From 45bfe2ad582e1e7c189c599b84e70f859c1bd6d0 Mon Sep 17 00:00:00 2001
From: Gregory Hainaut <gregory.hainaut@gmail.com>
Date: Thu, 28 Apr 2016 19:39:57 +0200
Subject: [PATCH] gsdx hw: trace some special post processing effect

* Double downscale is done in GTA
* Channel Shuffle is the top-left corner issue

So far nothing is emulated
---
 plugins/GSdx/GSRendererHW.cpp | 29 +++++++++++++++++++++++++++++
 plugins/GSdx/GSRendererHW.h   |  3 +++
 2 files changed, 32 insertions(+)

diff --git a/plugins/GSdx/GSRendererHW.cpp b/plugins/GSdx/GSRendererHW.cpp
index 3a45271af2..3130d365b0 100644
--- a/plugins/GSdx/GSRendererHW.cpp
+++ b/plugins/GSdx/GSRendererHW.cpp
@@ -29,6 +29,8 @@ GSRendererHW::GSRendererHW(GSTextureCache* tc)
 	, m_reset(false)
 	, m_upscale_multiplier(1)
 	, m_tc(tc)
+	, m_channel_shuffle(false)
+	, m_double_downscale(false)
 {
 	m_upscale_multiplier = theApp.GetConfig("upscale_multiplier", 1);
 	m_userhacks_skipdraw = !!theApp.GetConfig("UserHacks", 0) ? theApp.GetConfig("UserHacks_SkipDraw", 0) : 0;
@@ -370,6 +372,33 @@ void GSRendererHW::Draw()
 			(context->FRAME.FBP == context->ZBUF.ZBP && !PRIM->TME && !context->ZBUF.ZMSK && !context->FRAME.FBMSK && context->TEST.ZTE)
 			);
 
+	if (PRIM->TME && m_context->FRAME.Block() == m_context->TEX0.TBP0 && (m_vt.m_primclass == GS_SPRITE_CLASS)) {
+		// Special post-processing effect
+		GSVector4 delta_p =  m_vt.m_max.p - m_vt.m_min.p;
+
+		if (m_vertex.next == 4) {
+			// Note potentially we could also check the content of vertex (2nd
+			// sprite must be half of the first one)
+			m_double_downscale = true;
+			GL_INS("Double downscale effect detected");
+		} else if ((m_context->TEX0.PSM == PSM_PSMT8) && (delta_p.x <= 64.0f) && (delta_p.y <= 32.0f)) {
+			//fprintf(stderr, "delta_p %f %f\n", delta_p.x, delta_p.y);
+			if (m_channel_shuffle) {
+				GL_INS("Channel shuffle effect detected SKIP");
+			} else {
+				GL_INS("Channel shuffle effect detected");
+				m_channel_shuffle = true;
+			}
+		} else {
+			GL_INS("Special post-processing effect not supported");
+			m_channel_shuffle = false;
+			m_double_downscale = false;
+		}
+	} else {
+		m_channel_shuffle = false;
+		m_double_downscale = false;
+	}
+
 	GIFRegTEX0 TEX0;
 
 	TEX0.TBP0 = context->FRAME.Block();
diff --git a/plugins/GSdx/GSRendererHW.h b/plugins/GSdx/GSRendererHW.h
index df5222898a..24a0c0e6ab 100644
--- a/plugins/GSdx/GSRendererHW.h
+++ b/plugins/GSdx/GSRendererHW.h
@@ -152,6 +152,9 @@ protected:
 
 	int m_userhacks_round_sprite_offset;
 
+	bool m_channel_shuffle;
+	bool m_double_downscale;
+
 public:
 	GSRendererHW(GSTextureCache* tc);
 	virtual ~GSRendererHW();