Vk: store size in the Framebuffer and reuse it in RenderPassCreateInfo.

Since this is the most common use case, it makes sense.

src/Magnum/Vk/Framebuffer.cpp

@@ -92,21 +92,34 @@ FramebufferCreateInfo& FramebufferCreateInfo::operator=(FramebufferCreateInfo&&
     return *this;
 }
 
-Framebuffer Framebuffer::wrap(Device& device, const VkFramebuffer handle, const HandleFlags flags) {
+Framebuffer Framebuffer::wrap(Device& device, const VkFramebuffer handle, const Vector3i& size, const HandleFlags flags) {
     Framebuffer out{NoCreate};
     out._device = &device;
     out._handle = handle;
     out._flags = flags;
+
+    /* See the _size member for more information */
+    CORRADE_INTERNAL_ASSERT((size <= Vector3i{0xffff}).all());
+    out._size[0] = size.x();
+    out._size[1] = size.y();
+    out._size[2] = size.z();
+
     return out;
 }
 
 Framebuffer::Framebuffer(Device& device, const FramebufferCreateInfo& info): _device{&device}, _flags{HandleFlag::DestroyOnDestruction} {
     MAGNUM_VK_INTERNAL_ASSERT_SUCCESS(device->CreateFramebuffer(device, info, nullptr, &_handle));
+
+    /* See the _size member for more information */
+    CORRADE_INTERNAL_ASSERT(info->width <= 0xffff && info->height <= 0xffff && info->layers <= 0xffff);
+    _size[0] = info->width;
+    _size[1] = info->height;
+    _size[2] = info->layers;
 }
 
-Framebuffer::Framebuffer(NoCreateT): _device{}, _handle{} {}
+Framebuffer::Framebuffer(NoCreateT): _device{}, _handle{}, _size{} {}
 
-Framebuffer::Framebuffer(Framebuffer&& other) noexcept: _device{other._device}, _handle{other._handle}, _flags{other._flags} {
+Framebuffer::Framebuffer(Framebuffer&& other) noexcept: _device{other._device}, _handle{other._handle}, _flags{other._flags}, _size{other._size[0], other._size[1], other._size[2]} {
     other._handle = {};
 }
 
@@ -120,9 +133,14 @@ Framebuffer& Framebuffer::operator=(Framebuffer&& other) noexcept {
     swap(other._device, _device);
     swap(other._handle, _handle);
     swap(other._flags, _flags);
+    swap(other._size, _size);
     return *this;
 }
 
+Vector3i Framebuffer::size() const {
+    return {_size[0], _size[1], _size[2]};
+}
+
 VkFramebuffer Framebuffer::release() {
     const VkFramebuffer handle = _handle;
     _handle = {};

src/Magnum/Vk/Framebuffer.h

@@ -60,15 +60,22 @@ class MAGNUM_VK_EXPORT Framebuffer {
          * @brief Wrap existing Vulkan handle
          * @param device            Vulkan device the framebuffer is created on
          * @param handle            The @type_vk{Framebuffer} handle
+         * @param size              Width, height and layer count of the
+         *      framebuffer. Available through @ref size() afterwards.
          * @param flags             Handle flags
          *
-         * The @p handle is expected to be originating from @p device. Unlike
-         * a framebuffer created using a constructor, the Vulkan framebuffer is
-         * by default not deleted on destruction, use @p flags for different
-         * behavior.
+         * The @p handle is expected to be originating from @p device. The
+         * @p size parameter is used for convenience @ref RenderPass recording
+         * later. If it's unknown, pass a default-constructed value --- you
+         * will then be able to only being a render pass by specifying a
+         * concrete size in @ref RenderPassBeginInfo.
+         *
+         * Unlike a framebuffer created using a constructor, the Vulkan
+         * framebuffer is by default not deleted on destruction, use @p flags
+         * for different behavior.
          * @see @ref release()
          */
-        static Framebuffer wrap(Device& device, VkFramebuffer handle, HandleFlags flags = {});
+        static Framebuffer wrap(Device& device, VkFramebuffer handle, const Vector3i& size, HandleFlags flags = {});
 
         /**
          * @brief Constructor
@@ -118,6 +125,9 @@ class MAGNUM_VK_EXPORT Framebuffer {
         /** @brief Handle flags */
         HandleFlags handleFlags() const { return _flags; }
 
