Add to_file function for image

vulkan-rs/src/image.rs

@@ -5,6 +5,7 @@ use crate::prelude::*;
 use anyhow::Result;
 
 use std::cmp;
+use std::path::Path;
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
@@ -776,6 +777,88 @@ impl Image {
             VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL => VK_ACCESS_SHADER_READ_BIT.into(),
         }
     }
+
+    pub fn to_file(self: &Arc<Image>, path: impl AsRef<Path>) -> Result<()> {
+        let buffer = self.copy_image_to_buffer()?;
+        let memory = buffer.map_complete()?;
+
+        let image = image::RgbaImage::from_raw(
+            self.width,
+            self.height,
+            memory.iter().map(|&v| v).collect(),
+        )
+        .ok_or(anyhow::anyhow!(
+            "failed to create image from raw while saving to file: {:?}",
+            path.as_ref()
+        ))?;
+
+        image.save(path)?;
+
+        Ok(())
+    }
+
+    fn copy_image_to_buffer(self: &Arc<Image>) -> Result<Arc<Buffer<u8>>> {
+        let buffer = Buffer::builder()
+            .set_usage(VK_BUFFER_USAGE_TRANSFER_DST_BIT)
+            .set_memory_usage(MemoryUsage::GpuToCpu)
+            .set_size((self.width * self.height * 4) as VkDeviceSize)
+            .build(self.device.clone())?;
+
+        let command_buffer =
+            CommandBuffer::new_primary().build(self.device.clone(), self.queue.clone())?;
+
+        SingleSubmit::builder(&command_buffer, &self.queue, |recorder| {
+            // copy info for copying the content of the buffer into the image
+            let buffer_image_copy = VkBufferImageCopy {
+                bufferOffset: 0,
+                bufferRowLength: 0,
+                bufferImageHeight: 0,
+                imageSubresource: VkImageSubresourceLayers {
+                    aspectMask: VK_IMAGE_ASPECT_COLOR_BIT.into(),
+                    mipLevel: 0,
+                    baseArrayLayer: 0,
+                    layerCount: 1,
+                },
+                imageOffset: VkOffset3D { x: 0, y: 0, z: 0 },
+                imageExtent: VkExtent3D {
+                    width: self.width(),
+                    height: self.height(),
+                    depth: 1,
+                },
+            };
+
+            // subresource information
+            let subresource_range = VkImageSubresourceRange {
+                aspectMask: VK_IMAGE_ASPECT_COLOR_BIT.into(),
+                baseMipLevel: 0,
+                levelCount: 1,
+                baseArrayLayer: 0,
+                layerCount: 1,
+            };
+
+            let current_layout = self.image_layout();
+
+            recorder.set_image_layout(
+                self,
+                VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
+                subresource_range.clone(),
+            );
+
+            recorder.copy_image_to_buffer(
+                self,
+                VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
+                &buffer,
+                &[buffer_image_copy],
+            );
+
+            recorder.set_image_layout(self, current_layout, subresource_range);
+
+            Ok(())
+        })
+        .submit()?;
+
+        Ok(buffer)
+    }
 }
 
 impl VulkanDevice for Image {