optimised copying for animated tiles

1 files changed, 17 insertions, 0 deletions

diff --git a/src/animtiles.cpp b/src/animtiles.cpp
index 4213e6a..53a204b 100644
--- a/src/animtiles.cpp
+++ b/src/animtiles.cpp
@@ -51,3 +51,20 @@ void DoTiles(void* self) {
 void DestroyTiles(void *self) {
 	FreeFile(&fh);
 }
+
+
+extern "C" void CopyAnimTile(u8 *target, int tileNum, u8 *source, int frameNum) {
+	int tileRow = tileNum >> 5; // divided by 32
+	int tileColumn = tileNum & 31; // modulus by 32
+
+	u8 *baseRow = target + (tileRow * 2 * 32 * 1024);
+	u8 *baseTile = baseRow + (tileColumn * 32 * 4 * 2);
+
+	u8 *sourceRow = source + (frameNum * 2 * 32 * 32);
+
+	for (int i = 0; i < 8; i++) {
+		memcpy(baseTile, sourceRow, 32*4*2);
+		baseTile += (2 * 4 * 1024);
+		sourceRow += (2 * 32 * 4);
+	}
+}