From a2c6a4e8b02f2a45f48b600e05c71f9c56481b05 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Mon, 4 Mar 2019 18:00:51 +0100
Subject: [PATCH] 3d:: a system for drawing transparent things, with sorting
 being the responsibility of HR

---
 hyper.h      | 4 ++++
 polygons.cpp | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/hyper.h b/hyper.h
index 6fae4c63..3d8dc49f 100644
--- a/hyper.h
+++ b/hyper.h
@@ -2090,6 +2090,9 @@ enum class PPR {
   MINEMARK, ARROW,
   MOBILE_ARROW,
   LINE, 
+  // in depth tested models transparent surfaces need to be depth sorted by HyperRogue
+  // and set to PPR::TRANSPARENT to draw them after all the opaque ones
+  TRANSPARENT,
   // no depth testing for SUPERLINE and above
   SUPERLINE, TEXT, CIRCLE,
   MAX,
@@ -2832,6 +2835,7 @@ struct textureinfo {
 struct drawqueueitem {
   PPR prio;
   color_t color;
+  int subprio;
   virtual void draw() = 0;
   virtual void draw_back() {}
   virtual void draw_pre() {}
diff --git a/polygons.cpp b/polygons.cpp
index 522d41ac..3be7e8d4 100644
--- a/polygons.cpp
+++ b/polygons.cpp
@@ -1515,6 +1515,12 @@ void drawqueue() {
         < xintval(ap2.V * xpush0(.1));
       });
 
+  for(PPR p: {PPR::TRANSPARENT})
+    sort(&ptds[qp0[int(p)]], &ptds[qp[int(p)]], 
+      [] (const unique_ptr<drawqueueitem>& p1, const unique_ptr<drawqueueitem>& p2) {
+        return p1->subprio > p2->subprio;
+        });
+
   profile_stop(3);
 
 #if CAP_SDL