1 files changed, 47 insertions, 0 deletions
diff --git a/src/render/composite.rs b/src/render/composite.rs
new file mode 100644
index 0000000..51c6f6a
--- /dev/null
+++ b/src/render/composite.rs
@@ -0,0 +1,47 @@
+use image::ImageBuffer;
+use image::Rgba;
+
+pub const REGION_SIZE: usize = 16 * 8;
+pub const CHUNK_HEIGHT: usize = 384;
+pub const CHUNK_SIZE: usize = 16;
+
+pub fn image_buffer_blit(
+    target: &mut ImageBuffer<Rgba<u8>, Vec<u8>>,
+    source: &ImageBuffer<Rgba<u8>, Vec<u8>>,
+    offset: (u32, u32),
+) {
+    for (x, y, source_pixel) in source.enumerate_pixels() {
+        let target_pixel = target.get_pixel_mut(x + offset.0, y + offset.1);
+        let sa = source_pixel.0[3] as u16;
+        let new_pixel = Rgba::from([
+            ((target_pixel.0[0] as u16 * (255 - sa)) / 255 + (source_pixel.0[0] as u16 * sa) / 255)
+                as u8,
+            ((target_pixel.0[1] as u16 * (255 - sa)) / 255 + (source_pixel.0[1] as u16 * sa) / 255)
+                as u8,
+            ((target_pixel.0[2] as u16 * (255 - sa)) / 255 + (source_pixel.0[2] as u16 * sa) / 255)
+                as u8,
+            255 - (((255 - target_pixel.0[3] as u16) * (255 - sa)) / 255) as u8,
+        ]);
+        *target_pixel = new_pixel;
+    }
+}
+
+pub fn isometric_coord_mapping(x: i32, y: i32, z: i32) -> (u32, u32) {
+    // const BASE_X: i32 = 1016;
+    // const BASE_Y: i32 = 2040;
+    const BASE_X: i32 = 128 - 8;
+    const BASE_Y: i32 = 2040;
+
+    const XDIFF: (i32, i32) = (-8, 4);
+    const ZDIFF: (i32, i32) = (8, 4);
+    const YDIFF: (i32, i32) = (0, -8);
+
+    let diff = (
+        XDIFF.0 * x + YDIFF.0 * y + ZDIFF.0 * z,
+        XDIFF.1 * x + YDIFF.1 * y + ZDIFF.1 * z,
+    );
+
+    let coords = (BASE_X + diff.0, BASE_Y + diff.1);
+
+    (coords.0 as u32, coords.1 as u32)
+}