1 files changed, 43 insertions, 0 deletions
diff --git a/stockton-skeleton/src/texture/image.rs b/stockton-skeleton/src/texture/image.rs
new file mode 100644
index 0000000..f984b72
--- /dev/null
+++ b/stockton-skeleton/src/texture/image.rs
@@ -0,0 +1,43 @@
+use super::PIXEL_SIZE;
+
+use core::ptr::copy_nonoverlapping;
+use std::convert::TryInto;
+
+use image::RgbaImage;
+
+/// An object that can be loaded as an image into GPU memory
+pub trait LoadableImage {
+    fn width(&self) -> u32;
+    fn height(&self) -> u32;
+
+    /// # Safety
+    /// Ensure the ptr is at least width() * PIXEL_SIZE bytes.
+    unsafe fn copy_row(&self, y: u32, ptr: *mut u8);
+
+    /// # Safety
+    /// Ensure the ptr is at least row_size * height() * PIXEL_SIZE bytes.
+    unsafe fn copy_into(&self, ptr: *mut u8, row_size: usize) {
+        for y in 0..self.height() as usize {
+            let dest_base: isize = (y * row_size).try_into().unwrap();
+            self.copy_row(y as u32, ptr.offset(dest_base));
+        }
+    }
+}
+
+impl LoadableImage for RgbaImage {
+    fn width(&self) -> u32 {
+        self.width()
+    }
+
+    fn height(&self) -> u32 {
+        self.height()
+    }
+
+    unsafe fn copy_row(&self, y: u32, ptr: *mut u8) {
+        let row_size_bytes = self.width() as usize * PIXEL_SIZE;
+        let raw: &Vec<u8> = self.as_raw();
+        let row = &raw[y as usize * row_size_bytes..(y as usize + 1) * row_size_bytes];
+
+        copy_nonoverlapping(row.as_ptr(), ptr, row.len());
+    }
+}