reprap: c3 update

[simavr] / examples / board_reprap / src / c3 / README.md

diff --git a/examples/board_reprap/src/c3/README.md b/examples/board_reprap/src/c3/README.md
index b1e7090..31207ab 100644 (file)
--- a/examples/board_reprap/src/c3/README.md
+++ b/examples/board_reprap/src/c3/README.md
@@ -19,7 +19,10 @@ and *matrices* (c3mat3, c3mat4) with various tools to manipulate them.
 * c3quaternion: Quaternion implementation using c3algebra
 * c3camera/c3arcball: camera manipulation, not perfect
 
-The data structure is as follow:
+The basic data structure is as follow:
+* *c3context*:
+       Mostly placeholder for now, hosts a "root" object, can reproject the
+       objects & geometry, and call the callbacks to draw them.
 * *c3object*: 
        * Has a list of (sub) c3objects
        * Has a list of c3transforms (ie matrices)
@@ -28,7 +31,8 @@ The data structure is as follow:
   necessary have geometry and/or sub objects, and don't even need transforms if their
   vertices are already projected.
 * *c3geometry*:
-       * Has a 'type' (lines, quads, triangles..)
+       * Has a 'type' (raw for simple vertices, texture, triangles etc)
+       * Has a 'subtype' (mostly can be used to draw GL types)
        * Has a 'material' (ie color, texture... to be completed)
        * Has a list of vertices
        * Has a list of texture coordinates (optional)
@@ -37,19 +41,37 @@ The data structure is as follow:
 * *c3transform*:
        Is just a sugar coated matrix, with an optional name.
 
+Also there are:
+* *c3pixels*:
+       Is just a wrapper/holder for some pixels, either allocated, or inherited, 
+       it's mostly used for *c3texture*
+* *c3texture*:
+       Associates a *c3geometry* with a *c3pixels* and has a standard Quad
+       for vertices. The OpenGL drawing is not done there, it's done by the application using
+       the generic *c3context* driver.
+* *c3cairo*:
+       Placeholder for now, inherits from *c3texture* and will contain a
+       cairo surface mapped to a GL texture.
+* *c3pango*:
+       A text label, inherits from *c3cairo*
+
+Draw Drivers "Inheritance"
+------------
+Various object uses static tables of callbacks to implement their behaviours
+it's kinda cheap c++ inheritance, without the usual bloat.
+
+There just a couple macros to call the driver chain for a particular function call.
+The relevant bits are in c3driver*.h.
+
+Mostly the code looks for a matching callback in a static table, and call it if found.
+If that callback wants, it can also call the inherited object callback too.
+
 Dirtyness
 ---------
-There is a notion of 'dirtyness' in the tree, when you touch c3transform, and/remove
+There is a notion of 'dirtyness' in the tree, when you touch a *c3transform*, and/remove
 objects and geometry, a dirty bit is propagated up the tree of object. This tells the
 rendering it needs to reproject the dirty bits and repopulate the projected vertice
 cache.
 
 The 'dirty' bit moves both ways, when setting a dirty bit to true, it propagates upward,
 when you set it to false, it propagates downward in the tree.
-
-"Inheritance"
--------------
-There is a vague notion of inheritance for objects, where you can create more complex
-ones and install a 'driver' (ie a function pointer table) that will be called to
-perform various things. The skim is still evolving.
-