flat assembler
> OS Construction > Vesa Mode Colors??? - SOLVED |
| Author |
|
|
I have currently set up Vesa using the code below . However, this particular mode has a supposed 64k color palette. The problem is, I cannot figure out how to code a specific color. For example.. plotting a pixel with 0xFFFFFF produces a white pixel, 0x000000 produces a black pixel, but 0x00FF00 which should be green, produces a dark yellow color. Am I incorrect in correlating the color scheme to a standard rgb color palette? How can I determine the correct color I want???
Code:
mov ax, 4f01h
mov bx, 4114h ;800x600 - 64k - 16-bit (5:6:5)
mov di, Mode_Info
mov cx, bx
int 10h
mov ax, 4f02h
int 10h Last edited by newport on 07 Apr 2016, 19:14; edited 2 times in total |
|||
07 Apr 2016, 18:49 |
|
|
ok.. as always, i seem to find my answers after posting... lol - this link helped me understand how to convert rgb colors to 5:6:5 colors -
http://www.avrfreaks.net/forum/color-map-ili93401-tft-display ..and excerpt from the page states.. Code:
Pick some colours, for example I like the look of #66FF99 and then convert this 24 bit 8:8:8 value to
5:6:5 or 6:6:6 using the most significant bits. So for this lovely greeney-blue the 66FF99 is:
R: 0x66 = 0b01100110
G: 0xFF = 0b11111111
B: 0x99 = 0b10011001
To convert to 18 bit (6:6:6) just take the top 6 bits of each:
R: 011001
G: 111111
B: 100110
then add them together to make the 18bits
011001 111111 100110
grouping that in fours:
01 1001 1111 1110 0110
which in hex is:
0x19FE6
Doing the same for 16 bit (5:6:5) would be:
R: 01100
G: 111111
B: 10011
which is
0110 0111 1111 0011
0x67F3
So "limey green" is 0x19FE6 in 18 bit mode and 0x67F3 in 16 bit mode. |
|||
|
07 Apr 2016, 19:03 |
|
|
The VBE3 standard (http://www.petesqbsite.com/sections/tutorials/tuts/vbe3.pdf) defines the layouts for preset modes but also provides generic RGB field info in the get mode info function (#1), which could help - though to be honest I went straight to 24/32 bit modes for the simplicity
 |
|||
|
07 Apr 2016, 20:59 |
|
|
i wanted to use 24or 32 bit, but the only vesa modes that would work with my computer are .. 101h, 111h, 114h, and 117h...
|
|||
|
08 Apr 2016, 14:51 |
|
< Last Thread | Next Thread > |
Forum Rules:
|