The Sinclair QL Forum

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MODE 4 MODE 8 MODE 16 MODE 32 MODE 33
(Intel) (Motorola)
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Thanks for the list. Could you mark in this list what is an emulator and what is a real board? I ask this ...

The mode 32 colour word is actually rrrrrggg.gggbbbbb, so the 5-bit to 6-bit only applies to the green part.
Since the green part already has 6 bits, perhaps you mean that the transformation from 5 to 6 bits only applies to the red and blue parts?

A simple value doubling or left shift will make ...

This would allow variable size QL graphics files without the need to fit, stretch or centre the source file if it is not 512x256 pixels. In other words, graphics files can be any size, not just 512x256 pixels.

Added. Need to be tested.

But the same text also mentions Bit Replication which was ...

pjw wrote: Sun Apr 09, 2023 1:36 pmN x 3 in the byte table, and N x 3/2 in the nybble table

The main question is - are you sure that the tables contain the correct values? How were these values obtained?

Here is one way to convert Aurora mode 16 colours to 24 bit RGB, using a table

I'm not familiar with assembler and I can't understand this code. Is it possible to translate this into pseudo-code?

I may be wrong, correct me if so. The general color scheme is as follows ...

BTW. I can't find information on how the palette used is converted to RGB888. For example, for mode 16, I use this palette:

But what is the real palette?

Modes 32 and 33 use 5 and 6 bit colors, but how to correctly convert these colors to RGB888?

dilwyn wrote: Fri Apr 07, 2023 6:58 pmI rendered them on a QL-compatible display in QPC2 (mode 4 and mode 8)

Could you provide renders in PNG or BMP format. Jpeg images have compression artifacts and I can't see all the pixels. I don't need all the images. I will be satisfied with one render of the mode 4, and one render of the mode 8.

I have attached 4 QL PIC files in both mode 4 (_pic4 file ending) and mode 8 (_pic8 file ending)

I don't fully understand some of the details.

Lets compare internal file header structure of astronaut.pic4 and astronaut.pic8.

astronaut.pic4:
Width: 330
Height: 294
BPL: 84
Mode: 0
Spare: 0

Mode ...

I have attached 4 QL PIC files in both mode 4 (_pic4 file ending) and mode 8 (_pic8 file ending)
Could you also provide a rendering of your pic image. I mean how do they look on your QL monitor?
It looks like that the pixel encoding method in pic8 files is different from that of standard SCR8 ...

dilwyn wrote: Fri Apr 07, 2023 2:31 pmI wonder if it would be possible to add QL PIC files to the list of output formats for DaDither.exe ?

DaDither already uses PIC format for GD2 16/GD2 32/GD2 33 modes. If you want me to add PIC formats for QL 4/ QL 8 modes then provide me a sample of such images.