From aa61a5cc653f587f4dfae8e2d485f4e79dffdb27 Mon Sep 17 00:00:00 2001
From: Aqua <ollie@ollierobinson.co.uk>
Date: Mon, 2 Sep 2024 20:32:07 +0100
Subject: [PATCH] swapchain textures

---
 src/grabs.Graphics.Vulkan/VkSwapchain.cs      | 17 ++++-
 .../VkSwapchainTexture.cs                     | 64 +++++++++++++++++++
 tests/grabs.Tests/Program.cs                  |  4 ++
 3 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 src/grabs.Graphics.Vulkan/VkSwapchainTexture.cs

diff --git a/src/grabs.Graphics.Vulkan/VkSwapchain.cs b/src/grabs.Graphics.Vulkan/VkSwapchain.cs
index 1ca5399..221e8b8 100644
--- a/src/grabs.Graphics.Vulkan/VkSwapchain.cs
+++ b/src/grabs.Graphics.Vulkan/VkSwapchain.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Runtime.CompilerServices;
 using Silk.NET.Vulkan;
 using Silk.NET.Vulkan.Extensions.KHR;
@@ -9,6 +10,10 @@ public sealed unsafe class VkSwapchain : Swapchain
 {
     private readonly Vk _vk;
     private readonly VulkanDevice _device;
+
+    private readonly Format _format;
+    private uint _width;
+    private uint _height;
     
     private readonly KhrSwapchain _khrSwapchain;
     
@@ -33,6 +38,10 @@ public VkSwapchain(Vk vk, VkDevice device, SurfaceKHR surface, in SwapchainDescr
         _graphicsQueue = device.GraphicsQueue;
         _presentQueue = device.PresentQueue;
 
+        _format = description.Format;
+        _width = description.Width;
+        _height = description.Height;
+
         SwapchainCreateInfoKHR swapchainCreateInfo = new SwapchainCreateInfoKHR()
         {
             SType = StructureType.SwapchainCreateInfoKhr,
@@ -81,7 +90,13 @@ public VkSwapchain(Vk vk, VkDevice device, SurfaceKHR surface, in SwapchainDescr
     
     public override Texture GetSwapchainTexture()
     {
-        throw new System.NotImplementedException();
+        uint numImages;
+        _khrSwapchain.GetSwapchainImages(_device, Swapchain, &numImages, null);
+        Span<Image> images = stackalloc Image[(int) numImages];
+        fixed (Image* pImages = images)
+            _khrSwapchain.GetSwapchainImages(_device, Swapchain, &numImages, pImages);
+
+        return new VkSwapchainTexture(_vk, _device, images, _format, _width, _height);
     }
 
     public override void Resize(uint width, uint height)
diff --git a/src/grabs.Graphics.Vulkan/VkSwapchainTexture.cs b/src/grabs.Graphics.Vulkan/VkSwapchainTexture.cs
new file mode 100644
index 0000000..a91a952
--- /dev/null
+++ b/src/grabs.Graphics.Vulkan/VkSwapchainTexture.cs
@@ -0,0 +1,64 @@
+using System;
+using Silk.NET.Vulkan;
+using static grabs.Graphics.Vulkan.VkResult;
+
+namespace grabs.Graphics.Vulkan;
+
+public sealed unsafe class VkSwapchainTexture : Texture
+{
+    private readonly Vk _vk;
+    private readonly VulkanDevice _device;
+    
+    public readonly Image[] Images;
+    
+    public readonly ImageView[] Views;
+
+    public VkSwapchainTexture(Vk vk, VulkanDevice device, in ReadOnlySpan<Image> images, Format format, uint width, uint height) 
+        : base(TextureDescription.Texture2D(width, height, 1, format, TextureUsage.None))
+    {
+        _vk = vk;
+        _device = device;
+
+        Images = images.ToArray();
+        Views = new ImageView[images.Length];
+
+        for (int i = 0; i < Views.Length; i++)
+        {
+            ImageViewCreateInfo viewInfo = new ImageViewCreateInfo()
+            {
+                SType = StructureType.ImageViewCreateInfo,
+
+                Image = images[i],
+                ViewType = ImageViewType.Type2D,
+                Format = VkUtils.FormatToVk(format),
+
+                Components = new ComponentMapping()
+                {
+                    R = ComponentSwizzle.Identity,
+                    G = ComponentSwizzle.Identity,
+                    B = ComponentSwizzle.Identity,
+                    A = ComponentSwizzle.Identity
+                },
+
+                SubresourceRange = new ImageSubresourceRange()
+                {
+                    AspectMask = ImageAspectFlags.ColorBit,
+                    BaseMipLevel = 0,
+                    LevelCount = 1,
+                    BaseArrayLayer = 0,
+                    LayerCount = 1
+                }
+            };
+
+            CheckResult(_vk.CreateImageView(_device, &viewInfo, null, out Views[i]), "Create swapchain image view");
+        }
+    }
+    
+    public override void Dispose()
+    {
+        for (int i = 0; i < Images.Length; i++)
+            _vk.DestroyImageView(_device, Views[i], null);
+        
+        // Cannot destroy the actual images themselves as they are owned by the swapchain.
+    }
+}
\ No newline at end of file
diff --git a/tests/grabs.Tests/Program.cs b/tests/grabs.Tests/Program.cs
index cbb16c7..58a7534 100644
--- a/tests/grabs.Tests/Program.cs
+++ b/tests/grabs.Tests/Program.cs
@@ -12,6 +12,7 @@
 using Event = Silk.NET.SDL.Event;
 using Instance = grabs.Graphics.Instance;
 using Surface = grabs.Graphics.Surface;
+using Texture = grabs.Graphics.Texture;
 
 GrabsLog.LogMessage += (type, message) => Console.WriteLine($"[{type}] {message}");
 
@@ -122,6 +123,8 @@
     Swapchain swapchain =
         device.CreateSwapchain(new SwapchainDescription(width, height, bufferCount: 4, presentMode: PresentMode.VerticalSync));
 
+    Texture swapchainTexture = swapchain.GetSwapchainTexture();
+
     CommandList commandList = device.CreateCommandList();
 
     bool alive = true;
@@ -150,6 +153,7 @@
     }
     
     commandList.Dispose();
+    swapchainTexture.Dispose();
     swapchain.Dispose();
     device.Dispose();
     surface.Dispose();