From e9d56db11660142304f3415a30ece02ae672d242 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Mon, 14 Mar 2016 23:01:38 +0100
Subject: Fix scrolling with direction==1

---
 src/display.cc | 71 ++++++++++++++++++++++++++++++++++++++++++----------------
 src/display.h  |  2 +-
 src/system.cc  |  1 +
 3 files changed, 54 insertions(+), 20 deletions(-)

diff --git a/src/display.cc b/src/display.cc
index 025ebbf..f06b5e3 100644
--- a/src/display.cc
+++ b/src/display.cc
@@ -82,16 +82,16 @@ void Display::update() {
 					}
 				}
 
-				if (current_anim->direction == 0)
-					glyph_addr = (uint8_t *)pgm_read_ptr(&font[current_anim->data[str_pos]]);
-				else
-					glyph_addr = (uint8_t *)pgm_read_ptr(&font[current_anim->data[current_anim->length - 1 - str_pos]]); // XXX Broken by str_chunk changes, FIXME!
+				glyph_addr = (uint8_t *)pgm_read_ptr(&font[current_anim->data[str_pos]]);
 				glyph_len = pgm_read_byte(&glyph_addr[0]);
 				char_pos++;
 
 				if (char_pos > glyph_len) {
 					char_pos = 0;
-					str_pos++;
+					if (current_anim->direction == 0)
+						str_pos++;
+					else
+						str_pos--;
 				}
 
 				if (current_anim->direction == 0) {
@@ -114,26 +114,52 @@ void Display::update() {
 				}
 				str_pos += 8;
 			}
-			if ((current_anim->length >= 128) && (str_pos >= 128)) {
-				str_pos = 0;
-				str_chunk++;
-				storage.loadChunk(str_chunk, current_anim->data);
-			}
-			if ((str_chunk == (current_anim->length / 128))
-					&& (str_pos >= (current_anim->length % 128))) {
-				str_chunk = 0;
-				str_pos = 0;
-				if (current_anim->delay > 0) {
-					status = PAUSED;
-				}
-				if (current_anim->length >= 128) {
+			if (current_anim->direction == 0) {
+				if ((current_anim->length > 128) && (str_pos >= 128)) {
+					str_pos = 0;
+					str_chunk++;
 					storage.loadChunk(str_chunk, current_anim->data);
 				}
+				if ((str_chunk == ((current_anim->length - 1) / 128))
+						&& (str_pos > ((current_anim->length - 1) % 128))) {
+					str_chunk = 0;
+					str_pos = 0;
+					if (current_anim->delay > 0) {
+						status = PAUSED;
+					}
+					if (current_anim->length > 128) {
+						storage.loadChunk(str_chunk, current_anim->data);
+					}
+				}
+			} else {
+				if (str_pos >= 128) {
+					if (str_chunk == 0) {
+						if (current_anim->length > 128) {
+							str_chunk = (current_anim->length - 1) / 128;
+							storage.loadChunk(str_chunk, current_anim->data);
+						}
+						if (current_anim->delay > 0) {
+							str_pos = 0;
+							status = PAUSED;
+						} else {
+							str_pos = (current_anim->length - 1) % 128;
+						}
+					} else {
+						str_chunk--;
+						storage.loadChunk(str_chunk, current_anim->data);
+						str_pos = 127;
+					}
+				}
 			}
 		} else if (status == PAUSED) {
 			str_pos++;
 			if (str_pos >= current_anim->delay) {
-				str_pos = 0;
+				if (current_anim->direction == 0)
+					str_pos = 0;
+				else if (current_anim->length <= 128)
+					str_pos = current_anim->length - 1;
+				else
+					str_pos = 127;
 				status = RUNNING;
 			}
 		}
@@ -155,6 +181,13 @@ void Display::show(animation_t *anim)
 {
 	current_anim = anim;
 	reset();
+	if (current_anim->direction == 1) {
+		if (current_anim->length > 128) {
+			str_chunk = (current_anim->length - 1) / 128;
+			storage.loadChunk(str_chunk, current_anim->data);
+		}
+		str_pos = (current_anim->length - 1) % 128;
+	}
 }
 
 /*
diff --git a/src/display.h b/src/display.h
index b42c69e..a6c9024 100644
--- a/src/display.h
+++ b/src/display.h
@@ -48,7 +48,7 @@ struct animation {
 	uint8_t delay;
 
 	/**
-	 * Scroll mode / direction. Not yet supported.
+	 * Scroll mode / direction. Must be set to 0 if type != TEXT.
 	 */
 	uint8_t direction;
 
diff --git a/src/system.cc b/src/system.cc
index bf18003..e0765c2 100644
--- a/src/system.cc
+++ b/src/system.cc
@@ -88,6 +88,7 @@ void System::loadPattern_buf(uint8_t *pattern)
 	} else if (active_anim.type == AnimationType::FRAMES) {
 		active_anim.speed = ((pattern[2] & 0x0f) << 4) + 15;
 		active_anim.delay = (pattern[3] & 0x0f) << 2;
+		active_anim.direction = 0;
 	}
 
 	active_anim.data = pattern + 4;
-- 
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