[debug_print_text] add README

modules/le_debug_print_text/README.md

@@ -0,0 +1,50 @@
+# Debug Print Text
+
+## A stateful debug printer for debug messages
+
+The simplest way to print to screen is to use the Global Printer
+Singleton -- it is available to any file that includes this header.
+
+You can print like this:
+
+```cpp
+le::DebugPrint("I'm printing %04d", 1);
+```
+
+The debug printer supports `printf` formatting.
+
+To see the messages rendered on top of a specific renderpass,
+you must do this:
+
+```cpp
+le::DebugPrint::drawAllMessages(main_renderpass);
+```
+
+Otherwise, all messages are rendered into the last renderpass that is
+part of [the](the.md) rendergraph, assuming that this renderpass is
+going to the screen.
+
+`drawAllMessages()` clears the message state and resets the debug 
+message printer.
+
+Note that there is no implicit synchronisation - this printer is
+unaware that other threads might be using it.
+
+The cursor moves with text that has been printed, and there is support
+for multi-line text: If a newline `\n` character is detected, the
+cursor moves to the next line.
+
+You can set colour style information; Style info is on a stack to which
+you can push / pop. Yes, this is stateful. It is also concise and
+relatively simple (assuming a single-threaded environment) we might
+want to reconsider this architecture if we get into trouble with
+threading.
+
+On draw, all the text that has accumulated through the frame gets
+printed in one go, and the accumulated print instructions reset.
+
+# Acknowledgements
+
+* Pixel font data based on the free
+[Tamsyn](http://www.fial.com/~scott/tamsyn-font/) bitmap font
+

modules/le_debug_print_text/le_debug_print_text.h

@@ -8,39 +8,55 @@ struct le_renderpass_o;
 
 /*
 
-----------------------------------------------------------------------
-             A stateful debug printer for debug messages
-----------------------------------------------------------------------
+# Debug Print Text
+
+## A stateful debug printer for debug messages
 
 The simplest way to print to screen is to use the Global Printer
 Singleton -- it is available to any file that includes this header.
 
 You can print like this:
 
-    le::DebugPrint::printf("I'm printing %04d", 1);
+```cpp
+le::DebugPrint("I'm printing %04d", 1);
+```
+
+The debug printer supports `printf` formatting.
 
-To see the messages rendered on top of a renderpass, you must do this:
+To see the messages rendered on top of a specific renderpass,
+you must do this:
 
-    le::DebugPrint::drawAllMessages(main_renderpass);
+```cpp
+le::DebugPrint::drawAllMessages(main_renderpass);
+```
 
-Drawing the messages into a renderpass clears the message state and
-resets the debug message printer.
+Otherwise, all messages are rendered into the last renderpass that is
+part of [the](the.md) rendergraph, assuming that this renderpass is
+going to the screen.
+
+`drawAllMessages()` clears the message state and resets the debug 
+message printer.
 
 Note that there is no implicit synchronisation - this printer is
 unaware that other threads might be using it.
 
-Cursor moves with text that has been printed.
+The cursor moves with text that has been printed, and there is support
+for multi-line text: If a newline `\n` character is detected, the
+cursor moves to the next line.
 
-You can set color style information; style info is on a stack to which
+You can set colour style information; Style info is on a stack to which
 you can push / pop. Yes, this is stateful. It is also concise and
 relatively simple (assuming a single-threaded environment) we might
 want to reconsider this architecture if we get into trouble with
 threading.
 
 On draw, all the text that has accumulated through the frame gets
-printed in one go. and the accumulated print instructions reset.
+printed in one go, and the accumulated print instructions reset.
+
+# Acknowledgements
 
-----------------------------------------------------------------------
+* Pixel font data based on the free
+[Tamsyn](http://www.fial.com/~scott/tamsyn-font/) bitmap font
 
 */