Finally 2 things:

1) There is a video about the mode 7 example? I'd like to see it!

2) Now for the Admin of the Forum: I don't want to violate any rules of this forum, but I have a source-code of what I think was a famous game of Saturn. I'll talk with the programmer, if he agree, could I share in here? But I don't know how to deal with the Publisher.

[matteus]

I imagine that second point would definitely violate forum rules

[BonusKun]

2) Now for the Admin of the Forum: I don't want to violate any rules of this forum, but I have a source-code of what I think was a famous game of Saturn. I'll talk with the programmer, if he agree, could I share in here? But I don't know how to deal with the Publisher.

As much as I'd like to say yes, I'm going to have to ask you to not post it out in the open since it's still property of Sega themselves. If you do it in private in PMs then I don't mind but for now let's not get ourselves in trouble here.

[Johannes Fetz]

1) There is a video about the mode 7 example? I'd like to see it!

I will try to add something on youtube

BTW, I pushed a new version with a better sprite scalling implementation and other stuff (see the changelog)