Ensure minimum block size is respected when doing GPU to CPU copies of compressed textures

servers/rendering/rendering_device.cpp

@@ -1350,6 +1350,9 @@ Vector<uint8_t> RenderingDevice::texture_get_data(RID p_texture, uint32_t p_laye
 		thread_local LocalVector<RDD::BufferTextureCopyRegion> command_buffer_texture_copy_regions_vector;
 		command_buffer_texture_copy_regions_vector.clear();
 
+		uint32_t block_w = 0, block_h = 0;
+		get_compressed_image_format_block_dimensions(tex->format, block_w, block_h);
+
 		uint32_t w = tex->width;
 		uint32_t h = tex->height;
 		uint32_t d = tex->depth;
@@ -1365,8 +1368,8 @@ Vector<uint8_t> RenderingDevice::texture_get_data(RID p_texture, uint32_t p_laye
 			copy_region.texture_region_size.z = d;
 			command_buffer_texture_copy_regions_vector.push_back(copy_region);
 
-			w = MAX(1u, w >> 1);
-			h = MAX(1u, h >> 1);
+			w = MAX(block_w, w >> 1);
+			h = MAX(block_h, h >> 1);
 			d = MAX(1u, d >> 1);
 		}
 
@@ -1395,8 +1398,6 @@ Vector<uint8_t> RenderingDevice::texture_get_data(RID p_texture, uint32_t p_laye
 		for (uint32_t i = 0; i < tex->mipmaps; i++) {
 			uint32_t width = 0, height = 0, depth = 0;
 			uint32_t tight_mip_size = get_image_format_required_size(tex->format, w, h, d, 1, &width, &height, &depth);
-			uint32_t block_w = 0, block_h = 0;
-			get_compressed_image_format_block_dimensions(tex->format, block_w, block_h);
 			uint32_t tight_row_pitch = tight_mip_size / ((height / block_h) * depth);
 
 			// Copy row-by-row to erase padding due to alignments.
@@ -1408,8 +1409,8 @@ Vector<uint8_t> RenderingDevice::texture_get_data(RID p_texture, uint32_t p_laye
 				wp += tight_row_pitch;
 			}
 
-			w = MAX(1u, w >> 1);
-			h = MAX(1u, h >> 1);
+			w = MAX(block_w, w >> 1);
+			h = MAX(block_h, h >> 1);
 			d = MAX(1u, d >> 1);
 			read_ptr += mip_layouts[i].size;
 			write_ptr += tight_mip_size;