From ecc625f9faae73a0f33e2a70de652abcda6dd779 Mon Sep 17 00:00:00 2001
From: benfry <fry@processing.org>
Date: Mon, 2 May 2005 15:47:00 +0000
Subject: [PATCH] additional notes and docs

---
 core/PGraphics3.java | 67 +++++++++++++++++++++++++++++++++++++-------
 todo.txt             |  2 ++
 2 files changed, 59 insertions(+), 10 deletions(-)

diff --git a/core/PGraphics3.java b/core/PGraphics3.java
index d0672d3a0..1aeb14c16 100644
--- a/core/PGraphics3.java
+++ b/core/PGraphics3.java
@@ -2872,16 +2872,6 @@ public class PGraphics3 extends PGraphics {
   }
 
 
-  /**
-   * Calls camera() with Processing's standard camera setup.
-   */
-  public void camera() {
-    camera(cameraX, cameraY, cameraZ,
-           cameraX, cameraY, 0,
-           0, 1, 0);
-  }
-
-
   /**
    * Set camera to the default settings.
    * <P>
@@ -2934,6 +2924,63 @@ public class PGraphics3 extends PGraphics {
    * coordinates. OpenGL provides nothing of this sort, but Processing does!
    * This is the camera transform matrix.
    */
+  public void camera() {
+    camera(cameraX, cameraY, cameraZ,
+           cameraX, cameraY, 0,
+           0, 1, 0);
+  }
+
+
+  /**
+   * More flexible method for dealing with camera().
+   * <P>
+   * The actual call is like gluLookat. Here's the real skinny on
+   * what does what:
+   * <PRE>
+   * camera(); or
+   * camera(ex, ey, ez, cx, cy, cz, ux, uy, uz);
+   * </PRE>
+   * do not need to be called from with beginCamera();/endCamera();
+   * That's because they always apply to the camera transformation,
+   * and they always totally replace it. That means that any coordinate
+   * transforms done before camera(); in draw() will be wiped out.
+   * It also means that camera() always operates in untransformed world
+   * coordinates. Therefore it is always redundant to call resetMatrix();
+   * before camera(); This isn't technically true of gluLookat, but it's
+   * pretty much how it's used.
+   * <P>
+   * Now, beginCamera(); and endCamera(); are useful if you want to move
+   * the camera around using transforms like translate(), etc. They will
+   * wipe out any coordinate system transforms that occur before them in
+   * draw(), but they will not automatically wipe out the camera transform.
+   * This means that they should be at the top of draw(). It also means
+   * that the following:
+   * <PRE>
+   * beginCamera();
+   * rotateY(PI/80);
+   * endCamera();
+   * </PRE>
+   * will result in a camera that spins without stopping. If you want to
+   * just rotate a small constant amount, try this:
+   * <PRE>
+   * beginCamera();
+   * camera(); // sets up the default view
+   * rotateY(PI/80);
+   * endCamera();
+   * </PRE>
+   * That will rotate a little off of the default view. Note that this
+   * is entirely equivalent to
+   * <PRE>
+   * camera(); // sets up the default view
+   * beginCamera();
+   * rotateY(PI/80);
+   * endCamera();
+   * </PRE>
+   * because camera() doesn't care whether or not it's inside a
+   * begin/end clause. Basically it's safe to use camera() or
+   * camera(ex, ey, ez, cx, cy, cz, ux, uy, uz) as naked calls because
+   * they do all the matrix resetting automatically.
+   */
   public void camera(float eyeX, float eyeY, float eyeZ,
                      float centerX, float centerY, float centerZ,
                      float upX, float upY, float upZ) {
diff --git a/todo.txt b/todo.txt
index 988019a89..2b3613b88 100644
--- a/todo.txt
+++ b/todo.txt
@@ -12,6 +12,8 @@ _ make simple tool for casey to rebuild all the examples at once
 _   need to rebuild with this release because of 1.3/1.4 issues
 
 documentation
+_ small explanation and tiny example(s) for the following?
+_   modelX(), modelY(), modelZ(), screenZ(), openStream(), normal()
 _ auto-run the javadoc in dist.sh
 _   doctor a copy of the css file to use p5 defaults
 _   and re-copy the css in after generating the doc each time