diff --git a/src/graphics/BlocksRenderer.cpp b/src/graphics/BlocksRenderer.cpp
index eedcf862..59796837 100644
--- a/src/graphics/BlocksRenderer.cpp
+++ b/src/graphics/BlocksRenderer.cpp
@@ -292,11 +292,11 @@ vec4 BlocksRenderer::pickSoftLight(int x, int y, int z, ivec3 right, ivec3 up) c
 // Get texture atlas UV region for block face
 inline UVRegion uvfor(const Block& def, uint face, int atlas_size) {
 	float uvsize = 1.0f / (float)atlas_size;
-	float us = 0.0097; // TODO: replace with correct calculations (including 0.36)
+	float us = 1.0f / (float)atlas_size / (float)atlas_size * ATLAS_MARGIN_SIZE * 0.8f;
 	const uint id = def.textureFaces[face];
 	float u = (id % atlas_size) * uvsize;
 	float v = 1.0f - (id / atlas_size + 1) * uvsize;
-	return UVRegion(u+us, v+us, u + uvsize - us * 0.36f, v + uvsize - us * 0.36f);
+	return UVRegion(u+us, v+us, u + uvsize - us, v + uvsize - us);
 }
 
 void BlocksRenderer::render(const voxel* voxels, int atlas_size) {
diff --git a/src/graphics/ImageData.cpp b/src/graphics/ImageData.cpp
index c4897b4a..318043ca 100644
--- a/src/graphics/ImageData.cpp
+++ b/src/graphics/ImageData.cpp
@@ -59,8 +59,10 @@ ImageData* add_atlas_margins(ImageData* image, int grid_size) {
                     if (srcdata[((soy+ly) * srcwidth + sox + lx) * 4 + 3]) {
                         for (int c = 0; c < 3; c++) {
                             int val = srcdata[((soy+ly) * srcwidth + sox + lx) * 4 + c];
-                            dstdata[((doy+ly) * dstwidth + dox + lx + 1) * 4 + c] = val;
-                            dstdata[((doy+ly + 1) * dstwidth + dox + lx) * 4 + c] = val;
+                            if (dstdata[((doy+ly) * dstwidth + dox + lx + 1) * 4 + 3] == 0)
+                                dstdata[((doy+ly) * dstwidth + dox + lx + 1) * 4 + c] = val;
+                            if (dstdata[((doy+ly + 1) * dstwidth + dox + lx) * 4 + 3] == 0)
+                                dstdata[((doy+ly + 1) * dstwidth + dox + lx) * 4 + c] = val;
                         }
                     }
                 }