From 51fcd7b886bd463897864abde412af5509725b91 Mon Sep 17 00:00:00 2001
From: lightningterror <18107717+lightningterror@users.noreply.github.com>
Date: Wed, 3 Jul 2024 13:30:48 +0200
Subject: [PATCH] GS/HW: Check for full cover in more situations when we
 disable blending.

More hits on RTA Scaling/Descaling.
---
 pcsx2/GS/Renderers/HW/GSRendererHW.cpp | 17 +++++++++++++++--
 pcsx2/GS/Renderers/HW/GSRendererHW.h   |  2 +-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/pcsx2/GS/Renderers/HW/GSRendererHW.cpp b/pcsx2/GS/Renderers/HW/GSRendererHW.cpp
index 6093d80054..2655e35350 100644
--- a/pcsx2/GS/Renderers/HW/GSRendererHW.cpp
+++ b/pcsx2/GS/Renderers/HW/GSRendererHW.cpp
@@ -4052,7 +4052,7 @@ __ri bool GSRendererHW::EmulateChannelShuffle(GSTextureCache::Target* src, bool
 	return true;
 }
 
-void GSRendererHW::EmulateBlending(int rt_alpha_min, int rt_alpha_max, bool& DATE_PRIMID, bool& DATE_BARRIER,
+void GSRendererHW::EmulateBlending(int rt_alpha_min, int rt_alpha_max, const bool DATE, bool& DATE_PRIMID, bool& DATE_BARRIER,
 	GSTextureCache::Target* rt, bool can_scale_rt_alpha, bool& new_rt_alpha_scale)
 {
 	{
@@ -4070,6 +4070,8 @@ void GSRendererHW::EmulateBlending(int rt_alpha_min, int rt_alpha_max, bool& DAT
 			m_conf.blend = {};
 			m_conf.ps.no_color1 = true;
 
+			// TODO: Find games that may benefit from adding full coverage on RTA Scale when we're overwriting the whole target.
+
 			return;
 		}
 	}
@@ -4455,6 +4457,17 @@ void GSRendererHW::EmulateBlending(int rt_alpha_min, int rt_alpha_max, bool& DAT
 		// Output is Cd, set rgb write to 0.
 		m_conf.colormask.wrgba &= 0x8;
 
+		// TODO: Find games that may benefit from adding full coverage on RTA Scale when we're overwriting the whole target,
+		// then the rest of then conditions can be added.
+		if (can_scale_rt_alpha && !new_rt_alpha_scale && m_conf.colormask.wa)
+		{
+			const bool afail_fb_only = m_cached_ctx.TEST.AFAIL == AFAIL_FB_ONLY;
+			const bool full_cover = rt->m_valid.rintersect(m_r).eq(rt->m_valid) && m_primitive_covers_without_gaps == NoGapsType::FullCover && !(DATE || !afail_fb_only || !IsDepthAlwaysPassing());
+
+			// Restrict this to only when we're overwriting the whole target.
+			new_rt_alpha_scale = full_cover;
+		}
+
 		return;
 	}
 	else if (sw_blending)
@@ -5867,7 +5880,7 @@ __ri void GSRendererHW::DrawPrims(GSTextureCache::Target* rt, GSTextureCache::Ta
 
 	if ((!IsOpaque() || m_context->ALPHA.IsBlack()) && rt && ((m_conf.colormask.wrgba & 0x7) || (m_texture_shuffle && !m_copy_16bit_to_target_shuffle && !m_same_group_texture_shuffle)))
 	{
-		EmulateBlending(blend_alpha_min, blend_alpha_max, DATE_PRIMID, DATE_BARRIER, rt, can_scale_rt_alpha, new_scale_rt_alpha);
+		EmulateBlending(blend_alpha_min, blend_alpha_max, DATE, DATE_PRIMID, DATE_BARRIER, rt, can_scale_rt_alpha, new_scale_rt_alpha);
 	}
 	else
 	{
diff --git a/pcsx2/GS/Renderers/HW/GSRendererHW.h b/pcsx2/GS/Renderers/HW/GSRendererHW.h
index 094b7647b3..7ecfa5d285 100644
--- a/pcsx2/GS/Renderers/HW/GSRendererHW.h
+++ b/pcsx2/GS/Renderers/HW/GSRendererHW.h
@@ -95,7 +95,7 @@ private:
 	void SetupIA(float target_scale, float sx, float sy);
 	void EmulateTextureShuffleAndFbmask(GSTextureCache::Target* rt, GSTextureCache::Source* tex);
 	bool EmulateChannelShuffle(GSTextureCache::Target* src, bool test_only);
-	void EmulateBlending(int rt_alpha_min, int rt_alpha_max, bool& DATE_PRIMID, bool& DATE_BARRIER, GSTextureCache::Target* rt,
+	void EmulateBlending(int rt_alpha_min, int rt_alpha_max, const bool DATE, bool& DATE_PRIMID, bool& DATE_BARRIER, GSTextureCache::Target* rt,
 		bool can_scale_rt_alpha, bool& new_rt_alpha_scale);
 	void CleanupDraw(bool invalidate_temp_src);