Documentation:Tutorial Section 3.8 - Revision history

Clipka: Indexentries fix

2016-12-16T14:27:48Z

Indexentries fix

Jholsenback: 1 revision: link repair after reference reorg

2012-07-01T12:00:13Z

1 revision: link repair after reference reorg

Jholsenback: link repair

2012-07-01T01:54:56Z

link repair

ThorstenFroehlich at 20:08, 26 November 2011

2011-11-26T20:08:22Z

Jholsenback: missed a couple

2011-01-09T12:01:11Z

missed a couple

Jholsenback: cleaning up some validation errors

2011-01-09T11:58:31Z

cleaning up some validation errors

Jholsenback: continue cleanup pass

2010-09-17T11:03:44Z

continue cleanup pass

Jholsenback: completed grammar and wording cleanup!

2010-05-19T23:05:52Z

completed grammar and wording cleanup!

Show changes

Jholsenback: grammar, and working corrections

2010-05-19T19:21:26Z

grammar, and working corrections

Show changes

Jholsenback: heading changes

2010-03-25T08:56:24Z

heading changes

@@ Line 8: / Line 8: @@
 <!--</wikitalk>--->
 <!--REMOVE--->===Making Animations===<!--THIS--->
 {{#indexentry:Animation, not using jitter or crand with}}
 {{#indexentry:jitter, in animations}}
 {{#indexentry:crand, in animations}}
 <p> One last piece of basic information to save frustration. Because jitter
 is an element of anti-aliasing, we could just as easily have mentioned this
@@ Line 39: / Line 39: @@
 to any truly random texture elements, such as <code>[[Reference:Finish#Crand Graininess|crand]]</code>.</p>
 {{#indexentry:Animation, INI file settings for}}
 {{#indexentry:initial_frame, ini-option, tutorial}}
@@ Line 44: / Line 45: @@
 {{#indexentry:initial_clock, ini-option, tutorial}}
 {{#indexentry:final_clock, ini-option, tutorial}}
 <p>Okay, so we have a grasp of how to code our file for animation. We know
 about the clock variable, user declared clock-relative variables, and the

@@ Line 18: / Line 18: @@
 POV-Ray, so now is as good a time as any.</p>
 <p>
-<!--<linkto "Jitter">Jitter</linkto>--->[[Documentation:Reference Section 4.4#Area Lights|Jitter]] is a very small amount of random ray perturbation designed to diffuse
+[[Reference:Light Source#Area Lights|Jitter]] is a very small amount of random ray perturbation designed to diffuse
 tiny aliasing errors that might not otherwise totally disappear, even with
 intense anti-aliasing. By randomizing the placement of erroneous pixels, the
@@ Line 37: / Line 37: @@
 (relatively) small extra measure quality due to the use of jitter will be
 offset by the ocean of jumpies that results. This general rule also applies
-to any truly random texture elements, such as <code><!--<linkto "crand">crand</linkto>--->[[Documentation:Reference Section 5.1#Crand Graininess|crand]]</code>.</p>
+to any truly random texture elements, such as <code>[[Reference:Finish#Crand Graininess|crand]]</code>.</p>
 {{#indexentry:Animation, INI file settings for}}
@@ Line 51: / Line 51: @@
 <p>
 The first concept we will need to know is the INI file settings,
-<code><!--<linkto "Initial_Frame, ini-option">Initial_Frame</linkto>--->[[Documentation:Reference Section 1#Internal Animation Loop|Initial_Frame]]</code> and
+<code>[[Reference:Animation Options#Internal Animation Loop|Initial_Frame]]</code> and
-<code><!--<linkto "Final_Frame, ini-option">Final_Frame</linkto>--->[[Documentation:Reference Section 1#Internal Animation Loop|Final_Frame]]</code>. These are very handy
+<code>[[Reference:Animation Options#Internal Animation Loop|Final_Frame]]</code>. These are very handy
 settings that will allow us to render a particular number of frames and each
 with its own unique frame number, in a completely hands free way. It is of
@@ Line 79: / Line 79: @@
 example, from 0.0 to 2.0, we would just add to your INI file the lines</p>
 <code>
-<!--<linkto "Initial_Clock, ini-option">Initial_Clock</linkto>--->[[Documentation:Reference Section 1#Internal Animation Loop|Initial_Clock]] = 0.0<br>
+[[Reference:Animation Options#Internal Animation Loop|Initial_Clock]] = 0.0<br>
-<!--<linkto "Final_Clock, ini-option">Final_Clock</linkto>--->[[Documentation:Reference Section 1#Internal Animation Loop|Final_Clock]] = 2.0<br>
+[[Reference:Animation Options#Internal Animation Loop|Final_Clock]] = 2.0<br>
 </code>
@@ Line 100: / Line 100: @@
 need two new INI settings</p>
 <code>
-<!--<linkto "Subset_Start_Frame">Subset_Start_Frame</linkto>--->[[Documentation:Reference Section 1#Subsets of Animation Frames|Subset_Start_Frame]] = 51<br>
+[[Reference:Animation Options#Subsets of Animation Frames|Subset_Start_Frame]] = 51<br>
-<!--<linkto "Subset_End_Frame">Subset_End_Frame</linkto>--->[[Documentation:Reference Section 1#Subsets of Animation Frames|Subset_End_Frame]] = 75<br>
+[[Reference:Animation Options#Subsets of Animation Frames|Subset_End_Frame]] = 75<br>
 </code>
@@ Line 222: / Line 222: @@
 a&lt;10 &amp; b&gt;=20
 </pre>
-<p>For more information about these comparison operators, see the <!--<linkto "Float, operators">Float operators</linkto>--->[[Documentation:Reference Section 2#Operators|Float operators]] section of the POV-Ray documentation.</p>
+<p>For more information about these comparison operators, see the [[Reference:Numeric Expressions#Operators|Operators]] section of the POV-Ray documentation.</p>
 ====What about loop types other than simple for-loops?====

