How to do a fluid scrolling

[fafenstein]

Hi there,

first i introduce myself :
I'm french about 30 and i don' t know anything in programing....

I'm try to do a text scrolling in lua by using exemple find on this site (shine) and wiki one.

For the font code i use this one :

-- Global Variables
font = Image.load("bmf02_007.png")
LetterPixelsWide = 8
LetterPixelsTall = 8
InputString = [[ !"#$%&'()* ,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ]]

--Functions
function char2font(char_input)

IndexNumber = 0
for i = 1, string.len(InputString) do
if string.sub(InputString, i,i) == char_input then
return IndexNumber
end -- end if
IndexNumber = IndexNumber + LetterPixelsWide
end -- end if
return 0
end -- char2font
function blitChar(target, char, posx, posy)
target:blit(posx,posy, font,char2font(char),0,LetterPixelsWide,LetterPixelsTall,true)
end -- blitChar
function blitString(myTarget, possx, possy, thestring)
incX = 0
for w = 1, string.len(thestring) do
blitChar(myTarget, string.upper(string.sub(thestring, w,w)), possx + incX, possy)
incX = incX + LetterPixelsWide
end -- end for
end -- blitString

--main program
blitString(screen, 10, 10, "Hello World")
screen:flip()
screen.waitVblankStart(600)

---------------------------------------------------------

First problem :

-It' s impossible to lua to load a pgn bigger than PSP screen size, when i load a pgn how is 16*1136 for exemple lua say : "impossible to load image" or a thing like that.....


For scroll i use the exemple of wiki :


---------------------------------------------------------
System.usbDiskModeActivate()
green = Color.new(0, 255, 0)
time = 0
pi = math.atan(1) * 4
while true do
screen:clear()

x = math.sin(pi * 2 / 360 * time) * 150 + 192.5
screen:print(x, 100, "Hello World!", green)
time = time + 1
if time >= 360 then
time = 0
end

screen.waitVblankStart()
screen.flip()

pad = Controls.read()
if pad:start() then
break
end
end
-----------------------------------------------------------

-Animation of my scroll is a pure crap and mybee give epilepsy crisis to how want try to read it.....

Thx in advance to anyone how can answers to this 2 questions and can help me....


Sorry for my crapy english.

[LuMo]

first problem's answer:
its not possible to load a images bigger than 512*512 yet.
NOTE: you can add some code to the char2font-function, which does nothing more than entering line 2 when you are further than 512 px.
(use mod to do that)

second problem's answer:
if your scrolling is not smooth... check the sample code on my webpage;
there you can find some really basic things, and some more advanced ones too...

still some questions?
shoot!

greets

[fafenstein]

Ok thx 4 answer i will go on your web page to lurn some good tips but i ever go on your site (good one) but i never arrive to make work your windows lua player... ;).

If anyone can allready give here a good code for scrolling, don't hesite....

Can we use a font gif whith 2 or more levels ???

I explain :
Not : 123456789 azertyuiop^qsdfghjklmwxcvbn,;,

but :
123456789
azertyuiop
qsdfghjklm

I hope you will understand me.....

[LuMo]

thats what i meant by using math->mod
modulo, which would wrap into a new line...

greets

[fafenstein]

Ho yes sorry !!!
I don' t see it in your first post...

Anyway i'm not abble to do this thing whithout exemple . ;b ...

[fafenstein]

So finaly i keep old code because your news isn't beter...

And it was too hard to change font.pgn in new i don't understand the code....

function char2font(char_input)
if char_input == '' or char_input==nil then
--print('empty string or nil')
return 0
else
char = string.byte(char_input)
if char>=65 and char <=90 then --a..z return (char-65)*8+216 elseif char>=48 and char<=57 then --0..9
return (char-48)*8+103

May be some explications for newbee like me should be helpfull...

So finaly and after 9H i do a scroll in the game i do (modify to be honest), i think i loose to much time for nothing.....

Maybe after finish my job on this game i will read the lua help book...

Thx to lumo for his trying and thx for his little code how lurn me lot's of things.

[LuMo]

Code: Select all

function char2font(char_input)
if char_input == '' or char_input==nil then
--print('empty string or nil')
return 0
else
char = string.byte(char_input)
if char>=65 and char <=90 then --a..z return &#40;char-65&#41;*8+216 elseif char>=48 and char<=57 then --0..9
return &#40;char-48&#41;*8+103 

the ONLY thing this part of the code does is...
return 0 if its an empty char --> nothing returned
or return the position of the character on the picture (number of pixels before the character starts.)

greets