From 9ebb0d3d2db5b3abc65ddf9d27bec166f7ae2d39 Mon Sep 17 00:00:00 2001
From: Michel Heily <michelheily@gmail.com>
Date: Sat, 31 Aug 2019 14:13:21 +0200
Subject: [PATCH] Fix OBJ priorities (tonc prio_demo.gba works)

Former-commit-id: a55b3be7688ef7e1446a54c38fc5ddb5034cb4b9
---
 src/core/gpu/mod.rs | 2 ++
 src/core/gpu/obj.rs | 6 +++++-
 src/core/gpu/sfx.rs | 2 +-
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/core/gpu/mod.rs b/src/core/gpu/mod.rs
index 1b8b482..c0a94da 100644
--- a/src/core/gpu/mod.rs
+++ b/src/core/gpu/mod.rs
@@ -215,6 +215,7 @@ pub struct Gpu {
     pub bldy: u16,
 
     pub obj_line: Scanline<Rgb15>,
+    pub obj_line_priorities: Scanline<u16>,
     pub frame_buffer: FrameBuffer,
 }
 
@@ -238,6 +239,7 @@ impl Gpu {
             current_scanline: 0,
             cycles: 0,
             obj_line: Scanline::default(),
+            obj_line_priorities: Scanline([3; DISPLAY_WIDTH]),
             frame_buffer: FrameBuffer([0; DISPLAY_WIDTH * DISPLAY_HEIGHT]),
         }
     }
diff --git a/src/core/gpu/obj.rs b/src/core/gpu/obj.rs
index 6aabebe..3fafdc5 100644
--- a/src/core/gpu/obj.rs
+++ b/src/core/gpu/obj.rs
@@ -96,6 +96,7 @@ impl Gpu {
         let screen_y = self.current_scanline;
         // reset the scanline
         self.obj_line = Scanline::default();
+        self.obj_line_priorities = Scanline([3; DISPLAY_WIDTH]);
         for obj_num in (0..128).rev() {
             let obj = read_obj_attrs(sb, obj_num);
             if obj.is_hidden() {
@@ -140,6 +141,9 @@ impl Gpu {
                 if screen_x > DISPLAY_WIDTH {
                     break;
                 }
+                if self.obj_line_priorities[screen_x] < obj.2.priority() {
+                    continue;
+                }
                 let mut sprite_y = screen_y - obj_y;
                 let mut sprite_x = screen_x - obj_x;
                 if (!is_affine) {
@@ -169,8 +173,8 @@ impl Gpu {
                 let pixel_color =
                     self.get_palette_color(sb, pixel_index as u32, palette_bank, PALRAM_OFS_FG);
                 if pixel_color != Rgb15::TRANSPARENT {
-                    // TODO - handle priority
                     self.obj_line[screen_x] = pixel_color;
+                    self.obj_line_priorities[screen_x] = obj.2.priority();
                 }
             }
         }
diff --git a/src/core/gpu/sfx.rs b/src/core/gpu/sfx.rs
index 2bb7985..c06ccf9 100644
--- a/src/core/gpu/sfx.rs
+++ b/src/core/gpu/sfx.rs
@@ -47,12 +47,12 @@ impl Gpu {
         bflags: BlendFlags,
         wflags: WindowFlags,
     ) -> Option<Layer> {
-        // TODO - only BGs are supported, don't forget OBJs
         // priorities are 0-4 when 0 is the highest
         'outer: for priority in 0..4 {
             if bflags.contains(BlendFlags::OBJ)
                 && wflags.contains(WindowFlags::OBJ)
                 && !self.obj_line[screen_x].is_transparent()
+                && self.obj_line_priorities[screen_x] == priority
             {
                 return Some(Layer {
                     color: self.obj_line[screen_x],