@@ Line 8: / Line 8: @@
 <!--</wikitalk>--->
 <!--REMOVE--->===Making Animations===<!--THIS--->
 ====Do Not Use Jitter Or Crand====
 <p> One last piece of basic information to save frustration. Because jitter
 is an element of anti-aliasing, we could just as easily have mentioned this
@@ Line 39: / Line 39: @@
 to any truly random texture elements, such as <code><!--<linkto "crand">crand</linkto>--->[[Documentation:Reference Section 5.1#Crand Graininess|crand]]</code>.</p>
 ====INI File Settings====
 <p>Okay, so we have a grasp of how to code our file for animation. We know
 about the clock variable, user declared clock-relative variables, and the

@@ Line 146: / Line 146: @@
 ====How does a single while-loop work?====
-<p>The while loop works like this:
+<p>The while loop works like this:</p>
 <ol>
 <li>If the condition between the parentheses evaluates to false, jump to the command after the <code>#end</code> statement. If the condition evaluates to true, just continue normally.</li>
 <li>At the <code>#end</code> statement jump to the <code>#while</code> statement and start again.</li>
 </ol>
-</p>
+<p>That is:</p>
 <ul>
 <li>When POV-Ray gets to the <code>#while</code> statement it evaluates the condition between parentheses.</li>
@@ Line 159: / Line 158: @@
 <li>At an <code>#end</code> statement POV-Ray will just jump back to the corresponding <code>#while</code> statement, and will conditionally execute the commands, if the condition evaluates true.</li>
 </ul>
 <p>Note that nowhere there is any mention about any index variable or anything else that could be used to automatically end the loop. As said, it is just a &quot;simple&quot; loop that continues forever if necessary, only testing the statement between the parentheses, and it is not interested in what it is, only in its evaluated value.</p>
 <p>Although one could easily think that this kind of simple loop is bad, and it should be more intelligent, the fact is that this kind of simple loop is actually a lot more flexible and versatile. It allows you to make things not possible or very difficult to do with an intelligent for-loop with automatic index variables.</p>

