Archive for March, 2011

Molehill AGAL helper/wrapper… contributions welcome

Thursday, March 31st, 2011

NEW UPDATE COMING SOON (09.09.2011)- a few more functions and will proper code hints
UPDATE 19.05.2011
helper is now on google code
>>AGAL<<

these static functions ideally can help you build shaders in a more readable and more reusable way.
they are an incomplete set and require additions and improvement.

so feel free to post additions and alterations if I have cocked up somewhere (a good chance of that as I boshed this out in a rush)
and Ill see that they get worked in.

 
//util functions (this section is the one I would like to see grow)
 
//same as 'mix'
public static function lerp(target:String, source1:String, source2:String, ratio:String):String
{
	var code:String = "";
	code += sub(target, source2, source1);
	code += mul(target, target, ratio);
	code += add(target, target, source1);
	return code;
}
 
//should return the length of the source vector
public static function length(target:String, source:String):String
{
	var code:String = "";
	code += dp3(target, source, source);
	code += sqt(target, target);
	return code;
}
//calculates the reflection vector based on a view direction and a normal (formula:  r = V - 2(V.N)*N)
public static function reflect(target:String, view:String, normal:String):String
{
	var code:String = "";
	code += dp3(target+".w", view+".xyz", normal+".xyz");
	code += add(target+".w", target+".w", target+".w");
	code += mul(target+".xyz", normal+".xyz", target+".w");
	code += sub(target+".xyz", view+".xyz", target+".xyz");
	code += neg(target+".xyz", target+".xyz");
	return code;
}
 
//generic helpers (usefulness debatable)
 
//unit vector from Light to the Vertex position
public static function light(target:String, light:String, position:String):String
{
	var code:String = "";
	code += sub(target, position, light);
	code += nrm(target, target);
	return code;
}
//unit vector from Vertex P to the View position V
public static function view(target:String, position:String, camera:String):String
{
	var code:String = "";
	code += sub(target, camera, position);
	code += nrm(target, target);
	return code;
}
//unit vector halfway H, between L and V, used for Blinn simplification
public static function half(target:String, light:String, view:String):String
{
	var code:String = "";
	code += add(target, light, view);
	code += nrm(target, target);
	return code;
}
 
//wrappers for inbuilt functions (incomplete)
public static function mov(target:String, source:String):String
{
	return "mov " + target + " " + source + "\n";
}
public static function add(target:String, source1:String, source2:String):String
{
	return "add " + target + " " + source1 + " " + source2 + "\n";
}
public static function sub(target:String, source1:String, source2:String):String
{
	return "sub " + target + " " + source1 + " " + source2 + "\n";
}
public static function mul(target:String, source1:String, source2:String):String
{
	return "mul " + target + " " + source1 + " " + source2 + "\n";
}
public static function neg(target:String, source:String):String
{
	return "neg " + target + " " + source + "\n";
}
public static function sqt(target:String, source:String):String
{
	return "sqt " + target + " " + source + "\n";
}
public static function nrm(target:String, source:String):String
{
	return "nrm " + target + " " + source + "\n";
}
public static function dp3(target:String, source1:String, source2:String):String
{
	return "dp3 " + target + " " + source1 + " " + source2 + "\n";
}
public static function pow(target:String, source1:String, source2:String):String
{
	return "pow " + target + " " + source1 + " " + source2 + "\n";
}
public static function m33(target:String, source1:String, source2:String):String
{
	return "m33 " + target + " " + source1 + " " + source2 + "\n";
}
public static function tex(target:String, coord:String, texture:String, type:String, wrap:String, filter:String):String
{
	return "tex "+target+" "+coord+" "+texture+" <"+type+","+wrap+","+filter+">" + "\n";
}

:)

as an idea for some of the functions what I could do is add and optional boolean parameter called normalize and if its set I could automatically normalize the output.

would like to see the following functions added:
refract (tried to do this one myself but got scared and ran away)
smoothstep (see wikipedia about this one… the problem is that it requires the use of a constant or two and ideally these wouldn’t have to be passed in as parameters.. any idea if that is possible?)
..and anything else anyone can think of that the api is currently misisng
and I’ll soon be putting in some lighting methods for helping people get diffuse and specular lighting.