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tutorials:a-beginners-tutorial [2024/12/19 11:39] – Timtutorials:a-beginners-tutorial [2024/12/19 13:34] (current) – barley1965
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 Installing the platform GroIMP on your computer is actually quite straightforward if you carefully follow the instructions below. GroIMP runs on Java, so first of all, make sure you have a recent version of Java installed. To check if you have Java installed on your machine you open the command prompt window (type cmd in the search window), then type “java -version”, followed by Enter:\\ Installing the platform GroIMP on your computer is actually quite straightforward if you carefully follow the instructions below. GroIMP runs on Java, so first of all, make sure you have a recent version of Java installed. To check if you have Java installed on your machine you open the command prompt window (type cmd in the search window), then type “java -version”, followed by Enter:\\
-{{:tutorials:beginnerstut_image1.png?303x42.5}}+{{:tutorials:beginnerstut_image1.png?393x54.5}}
  
 I have version 22 on my computer, which is one of the latest versions. If you don’t see this message or you know you don’t have Java, make sure to install Java version 22 before proceeding to the next step (you can find it here: https://jdk.java.net/22/) I have version 22 on my computer, which is one of the latest versions. If you don’t see this message or you know you don’t have Java, make sure to install Java version 22 before proceeding to the next step (you can find it here: https://jdk.java.net/22/)
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 After this you click on ‘Install’ and wait for the installation to finish (this can take more than ten minutes). After this you click on ‘Install’ and wait for the installation to finish (this can take more than ten minutes).
  
-After the installation, a folder “GroIMP-2.1.3” should be available under something like this address: “C:\Program Files\”.+After the installation, a folder “GroIMP-2.1.5” should be available under something like this address: “C:\Program Files\”.
  
 GroIMP will now be available either on your desktop or in the list of programmes: GroIMP will now be available either on your desktop or in the list of programmes:
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 {{:tutorials:beginnerstut_image15.png?536x291}} {{:tutorials:beginnerstut_image15.png?536x291}}
  
-Note that on your machine, the naming of the menu items might vary, due to the language settings of your Java version (I have a French Java installation, so some of the menu items will appear in French, others in English).\\+Note that on your machine, the naming of the menu items might vary, due to the language settings of your Java version (in this tutorial, the menu items will appear in English).\\
 GroIMP is a multi-windows platform, i.e. it consists in fact of a (large) number of windows, which can be piled upon each other (like the sheets in an Excel file), “glued” side by side, or be viewed separately (this is handy if your computer is connected to more than one computer screen). To change the size of an integrated window you can simply click and drag on one of the grey hatched lines separating two windows. To change the position of a window you can click on the tab, hold and drag the whole window to its new position. You will see on your left a window called “View”, which contains the visual output of a model (currently a blue cylinder on its side, with a label “A” below it) and on your right a window called “jEdit – Alga.rgg”, in which you see the code of the model (you can scroll down the code using the slider on the right of the window). Another important window is located on the top left of your screen: on it you will find four buttons: GroIMP is a multi-windows platform, i.e. it consists in fact of a (large) number of windows, which can be piled upon each other (like the sheets in an Excel file), “glued” side by side, or be viewed separately (this is handy if your computer is connected to more than one computer screen). To change the size of an integrated window you can simply click and drag on one of the grey hatched lines separating two windows. To change the position of a window you can click on the tab, hold and drag the whole window to its new position. You will see on your left a window called “View”, which contains the visual output of a model (currently a blue cylinder on its side, with a label “A” below it) and on your right a window called “jEdit – Alga.rgg”, in which you see the code of the model (you can scroll down the code using the slider on the right of the window). Another important window is located on the top left of your screen: on it you will find four buttons:
  
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 {{:tutorials:beginnerstut_image20.png?375x139}} {{:tutorials:beginnerstut_image20.png?375x139}}
  
