GS/HW: Improve detection of reverse texture shuffles

pcsx2/GS/Renderers/HW/GSRendererHW.cpp

@@ -349,14 +349,14 @@ void GSRendererHW::ConvertSpriteTextureShuffle(bool& write_ba, bool& read_ba)
 	const u32 count = m_vertex.next;
 	GSVertex* v = &m_vertex.buff[0];
 	const GIFRegXYOFFSET& o = m_context->XYOFFSET;
-
+	const GSVertex first_vert = (v[0].XYZ.X <= v[m_vertex.tail - 2].XYZ.X) ? v[0] : v[m_vertex.tail - 2];
 	// vertex position is 8 to 16 pixels, therefore it is the 16-31 bits of the colors
-	const int pos = (v[0].XYZ.X - o.OFX) & 0xFF;
+	const int pos = (first_vert.XYZ.X - o.OFX) & 0xFF;
 	write_ba = (pos > 112 && pos < 136);
 
 	// Read texture is 8 to 16 pixels (same as above)
 	const float tw = static_cast<float>(1u << m_cached_ctx.TEX0.TW);
-	int tex_pos = (PRIM->FST) ? v[0].U : static_cast<int>(tw * v[0].ST.S);
+	int tex_pos = (PRIM->FST) ? first_vert.U : static_cast<int>(tw * first_vert.ST.S);
 	tex_pos &= 0xFF;
 	read_ba = (tex_pos > 112 && tex_pos < 144);