vkgears: do swapchain configuration up-front

There's no point in redoing all of the swapchain configuration when
resizing the window; yeah, something's changed, but not *everything*.

Let's move all configuration decisions to its own function, which runs
before all the other logic. This is going to help us properly pick color
formats in the next patch also.

Acked-by: Hoe Hao Cheng <haochengho12907@gmail.com>

1 files changed, 23 insertions, 21 deletions

diff --git a/src/vulkan/vkgears.c b/src/vulkan/vkgears.c
index d598e12b..04335464 100644
--- a/src/vulkan/vkgears.c
+++ b/src/vulkan/vkgears.c
@@ -59,8 +59,10 @@ static VkSampleCountFlagBits sample_count;
 static uint32_t image_count;
 static VkRenderPass render_pass;
 static VkCommandPool cmd_pool;
+static VkPresentModeKHR present_mode;
 static VkFormat image_format;
 static VkFormat depth_format;
+uint32_t min_image_count = 2;
 static VkSurfaceKHR surface;
 static VkSwapchainKHR swap_chain;
 static VkImage color_msaa, depth_image;
@@ -419,7 +421,7 @@ create_render_pass()
 }
 
 static void
-create_swapchain()
+configure_swapchain()
 {
    VkSurfaceCapabilitiesKHR surface_caps;
    vkGetPhysicalDeviceSurfaceCapabilitiesKHR(physical_device, surface,
@@ -439,7 +441,7 @@ create_swapchain()
    vkGetPhysicalDeviceSurfacePresentModesKHR(physical_device, surface,
                                              &count, present_modes);
    int i;
-   VkPresentModeKHR present_mode = VK_PRESENT_MODE_FIFO_KHR;
+   present_mode = VK_PRESENT_MODE_FIFO_KHR;
    for (i = 0; i < count; i++) {
       if (present_modes[i] == desidered_present_mode) {
          present_mode = desidered_present_mode;
@@ -447,25 +449,37 @@ create_swapchain()
       }
    }
 
-   uint32_t minImageCount = 2;
-   if (minImageCount < surface_caps.minImageCount) {
+   min_image_count = 2;
+   if (min_image_count < surface_caps.minImageCount) {
       if (surface_caps.minImageCount > ARRAY_SIZE(swap_chain_data))
           error("surface_caps.minImageCount is too large (is: %d, max: %d)",
                 surface_caps.minImageCount, ARRAY_SIZE(swap_chain_data));
-      minImageCount = surface_caps.minImageCount;
+      min_image_count = surface_caps.minImageCount;
    }
 
    if (surface_caps.maxImageCount > 0 &&
-       minImageCount > surface_caps.maxImageCount) {
-      minImageCount = surface_caps.maxImageCount;
+       min_image_count > surface_caps.maxImageCount) {
+      min_image_count = surface_caps.maxImageCount;
    }
 
+   image_format = VK_FORMAT_B8G8R8A8_SRGB;
+
+   // either VK_FORMAT_D32_SFLOAT or VK_FORMAT_X8_D24_UNORM_PACK32 needs to be supported; find out which one
+   VkFormatProperties props;
+   vkGetPhysicalDeviceFormatProperties(physical_device, VK_FORMAT_D32_SFLOAT, &props);
+   depth_format = (props.optimalTilingFeatures & VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT) ?
+      VK_FORMAT_D32_SFLOAT : VK_FORMAT_X8_D24_UNORM_PACK32;
+}
+
+static void
+create_swapchain()
+{
    vkCreateSwapchainKHR(device,
       &(VkSwapchainCreateInfoKHR) {
          .sType = VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR,
          .flags = 0,
          .surface = surface,
-         .minImageCount = minImageCount,
+         .minImageCount = min_image_count,
          .imageFormat = image_format,
          .imageColorSpace = VK_COLOR_SPACE_SRGB_NONLINEAR_KHR,
          .imageExtent = { width, height },
@@ -1307,16 +1321,6 @@ print_info()
    }
 }
 
-static VkFormat
-find_depth_format()
-{
-   // either VK_FORMAT_D32_SFLOAT or VK_FORMAT_X8_D24_UNORM_PACK32 needs to be supported; find out which one
-   VkFormatProperties props;
-   vkGetPhysicalDeviceFormatProperties(physical_device, VK_FORMAT_D32_SFLOAT, &props);
-   return (props.optimalTilingFeatures & VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT) ?
-      VK_FORMAT_D32_SFLOAT : VK_FORMAT_X8_D24_UNORM_PACK32;
-}
-
 static VkSampleCountFlagBits
 sample_count_flag(int sample_count)
 {
@@ -1479,16 +1483,14 @@ main(int argc, char *argv[])
       error("Sample count not supported");
 
    int attachment_count = sample_count != VK_SAMPLE_COUNT_1_BIT ? 3 : 2;
-   image_format = VK_FORMAT_B8G8R8A8_SRGB;
 
    if (printInfo)
       print_info();
 
-   depth_format = find_depth_format();
-
    if (!wsi.create_surface(physical_device, instance, &surface))
       error("Failed to create surface!");
 
+   configure_swapchain();
    create_render_pass();
    create_swapchain();
    init_gears();