From e3c7d782bda3fa007449bf1ec7c283a4f30b53ad Mon Sep 17 00:00:00 2001
From: Ylva Selling <ylva.selling@gmail.com>
Date: Wed, 18 Jan 2023 18:08:18 -0500
Subject: [PATCH] Make tiles get correct part of texture for ffmpegtileprovider

---
 .../src/tileprovider/ffmpegtileprovider.cpp   | 26 ++++++++++++++++---
 .../src/tileprovider/ffmpegtileprovider.h     |  2 ++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/modules/globebrowsing/src/tileprovider/ffmpegtileprovider.cpp b/modules/globebrowsing/src/tileprovider/ffmpegtileprovider.cpp
index 78f938c0cf..cd4c042e53 100644
--- a/modules/globebrowsing/src/tileprovider/ffmpegtileprovider.cpp
+++ b/modules/globebrowsing/src/tileprovider/ffmpegtileprovider.cpp
@@ -616,6 +616,26 @@ void FfmpegTileProvider::handleMpvProperties(mpv_event* event) {
     }
 }
 
+ChunkTile FfmpegTileProvider::chunkTile(TileIndex tileIndex, int parents, int maxParents) {
+    ZoneScoped
+
+    ghoul_assert(_isInitialized, "FfmpegTileProvider was not initialized");
+
+    lambda ascendToParent = [](TileIndex& ti, TileUvTransform& uv) {
+        ti.level--;
+    };
+
+    glm::vec2 noOfTiles = { pow(2, tileIndex.level), pow(2, tileIndex.level - 1) };
+    glm::vec2 ratios = { 1.f / noOfTiles.x, 1.f / noOfTiles.y };
+    float offsetX = ratios.x * static_cast<float>(tileIndex.x);
+    // The tiles on the y-axis should be traversed backwards
+    float offsetY = ratios.y * (noOfTiles.y - static_cast<float>(tileIndex.y - 1));
+
+    TileUvTransform uvTransform = { glm::vec2(offsetX, offsetY), ratios };
+
+    return traverseTree(tileIndex, parents, maxParents, ascendToParent, uvTransform);
+}
+
 void FfmpegTileProvider::handleMpvEvents() {
     while (_mpvHandle) {
         mpv_event* event = mpv_wait_event(_mpvHandle, 0);
@@ -702,9 +722,9 @@ int FfmpegTileProvider::minLevel() {
 }
 
 int FfmpegTileProvider::maxLevel() {
-    // Every tile needs to be 512 by 512, how far can we subdivide this video
-    // TODO: Check if it should be floor or ceil
-    return std::floor(std::log2(_resolution.x) - std::log2(1024)) + 1;
+    // This is the level where above the tile is marked as unavailable and is no longer 
+    // displayed. Since we want to display the tiles at all times we set the max level
+    return 1337;
 }
 
 void FfmpegTileProvider::reset() {
diff --git a/modules/globebrowsing/src/tileprovider/ffmpegtileprovider.h b/modules/globebrowsing/src/tileprovider/ffmpegtileprovider.h
index 6c73243b81..7aa2f6fc55 100644
--- a/modules/globebrowsing/src/tileprovider/ffmpegtileprovider.h
+++ b/modules/globebrowsing/src/tileprovider/ffmpegtileprovider.h
@@ -55,6 +55,8 @@ public:
     int maxLevel() override final;
     float noDataValueAsFloat() override final;
 
+    ChunkTile chunkTile(TileIndex tileIndex, int parents, int maxParents = 1337) override;
+
     static documentation::Documentation Documentation();
 
 private: