HowTo:Use macros and loops - Revision history

Chrisb: /* Loops */

2008-06-10T20:08:46Z

Loops

PlayBunny at 10:31, 26 April 2008

2008-04-26T10:31:41Z

Zemoxian: Added a macro example that expands on the previous loop example

2008-04-01T03:52:13Z

Added a macro example that expands on the previous loop example

Coolhand2: /* Macros */

2007-12-12T07:47:44Z

Macros

Bathurstfreak at 22:00, 8 December 2007

2007-12-08T22:00:54Z

Chrisc: Add source tag for highlighting POV SDL

2007-12-08T13:31:11Z

Add source tag for highlighting POV SDL

Bathurstfreak: New page: == Loops == Loops are usually created to do one set of code thousands of times. The beauty of the loop is that the code can reference an array or a spline to write a rollercoaster track or...

2007-12-07T23:46:56Z

New page: == Loops == Loops are usually created to do one set of code thousands of times. The beauty of the loop is that the code can reference an array or a spline to write a rollercoaster track or...

New page

== Loops ==
Loops are usually created to do one set of code thousands of times. The beauty of the loop is that the code can reference an array or a spline to write a rollercoaster track or a roadway such that very complicated scenes can be created with the use of simple structures.

Loops may be constructed through the use of the #while statement. A typical loop may be constructed as follows.

#declare step = 0;
#declare steps = 100;
#while (step <= steps)
#sphere { step*x, 0.4 pigment {Blue} }
#declare step = step + 1;
#end

Nested loops may be created to generate a two or three dimensional aspect to the scene. Beware that creating extra nested loops will dramatically increase the parse time for the scene.

The following nested loop will draw a series of Blue balls on the XZ plain

#declare xpos = 0;
#declare zpos = 0;
#declare xfinal = 10;
#declare zfinal = 10;
#while (xpos <= xfinal)
#while (zpos <= zfinal)
#sphere { <xpos,0,zpos> 0.4 pigment {Blue} }
#declare zpos = zpos + 1;
#end
#declare xpos = xpos + 1;
#declare zpos = 0;
#end

← Older revision		Revision as of 20:08, 10 June 2008
Line 2:		Line 2:

	== Loops ==		== Loops ==
		+	See also [[HowTo:Use_conditional_structures#The_.23while.2C_.23end_construct_.28Loops.29\|HowTo:Use_conditional_structures#The #while, #end construct]]

	Loops may be constructed through the use of the #while statement. A typical loop may be constructed as follows.		Loops may be constructed through the use of the #while statement. A typical loop may be constructed as follows.

@@ Line 1: / Line 1: @@
-Loops and Macros are usually created to do one set of code thousands of times. The beauty of the loop is that the code can reference an array or a spline to write a rollercoaster track or a roadway such that very complicated scenes can be created with the use of simple declared variables.
+Loops and Macros are usually created to do one set of code many times. The beauty of the loop is that the code can reference an array or a spline to write a rollercoaster track or a roadway such that very complicated scenes can be created with the use of simple declared variables.
 == Loops ==
@@ Line 14: / Line 14: @@
 </source>
-Nested loops may be created to generate a two or three dimensional aspect to the scene. Beware that creating extra nested loops will dramatically increase the parse time for the scene.
+Nested loops may be created to generate a two or three dimensional aspect to the scene. Beware that creating extra nested loops may dramatically increase the parse time for the scene.
 The following nested loop will draw a series of Blue balls on the XZ plain

@@ Line 44: / Line 44: @@
 The name of the macro. Can be as simple or as complex as you want it to be. From a programmer's perspective, it's best to name it in a semi-descriptive way of what you're trying to do.
-<source lang="pov">#macro MakeMetal()
+<source lang="pov">#macro MakeSpheres()
-//Make a metal-type material
+//Make a layer of spheres
 #end</source>
 is much more understandable than
-<source lang="pov">#macro MM()
+<source lang="pov">#macro MS()
-//make a metal-type material
+//Make a layer of spheres
 #end</source>
-Where as the latter of the two could be confused with "MakeMatte" or something. You never know.
+Where as the latter of the two could be confused with "MakeSplines" or something. You never know.
 ===Macro Parameters===
 A comma delineated list of variables that you will use in the macro.
 They can be changed if needed, but don't have to be always.
 ===Macro Body===
 The real juice of the macro. This is where you do loops or object creation or loops with object creation, whatever. This is where you get the job done.

← Older revision		Revision as of 07:47, 12 December 2007
Line 34:		Line 34:

	== Macros ==		== Macros ==
		+	The essential custom functions of PoV-Ray. These are blocks of code that make calculations, or make objects, or if used in a series can make many objects with all of them different.
		+
		+	Macros are declared like this:
		+	<source lang="pov">#macro {Macro_Name}({Macro_Parameters})
		+	{Macro_Body}
		+	#end</source>
		+
		+	===Macro Name===
		+	The name of the macro. Can be as simple or as complex as you want it to be. From a programmer's perspective, it's best to name it in a semi-descriptive way of what you're trying to do.
		+
		+	<source lang="pov">#macro MakeMetal()
		+	//Make a metal-type material
		+	#end</source>
		+	is much more understandable than
		+	<source lang="pov">#macro MM()
		+	//make a metal-type material
		+	#end</source>
		+	Where as the latter of the two could be confused with "MakeMatte" or something. You never know.
		+
		+	===Macro Parameters===
		+	A comma delineated list of variables that you will use in the macro.
		+	They can be changed if needed, but don't have to be always.
		+
		+	===Macro Body===
		+	The real juice of the macro. This is where you do loops or object creation or loops with object creation, whatever. This is where you get the job done.

@@ Line 1: / Line 1: @@
 == Loops ==
 Loops may be constructed through the use of the #while statement. A typical loop may be constructed as follows.
@@ Line 31: / Line 32: @@
 #end
 </source>

@@ Line 4: / Line 4: @@
 Loops may be constructed through the use of the #while statement. A typical loop may be constructed as follows.
-  #declare step = 0;
+<source lang="pov">
-  #declare steps = 100;
+#declare step = 0;
-  #while (step <= steps)
+#declare steps = 100;
-    #sphere { step*x, 0.4 pigment {Blue} }
+#while (step <= steps)
-    #declare step = step + 1;
+  #sphere { step*x, 0.4 pigment {Blue} }
-  #end
+  #declare step = step + 1;
 Nested loops may be created to generate a two or three dimensional aspect to the scene. Beware that creating extra nested loops will dramatically increase the parse time for the scene.
@@ Line 15: / Line 17: @@
 The following nested loop will draw a series of Blue balls on the XZ plain
-   #declare xpos = 0;
+<source lang="pov">
    #declare zpos = 0;
-  #declare xfinal = 10;
+#end
-  #declare zfinal = 10;
+</source>