docs: add getting started section with maven dependency info

- Add new "How take engine into use" section with Maven dependency
  coordinates and repository configuration
- Document Java 21+ requirement
- Consolidate getting started links (demos, JavaDoc, class diagrams)
- Remove redundant "Understanding the Sixth 3D source code" section

diff --git a/doc/index.org b/doc/index.org
index 6407c9e..1fbf08f 100644 (file)
--- a/doc/index.org
+++ b/doc/index.org
@@ -104,15 +104,52 @@ of providing a platform for 3D user interfaces and interactive data
 visualization. It can also be used as a standalone 3D engine in any
 Java project. See the [[https://www3.svjatoslav.eu/projects/sixth-3d-demos/][demos]] for examples of what it can do today.
 
+* How take engine into use
+:PROPERTIES:
+:CUSTOM_ID: taking-engine-into-use
+:END:
+
+Add the *Sixth 3D* dependency to your Maven project:
+
+#+BEGIN_SRC xml
+<dependencies>
+    <dependency>
+        <groupId>eu.svjatoslav</groupId>
+        <artifactId>sixth-3d</artifactId>
+        <version>1.4</version>
+    </dependency>
+</dependencies>
+#+END_SRC
+
+Also add the repository (the library is not on Maven Central):
+
+#+BEGIN_SRC xml
+<repositories>
+    <repository>
+        <id>svjatoslav.eu</id>
+        <name>Svjatoslav repository</name>
+        <url>https://www3.svjatoslav.eu/maven/</url>
+    </repository>
+</repositories>
+#+END_SRC
+
+- Library requires Java 21 or newer.
+
+- Study the [[https://www3.svjatoslav.eu/projects/sixth-3d-demos/][demo applications]] for practical examples. Start with the
+  [[https://www3.svjatoslav.eu/projects/sixth-3d-demos/#minimal-example][minimal example]] to see the basic boilerplate needed to render a 3D
+  scene.
+
+- Study how [[id:4b6c1355-0afe-40c6-86c3-14bf8a11a8d0][Sixth 3D engine]] works.
+- Read online [[https://www3.svjatoslav.eu/projects/sixth-3d/apidocs/][JavaDoc]].
+- See [[https://www3.svjatoslav.eu/projects/sixth-3d/graphs/][*Sixth 3D* class diagrams]]. (Diagrams were generated by using
+  [[https://www3.svjatoslav.eu/projects/javainspect/][JavaInspect]] utility)
+
 * Understanding 3D engine
 :PROPERTIES:
 :CUSTOM_ID: defining-scene
 :ID:       4b6c1355-0afe-40c6-86c3-14bf8a11a8d0
 :END:
 
-- Study [[https://www3.svjatoslav.eu/projects/sixth-3d-demos/][demo applications]] for practical examples. Start with [[https://www3.svjatoslav.eu/projects/sixth-3d-demos/#minimal-example][minimal
-  example]].
-
 ** Main render loop
 
 - To understand main render loop, see dedicated page: [[file:rendering-loop/][Rendering loop]]
@@ -792,15 +829,3 @@ so multiple views can have different debug configurations simultaneously.
 - [[https://www2.svjatoslav.eu/gitweb/?p=sixth-3d.git;a=summary][Browse Git repository online]]
 - Clone Git repository using command:
   : git clone https://www3.svjatoslav.eu/git/sixth-3d.git
-
-** Understanding the Sixth 3D source code
-:PROPERTIES:
-:CUSTOM_ID: understanding-source-code
-:END:
-
-- Study how [[id:4b6c1355-0afe-40c6-86c3-14bf8a11a8d0][scene definition]] works.
-- Understand [[file:rendering-loop/][main rendering loop]].
-- Read online [[https://www3.svjatoslav.eu/projects/sixth-3d/apidocs/][JavaDoc]].
-- See [[https://www3.svjatoslav.eu/projects/sixth-3d/graphs/][*Sixth 3D* class diagrams]]. (Diagrams were generated by using
-  [[https://www3.svjatoslav.eu/projects/javainspect/][JavaInspect]] utility)
-- Study [[https://www3.svjatoslav.eu/projects/sixth-3d-demos/][demo applications]].