Multiple IF statements?

What's wrong here?

adding 1 to the value of "col" if this goes over 15 it's set back to 1 and according to what value it is, it sets the values of r g and b.

Obviously I'm making some fundamental mistake



if( str=="colour" )

{
col += 1;
if(col > 15)

{
col = 1;
}

if(col = 1) r = 0; g = 0; b = 0;

if(col = 2) r = 0; g = 0; b = 1;

if(col = 3) r = 1; g = 0; b = 0;

if(col = 4) r = 1; g = 0; b = 1;

You are using the assignment operator "=" in the test; you should be using the logical comparison operator "==", and possibly you want to enclose the other assignments inside braces so that they too execute conditonally:

if (col == 1) {r = 0; g = 0; b = 0;}

Is this a good place to introduce you to colours as vectors?

vector red = <1.0, 0.0, 0.0>;
llSetColor (red, ALL_SIDES);

And it also looks like using a list of colours and cycling through the index would help in what you're doing. But that is another can of worms, which you may prefer to avoid for the time being.

Curly brackets enclose bodies of code that are meant to be executed as a block. The block may define an event, for example, or a subset of an event, like a condition test. So when you write an if test, the statements to be executed if the test condition is TRUE must be in curly brackets....

if (col ==1) //If this test evaluates as TRUE
{ //then do everything from here ...
r = 0;
g = 0;
b = 0;
} // ...to here.

Omitting the brackets means ...

if (col ==1) //If this test evaluates as TRUE
r = 0;//... do this...
g = 0; // .. and then do this and anything after it, even if (col ==1) is FALSE
b = 0;

To be sure that you don't fall into this trap, always use the brackets even if you only have one statement to execute.

Thanks to you all for your help, and putting up with my very basic questions.

I'm at the base of the cliff, looking up and I'm about 1 or 2 feet of the ground at the moment, making progress, but strugging to find a good foot hold quite often

It was the == rather then the = that was the biggest issue.

I had originally got them rgb on seperate lines within the curley brackets before Wiki showed me I could have it on 1 line. I've also enclosed them in brackets (on the 1 line) as per your example.

There are still many terms people use here, which I'm not understanding, but I like to work backwards in a way, get something up and running, then often re work it, and kinda work backwards, later on learning things I should have done from the start.

Not a good way to start, but I like to get some "Results" 1st and something working, as it gives me satisfactions and encouragement, even if it's not done the right way.

I can always re-do things better later when I have more understanding

vector color; //--aka col = 1

if (col == 2) color.z = 1.0;
else if (col == 3) color.x = 1.0;
else if (col == 4) color = < 1.0, 0.0, 1.0 >;

else lets you exit early, if you have 4 or more tests a binary tree is probably a better structure for lest amount of test for for ALL values (assuming an equal chance of any color)

example:

if (col & 4){
  if (col & 2){
    if (col & 1){
      //-- col = 7
    }else{
      //-- clo = 6
    }
  }else{
    if (col & 1){
      //-- col = 5
    }else{
      //-- col = 4
  }
}else{
  if (col & 2){
    if (col & 1){
      //-- col = 3
    }else{
      //-- col = 2
    }
  }else{
    if (col & 1){
      //-- col = 1
    }else{
      //-- col = 0
    }
  }
}

(technically you can collapse any "if" into a preceding "}else{" but it shouldn't matter if you do the full range and the compiler should be doing it for you in most cases... I think this is more readable in most case)