From e006442e4f7ebf3f6d0516830c662a114a1e4a90 Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <stenzek@gmail.com>
Date: Tue, 21 Dec 2021 18:02:16 +1000
Subject: [PATCH] GSRendererNew: Remove another constant buffer copy

---
 pcsx2/GS/Renderers/Common/GSDevice.h    |  8 ++++----
 pcsx2/GS/Renderers/HW/GSRendererNew.cpp | 25 ++++++++++---------------
 2 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/pcsx2/GS/Renderers/Common/GSDevice.h b/pcsx2/GS/Renderers/Common/GSDevice.h
index 54dfa46c9a..516a5e214f 100644
--- a/pcsx2/GS/Renderers/Common/GSDevice.h
+++ b/pcsx2/GS/Renderers/Common/GSDevice.h
@@ -135,7 +135,7 @@ struct HWBlend
 	u16 flags, op, src, dst;
 };
 
-struct GSHWDrawConfig
+struct alignas(16) GSHWDrawConfig
 {
 	enum class Topology: u8
 	{
@@ -476,9 +476,6 @@ struct GSHWDrawConfig
 	DestinationAlphaMode destination_alpha;
 	bool datm;
 
-	VSConstantBuffer cb_vs;
-	PSConstantBuffer cb_ps;
-
 	struct AlphaSecondPass
 	{
 		bool enable;
@@ -487,6 +484,9 @@ struct GSHWDrawConfig
 		PSSelector ps;
 		float ps_aref;
 	} alpha_second_pass;
+
+	VSConstantBuffer cb_vs;
+	PSConstantBuffer cb_ps;
 };
 
 class GSDevice : public GSAlignedClass<32>
diff --git a/pcsx2/GS/Renderers/HW/GSRendererNew.cpp b/pcsx2/GS/Renderers/HW/GSRendererNew.cpp
index 29d3ecb1c6..cb60aba690 100644
--- a/pcsx2/GS/Renderers/HW/GSRendererNew.cpp
+++ b/pcsx2/GS/Renderers/HW/GSRendererNew.cpp
@@ -1113,27 +1113,27 @@ void GSRendererNew::EmulateATST(float& AREF, GSHWDrawConfig::PSSelector& ps, boo
 	switch (atst)
 	{
 		case ATST_LESS:
-			AREF = (float)m_context->TEST.AREF - 0.1f;
+			AREF = static_cast<float>(m_context->TEST.AREF) - 0.1f;
 			ps.atst = 1;
 			break;
 		case ATST_LEQUAL:
-			AREF = (float)m_context->TEST.AREF - 0.1f + 1.0f;
+			AREF = static_cast<float>(m_context->TEST.AREF) - 0.1f + 1.0f;
 			ps.atst = 1;
 			break;
 		case ATST_GEQUAL:
-			AREF = (float)m_context->TEST.AREF - 0.1f;
+			AREF = static_cast<float>(m_context->TEST.AREF) - 0.1f;
 			ps.atst = 2;
 			break;
 		case ATST_GREATER:
-			AREF = (float)m_context->TEST.AREF - 0.1f + 1.0f;
+			AREF = static_cast<float>(m_context->TEST.AREF) - 0.1f + 1.0f;
 			ps.atst = 2;
 			break;
 		case ATST_EQUAL:
-			AREF = (float)m_context->TEST.AREF;
+			AREF = static_cast<float>(m_context->TEST.AREF);
 			ps.atst = 3;
 			break;
 		case ATST_NOTEQUAL:
-			AREF = (float)m_context->TEST.AREF;
+			AREF = static_cast<float>(m_context->TEST.AREF);
 			ps.atst = 4;
 			break;
 		case ATST_NEVER: // Draw won't be done so no need to implement it in shader
@@ -1146,11 +1146,9 @@ void GSRendererNew::EmulateATST(float& AREF, GSHWDrawConfig::PSSelector& ps, boo
 
 void GSRendererNew::ResetStates()
 {
-	GSHWDrawConfig::VSConstantBuffer vs_tmp = m_conf.cb_vs;
-	GSHWDrawConfig::PSConstantBuffer ps_tmp = m_conf.cb_ps;
-	memset(&m_conf, 0, sizeof(m_conf));
-	m_conf.cb_vs = vs_tmp;
-	m_conf.cb_ps = ps_tmp;
+	// We don't want to zero out the constant buffers, since fields used by the current draw could result in redundant uploads.
+	// This memset should be pretty efficient - the struct is 16 byte aligned, as is the cb_vs offset.
+	memset(&m_conf, 0, reinterpret_cast<const char*>(&m_conf.cb_vs) - reinterpret_cast<const char*>(&m_conf));
 }
 
 void GSRendererNew::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Source* tex)
@@ -1592,10 +1590,7 @@ void GSRendererNew::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 		m_conf.require_one_barrier = true;
 	}
 
-	if (m_conf.require_full_barrier && m_vt.m_primclass == GS_SPRITE_CLASS)
-	{
-		m_conf.drawlist = &m_drawlist;
-	}
+	m_conf.drawlist = (m_conf.require_full_barrier && m_vt.m_primclass == GS_SPRITE_CLASS) ? &m_drawlist : nullptr;
 
 	m_conf.rt = rt;
 	m_conf.ds = ds;