From 773cb5fa70ecb34e9a70b6ec855b0c2db5fd6eb6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Wed, 21 Aug 2019 21:13:56 +0200
Subject: [PATCH] Stop renderpass merging at readbacks.

---
 ext/native/thin3d/VulkanQueueRunner.cpp | 27 ++++++++++++++-----------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/ext/native/thin3d/VulkanQueueRunner.cpp b/ext/native/thin3d/VulkanQueueRunner.cpp
index 4021e93d62..b2468b556c 100644
--- a/ext/native/thin3d/VulkanQueueRunner.cpp
+++ b/ext/native/thin3d/VulkanQueueRunner.cpp
@@ -380,7 +380,6 @@ void VulkanQueueRunner::RunSteps(VkCommandBuffer cmd, std::vector<VKRStep *> &st
 	// Planned optimizations: 
 	//  * Create copies of render target that are rendered to multiple times and textured from in sequence, and push those render passes
 	//    as early as possible in the frame (Wipeout billboards).
-	//  * Merge subsequent render passes to the same target that are interspersed with unrelated draws to other render targets (God of War).
 
 	for (int j = 0; j < (int)steps.size(); j++) {
 		if (steps[j]->stepType == VKRStepType::RENDER &&
@@ -721,10 +720,10 @@ std::string VulkanQueueRunner::StepToString(const VKRStep &step) const {
 		snprintf(buffer, sizeof(buffer), "Blit (%dx%d->%dx%d)", step.blit.srcRect.extent.width, step.blit.srcRect.extent.height, step.blit.dstRect.extent.width, step.blit.dstRect.extent.height);
 		break;
 	case VKRStepType::READBACK:
-		snprintf(buffer, sizeof(buffer), "Readback (%dx%d)", step.readback.srcRect.extent.width, step.readback.srcRect.extent.height);
+		snprintf(buffer, sizeof(buffer), "Readback (%dx%d, fb: %p)", step.readback.srcRect.extent.width, step.readback.srcRect.extent.height, step.readback.src);
 		break;
 	case VKRStepType::READBACK_IMAGE:
-		snprintf(buffer, sizeof(buffer), "ReadbackImage");
+		snprintf(buffer, sizeof(buffer), "ReadbackImage (%dx%d)", step.readback_image.srcRect.extent.width, step.readback_image.srcRect.extent.height);
 		break;
 	case VKRStepType::RENDER_SKIP:
 		snprintf(buffer, sizeof(buffer), "(SKIPPED RenderPass)");
@@ -740,7 +739,6 @@ std::string VulkanQueueRunner::StepToString(const VKRStep &step) const {
 // much a guaranteed neutral or win in terms of GPU power. However, dependency calculation really
 // must be perfect!
 void VulkanQueueRunner::ApplyRenderPassMerge(std::vector<VKRStep *> &steps) {
-	return;
 	// First let's count how many times each framebuffer is rendered to.
 	// If it's more than one, let's do our best to merge them. This can help God of War quite a bit.
 
@@ -784,6 +782,11 @@ void VulkanQueueRunner::ApplyRenderPassMerge(std::vector<VKRStep *> &steps) {
 						goto done_fb;
 					}
 					break;
+				case VKRStepType::READBACK:
+					if (steps[j]->readback.src == fb) {
+						goto done_fb;
+					}
+					break;
 				}
 			}
 			done_fb:
@@ -864,20 +867,20 @@ void VulkanQueueRunner::LogRenderPass(const VKRStep &pass) {
 	ILOG("RenderPass End(%x)", fb);
 }
 
-void VulkanQueueRunner::LogCopy(const VKRStep &pass) {
-	ILOG("Copy()");
+void VulkanQueueRunner::LogCopy(const VKRStep &step) {
+	ILOG("%s", StepToString(step).c_str());
 }
 
-void VulkanQueueRunner::LogBlit(const VKRStep &pass) {
-	ILOG("Blit()");
+void VulkanQueueRunner::LogBlit(const VKRStep &step) {
+	ILOG("%s", StepToString(step).c_str());
 }
 
-void VulkanQueueRunner::LogReadback(const VKRStep &pass) {
-	ILOG("Readback");
+void VulkanQueueRunner::LogReadback(const VKRStep &step) {
+	ILOG("%s", StepToString(step).c_str());
 }
 
-void VulkanQueueRunner::LogReadbackImage(const VKRStep &pass) {
-	ILOG("ReadbackImage");
+void VulkanQueueRunner::LogReadbackImage(const VKRStep &step) {
+	ILOG("%s", StepToString(step).c_str());
 }
 
 void VulkanQueueRunner::PerformRenderPass(const VKRStep &step, VkCommandBuffer cmd) {