I should have a new patch within the next couple of weeks ready. It will
be a updated fastrom patch combined with my new decompressed gfx/data
patch that I'm currently working on.
The grid collision for the bubbles is like a secondary collision. Its only
for bubbles having contact with other bubbles. The main collision is like the
bounding box collision that you described. If you look at the ram data for the
bubbles the ram 0x28-0x2b is the dimensions for the bubbles main collision.
This collision is for when your ship touches it, when your ships bullets hit it
and for the bounding box. 0x0b 0x00, 0x0b 0x00 is for 32x32 bubbles main
collision and 0x05 0x00, 0x05 0x00 is for 16x16 bubbles.
Here is a small tool that I'm working on to help with creating my next patch.http://www.mediafire.com/file/23np4ja4dzd4pua/gradius_3_data_decomp.zip/file
This tool decompresses lots gradius 3 graphics to files and puts them in their
own directory. I currently only have it decompressing the graphics and data
in bank $06 but I do already have all of the data for all of the banks. This is
just a test program and it is not optimized yet. To use the tool load a headerless
Gradius III (U) [!] rom and then push the create files button and it should create
a folder "068000" in the same directory as the tool. Do not load any other file into
this program and do not edit the data.bin file and you shouldn't run into any
problems. The decompressed .bin files that this tool creates can be loaded into your
favorite tile editor to view the decompressed graphics. I think only 1 of the
decompressed .bin files(06f57a) is data and the rest are graphics.