From 40f9653b1c8eb79fcb5356e381fe15019bbbceb4 Mon Sep 17 00:00:00 2001
From: saulfabreg Wii VC Project <saulfabregamboa@outlook.com>
Date: Tue, 9 Apr 2024 14:03:21 -0500
Subject: [PATCH] gpulib: (maybe) rework buffering to reduce flickering

was originally made for GPU NEON but i think it should work on current GPU too :P

https://github.com/notaz/pcsx_rearmed/issues/324

https://github.com/notaz/pcsx_rearmed/commit/2da2fc7676c1fc40d26226a7a4c43728d9a2eedf
---
 SoftGPU/gpulib_if.c |  2 +-
 gpulib/gpu.h        |  2 +-
 gpulib/gpulib.c     | 22 +++++++++++++---------
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/SoftGPU/gpulib_if.c b/SoftGPU/gpulib_if.c
index af04d279..31311341 100644
--- a/SoftGPU/gpulib_if.c
+++ b/SoftGPU/gpulib_if.c
@@ -277,7 +277,7 @@ void renderer_notify_res_change(uint32_t gdata)
     PSXDisplay.Interlaced = ((gdata & 0x24) ^ 0x24)?FALSE:TRUE; // if 0 - Interlace
 }
 
-void renderer_notify_scanout_x_change(int x, int w)
+void renderer_notify_scanout_change(int x, int y)
 {
 }
 
diff --git a/gpulib/gpu.h b/gpulib/gpu.h
index 719ec4bd..a6f0314e 100644
--- a/gpulib/gpu.h
+++ b/gpulib/gpu.h
@@ -179,7 +179,7 @@ void renderer_set_config(const struct rearmed_cbs *config);
 void renderer_notify_res_change(uint32_t data);
 void renderer_notify_update_lace(int updated);
 void renderer_sync(void);
-void renderer_notify_scanout_x_change(int x, int w);
+void renderer_notify_scanout_change(int x, int y);
 
 int  vout_init(void);
 int  vout_finish(void);
diff --git a/gpulib/gpulib.c b/gpulib/gpulib.c
index 4ac36e42..818e3766 100644
--- a/gpulib/gpulib.c
+++ b/gpulib/gpulib.c
@@ -307,6 +307,7 @@ long LIB_GPUshutdown(void)
 void LIB_GPUwriteStatus(uint32_t data)
 {
   uint32_t cmd = data >> 24;
+  int src_x, src_y;
 
   if (cmd < ARRAY_SIZE(gpu.regs)) {
     if (cmd > 1 && cmd != 5 && gpu.regs[cmd] == data)
@@ -341,14 +342,17 @@ void LIB_GPUwriteStatus(uint32_t data)
       break;
     // setting display position
     case 0x05:
-      gpu.screen.src_x = data & 0x3ff;
-      gpu.screen.src_y = (data >> 10) & 0x1ff;
-      renderer_notify_scanout_x_change(gpu.screen.src_x, gpu.screen.hres);
-      if (gpu.frameskip.set) {
-        decide_frameskip_allow(gpu.ex_regs[3]);
-        if (gpu.frameskip.last_flip_frame != *gpu.state.frame_count) {
-          decide_frameskip();
-          gpu.frameskip.last_flip_frame = *gpu.state.frame_count;
+      src_x = data & 0x3ff; src_y = (data >> 10) & 0x1ff;
+      if (src_x != gpu.screen.src_x || src_y != gpu.screen.src_y) {
+        gpu.screen.src_x = src_x;
+        gpu.screen.src_y = src_y;
+        renderer_notify_scanout_change(src_x, src_y);
+        if (gpu.frameskip.set) {
+          decide_frameskip_allow(gpu.ex_regs[3]);
+          if (gpu.frameskip.last_flip_frame != *gpu.state.frame_count) {
+            decide_frameskip();
+            gpu.frameskip.last_flip_frame = *gpu.state.frame_count;
+          }
         }
       }
       break;
@@ -888,7 +892,7 @@ long LIB_GPUfreeze(uint32_t type, struct GPUFreeze *freeze)
         LIB_GPUwriteStatus((i << 24) | (gpu.regs[i] ^ 1));
       }
       renderer_sync_ecmds(gpu.ex_regs);
-      renderer_update_caches(0, 0, 1024, 512, 1);
+      renderer_update_caches(0, 0, 1024, 512, 0);
       break;
   }