Macro error

[tomcant]

Hi. I am currently reading a book on wingows game programming. It has proved to be extremely good so far. However, I am at a stage where I am learning about simple pixel plotting and it is all very simple, except for 32-bit pixel plotting. In the book it says to use this macro: #define _RGB32BIT(a, r, g, b) ( + ((g) << + ((r) << 16) + ( << 24)), which I am. VC++ returns an error: error C2059: syntax error : '<<'. I can see where it's getting it from, but does this mean that the book is wrong?

Any help appreciated.

________
Tom

[Dudi Hatotah]

First of all, use code tags when writing code. It will prevent the annoying .

At any rate, I'm assuming the book ment:

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#define _RGB32BIT(a, r, g, b) ( + ((g) << 8) + ((r) << 16) + ( << 24))


The syntax is very wrong, and 'b' and 'a' are not used.
If the book really said so, then the book is wrong.

I would suggest doing as following:
(Assuming that the 4-byte structure is ARGB, which I'm really not sure of)

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#define _RGB32BIT(a, r, g, b) ((b) + ((g) << 8) + ((r) << 16) + ((a) << 24))


[tomcant]

The new macro works great, thx!

One more thing, could you possibly write me a macro for 16 BIT pixel plotting? Its just that the one supplied in the book makes the pixels slightily obscure to the eye.

Appreciated,

_______
Tom

[Dudi Hatotah]

I'm glad I could help.
However, I really don't know how to write a "macro for 16 BIT pixel plotting". I don't even know WHAT IS 16 BIT pixel plotting.
Is it inserting a RGB value into a 16-bit integer?
If it is, then I guess it should look worse than the 32-bit version. It would be impossible for all the colors to be 8-bit, so the quality must be slightly worse.

At any rate, you can post the book's macro though and I'd try to figure it out and fix it if it is possible...

[MXP]

If I recall correctly from my DirectDraw days 16 bits per pixel has two formats (without alpha): 555 and 565. The first being of the form XRRRGGGBBB and the second being of the form RRRGGGGBBB. Which of these are you using?

[tomcant]

I am using non-alpha, 555 I do believe

[jgbauman]

Try

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typedef unsigned char u8_t;
typedef unsigned short u16_t;

inline u16_t rgb555(u8_t r, u8_t g, u8_t b) {
  return
    (u16_t(r & 0xf8) << 7) ||
    (u16_t(g & 0xf8) << 2) ||
    (u16_t(b & 0xf8) >> 3);
}

[saramakos]

I think I have read a very similar tutorial to the one you are using. Here are the defines that worked for me:

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#define RGB_16(r, g, b) (((r) << 11) | ((g) << 5) | (b))
#define RGB_32(r, g, b) (((r) << 16) | ((g) << 8) | (b))


Hope this helps somewhat

[tomcant]

Thank you, this helps greatly