For an SGDK example of how to change colors each scan line you can have a look here:
https://github.com/a-dietrich/SEGA-Gene ... e/main/tf2
In src/main.c look for scene4().
Search found 17 matches
- Sun Dec 26, 2021 6:30 pm
- Forum: SGDK
- Topic: Sky Gradients?
- Replies: 5
- Views: 8603
- Sun Dec 26, 2021 6:24 pm
- Forum: SGDK
- Topic: Thunder Force II Intro Sequence
- Replies: 0
- Views: 97965
Thunder Force II Intro Sequence
I made a Genesis port of the Thunder Force II intro sequence from the Sharp X68000 version. The binary has been tested on a real machine. On a PAL system, graphics should be displayed at 320x240 pixels resolution, it will also work on NTSC systems (320x228 pixels). For now the overlay text is in Jap...
- Fri Mar 05, 2021 8:42 pm
- Forum: Demos
- Topic: SOR4 Mega Drive Slideshow
- Replies: 0
- Views: 103223
SOR4 Mega Drive Slideshow
I finally found some time to play through Streets of Rage 4. Naturally, I was curious how it would look on a Mega Drive, so I made a very small slideshow with SGDK using a couple of images I found on Google. Turns out even with 16 colors this does not look so bad. With a more sophisticated tiling an...
- Tue Feb 09, 2021 8:29 pm
- Forum: SGDK
- Topic: Raster Effect with Gendev ( SGDK)
- Replies: 33
- Views: 36413
Re: Raster Effect with Gendev ( SGDK)
You can think of each line as a "window" of height 1. The vertical scroll value applies to such a "window" in the same way as it does to the full plane. So we can vertically scroll what is displayed in each line if we set the vertical scroll value with HInt. It is important that VDP_setVerticalScrol...
- Tue Feb 02, 2021 9:16 pm
- Forum: SGDK
- Topic: Raster Effect with Gendev ( SGDK)
- Replies: 33
- Views: 36413
Re: Raster Effect with Gendev ( SGDK)
Here's a quick example how this can be done with SGDK 1.60. scaling.png In this example HInt and VInt look like this: static u8 lineDisplay = 0; // line position on display screen static fix16 lineGraphics = 0; // line position in graphics texture static fix16 scroll = 0; // scrolling offset static ...
- Tue Jan 26, 2021 7:51 pm
- Forum: SGDK
- Topic: Writing multiple VSRAM values per scanline
- Replies: 3
- Views: 8915
Re: Writing multiple VSRAM values per scanline
Thanks ob1 and Stef! Yes, the transfer is limited to 6 values (the logo is 96 pixels wide). I had to use some inline assembly and a lot of trial and error to get there. I haven't done any cycle counting, but I don't think it can be much more. One could try to move the HInt code to Sega.s, or maybe u...
- Sat Jan 23, 2021 11:58 pm
- Forum: SGDK
- Topic: Writing multiple VSRAM values per scanline
- Replies: 3
- Views: 8915
Writing multiple VSRAM values per scanline
I've been experimenting with writing multiple values to VSRAM in the HInt routine each line in order to set vertical scroll values for a number of two-tile columns. In the example shown here, this is used to generate a fake transparent highlight bar by setting the vertical scroll value to select a s...
- Fri Jan 08, 2021 4:46 pm
- Forum: SGDK
- Topic: Get Tile Index of background specific position (X, Y)
- Replies: 6
- Views: 13746
Re: Get Tile Index of background specific position (X, Y)
I just ran into the same problem. SGDK does have a VDP_setTileMapXY() function in SGDK/src/vdp_tile.c. You can modify the code so that it reads from VRAM, something like: u16 VDP_getTileMapXY(VDPPlane plane, u16 x, u16 y) { vu32* const plctrl = (u32*)GFX_CTRL_PORT; vu16* const pwdata = (u16*)GFX_DAT...
- Thu Dec 31, 2020 6:47 pm
- Forum: SGDK
- Topic: Screen wobble SGDK sample
- Replies: 5
- Views: 12065
Re: Screen wobble SGDK sample
Very nice example! Love it! Is there any possibility to make this in horizontal instead vertical? Thanks! It's possible to shift each line horizontally, but that would not warp (or scale) the line, just move it. Thinking more of it, one could pre-compute some warping as tiles, and then repeat them ...
- Thu Dec 31, 2020 6:42 pm
- Forum: SGDK
- Topic: Screen wobble SGDK sample
- Replies: 5
- Views: 12065
Re: Screen wobble SGDK sample
The effect looks gorgeous ! well done ! And the settings menu is really nicely done too. Can i eventually use it as default sample ? that is the kind of sample i always wanted to do but never spent time for that. Of course you will be credited for that :) Also it's good that you made it for SGDK 1....
- Thu Dec 31, 2020 6:07 pm
- Forum: SGDK
- Topic: Namco arcade font
- Replies: 3
- Views: 38792
Re: Namco arcade font
Yup, I have seen it even on black and white Atari machines like Dominos (1977), but I did not know Quiz Show is considered to be the first one to use it (https://www.arcade-history.com/?n=quiz- ... il&id=3345)
- Wed Dec 30, 2020 7:23 pm
- Forum: SGDK
- Topic: Namco arcade font
- Replies: 3
- Views: 38792
Namco arcade font
While, I'm at it ... I've seen some demos and games on the Genesis that were using the classic Namco arcade font (e.g., from Pac Man). However, I did not find an SGDK "compatible" version, so I made one using the font files found here: http://www.zone38.net/font. The nice thing is that it also inclu...
- Wed Dec 30, 2020 6:30 pm
- Forum: SGDK
- Topic: Screen wobble SGDK sample
- Replies: 5
- Views: 12065
Screen wobble SGDK sample
Hi, I wanted to get a bit more used to the new SGDK 1.60 release, so I programmed a sample as an exercise. Something I always wanted to try on the Genesis is screen warping. To achieve this, the demo uses a horizontal interrupt handler which modifies the vertical scrolling settings each line. Includ...
- Sat May 11, 2019 5:47 pm
- Forum: SGDK
- Topic: Configurable "out" folder location
- Replies: 1
- Views: 4520
Configurable "out" folder location
Just in case anyone is interested in this... I recently wanted the change the name of the "out" directory for my current project. When trying to introduce a variable "$(OUT)" for this in the makefile, I ran into the problem that the output location is hardcoded in boot/sega.s: .incbin "out/rom_head....
- Sat Dec 15, 2018 9:38 pm
- Forum: SGDK
- Topic: Sprite Engine Problem
- Replies: 6
- Views: 5571
Re: Sprite Engine Problem
If going up to 32 internal sprites would work with little performance loss, that sounds like a good compromise. That should probably be enough in most situations. In my current project I'm using the sprites for letters in a title screen. Here, 16 is not enough, 32 would work though. In any case, the...