From 836daad0ae3690fdc01e435d16acf1e7142b40f3 Mon Sep 17 00:00:00 2001
From: David Allemang <david.allemang@kitware.com>
Date: Mon, 1 Apr 2024 22:12:22 -0400
Subject: [PATCH] create swapchain, fetch images, image views

---
 src/main.zig | 121 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 105 insertions(+), 16 deletions(-)

diff --git a/src/main.zig b/src/main.zig
index fd12717..9427a78 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -246,12 +246,12 @@ fn create_device(
 
 fn find_surface_format(
     pdev: vk.PhysicalDevice,
+    vki: gfx.InstanceDispatch,
     surface: vk.SurfaceKHR,
     preferred: vk.SurfaceFormatKHR,
-    vki: gfx.InstanceDispatch,
 ) !vk.SurfaceFormatKHR {
     var formats_buf: [64]vk.SurfaceFormatKHR = undefined;
-    var formats_count: u32 = 64;
+    var formats_count: u32 = @intCast(formats_buf.len);
     _ = try vki.getPhysicalDeviceSurfaceFormatsKHR(pdev, surface, &formats_count, &formats_buf);
     const formats = formats_buf[0..formats_count];
 
@@ -264,6 +264,57 @@ fn find_surface_format(
     return formats[0];
 }
 
+fn find_present_mode(
+    pdev: vk.PhysicalDevice,
+    vki: gfx.InstanceDispatch,
+    surface: vk.SurfaceKHR,
+    preferred: vk.PresentModeKHR,
+) !vk.PresentModeKHR {
+    var modes_buf: [8]vk.PresentModeKHR = undefined;
+    var modes_count: u32 = @intCast(modes_buf.len);
+    _ = try vki.getPhysicalDeviceSurfacePresentModesKHR(pdev, surface, &modes_count, &modes_buf);
+    const modes = modes_buf[0..modes_count];
+
+    for (modes) |mode| {
+        if (std.meta.eql(mode, preferred)) {
+            return mode;
+        }
+    }
+
+    return .mailbox_khr;
+}
+
+fn find_swap_extent(
+    pdev: vk.PhysicalDevice,
+    vki: gfx.InstanceDispatch,
+    surface: vk.SurfaceKHR,
+    window: *c.GLFWwindow,
+) !vk.Extent2D {
+    const caps = try vki.getPhysicalDeviceSurfaceCapabilitiesKHR(pdev, surface);
+    var extent = caps.current_extent;
+
+    if (extent.width == std.math.maxInt(u32)) {
+        c.glfwGetFramebufferSize(window, @ptrCast(&extent.width), @ptrCast(&extent.height));
+        extent.width = std.math.clamp(extent.width, caps.min_image_extent.width, caps.max_image_extent.width);
+        extent.height = std.math.clamp(extent.height, caps.min_image_extent.height, caps.max_image_extent.height);
+    }
+
+    return extent;
+}
+
+fn find_swap_image_count(
+    pdev: vk.PhysicalDevice,
+    vki: gfx.InstanceDispatch,
+    surface: vk.SurfaceKHR,
+) !u32 {
+    const caps = try vki.getPhysicalDeviceSurfaceCapabilitiesKHR(pdev, surface);
+    var count = caps.min_image_count + 1;
+    if (caps.max_image_count > 0) {
+        count = @min(count, caps.max_image_count);
+    }
+    return count;
+}
+
 pub fn main() !void {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     defer _ = gpa.deinit();
@@ -302,22 +353,60 @@ pub fn main() !void {
         .format = .b8g8r8a8_srgb,
         .color_space = .srgb_nonlinear_khr,
     };
-    const format = try find_surface_format(pdev, surface, preferred_format, vki);
+    const format = try find_surface_format(pdev, vki, surface, preferred_format);
+    extent = try find_swap_extent(pdev, vki, surface, window);
 
-    _ = &extent;
+    const present_mode = try find_present_mode(pdev, vki, surface, .mailbox_khr);
 
-    // const gc: Context = .{
-    //     .vki = vki,
-    //     .vkd = vkd,
-    //     .pdev = pdev,
-    //     .dev = dev,
-    //     .surface = surface,
-    //     .queue = queue,
-    //     .family = family,
-    // };
-    //
-    // var swapchain = try Swapchain.init(&gc, ally, extent, format);
-    // defer swapchain.deinit();
+    const swap_image_count = try find_swap_image_count(pdev, vki, surface);
+
+    var swapchain: vk.SwapchainKHR = .null_handle;
+    defer vkd.destroySwapchainKHR(dev, swapchain, null);
+
+    var image_buf: [8]vk.Image = undefined;
+    @memset(&image_buf, .null_handle);
+    var images: []vk.Image = &.{};
+    var image_views_buf: [8]vk.ImageView = undefined;
+    @memset(&image_views_buf, .null_handle);
+    var image_views: []vk.ImageView = &.{};
+
+    swapchain = try vkd.createSwapchainKHR(dev, &.{
+        .surface = surface,
+        .min_image_count = swap_image_count,
+        .image_format = format.format,
+        .image_color_space = format.color_space,
+        .image_extent = extent,
+        .image_array_layers = 1,
+        .image_usage = .{ .color_attachment_bit = true },
+        .image_sharing_mode = .exclusive,
+        .pre_transform = .{ .identity_bit_khr = true },
+        .composite_alpha = .{ .opaque_bit_khr = true },
+        .present_mode = present_mode,
+        .clipped = vk.TRUE,
+        .old_swapchain = swapchain,
+    }, null);
+
+    var image_count: u32 = @intCast(image_buf.len);
+    _ = try vkd.getSwapchainImagesKHR(dev, swapchain, &image_count, &image_buf);
+    images = image_buf[0..image_count];
+    image_views = image_views_buf[0..image_count];
+    defer for (image_views) |view| vkd.destroyImageView(dev, view, null);
+
+    for (images, image_views) |image, *view| {
+        view.* = try vkd.createImageView(dev, &.{
+            .image = image,
+            .view_type = .@"2d",
+            .format = format.format,
+            .components = .{ .r = .identity, .g = .identity, .b = .identity, .a = .identity },
+            .subresource_range = .{
+                .aspect_mask = .{ .color_bit = true },
+                .base_mip_level = 0,
+                .level_count = 1,
+                .base_array_layer = 0,
+                .layer_count = 1,
+            },
+        }, null);
+    }
 
     const pipeline_layout = try vkd.createPipelineLayout(dev, &.{
         .flags = .{},