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Vintage Computing Christmas Challenge 2022 (VC³ 2022)

Author: Chris Barrett / BaZ4096
Category: Christmas Challenge
System:   Acorn BBC Microcomputer Model B
Language: BBC BASIC 2
Len source code: 125 tokenized / 167 as text
Instructions:

Visit this URL:

https://bbcmic.ro/#%7B%22v%22%3A1%2C%22program%22%3A%22MODE1%5CnVDU5%5CnA%25%3D480%5CnX%25%3D640%5CnFORI%25%3D32TO416STEP32%5CnS%24%3DS%24%2B%5C%22*%5C%22%5CnY%25%3D208%2BI%25%5CnW%25%3D128-I%25%5CnV%25%3D784-I%25%5CnMOVEA%25%2CY%25%5CnPRINTS%24%5CnMOVEX%25%2BW%25%2CY%25%5CnPRINTS%24%5CnMOVEA%25%2CV%25%5CnPRINTS%24%5CnMOVEX%25%2BW%25%2CV%25%5CnPRINTS%24%5CnNEXT%22%7D

Description:

This program uses BBC BASIC's ability to print text at the graphics cursor (VDU 5 enables this) - The MOVE command works on a virtual grid of 1280x1024, each character in MODE 1 is 32x32.
I realised that the star is just 4 overlapping triangles, starting from 1 asterisk wide and ending at 13 wide.
The main loop iterates 13 times, drawing one row of each of the four triangles each time, each time the row of asterisks grows by one. Magic numbers provide the X & Y origin of each triangle, centering them to the MODE 1 screen.

Please see the four partial PNG images that demonstrate each triangle.
Given many of the asterisks are overwritten, this program is optimised for source size and not speed.

Comments:

BBC BASIC is stored in tokenized format, hence the 125 character count.
In human-readable text, it's 167 chars.

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	Vintage Computing Christmas Challenge 2022 (VC³ 2022)

Author: Chris Barrett / BaZ4096
Category: Christmas Challenge
System:   Acorn BBC Microcomputer Model B
Language: BBC BASIC 2
Len source code: 73 tokenized / 97 as text
Instructions:

Visit this URL:

https://bbcmic.ro/#%7B%22v%22%3A1%2C%22program%22%3A%22CLS%3AFORI%3D1TO13%3AS%24%3DS%24%2B%5C%22*%5C%22%3AJ%3D18-I%3APRINTTAB%289%2CJ%29S%24TAB%28J%2CJ%29S%24TAB%28J%2CI%29S%24TAB%289%2CI%29S%24%3ANEXT%22%7D

Description:

This program uses BBC BASIC's MODE 7 text mode.
I realised that the star is just 4 overlapping triangles, starting from 1 asterisk wide and ending at 13 wide.
The main loop iterates 13 times, drawing one row of each of the four triangles each time, each time the row of asterisks grows by one.

Please see the four partial PNG images that demonstrate each triangle.
Given many of the asterisks are overwritten, this program is optimised for source size and not speed.

Comments:

BBC BASIC is stored in tokenized format, hence the 58 character count.
In human-readable text, it's 82 chars.
The BASIC file is different again, I think because of the encoding (64 bytes).