# HG changeset patch
# User sheepluva
# Date 1624652201 -7200
# Node ID 67f83b7dfc6cfb4ae264ea6caf18f0dfa9c3bf2f
# Parent  36816af30583b533da1f4d2a0ad79b206fcb84a2
hedgewars-engine (rust): do something I consider approximate linear filtering for prettier previews

diff -r 36816af30583 -r 67f83b7dfc6c rust/hedgewars-engine/src/main.rs
--- a/rust/hedgewars-engine/src/main.rs	Fri Jun 25 21:44:29 2021 +0200
+++ b/rust/hedgewars-engine/src/main.rs	Fri Jun 25 22:16:41 2021 +0200
@@ -34,6 +34,7 @@
 const PREVIEW_HEIGHT: u32 = 128;
 const PREVIEW_NPIXELS: usize = (PREVIEW_WIDTH * PREVIEW_HEIGHT) as usize;
 const SCALE_FACTOR: u32 = 16;
+const VALUE_PER_INPIXEL: u8 = 1;
 
 fn resize_mono_preview(mono_pixels: &[u8], in_width: u32, in_height: u32, preview_pixels: &mut [u8]) {
 
@@ -51,9 +52,21 @@
             let in_x = h_offset + (x * SCALE_FACTOR);
 
             let out_px_address = (PREVIEW_WIDTH * y + x) as usize;
-            let in_px_address = (in_width * in_y + in_x) as usize;
+
+            let mut in_px_address = (in_width * in_y + in_x) as usize;
+
+            let mut value = 0;
 
-            preview_pixels[out_px_address] = mono_pixels[in_px_address];
+            for i in 0..SCALE_FACTOR as usize {
+                for j in 0..SCALE_FACTOR as usize {
+                    if (value < 0xff) && (mono_pixels[in_px_address + j] != 0) {
+                        value += VALUE_PER_INPIXEL;
+                    }
+                }
+                in_px_address += in_width as usize;
+            }
+
+            preview_pixels[out_px_address] = value;
         }
     }
 }