vulkan: Only update descriptor sets with contents

If one of the descriptor sets doesn't have any items, don't include it
in the sets passed to vkUpdateDescriptorSets().

This has no effect right now, because we either have both images and
samplers or neither, but it will become relevant once we also support
buffers.

diff --git a/gsk/vulkan/gskvulkanrender.c b/gsk/vulkan/gskvulkanrender.c
index 0e3d7dfaa4efceb3f620a3d1de064cc3d9910928..1ddd1017d16f71655bf83bf0341a48bc11153c9c 100644 (file)
--- a/gsk/vulkan/gskvulkanrender.c
+++ b/gsk/vulkan/gskvulkanrender.c
@@ -524,6 +524,8 @@ static void
 gsk_vulkan_render_prepare_descriptor_sets (GskVulkanRender *self)
 {
   VkDevice device;
+  VkWriteDescriptorSet descriptor_sets[3];
+  gsize n_descriptor_sets;
   GList *l;
 
   device = gdk_vulkan_context_get_device (self->vulkan);
@@ -555,28 +557,36 @@ gsk_vulkan_render_prepare_descriptor_sets (GskVulkanRender *self)
                                           },
                                           &self->descriptor_set);
 
+  n_descriptor_sets = 0;
+  if (gsk_descriptor_image_infos_get_size (&self->descriptor_images) > 0)
+    {
+      descriptor_sets[n_descriptor_sets++] = (VkWriteDescriptorSet) {
+          .sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET,
+          .dstSet = self->descriptor_set,
+          .dstBinding = 0,
+          .dstArrayElement = 0,
+          .descriptorCount = gsk_descriptor_image_infos_get_size (&self->descriptor_images),
+          .descriptorType = VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE,
+          .pImageInfo = gsk_descriptor_image_infos_get_data (&self->descriptor_images)
+      };
+    }
+
+  if (gsk_descriptor_image_infos_get_size (&self->descriptor_samplers) > 0)
+    {
+      descriptor_sets[n_descriptor_sets++] = (VkWriteDescriptorSet) {
+          .sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET,
+          .dstSet = self->descriptor_set,
+          .dstBinding = 1,
+          .dstArrayElement = 0,
+          .descriptorCount = gsk_descriptor_image_infos_get_size (&self->descriptor_samplers),
+          .descriptorType = VK_DESCRIPTOR_TYPE_SAMPLER,
+          .pImageInfo = gsk_descriptor_image_infos_get_data (&self->descriptor_samplers)
+      };
+    }
+
   vkUpdateDescriptorSets (device,
-                          2,
-                          (VkWriteDescriptorSet[2]) {
-                              {
-                                  .sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET,
-                                  .dstSet = self->descriptor_set,
-                                  .dstBinding = 0,
-                                  .dstArrayElement = 0,
-                                  .descriptorCount = gsk_descriptor_image_infos_get_size (&self->descriptor_images),
-                                  .descriptorType = VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE,
-                                  .pImageInfo = gsk_descriptor_image_infos_get_data (&self->descriptor_images)
-                              },
-                              {
-                                  .sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET,
-                                  .dstSet = self->descriptor_set,
-                                  .dstBinding = 1,
-                                  .dstArrayElement = 0,
-                                  .descriptorCount = gsk_descriptor_image_infos_get_size (&self->descriptor_samplers),
-                                  .descriptorType = VK_DESCRIPTOR_TYPE_SAMPLER,
-                                  .pImageInfo = gsk_descriptor_image_infos_get_data (&self->descriptor_samplers)
-                              }
-                          },
+                          n_descriptor_sets,
+                          descriptor_sets,
                           0, NULL);
 }