-From the lecture, you will already know that the text in line 24 is a rule, with a left-hand-side and a right-hand-side. The keyword ‘Axiom’ refers to the start word of the L-system, and ‘==>’ is an operator that essentially means “//replace the left-hand side with the right-hand side//”. Delete the semicolon and save the code. What happens is that the code will not be compiled. Instead, you will find in the Message window on the bottom of the jEdit window the following error message:+The text in line 24 is a rule, with a left-hand-side and a right-hand-side. The keyword ‘Axiom’ refers to the start word of the L-system, and ‘%%==>%%’ is an operator that essentially means “//replace the left-hand side with the right-hand side//”. Delete the semicolon and save the code. What happens is that the code will not be compiled. Instead, you will find in the Message window on the bottom of the jEdit window the following error message:
  
 {{:tutorials:beginnerstut_image21.png?357x247}} {{:tutorials:beginnerstut_image21.png?357x247}}
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 Let’s have a closer look at the code surrounding the Axiom rule: Let’s have a closer look at the code surrounding the Axiom rule:
  
-protected void init ()+''protected void init ()''
  
 init () is what is called a method in the Java language. Whenever you see a name followed by a pair of simple brackets, (), you can be almost certain that you are dealing with a method. A method is a little //programme within the programme//, a procedure that //does stuff//. The method init() carries out the Axiom rule. It is preceded by two key words, protected and void. protected refers to the type or visibility of the method. Here it means that the method is not visible to, or directly invokable by, the user. void refers to the type of output of the method. Java methods can be written such that they output a result of a certain type as we will see later. Our init() method just carries out a rule, but returns nothing otherwise, therefore its type is void, which means something like “empty”. Note that we also have a pair of square brackets surrounding the Axiom rule, [ and ] in lines 23 and 25, these are necessary to mark the beginning and end of the method code.\\ init () is what is called a method in the Java language. Whenever you see a name followed by a pair of simple brackets, (), you can be almost certain that you are dealing with a method. A method is a little //programme within the programme//, a procedure that //does stuff//. The method init() carries out the Axiom rule. It is preceded by two key words, protected and void. protected refers to the type or visibility of the method. Here it means that the method is not visible to, or directly invokable by, the user. void refers to the type of output of the method. Java methods can be written such that they output a result of a certain type as we will see later. Our init() method just carries out a rule, but returns nothing otherwise, therefore its type is void, which means something like “empty”. Note that we also have a pair of square brackets surrounding the Axiom rule, [ and ] in lines 23 and 25, these are necessary to mark the beginning and end of the method code.\\
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 Open Ex08.gsz ([[#appendix_9ex08rgg|Appendix 9]]). Again, we are working with the Koch snowflake curve. You might have noticed that writing the right-hand-side of the derivation rule is quite tedious and error-prone, especially the rotations and their arguments:\\ Open Ex08.gsz ([[#appendix_9ex08rgg|Appendix 9]]). Again, we are working with the Koch snowflake curve. You might have noticed that writing the right-hand-side of the derivation rule is quite tedious and error-prone, especially the rotations and their arguments:\\
 +<code java>
 F(x/3) RU(-60) F(x/3) RU(120) F(x/3) RU(-60) F(x/3) F(x/3) RU(-60) F(x/3) RU(120) F(x/3) RU(-60) F(x/3)
 +</code>
 Suppose we want to change the angle of the RU rotation, from 60 and -60 to 55 and -55. We could do this manually by changing all the arguments one by one (note that we replaced 120 by 2*55=110):\\ Suppose we want to change the angle of the RU rotation, from 60 and -60 to 55 and -55. We could do this manually by changing all the arguments one by one (note that we replaced 120 by 2*55=110):\\
 F(x/3) RU(-55) F(x/3) RU(110) F(x/3) RU(-55) F(x/3) F(x/3) RU(-55) F(x/3) RU(110) F(x/3) RU(-55) F(x/3)
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 Open Ex09.gsz ([[#appendix_10ex09rgg|Appendix 10]]). In the example Ex03.gsz you already came across this tree model, it described the architecture of a forking tree, i.e. where at the tip of each annual shoot we find no terminal bud but two lateral buds opposite each other and inclined at a divergence angle of 30 degrees. This yielded a very regular architecture, in fact completely deterministic and completely flat. This is not what we see in nature. In the example Ex06 we had already seen how we could make the tree crown 3D by introducing the 90° turn around the head of the turtle (RH(90)), this leading to a decussate branching and a distribution of branches in 3D space. In this example we are going to introduce leaves. First of all, we have to define a module for this:\\ Open Ex09.gsz ([[#appendix_10ex09rgg|Appendix 10]]). In the example Ex03.gsz you already came across this tree model, it described the architecture of a forking tree, i.e. where at the tip of each annual shoot we find no terminal bud but two lateral buds opposite each other and inclined at a divergence angle of 30 degrees. This yielded a very regular architecture, in fact completely deterministic and completely flat. This is not what we see in nature. In the example Ex06 we had already seen how we could make the tree crown 3D by introducing the 90° turn around the head of the turtle (RH(90)), this leading to a decussate branching and a distribution of branches in 3D space. In this example we are going to introduce leaves. First of all, we have to define a module for this:\\
 +<code java>
 module Leaf(float len, float width) extends Parallelogram(len, width) module Leaf(float len, float width) extends Parallelogram(len, width)
  
