From 15af767e25a03901db4f754215a343c14d9412e6 Mon Sep 17 00:00:00 2001
From: Lubos <tridosm@gmail.com>
Date: Mon, 24 Jun 2024 17:26:38 +0200
Subject: [PATCH] OpenXR - SBS support prepared

---
 Common/VR/PPSSPPVR.cpp   |  6 ++++--
 Common/VR/VRRenderer.cpp | 22 ++++++++++++++++++----
 Common/VR/VRRenderer.h   |  2 ++
 3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/Common/VR/PPSSPPVR.cpp b/Common/VR/PPSSPPVR.cpp
index ff6fd60f6f..173243fda9 100644
--- a/Common/VR/PPSSPPVR.cpp
+++ b/Common/VR/PPSSPPVR.cpp
@@ -670,11 +670,13 @@ bool StartVRRender() {
 		if (g_Config.bEnableVR && !vrIncompatibleGame && (appMode == VR_GAME_MODE) && vrScene) {
 			VR_SetConfig(VR_CONFIG_MODE, vrStereo ? VR_MODE_STEREO_6DOF : VR_MODE_MONO_6DOF);
 			vrFlatGame = false;
-		} else {
+		} else if (appMode == VR_GAME_MODE) {
 			VR_SetConfig(VR_CONFIG_MODE, vrStereo ? VR_MODE_STEREO_SCREEN : VR_MODE_MONO_SCREEN);
 			if (IsGameVRScene()) {
 				vrFlatGame = true;
 			}
+		} else {
+			VR_SetConfig(VR_CONFIG_MODE, VR_MODE_MONO_SCREEN);
 		}
 		vr3DGeometryCount /= 2;
 
@@ -709,7 +711,7 @@ int GetVRFBOIndex() {
 
 int GetVRPassesCount() {
 	bool vrStereo = !PSP_CoreParameter().compat.vrCompat().ForceMono && g_Config.bEnableStereo;
-    return vrStereo ? 2 : 1;
+	return vrStereo ? 2 : 1;
 }
 
 bool IsPassthroughSupported() {
diff --git a/Common/VR/VRRenderer.cpp b/Common/VR/VRRenderer.cpp
index f9a55fcb5f..441eac8f8b 100644
--- a/Common/VR/VRRenderer.cpp
+++ b/Common/VR/VRRenderer.cpp
@@ -384,14 +384,14 @@ void VR_EndFrame( engine_t* engine ) {
 void VR_FinishFrame( engine_t* engine ) {
 	int vrMode = vrConfig[VR_CONFIG_MODE];
 	XrCompositionLayerProjectionView projection_layer_elements[2] = {};
-	if ((vrMode == VR_MODE_MONO_6DOF) || (vrMode == VR_MODE_STEREO_6DOF)) {
+	if ((vrMode == VR_MODE_MONO_6DOF) || (vrMode == VR_MODE_SBS_6DOF) || (vrMode == VR_MODE_STEREO_6DOF)) {
 		VR_SetConfigFloat(VR_CONFIG_MENU_YAW, hmdorientation.y);
 
 		for (int eye = 0; eye < ovrMaxNumEyes; eye++) {;
 			ovrFramebuffer* frameBuffer = &engine->appState.Renderer.FrameBuffer[0];
 			XrPosef pose = invViewTransform[0];
-			if (vrMode != VR_MODE_MONO_6DOF) {
-                frameBuffer = &engine->appState.Renderer.FrameBuffer[eye];
+			if (vrMode == VR_MODE_STEREO_6DOF) {
+				frameBuffer = &engine->appState.Renderer.FrameBuffer[eye];
 				pose = invViewTransform[eye];
 			}
 
@@ -407,6 +407,13 @@ void VR_FinishFrame( engine_t* engine ) {
 			projection_layer_elements[eye].subImage.imageRect.extent.width = frameBuffer->ColorSwapChain.Width;
 			projection_layer_elements[eye].subImage.imageRect.extent.height = frameBuffer->ColorSwapChain.Height;
 			projection_layer_elements[eye].subImage.imageArrayIndex = 0;
+
+			if (vrMode == VR_MODE_SBS_6DOF) {
+				projection_layer_elements[eye].subImage.imageRect.extent.width /= 2;
+				if (eye == 1) {
+					projection_layer_elements[eye].subImage.imageRect.offset.x += frameBuffer->ColorSwapChain.Width / 2;
+				}
+			}
 		}
 
 		XrCompositionLayerProjection projection_layer = {};
@@ -418,7 +425,7 @@ void VR_FinishFrame( engine_t* engine ) {
 		projection_layer.views = projection_layer_elements;
 
 		engine->appState.Layers[engine->appState.LayerCount++].Projection = projection_layer;
-	} else if ((vrMode == VR_MODE_MONO_SCREEN) || (vrMode == VR_MODE_STEREO_SCREEN)) {
+	} else if ((vrMode == VR_MODE_MONO_SCREEN) || (vrMode == VR_MODE_SBS_SCREEN) || (vrMode == VR_MODE_STEREO_SCREEN)) {
 
 		// Flat screen pose
 		float distance = VR_GetConfigFloat(VR_CONFIG_CANVAS_DISTANCE) / 4.0f - 1.0f;
@@ -455,6 +462,13 @@ void VR_FinishFrame( engine_t* engine ) {
 		if (vrMode == VR_MODE_MONO_SCREEN) {
 			cylinder_layer.eyeVisibility = XR_EYE_VISIBILITY_BOTH;
 			engine->appState.Layers[engine->appState.LayerCount++].Cylinder = cylinder_layer;
+		} else if (vrMode == VR_MODE_SBS_SCREEN) {
+			cylinder_layer.eyeVisibility = XR_EYE_VISIBILITY_LEFT;
+			cylinder_layer.subImage.imageRect.extent.width /= 2;
+			engine->appState.Layers[engine->appState.LayerCount++].Cylinder = cylinder_layer;
+			cylinder_layer.eyeVisibility = XR_EYE_VISIBILITY_RIGHT;
+			cylinder_layer.subImage.imageRect.offset.x += cylinder_layer.subImage.imageRect.extent.width;
+			engine->appState.Layers[engine->appState.LayerCount++].Cylinder = cylinder_layer;
 		} else {
 			cylinder_layer.eyeVisibility = XR_EYE_VISIBILITY_LEFT;
 			engine->appState.Layers[engine->appState.LayerCount++].Cylinder = cylinder_layer;
diff --git a/Common/VR/VRRenderer.h b/Common/VR/VRRenderer.h
index a86a859219..6c86761730 100644
--- a/Common/VR/VRRenderer.h
+++ b/Common/VR/VRRenderer.h
@@ -27,8 +27,10 @@ enum VRConfigFloat {
 
 enum VRMode {
 	VR_MODE_MONO_SCREEN,
+	VR_MODE_SBS_SCREEN,
 	VR_MODE_STEREO_SCREEN,
 	VR_MODE_MONO_6DOF,
+	VR_MODE_SBS_6DOF,
 	VR_MODE_STEREO_6DOF
 };