03-26-2020, 06:05 PM
(This post was last modified: 03-26-2020, 06:11 PM by rufaswan.
Edit Reason: typo, sectioning
)
Keep crunching numbers night by night, I begin to understand how Playstation do alpha-blending.
For example, this sprite:
Don't you find it strange the clouds are black? It doesn't matter how transparent you make it, the clouds is still black and not going to become white.
As it turns out, that's because the clouds isn't an image to begin with. It is an alpha mask. If you add the value of both foreground and background pixels together, you'll get the same value from the in-game screenshot:
Since alpha mask are grayscale, we can also say any 16-color palette that are grayscale are actually alpha mask. And indeed, sprites with semi-transparency has grayscale parts:
(/ana/twr_bs01_img_0/070.png)
From Wikipedia, there are different modes of blending too. The clouds on Norn Peak has the data value of 1, which is additive blending. I also see data value of 3, like Roa.
I haven't figure out what 3 is yet, all I know 3 is less brighter than 1. The pixel value may decrease after the blending.
Need more research on the subject.
@SmithyGCN It is more technical to rip from game files than on VRAM. For one, you don't have to deal with decompression and decryption. VRAM is just raw image data, and there are many VRAM ripping tools and tutorials for non-technical ripper.
On the other hand, The Legend of Mana map files on /map/*/*.prs are compressed. You'll need some knowledge on MIPS assembly to understand how to decompress them.
And then we have reassembling parts into sprites. Even from the same game, the parts data is not the same for /ana/*/*.img , /wm/wmland/*.dat , /wm/*/*.dat + *.tim pair , /map/*/*.prs.dec . You'll need to write tools for each of them.
That's just too technical for most casual ripper.
By the way, I just took a quick look over 3 NDS Castlevania game files, and it seems pretty straight-forward. Files on /data/sc and /data/sc2 are just pixel data, 4-bit, 128 width. Corresponding files on /data/so are the sprite parts data.
What is missing is the sprite groups data to reassemble all required parts into a sprite. And figure out 3 unknown bytes on the sprite parts data.
I also need to find the palette data. Where do you get 286.cvpal and 290.cvpal for Loretta on Potrait of Ruins?
In any case, I'll look more into it only after I've finish up with Legend of Mana rip. Don't bite more than you can chew. Finish a project first before start another one
Take care,
- Rufas
For example, this sprite:
Don't you find it strange the clouds are black? It doesn't matter how transparent you make it, the clouds is still black and not going to become white.
As it turns out, that's because the clouds isn't an image to begin with. It is an alpha mask. If you add the value of both foreground and background pixels together, you'll get the same value from the in-game screenshot:
Since alpha mask are grayscale, we can also say any 16-color palette that are grayscale are actually alpha mask. And indeed, sprites with semi-transparency has grayscale parts:
(/ana/twr_bs01_img_0/070.png)
From Wikipedia, there are different modes of blending too. The clouds on Norn Peak has the data value of 1, which is additive blending. I also see data value of 3, like Roa.
I haven't figure out what 3 is yet, all I know 3 is less brighter than 1. The pixel value may decrease after the blending.
Need more research on the subject.
Quote:Why aren't more rippers ripping like this? There are games like the DS Castlevanias and Magical Starsign that could use it.
@SmithyGCN It is more technical to rip from game files than on VRAM. For one, you don't have to deal with decompression and decryption. VRAM is just raw image data, and there are many VRAM ripping tools and tutorials for non-technical ripper.
On the other hand, The Legend of Mana map files on /map/*/*.prs are compressed. You'll need some knowledge on MIPS assembly to understand how to decompress them.
And then we have reassembling parts into sprites. Even from the same game, the parts data is not the same for /ana/*/*.img , /wm/wmland/*.dat , /wm/*/*.dat + *.tim pair , /map/*/*.prs.dec . You'll need to write tools for each of them.
That's just too technical for most casual ripper.
By the way, I just took a quick look over 3 NDS Castlevania game files, and it seems pretty straight-forward. Files on /data/sc and /data/sc2 are just pixel data, 4-bit, 128 width. Corresponding files on /data/so are the sprite parts data.
What is missing is the sprite groups data to reassemble all required parts into a sprite. And figure out 3 unknown bytes on the sprite parts data.
I also need to find the palette data. Where do you get 286.cvpal and 290.cvpal for Loretta on Potrait of Ruins?
In any case, I'll look more into it only after I've finish up with Legend of Mana rip. Don't bite more than you can chew. Finish a project first before start another one
Take care,
- Rufas