Update comments on renderer.c

1 files changed, 18 insertions, 0 deletions

diff --git a/src/renderer.c b/src/renderer.c
index ec54411..bddaacd 100644
--- a/src/renderer.c
+++ b/src/renderer.c
@@ -1,3 +1,20 @@
+//
+// This Mode 0 renderer provides a way of drawing directly to a framebuffer
+// (similar to Mode 3 and 4) while retaining the flexibility of using other
+// backgrounds if needed. It also performs double buffering to avoid tearing
+// artifacts and tries to only draw tiles that changed on each frame.
+//
+// In addition to the frontbuffer (displayed on background 0), a tiled text
+// layer is displayed on background 1, which can be used for application
+// development or for debug information.
+//
+// These two layers occupy the first and second background charblocks, leaving
+// the remaining two available for other background layers. There are 14KB of
+// sprite memory available, since the backbuffer is located at the end of the
+// VRAM, but if more space is needed it can be moved to the end of the BG
+// charblocks instead.
+//
+
 #include "bd-font.c"
 
 // The frontbuffer is located at the beginning of the VRAM, and requires 20KB of
@@ -24,6 +41,7 @@
 #define FONT_TILEMAP ((u16*)(MEM_VRAM + KB(30)))
 #define FONT_SB      15
 
+// Keep track of which tiles need to be copied to the frontbuffer.
 static u32 dirty_tiles[21] = {0};
 
 // TODO: Allow disable bound checking at compile time.