From abc05c68b836ba7c1d1465130a20eee146b570e4 Mon Sep 17 00:00:00 2001
From: Charlie Birks <charlie@daft.games>
Date: Tue, 22 Dec 2020 15:50:12 +0000
Subject: [PATCH 1/2] Update buttons pressed/released before calling update

Instead of up to 1000s of times a second.
---
 32blit/engine/engine.cpp | 9 +++++++--
 32blit/engine/input.hpp  | 6 +-----
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/32blit/engine/engine.cpp b/32blit/engine/engine.cpp
index d4173767e..8883f7359 100644
--- a/32blit/engine/engine.cpp
+++ b/32blit/engine/engine.cpp
@@ -77,10 +77,15 @@ namespace blit {
     // catch up on updates if any pending
     pending_update_time += (time - last_tick_time);
     while (pending_update_time >= update_rate_ms) {
+      // button state changes
+      uint32_t changed = api.buttons.state ^ api.buttons.last_state;
+
+      api.buttons.pressed = changed & api.buttons.state;
+      api.buttons.released = changed & api.buttons.last_state;
+      api.buttons.last_state = api.buttons.state;
+
       update(time - pending_update_time); // create fake timestamp that would have been accurate for the update event
       pending_update_time -= update_rate_ms;
-
-      api.buttons.pressed = api.buttons.released = 0;
     }
 
     last_tick_time = time;
diff --git a/32blit/engine/input.hpp b/32blit/engine/input.hpp
index b82dae5d7..e4d18e70a 100644
--- a/32blit/engine/input.hpp
+++ b/32blit/engine/input.hpp
@@ -21,11 +21,6 @@ namespace blit {
 
   struct ButtonState {
     ButtonState &operator=(uint32_t v) {
-      uint32_t changed = state ^ v;
-
-      pressed |= changed & v;
-      released |= changed & state;
-
       state = v;
 
       return *this;
@@ -37,6 +32,7 @@ namespace blit {
 
     uint32_t state;
     uint32_t pressed, released; // state change since last update
+    uint32_t last_state = 0;
   };
 
   extern bool pressed(uint32_t button);

From f0dd0637076404176af7252fc34c7bbc7e20ac9e Mon Sep 17 00:00:00 2001
From: Phil Howard <phil@gadgetoid.com>
Date: Sat, 2 Jan 2021 15:24:41 +0000
Subject: [PATCH 2/2] Avoid API break with last_state

---
 32blit/engine/engine.cpp | 7 ++++---
 32blit/engine/input.hpp  | 1 -
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/32blit/engine/engine.cpp b/32blit/engine/engine.cpp
index 8883f7359..519721057 100644
--- a/32blit/engine/engine.cpp
+++ b/32blit/engine/engine.cpp
@@ -64,6 +64,7 @@ namespace blit {
   uint32_t pending_render_time = 0;
 
   uint32_t last_tick_time = 0;
+  uint32_t last_state = 0;
 
   bool tick(uint32_t time) {
     if (last_tick_time == 0) {
@@ -78,11 +79,11 @@ namespace blit {
     pending_update_time += (time - last_tick_time);
     while (pending_update_time >= update_rate_ms) {
       // button state changes
-      uint32_t changed = api.buttons.state ^ api.buttons.last_state;
+      uint32_t changed = api.buttons.state ^ last_state;
 
       api.buttons.pressed = changed & api.buttons.state;
-      api.buttons.released = changed & api.buttons.last_state;
-      api.buttons.last_state = api.buttons.state;
+      api.buttons.released = changed & last_state;
+      last_state = api.buttons.state;
 
       update(time - pending_update_time); // create fake timestamp that would have been accurate for the update event
       pending_update_time -= update_rate_ms;
diff --git a/32blit/engine/input.hpp b/32blit/engine/input.hpp
index e4d18e70a..6e5c423ed 100644
--- a/32blit/engine/input.hpp
+++ b/32blit/engine/input.hpp
@@ -32,7 +32,6 @@ namespace blit {
 
     uint32_t state;
     uint32_t pressed, released; // state change since last update
-    uint32_t last_state = 0;
   };
 
   extern bool pressed(uint32_t button);