@@ Line 141: / Line 141: @@
 </pre>
 <p>The commands between <code>#while</code> and <code>#end</code> are run over and over as long as the condition evaluates to true.</p>
-<p>A while-loop <b>is not</b> a for-loop nor any kind of loop which has an index variable that may be incremented automatically with each iteration.</p>
+<p>A while-loop <strong>is not</strong> a for-loop nor any kind of loop which has an index variable that may be incremented automatically with each iteration.</p>
-<p>The while loop <b>does not</b> care what the conditions are between the parentheses as long as they evaluate to some value, nor what the block between <code>#while</code> and <code>#end</code> contains. It will just execute that block until the condition becomes false.</p>
+<p>The while loop <strong>does not</strong> care what the conditions are between the parentheses as long as they evaluate to some value, nor what the block between <code>#while</code> and <code>#end</code> contains. It will just execute that block until the condition becomes false.</p>
 <p>The while-loop does not do anything else. You can think of it as a &quot;simple&quot; loop, which does not do anything automatically. This is not necessarily a bad thing.</p>
@@ Line 220: / Line 220: @@
 <p>If the identifier called 'version' has a value which is less than 3.1 the <code>#error</code> line will be executed. If 'version' has a value which is 3.1 or greater, the <code>#error</code> line is just skipped.</p>
 <p>You can combine conditions together with the boolean operators &amp; (and) and | (or). You can also invert the value of a condition with ! (not).</p>
-<p>For example, if you want something to be done when 'a' is less than 10 <b>and</b> 'b' is greater or equal to 20, the condition would be:</p>
+<p>For example, if you want something to be done when 'a' is less than 10 <strong>and</strong> 'b' is greater or equal to 20, the condition would be:</p>
 <pre>
 a&lt;10 &amp; b&gt;=20
@@ Line 241: / Line 241: @@
 <li>It does not have any 'index' value which gets consecutive values during the loop.</li>
 <li>We do not know how many times it will loop. In this case it loops a random number of times.</li>
-<li>Usually for-loops are used to place or create a series of objects. For each iteration another instance of that object is created. Here, however, we are only interested in the value that results <b>after</b> the loop, not the values inside it.</li>
+<li>Usually for-loops are used to place or create a series of objects. For each iteration another instance of that object is created. Here, however, we are only interested in the value that results <strong>after</strong> the loop, not the values inside it.</li>
 </ul>
 <p>As we can see, a while-loop can also be used for a variety of tasks, for instance, to calculate a value or some values until the result is inside a specified range.</p>
@@ Line 266: / Line 266: @@
 <li>We added an extra condition to the while-loop: Besides testing that the point is outside the unit sphere it also tests that our index
 variable has not bailed out. So now there are two conditions for the loop to continue: The 'Index' value must be less or equal to 10
-<b>and</b> the 'Point' has to be outside the unit sphere. If either one of them fails, the loop is ended.</li>
+<strong>and</strong> the 'Point' has to be outside the unit sphere. If either one of them fails, the loop is ended.</li>
 <li>Then we check if the point is still outside the unit sphere. If it is, we just take &lt;0,0,0&gt;.</li>
 </ul>

← Older revision	Revision as of 12:00, 1 July 2012
(No difference)

@@ Line 191: / Line 191: @@
 <li>Then it sees the <code>#while</code> statement and evaluates what is between the parentheses: Index &lt;= 10</li>
 <li>As 'Index' has the value of 1 and 1 &lt;= 10, the condition evaluates to true.</li>
-<li>So, it just continues normally, and executes the commands following the <code>#while</code> statement, as noted in the above example as &quot;(some commands here)&quot;).</li>
+<li>So, it just continues normally, and executes the commands following the <code>#while</code> statement, as noted in the above example as (some commands here).</li>
 <li>Then it arrives normally to the last #declare command in the block. This causes the value 2 to be assigned to 'Index'.</li>
 <li>Now it arrives the the <code>#end</code> command and so it just jumps to the <code>#while</code>.</li>
@@ Line 224: / Line 224: @@
 a&lt;10 &amp; b&gt;=20
 </pre>
-<p>For more information about these comparison operators, see the <!--<linkto "Float, operators">'Float operators'</linkto>--->[[Documentation:Reference Section 2#Operators|'Float operators']] section of the POV-Ray documentation.</p>
+<p>For more information about these comparison operators, see the <!--<linkto "Float, operators">Float operators</linkto>--->[[Documentation:Reference Section 2#Operators|Float operators]] section of the POV-Ray documentation.</p>
 ====What about loop types other than simple for-loops?====
@@ Line 324: / Line 324: @@
 #end
 </pre>
-<p>Note how we now start from 0 and continue to 9 in the outer loop and from 0 to 19 in the inner loop. This has been done to get the sphere array start from the origin, instead of starting from &lt;1, 1, 0&gt;, of course we could have made the 'Index1' and 'Index2' go from 1 to 10 and from 1 to 20 respectively and then created the sphere in this way:</p>
+<p>Notice how we now start from 0 and continue to 9 in the outer loop and from 0 to 19 in the inner loop. This has been done to get the sphere array start from the origin, instead of starting from &lt;1, 1, 0&gt;, of course we could have made the 'Index1' and 'Index2' go from 1 to 10 and from 1 to 20 respectively and then created the sphere in this way:</p>
 <pre>
    sphere { &lt;Index1-1, Index2-1, 0&gt;, .5 }
@@ Line 449: / Line 449: @@
 POV-Ray's raytracing part to just get the image on screen.</p>
-<p>What obscure idea could be behind this weirdness (besides a very serious
+<p>What obscure idea could be behind this weirdness? Why do not just use POV-Ray itself to raytrace the spheres a lot faster and that is it?</p>
 <p>The idea is not speed nor quality, but to show the power of the POV-Ray SDL.
@@ Line 472: / Line 470: @@
 knowledge. Also more advanced users may get some new info from it.</p>
-<p class="Note"><strong>Note:</strong> in some places some mathematics is needed, so you would better not
+<p class="Note"><strong>Note:</strong> In some places some mathematics is needed, so you would better not
 be afraid of math.</p>

