Vk: add MemoryRequirements::alignedSize().

Realized usefulness of such an utility while writing a documentation
snippet.

src/Magnum/Vk/CMakeLists.txt

@@ -32,7 +32,6 @@ set(MagnumVk_SRCS
     Extensions.cpp
     Handle.cpp
     Instance.cpp
-    Memory.cpp
     Result.cpp
     Shader.cpp
     Version.cpp
@@ -48,7 +47,8 @@ set(MagnumVk_GracefulAssert_SRCS
     Enums.cpp
     ExtensionProperties.cpp
     Image.cpp
-    LayerProperties.cpp)
+    LayerProperties.cpp
+    Memory.cpp)
 
 set(MagnumVk_HEADERS
     Assert.h

src/Magnum/Vk/Memory.cpp

@@ -46,6 +46,11 @@ MemoryRequirements::MemoryRequirements(const VkMemoryRequirements2& requirements
        member instead of doing a copy */
     _requirements(requirements) {}
 
+UnsignedLong MemoryRequirements::alignedSize(const UnsignedLong alignment) const {
+    CORRADE_ASSERT(alignment, "Vk::MemoryRequirements::alignedSize(): alignment can't be zero", {});
+    return ((_requirements.memoryRequirements.size + alignment - 1)/alignment)*alignment;
+}
+
 MemoryAllocateInfo::MemoryAllocateInfo(UnsignedLong size, UnsignedInt memory): _info{} {
     _info.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
     _info.allocationSize = size;

src/Magnum/Vk/Memory.h

@@ -161,16 +161,35 @@ class MAGNUM_VK_EXPORT MemoryRequirements {
         /** @overload */
         const VkMemoryRequirements2* operator->() const { return &_requirements; }
 
-        /** @brief Required memory size */
+        /**
+         * @brief Required memory size
+         *
+         * @see @ref alignedSize()
+         */
         UnsignedLong size() const {
             return _requirements.memoryRequirements.size;
         }
 
-        /** @brief Required memory alignment */
+        /**
+         * @brief Required memory alignment
+         *
+         * @see @ref alignedSize()
+         */
         UnsignedLong alignment() const {
             return _requirements.memoryRequirements.alignment;
         }
 
+        /**
+         * @brief Required memory size rounded up for given alignment
+         *
+         * Pads @ref size() with given alignment requirements. For example, a
+         * 13765-byte buffer aligned to 4 kB would be 16384 bytes. See the
+         * @ref Memory class for more information and example usage.
+         *
+         * The alignment is expected to be non-zero.
+         */
+        UnsignedLong alignedSize(UnsignedLong alignment) const;
+
         /** @brief Bits indicating which memory  */
         UnsignedInt memories() const {
             return _requirements.memoryRequirements.memoryTypeBits;

src/Magnum/Vk/Test/CMakeLists.txt

@@ -37,7 +37,7 @@ corrade_add_test(VkImageTest ImageTest.cpp LIBRARIES MagnumVkTestLib)
 corrade_add_test(VkInstanceTest InstanceTest.cpp LIBRARIES MagnumVk)
 corrade_add_test(VkIntegrationTest IntegrationTest.cpp LIBRARIES MagnumVk)
 corrade_add_test(VkLayerPropertiesTest LayerPropertiesTest.cpp LIBRARIES MagnumVk)
-corrade_add_test(VkMemoryTest MemoryTest.cpp LIBRARIES MagnumVk)
+corrade_add_test(VkMemoryTest MemoryTest.cpp LIBRARIES MagnumVkTestLib)
 corrade_add_test(VkResultTest ResultTest.cpp LIBRARIES MagnumVk)
 corrade_add_test(VkShaderTest ShaderTest.cpp LIBRARIES MagnumVk)
 

src/Magnum/Vk/Test/MemoryTest.cpp

@@ -37,6 +37,9 @@ struct MemoryTest: TestSuite::Tester {
     void requirementsConstructNoInit();
     void requirementsConstructFromVk();
 
+    void requirementsAlignedSize();
+    void requirementsAlignedSizeZeroAlignement();
+
     void allocateInfoConstruct();
     void allocateInfoConstructNoInit();
     void allocateInfoConstructFromVk();
@@ -52,6 +55,9 @@ MemoryTest::MemoryTest() {
     addTests({&MemoryTest::requirementsConstructNoInit,
               &MemoryTest::requirementsConstructFromVk,
 
+              &MemoryTest::requirementsAlignedSize,
+              &MemoryTest::requirementsAlignedSizeZeroAlignement,
+
               &MemoryTest::allocateInfoConstruct,
               &MemoryTest::allocateInfoConstructNoInit,
               &MemoryTest::allocateInfoConstructFromVk,
@@ -83,6 +89,36 @@ void MemoryTest::requirementsConstructFromVk() {
     CORRADE_COMPARE(requirements->sType, VK_STRUCTURE_TYPE_APPLICATION_INFO);
 }
 
+void MemoryTest::requirementsAlignedSize() {
+    /* Creating from a raw Vulkan structure because there's no other way */
+    VkMemoryRequirements2 vkRequirements{};
+    vkRequirements.memoryRequirements.size = 13765;
+    CORRADE_COMPARE(MemoryRequirements{vkRequirements}.alignedSize(4096), 16384);
+
+    vkRequirements.memoryRequirements.size = 16383;
+    CORRADE_COMPARE(MemoryRequirements{vkRequirements}.alignedSize(4096), 16384);
+
+    vkRequirements.memoryRequirements.size = 16384;
+    CORRADE_COMPARE(MemoryRequirements{vkRequirements}.alignedSize(4096), 16384);
+
+    vkRequirements.memoryRequirements.size = 0;
+    CORRADE_COMPARE(MemoryRequirements{vkRequirements}.alignedSize(4096), 0);
+}
+
+void MemoryTest::requirementsAlignedSizeZeroAlignement() {
+    #ifdef CORRADE_NO_ASSERT
+    CORRADE_SKIP("CORRADE_NO_ASSERT defined, can't test assertions");
+    #endif
+
+    VkMemoryRequirements2 vkRequirements{};
+    vkRequirements.memoryRequirements.size = 16384;
+
+    std::ostringstream out;
+    Error redirectError{&out};
+    MemoryRequirements{vkRequirements}.alignedSize(0);
+    CORRADE_COMPARE(out.str(), "Vk::MemoryRequirements::alignedSize(): alignment can't be zero\n");
+}
+
 void MemoryTest::allocateInfoConstruct() {
     MemoryAllocateInfo info{65536, 1};
     CORRADE_COMPARE(info->allocationSize, 65536);