 {{setShader(GREEN);}}; {{setShader(GREEN);}};
 +</code>
 The leaf is defined as an extension of a Parallelogram object. You can have a look at how such an object looks like, by inserting it into the scene. For this, use the menu item “Objects” 🡪 “Primitives” 🡪 “Parallelogram”: The leaf is defined as an extension of a Parallelogram object. You can have a look at how such an object looks like, by inserting it into the scene. For this, use the menu item “Objects” 🡪 “Primitives” 🡪 “Parallelogram”:
  
 {{:tutorials:beginnerstut_image36.png?240x270}} {{:tutorials:beginnerstut_image36.png?240x270}}
  
-The Leaf module is defined with two parameters, len and width, both of type float (floating point number), which will be used to draw a parallelogram of length len and width width. Finally, the definition invokes the method setShader of Parallelogram to paint the leaves green. Note that for this you need to write {{ in the beginning, and }} at the end.+The Leaf module is defined with two parameters, len and width, both of type float (floating point number), which will be used to draw a parallelogram of length len and width width. Finally, the definition invokes the method setShader of Parallelogram to paint the leaves green. Note that for this you need to write ''%%{{%%'' in the beginning, and ''%%}}%%'' at the end.
  
 The leaf petiole is defined as an extension of F: The leaf petiole is defined as an extension of F:
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 STRENGTH_LIMIT is a constant parameter that we are going to use to define a certain lower limit of the strength variable of Bud. Have a look at the new condition in the production rule of the method grow: STRENGTH_LIMIT is a constant parameter that we are going to use to define a certain lower limit of the strength variable of Bud. Have a look at the new condition in the production rule of the method grow:
 +<code java>
 (b[order] <= MAX_ORDER_ALLOWED && b[strength] > STRENGTH_LIMIT) (b[order] <= MAX_ORDER_ALLOWED && b[strength] > STRENGTH_LIMIT)
 +</code>
 We see a new condition, b[strength] > STRENGTH_LIMIT, and it is connected to the old one by using “&&”. This “logical AND” means that both conditions need to be true before the rule can be applied. There are other possibilities: for instance, if we had used “||” instead (“logical OR”), it means that only one of the two conditions need to be true for the rule to be applied. This could be used in cases where several different circumstances lead to the same outcome. We see a new condition, b[strength] > STRENGTH_LIMIT, and it is connected to the old one by using “&&”. This “logical AND” means that both conditions need to be true before the rule can be applied. There are other possibilities: for instance, if we had used “||” instead (“logical OR”), it means that only one of the two conditions need to be true for the rule to be applied. This could be used in cases where several different circumstances lead to the same outcome.
  
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 //Write the following two rules in the editor window below the comment (“%%//%%simple stem, unbranched:”)//: //Write the following two rules in the editor window below the comment (“%%//%%simple stem, unbranched:”)//:
  
-**Axiom ==> Bud**+**Axiom %%==>%% Bud**
  
-**Bud ==> Internode Node Bud**+**Bud %%==>%% Internode Node Bud**
  
 In order for this to work as a program, we have to write a bit more (by “wrapping” the rules with some method code): In order for this to work as a program, we have to write a bit more (by “wrapping” the rules with some method code):
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 ] ]
  
-public void executer ()+public void run ()
 [ [
  A ==> A B;  A ==> A B;
tutorials/a-beginners-tutorial.1734604777.txt.gz · Last modified: 2024/12/19 11:39 by Tim