Fix allocating multiple sets from desc pool

vulkan-rs/src/descriptorpool.rs

@@ -6,6 +6,7 @@ use std::sync::Arc;
 
 pub struct DescriptorPoolBuilder {
     layout: Option<Arc<DescriptorSetLayout>>,
+    descriptor_count: u32,
     flags: VkDescriptorPoolCreateFlagBits,
 }
 
@@ -16,6 +17,12 @@ impl DescriptorPoolBuilder {
         self
     }
 
+    pub fn set_descriptor_set_count(mut self, count: u32) -> Self {
+        self.descriptor_count = count;
+
+        self
+    }
+
     pub fn set_layout(mut self, layout: Arc<DescriptorSetLayout>) -> Self {
         self.layout = Some(layout);
 
@@ -27,24 +34,29 @@ impl DescriptorPoolBuilder {
             if self.layout.is_none() {
                 panic!("no layout set!");
             }
-        }
 
-        let layout = self.layout.expect("descriptor set layout was not set!");
+            if self.descriptor_count == 0 {
-
-        let descriptor_count: u32 = layout
-            .pool_sizes()
-            .iter()
-            .map(|pool| pool.descriptorCount)
-            .sum();
-
-        if cfg!(debug_assertions) {
-            if descriptor_count == 0 {
                 panic!("descriptor count must be greater than 0");
             }
         }
 
-        let descriptor_pool_ci =
+        let layout = self.layout.expect("descriptor set layout was not set!");
-            VkDescriptorPoolCreateInfo::new(self.flags, descriptor_count, layout.pool_sizes());
+
+        let pool_sizes: Vec<VkDescriptorPoolSize> = layout
+            .pool_sizes()
+            .iter()
+            .cloned()
+            .map(|mut pool_size| {
+                pool_size.descriptorCount *= self.descriptor_count;
+                pool_size
+            })
+            .collect();
+
+        let descriptor_pool_ci = VkDescriptorPoolCreateInfo::new(
+            self.flags,
+            self.descriptor_count,
+            pool_sizes.as_slice(),
+        );
 
         let descriptor_pool = device.create_descriptor_pool(&descriptor_pool_ci)?;
 
@@ -67,6 +79,7 @@ impl DescriptorPool {
     pub fn builder() -> DescriptorPoolBuilder {
         DescriptorPoolBuilder {
             layout: None,
+            descriptor_count: 1,
             flags: VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT.into(),
         }
     }

vulkan-rs/src/descriptorset.rs

@@ -359,11 +359,11 @@ mod test {
                 VK_SHADER_STAGE_FRAGMENT_BIT,
                 0,
             )
-            .change_descriptor_count(DESCRIPTOR_COUNT)
             .build(device.clone())?;
 
         let descriptor_pool = DescriptorPool::builder()
             .set_layout(descriptor_layout.clone())
+            .set_descriptor_set_count(DESCRIPTOR_COUNT)
             .build(device.clone())?;
 
         let descriptors: Vec<Arc<DescriptorSet>> = (0..DESCRIPTOR_COUNT)

vulkan-sys/src/structs/core/descriptorpoolsize.rs

@@ -1,7 +1,7 @@
 use crate::prelude::*;
 
 #[repr(C)]
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct VkDescriptorPoolSize {
     pub ty: VkDescriptorType,
     pub descriptorCount: u32,