rsx: Blit engine tuning

- Attempt to identify blit operations that will be flushed immediately
after and just do them on CPU instead if the transformation is trivial.
- If only a single blit section is contributing to an atlas merge op, the
threshold should be 100%. The only acceptable result here is a
truncation.

rpcs3/Emu/RSX/Common/texture_cache.h

@@ -213,7 +213,8 @@ namespace rsx
 				}
 			}
 
-			bool atlas_covers_target_area() const
+			// Returns true if at least threshold% is covered in pixels
+			bool atlas_covers_target_area(u32 threshold) const
 			{
 				if (external_subresource_desc.op != deferred_request_command::atlas_gather)
 					return true;
@@ -222,7 +223,7 @@ namespace rsx
 					max_x = 0, max_y = 0;
 
 				// Require at least 90% coverage
-				const u32 target_area = ((min_x * min_y) * 90u) / 100u;
+				const u32 target_area = ((min_x * min_y) * threshold) / 100u;
 
 				for (const auto &section : external_subresource_desc.sections_to_copy)
 				{
@@ -1654,8 +1655,8 @@ namespace rsx
 						return {};
 					}
 
-					if (!result.external_subresource_desc.sections_to_copy.empty() &&
+					if (const auto section_count = result.external_subresource_desc.sections_to_copy.size();
-						(_pool == 0 || result.atlas_covers_target_area()))
+						section_count > 0 && result.atlas_covers_target_area(section_count == 1? 99 : 90))
 					{
 						// TODO: Overlapped section persistance is required for framebuffer resources to work with this!
 						// Yellow filter in SCV is because of a 384x384 surface being reused as 160x90 (and likely not getting written to)
@@ -1921,6 +1922,7 @@ namespace rsx
 
 			const bool is_copy_op = (fcmp(scale_x, 1.f) && fcmp(scale_y, 1.f));
 			const bool is_format_convert = (dst_is_argb8 != src_is_argb8);
+			bool skip_if_collision_exists = false;
 
 			// Offset in x and y for src is 0 (it is already accounted for when getting pixels_src)
 			// Reproject final clip onto source...
@@ -2075,6 +2077,9 @@ namespace rsx
 							return false;
 						}
 					}
+
+					// If a matching section exists with a different use-case, fall back to CPU memcpy
+					skip_if_collision_exists = true;
 				}
 
 				if (!g_cfg.video.use_gpu_texture_scaling)
@@ -2176,9 +2181,20 @@ namespace rsx
 			if (!dst_is_render_target)
 			{
 				// Check for any available region that will fit this one
-				const auto required_type = (use_null_region) ? texture_upload_context::dma : texture_upload_context::blit_engine_dst;
+				u32 required_type_mask;
+				if (use_null_region)
+				{
+					required_type_mask = texture_upload_context::dma;
+				}
+				else
+				{
+					required_type_mask = texture_upload_context::blit_engine_dst;
+					if (skip_if_collision_exists) required_type_mask |= texture_upload_context::shader_read;
+				}
+
 				const auto dst_range = address_range::start_length(dst_address, dst_payload_length);
-				auto overlapping_surfaces = find_texture_from_range(dst_range, dst.pitch, required_type);
+				auto overlapping_surfaces = find_texture_from_range(dst_range, dst.pitch, required_type_mask);
+
 				for (const auto &surface : overlapping_surfaces)
 				{
 					if (!surface->is_locked())
@@ -2194,23 +2210,30 @@ namespace rsx
 						continue;
 					}
 
+					if (!dst_range.inside(surface->get_section_range()))
+					{
+						// Hit test failed
+						continue;
+					}
+
 					if (use_null_region)
 					{
-						if (dst_range.inside(surface->get_section_range()))
+
-						{
 						// Attach to existing region
 						cached_dest = surface;
-						}
 
 						// Technically it is totally possible to just extend a pre-existing section
 						// Will leave this as a TODO
 						continue;
 					}
 
-					const auto this_address = surface->get_section_base();
+					if (UNLIKELY(skip_if_collision_exists))
-					if (this_address > dst_address)
 					{
-						continue;
+						if (surface->get_context() != texture_upload_context::blit_engine_dst)
+						{
+							// This section is likely to be 'flushed' to CPU for reupload soon anyway
+							return false;
+						}
 					}
 
 					switch (surface->get_gcm_format())
@@ -2227,7 +2250,8 @@ namespace rsx
 						continue;
 					}
 
-					if (const u32 address_offset = dst_address - this_address)
+					if (const auto this_address = surface->get_section_base();
+						const u32 address_offset = dst_address - this_address)
 					{
 						const u16 offset_y = address_offset / dst.pitch;
 						const u16 offset_x = address_offset % dst.pitch;