Bmp2g9b with 8 bits/pixel V9990

Page 1/4
| 2 | 3 | 4

By Manel46

Champion (431)

Manel46's picture

16-11-2018, 17:23

Hi, people
I am testing with bitmap graphics for V9990, with uncompressed bmp2g9b (-b) files.
Thus I get BD16 (16 bits / pixel), BP6 (6 bits / pixel) and BP4 (4 bits / pixel) graphics, starting from the appropriate BMPs. But I can not make graphics in BD8 mode (8 bits / pixel). If the BMP has 256 colors gives error. For this reason I have to use SR8 files, which limits me to a 256x212 pixel screen.
Is it possible to make g9b files of any size in this mode?

Login or register to post comments

By msd

Paragon (1372)

msd's picture

17-11-2018, 10:02

The problem is that the v9990 only has 8 bit 64 color mode with palette support and a 8 bit mode fixed palette like the v99x8. I never thought it was interesting to add the 8 bit 256 color mode. It would not be difficault to add this mode .

By msd

Paragon (1372)

msd's picture

17-11-2018, 10:06

It only needs to be added to bmp2g9b. The g9klib already supports it

By Manel46

Champion (431)

Manel46's picture

17-11-2018, 11:13

msd wrote:

I never thought it was interesting to add the 8 bit 256 color mode. It would not be difficault to add this mode .

Yes friend, to this I mean, the fixed palette of 256 colors, which is the BD8. It would be nice to have bmp2g9b in this mode. As I said, I have to use SR8 for these graphics, with the limitation of the screen dimension.

By Manel46

Champion (431)

Manel46's picture

17-11-2018, 12:08

msd wrote:

It only needs to be added to bmp2g9b. The g9klib already supports it

It would be something great. If, as I said, I use the 8-bit / pixel mode, 256 colors, but for 256-by-wide screens.

By Manel46

Champion (431)

Manel46's picture

18-11-2018, 16:57

Hi msd
It is very interesting that you implement the 256 color mode (8 bits / pixel) for the bmp2g9b. When you can.
I wait for news. Smile

By Manel46

Champion (431)

Manel46's picture

28-11-2018, 15:38

Seeing the possibilities of BMP2G9B, I reaffirm the need that 256 color bmp can be converted.
A die, for me of a lot of weight:
It works perfectly with 64 color bmp, but it turns out that this (6 bit / pixel) dismisses two bits in each byte, while the 256 color mode uses them all. A graphic of 64 colors occupies the same as that of 256, which is much better.
I solve the loading of a 512x424 screen, in this mode, by four SR8, which I then charge with LMMC. But it is a cumbersome process.

By msd

Paragon (1372)

msd's picture

28-11-2018, 16:47

Yes but it is 64 colors out of 32768 versus 256 out of a fixed pallet

By msd

Paragon (1372)

msd's picture

28-11-2018, 16:57

There are two possibilities
24 bit fixed palette to 8 bit fixed palette
8 bit with 24 bit palette to 8 bit fixed palette

Which one?

By Manel46

Champion (431)

Manel46's picture

28-11-2018, 17:01

If right. But the quality of the resulting image is superior. Better "dither". The BMP2MSX converter works very well for this.

By Manel46

Champion (431)

Manel46's picture

28-11-2018, 17:46

msd wrote:

There are two possibilities
24 bit fixed palette to 8 bit fixed palette
8 bit with 24 bit palette to 8 bit fixed palette

Which one?

Here there is no palette, as with the 16 bit / pixel BD16 mode
Analyzing B9G, the bitmap data is continuation of the header, in these modes. The 8-bit / pixel mode is the BD8.
Look link.

http://msxbanzai.tni.nl/v9990/manual.html

Page 1/4
| 2 | 3 | 4