From bb5f062751c3492e4916675326ca780f2bf3d4b2 Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@member.fsf.org>
Date: Thu, 23 Dec 2021 11:03:38 +0200
Subject: [PATCH] init flags mechanism

---
 src/app.c |   10 +++++++++-
 src/vk.c  |   30 +++++++++++++++++++++++++++---
 src/vk.h  |    8 +++++++-
 3 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/src/app.c b/src/app.c
index 1d97906..0dca609 100644
--- a/src/app.c
+++ b/src/app.c
@@ -1,12 +1,20 @@
+#include <stdio.h>
 #include <stdlib.h>
 #include "app.h"
 #include "vk.h"
 
 int app_init(void)
 {
-	if(vk_init() == -1) {
+	unsigned int flags;
+
+	if(vk_init(VKINIT_DEPTH | VKINIT_RAY, &flags) == -1) {
 		return -1;
 	}
+	if(!(flags & VKINIT_RAY)) {
+		fprintf(stderr, "Vulkan raytracing extensions not available\n");
+		/*vk_cleanup();
+		return -1;*/
+	}
 	return 0;
 }
 
diff --git a/src/vk.c b/src/vk.c
index f3cb508..917a801 100644
--- a/src/vk.c
+++ b/src/vk.c
@@ -26,6 +26,7 @@ static int have_ext(VkExtensionProperties *ext, int next, const char *name);
 
 static Display *dpy;
 static Window win;
+static int initflags;
 
 static VkInstance vk;
 static VkPhysicalDevice vkpdev;
@@ -57,12 +58,22 @@ void vk_init_xwin(Display *d, Window w)
 	win = w;
 }
 
-int vk_init(void)
+int vk_init(unsigned int flags, unsigned int *usedflags)
 {
+	initflags = flags;
 	if(create_instance() == -1)	return -1;
 	if(create_surface() == -1) return -1;
 	if(choose_phys_dev() == -1) return -1;
 	if(create_device() == -1) return -1;
+
+	if(initflags != flags) {
+		if(usedflags) {
+			*usedflags = initflags;
+		} else {
+			vk_cleanup();
+			return -1;
+		}
+	}
 	return 0;
 }
 
@@ -124,7 +135,10 @@ int vk_reshape(int xsz, int ysz)
 	vksc_extent.width = xsz;
 	vksc_extent.height = ysz;
 
-	return create_swapchain();
+	if(create_swapchain() == -1) return -1;
+
+	/* TODO create depth/stencil buffers as needed (initflags) */
+	return 0;
 }
 
 #define ARRSZ(arr)	(sizeof arr / sizeof *arr)
@@ -316,7 +330,7 @@ static int create_device(void)
 	VkDeviceQueueCreateInfo qinf = {0};
 	VkPhysicalDeviceFeatures feat = {0};
 	VkDeviceCreateInfo devinf = {0};
-	const char *ext[ARRSZ(known_devext_list)];
+	const char *ext[ARRSZ(known_devext_list) + 16];
 	int i, num_ext;
 
 	vkEnumerateDeviceExtensionProperties(vkpdev, 0, &dev_ext_count, 0);
@@ -334,6 +348,16 @@ static int create_device(void)
 		}
 	}
 
+	if(initflags & VKINIT_RAY) {
+		if(have_ext(dev_ext, dev_ext_count, "VK_KHR_acceleration_structure") &&
+				have_ext(dev_ext, dev_ext_count, "VK_KHR_ray_tracing_pipeline")) {
+			ext[num_ext++] = "VK_KHR_acceleration_structure";
+			ext[num_ext++] = "VK_KHR_ray_tracing_pipeline";
+		} else {
+			initflags &= ~VKINIT_RAY;
+		}
+	}
+
 	qinf.sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
 	qinf.queueFamilyIndex = vkqfam_idx;
 	qinf.queueCount = 1;
diff --git a/src/vk.h b/src/vk.h
index 746b0e0..39e2df9 100644
--- a/src/vk.h
+++ b/src/vk.h
@@ -3,9 +3,15 @@
 
 #include <X11/Xlib.h>
 
+enum {
+	VKINIT_DEPTH	= 1,
+	VKINIT_STENCIL	= 2,
+	VKINIT_RAY		= 0x100
+};
+
 void vk_init_xwin(Display *dpy, Window win);
 
-int vk_init(void);
+int vk_init(unsigned int flags, unsigned int *usedflags);
 void vk_cleanup(void);
 
 int vk_reshape(int xsz, int ysz);
-- 
1.7.10.4