use unsafe access to write pixelbuf

src/main.rs

@@ -43,7 +43,7 @@ fn main() {
     let model = Model::from_obj("diablo3_pose.obj");
     model.render_triangles(&mut fb);
 
-    //fb.write_file("triangle.tga", true).unwrap();
+    fb.write_file("triangle.tga", true).unwrap();
 }
 
 fn line(mut a: Point2i, mut b: Point2i, color: TGAColor, mut fb: &mut TGAImage) {

src/triangle.rs

@@ -146,9 +146,6 @@ pub struct Triangle3i {
     c: Point3i,
 }
 
-struct Wrapper<T>(T);
-unsafe impl<T> Send for Wrapper<T> {}
-
 impl Triangle3i {
     pub fn new(a: Point3i, b: Point3i, c: Point3i) -> Self {
         Self { a, b, c }
@@ -173,8 +170,10 @@ impl Triangle3i {
     }
 
     pub fn render_filled(&self, color: TGAColor, fb: &mut TGAImage, depth_buffer: &mut TGAImage) {
-        let fb = Arc::new(Mutex::new(fb));
-        let zb = Arc::new(Mutex::new(depth_buffer));
+        let w = fb.width as usize;
+        let bpp = fb.bytes_per_pixel() as usize;
+        let fb = &Wrapper(fb.data.as_mut_ptr());
+        let zb = &Wrapper(depth_buffer.data.as_mut_ptr());
         let bb = self.bb();
         let total_area = self.signed_area();
         if total_area < 1.0 {
@@ -201,14 +200,10 @@ impl Triangle3i {
                         + beta * self.b.z as f32
                         + gamma * self.c.z as f32)
                         .round_ties_even() as u8;
-                    if let Ok(mut zb) = zb.lock() {
-                        let oz = zb.get(x as u32, y as u32).unwrap_or_default().b();
-                        if oz <= z {
-                            if let Ok(mut fb) = fb.lock() {
-                                zb.set(x as u32, y as u32, z.into());
-                                fb.set(x as u32, y as u32, color);
-                            }
-                        }
+                    let pxl = (x + y * w as i32) as isize;
+                    let start = pxl * bpp as isize;
+                    unsafe {
+                        write_pixel(fb, zb, z, start, pxl, bpp, color);
                     }
                 };
             });
@@ -232,3 +227,28 @@ impl Triangle3i {
         Point3i { x, y, z, color }
     }
 }
+
+struct Wrapper<T>(T);
+unsafe impl<T> Send for Wrapper<T> {}
+unsafe impl<T> Sync for Wrapper<T> {}
+
+unsafe fn write_pixel(
+    fb: &Wrapper<*mut u8>,
+    zb: &Wrapper<*mut u8>,
+    z: u8,
+    fb_offset: isize,
+    zb_offset: isize,
+    len: usize,
+    color: TGAColor,
+) {
+    unsafe {
+        let oz = zb.0.offset(zb_offset);
+        if *oz <= z {
+            *oz = z;
+            for i in 0..len as isize {
+                let offset = fb_offset + i;
+                *fb.0.offset(offset) = color[i as usize];
+            }
+        }
+    }
+}