What decides chords in a scale?

was going through a book (from: http://www.true-piano-lessons.com/piano-player.html), which I like.

There it is written:

Within  every  major  or  minor  scale,  there  are  seven  chords    —  one  for  each  tone  of  the  scale,  and  numbered  accordingly.    As  an  example,  if  you  were  to  number  and  name  the  chords  of  the  C-­‐major  scale,  you  would  get  the  following:  the  I-­‐chord is  C  Major,  the  ii-­‐chord  is  D  Minor,  the  iii-­‐chord  is  E  Minor,  the  IV-­‐chord  is  F  Major,  the  V-­‐chord  is  G  Major,  the  vi-­‐chord  is  A  Minor,  and  the  vii°-­‐chord  is  B  Diminished.  Every  major  scale  has  the  same  pattern  of  major,  minor,  and  diminished  triads....

How are these patterns decided? If I just start and play the major keys in 1-5-8 pattern I will just get all the major chords. As described below:

 

C

?

D

?

E

F

?

G

?

A

?

B

C

*

*

*

C#

*

*

*

D

*

*

*

D#

*

*

*

E

*

*

*

F

*

*

*

F#

*

*

*

G

*

*

*

G#

*

*

*

A

*

*

*

A#

*

*

*

B

*

*

*

There must be some logic behind it. What is it?

Learning Music

Since childhood I wanted to learn music, but was so stupid that never really tried that.

Once I went for my MTech at IIT Bombay (The place to be), I bought an acoustic guitar. With my crazy research ideas, work load at IIT B and lack of concepts from my BTech days, hardly left me any time for guitar (or so I thought).

Still learned few songs. All the people at IITB (whom I interacted with) who were guitarist (with just one exception) started playing some musical instrument from 7th grade or even earlier.

Playing bar chords was not tough. Practicing half notes also came with a little practice. But switching from one chord to other (especially when later is a bar chord) was tough. In fact was the root cause why I.... Other thing which always eluded me is music sense.

I tried to master few songs. But whenever I play chords for them, for almost all of them I was not able to feel the music (that, the song is being played). For very few songs for which I was able to feel, that yes! song is being played (like: O Soniyo from Raaz 2), I felt that strumming pattern was what causing it (and chords were not the major cause producing music).

Well my guitarist friends didn't agreed. After completing my MTech, while working as well I tried it but I guess musical sense is very tough to acquire...

Few of my friends suggested practicing on piano and I bought one (CASIO CTK-2300 Standard Keyboard). So far it looks much-much simpler than a guitar. I also found the lessons at:http://www.true-piano-lessons.com/
Also there book: http://www.true-piano-lessons.com/piano-player.html