add wrapped padding to sprite for repeating images

fixes #798
js: e732e784e41bef35bd40de27fdbfa3e8f9588038

3 files changed, 28 insertions, 15 deletions

diff --git a/src/mbgl/geometry/sprite_atlas.cpp b/src/mbgl/geometry/sprite_atlas.cpp
index 35365c7e4d..7b6184ae73 100644
--- a/src/mbgl/geometry/sprite_atlas.cpp
+++ b/src/mbgl/geometry/sprite_atlas.cpp
@@ -67,12 +67,24 @@ bool SpriteAtlas::resize(const float newRatio) {
 
 void copy_bitmap(const uint32_t *src, const int src_stride, const int src_x, const int src_y,
                 uint32_t *dst, const int dst_stride, const int dst_x, const int dst_y,
-                const int width, const int height) {
-    src += src_y * src_stride + src_x;
+                const int width, const int height, const bool wrap) {
     dst += dst_y * dst_stride + dst_x;
-    for (int y = 0; y < height; y++, src += src_stride, dst += dst_stride) {
-        for (int x = 0; x < width; x++) {
-            dst[x] = src[x];
+    if (wrap) {
+        dst -= dst_stride;
+        int srcI;
+        // add 1 pixel wrapped padding on each side of the image
+        for (int y = 0; y < height; y++, srcI = (((y + height) % height) + src_y) * src_stride + src_x, dst += dst_stride) {
+            for (int x = -1; x <= width; x++) {
+                dst[x] = src[srcI + ((x + width) % width)];
+            }
+        }
+
+    } else {
+        src += src_y * src_stride + src_x;
+        for (int y = 0; y < height; y++, src += src_stride, dst += dst_stride) {
+            for (int x = 0; x < width; x++) {
+                dst[x] = src[x];
+            }
         }
     }
 }
@@ -97,7 +109,7 @@ Rect<SpriteAtlas::dimension> SpriteAtlas::allocateImage(const size_t pixel_width
     return rect;
 }
 
-Rect<SpriteAtlas::dimension> SpriteAtlas::getImage(const std::string& name) {
+Rect<SpriteAtlas::dimension> SpriteAtlas::getImage(const std::string& name, const bool wrap) {
     std::lock_guard<std::recursive_mutex> lock(mtx);
 
     auto rect_it = images.find(name);
@@ -120,7 +132,7 @@ Rect<SpriteAtlas::dimension> SpriteAtlas::getImage(const std::string& name) {
 
     images.emplace(name, rect);
 
-    copy(rect, pos);
+    copy(rect, pos, wrap);
 
     return rect;
 }
@@ -128,7 +140,7 @@ Rect<SpriteAtlas::dimension> SpriteAtlas::getImage(const std::string& name) {
 SpriteAtlasPosition SpriteAtlas::getPosition(const std::string& name, bool repeating) {
     std::lock_guard<std::recursive_mutex> lock(mtx);
 
-    Rect<dimension> rect = getImage(name);
+    Rect<dimension> rect = getImage(name, repeating);
     if (repeating) {
         // When the image is repeating, get the correct position of the image, rather than the
         // one rounded up to 4 pixels.
@@ -157,7 +169,7 @@ void SpriteAtlas::allocate() {
     }
 }
 
-void SpriteAtlas::copy(const Rect<dimension>& dst, const SpritePosition& src) {
+void SpriteAtlas::copy(const Rect<dimension>& dst, const SpritePosition& src, const bool wrap) {
     if (!sprite->raster) return;
     const uint32_t *src_img = reinterpret_cast<const uint32_t *>(sprite->raster->getData());
     if (!src_img) return;
@@ -174,7 +186,8 @@ void SpriteAtlas::copy(const Rect<dimension>& dst, const SpritePosition& src) {
         /* dest x */         dst.x * pixelRatio,
         /* dest y */         dst.y * pixelRatio,
         /* icon dimension */ src.width,
-        /* icon dimension */ src.height
+        /* icon dimension */ src.height,
+        /* wrap padding */   wrap
     );
 
     dirty = true;
@@ -188,7 +201,7 @@ void SpriteAtlas::setSprite(util::ptr<Sprite> sprite_) {
     if (!sprite->isLoaded()) return;
 
     util::erase_if(uninitialized, [this](const std::string &name) {
-        Rect<dimension> dst = getImage(name);
+        Rect<dimension> dst = getImage(name, false);
         const SpritePosition& src = sprite->getSpritePosition(name);
         if (!src) {
             if (debug::spriteWarnings) {
@@ -198,7 +211,7 @@ void SpriteAtlas::setSprite(util::ptr<Sprite> sprite_) {
         }
 
         if (src.width == dst.w * pixelRatio && src.height == dst.h * pixelRatio && src.pixelRatio == pixelRatio) {
-            copy(dst, src);
+            copy(dst, src, false);
             return true;
         } else {
             if (debug::spriteWarnings) {
diff --git a/src/mbgl/geometry/sprite_atlas.hpp b/src/mbgl/geometry/sprite_atlas.hpp
index ebfd69edf5..079c15cefd 100644
--- a/src/mbgl/geometry/sprite_atlas.hpp
+++ b/src/mbgl/geometry/sprite_atlas.hpp
@@ -46,7 +46,7 @@ public:
     // This getter attempts to read the image from the sprite if it is already loaded.
     // In that case, it copies it into the sprite atlas and returns the dimensions.
     // Otherwise, it returns a 0/0/0/0 rect.
-    Rect<dimension> getImage(const std::string& name);
+    Rect<dimension> getImage(const std::string& name, const bool wrap);
 
     SpriteAtlasPosition getPosition(const std::string& name, bool repeating = false);
 
@@ -66,7 +66,7 @@ public:
 private:
     void allocate();
     Rect<SpriteAtlas::dimension> allocateImage(size_t width, size_t height);
-    void copy(const Rect<dimension>& dst, const SpritePosition& src);
+    void copy(const Rect<dimension>& dst, const SpritePosition& src, const bool wrap);
 
     std::recursive_mutex mtx;
     float pixelRatio = 1.0f;
diff --git a/src/mbgl/renderer/symbol_bucket.cpp b/src/mbgl/renderer/symbol_bucket.cpp
index c6a7c8c4e1..a5043a3739 100644
--- a/src/mbgl/renderer/symbol_bucket.cpp
+++ b/src/mbgl/renderer/symbol_bucket.cpp
@@ -195,7 +195,7 @@ void SymbolBucket::addFeatures(const VectorTileLayer &layer, const FilterExpress
         // if feature has icon, get sprite atlas position
         if (feature.sprite.length()) {
             sprite.waitUntilLoaded();
-            image = spriteAtlas.getImage(feature.sprite);
+            image = spriteAtlas.getImage(feature.sprite, false);
 
             if (sprite.getSpritePosition(feature.sprite).sdf) {
                 sdfIcons = true;