@@ Line 7: / Line 7: @@
 <br>
 <!--</wikitalk>--->
-===Do Not Use Jitter Or Crand===
+<!--REMOVE--->===Making Animations===<!--THIS--->
 <!--<indexentry "Animation, not using jitter or crand with">--->
 <!--<indexentry "jitter, in animations">--->
@@ Line 38: / Line 39: @@
 to any truly random texture elements, such as <code><!--<linkto "crand">crand</linkto>--->[[Documentation:Reference Section 5.1#Crand Graininess|crand]]</code>.</p>
-===INI File Settings===
+====INI File Settings====
 <!--<indexentry "Animation, INI file settings for">--->
 <!--<indexentry "initial_frame, ini-option, tutorial">--->
@@ Line 139: / Line 140: @@
 </p>
-===What a while-loop is and what it is not===
+====What a while-loop is and what it is not====
 <p>A while-loop in POV-Ray is just a control structure which tells POV-Ray
 to loop a command block while the specified condition is true (ie.
@@ Line 172: / Line 173: @@
 necessarily a bad thing).</p>
-===How does a single while-loop work?===
+====How does a single while-loop work?====
 <p>The while-loop works like this:
@@ Line 212: / Line 213: @@
 for-loop with automatic index variables.</p>
-===How do I make a while-loop?===
+====How do I make a while-loop?====
 <p>It depends on what you are trying to make.
@@ Line 297: / Line 298: @@
 simple for-loop in most programming languages (like BASIC, etc).</p>
-===What is a condition and how do I make one?===
+====What is a condition and how do I make one?====
 <p>A condition is an expression that evaluates to a boolean value (ie. true
 or false) and is used in POV-Ray in <code>#while</code>-loops and <code>#if</code>-statements.
@@ Line 348: / Line 349: @@
 section of the POV-Ray documentation.</p>
-===What about loop types other than simple for-loops?===
+====What about loop types other than simple for-loops?====
 <p>As POV-Ray does not care what the condition is and what we are using to
 make that condition, we can use the while-loop in many other ways.
@@ Line 458: / Line 459: @@
 </p>
-===What about nested loops?===
+====What about nested loops?====
 <p>Even when one masters simple loops, nested loops can be a frightening
 thing (or at least hard to understand).
@@ Line 569: / Line 570: @@
 </p>
-===Mixed-type nested loops===
+====Mixed-type nested loops====
 <p>It is perfectly possible to put a for-loop inside a non-for-loop or
 vice-versa. Again, you just have to be careful (with experience it gets
@@ Line 613: / Line 614: @@
 </p>
-===Other things to note===
+====Other things to note====
 <p>There is no reason why the index value in your simple for-loop should step
 one unit at a time. Since the while-loop does not care how the index changes,
@@ Line 628: / Line 629: @@
 etc.
 </pre>
 </p>
@@ Line 754: / Line 753: @@
 ===SDL tutorial: A raytracer===
-===Introduction===
+====Introduction====
 <p>A raytracer made with POV-Ray sounds really weird, doesn't it? What is it
 anyways? POV-Ray is already a raytracer in itself, how can we use it