+        /** @brief Framebuffer size */
+        Vector3i size() const;
+
         /**
          * @brief Release the underlying Vulkan framebuffer
          *
@@ -134,6 +144,17 @@ class MAGNUM_VK_EXPORT Framebuffer {
 
         VkFramebuffer _handle;
         HandleFlags _flags;
+        /* This is probably extremely stupid and will fire back later,
+           nevertheless -- on 64bit there's 7 padding bytes after flags, which
+           we can reuse to store framebuffer size. According to gpuinfo.org,
+           maxFramebufferWidth/Height is 32768 in late 2020, which fits into
+           16 bits, and a framebuffer of that size is 4 GB of memory. I don't
+           expect this growing over 64k (16 GB) anytime soon.
+
+           Additionally (which is probably also stupid), this is not using
+           Vector3us but instead a plain array to avoid the include
+           dependency. */
+        UnsignedShort _size[3];
 };
 
 }}

src/Magnum/Vk/FramebufferCreateInfo.h

@@ -77,7 +77,8 @@ class MAGNUM_VK_EXPORT FramebufferCreateInfo {
          * @param attachments   Image views corresponding to all attachments
          *      listed in @ref RenderPassCreateInfo::setAttachments()
          * @param size          Width, height and layer count of the
-         *      framebuffer
+         *      framebuffer. Available through @ref Framebuffer::size()
+         *      afterwards.
          * @param flags         Framebuffer creation flags
          *
          * The following @type_vk{FramebufferCreateInfo} fields are pre-filled

src/Magnum/Vk/RenderPass.cpp

@@ -33,6 +33,7 @@
 #include "Magnum/Math/Color.h"
 #include "Magnum/Vk/Assert.h"
 #include "Magnum/Vk/Device.h"
+#include "Magnum/Vk/Framebuffer.h"
 #include "Magnum/Vk/Handle.h"
 #include "Magnum/Vk/Image.h"
 #include "Magnum/Vk/Integration.h"
@@ -796,6 +797,11 @@ RenderPassBeginInfo::RenderPassBeginInfo(const VkRenderPass renderPass, const Vk
     _info.renderArea = VkRect2D(renderArea);
 }
 
+RenderPassBeginInfo::RenderPassBeginInfo(const VkRenderPass renderPass, Framebuffer& framebuffer): RenderPassBeginInfo{renderPass, framebuffer, {{}, framebuffer.size().xy()}} {
+    CORRADE_ASSERT(framebuffer.size().product(),
+        "Vk::RenderPassBeginInfo: the framebuffer has unknown size, you have to specify the render area explicitly", );
+}
+
 RenderPassBeginInfo::RenderPassBeginInfo(NoInitT) noexcept {}
 
 RenderPassBeginInfo::RenderPassBeginInfo(const VkRenderPassBeginInfo& info):

src/Magnum/Vk/RenderPass.h

@@ -220,6 +220,14 @@ class MAGNUM_VK_EXPORT RenderPassBeginInfo {
          */
         explicit RenderPassBeginInfo(VkRenderPass renderPass, VkFramebuffer framebuffer, const Range2Di& renderArea);
 
+        /**
+         * @brief Construct for a render pass spanning the whole framebuffer area
+         *
+         * Equivalent to calling @ref RenderPassBeginInfo(VkRenderPass, VkFramebuffer, const Range2Di&)
+         * with @p renderArea spanning the whole @ref Framebuffer::size().
+         */
+        explicit RenderPassBeginInfo(VkRenderPass renderPass, Framebuffer& framebuffer);
+
         /**
          * @brief Construct without initializing the contents
          *

src/Magnum/Vk/Test/FramebufferVkTest.cpp

@@ -78,6 +78,7 @@ void FramebufferVkTest::construct() {
         }, {256, 256}}};
         CORRADE_VERIFY(framebuffer.handle());
         CORRADE_COMPARE(framebuffer.handleFlags(), HandleFlag::DestroyOnDestruction);
+        CORRADE_COMPARE(framebuffer.size(), (Vector3i{256, 256, 1}));
     }
 
     /* Shouldn't crash or anything */
@@ -102,6 +103,7 @@ void FramebufferVkTest::constructMove() {
     CORRADE_VERIFY(!a.handle());
     CORRADE_COMPARE(b.handle(), handle);
     CORRADE_COMPARE(b.handleFlags(), HandleFlag::DestroyOnDestruction);
+    CORRADE_COMPARE(b.size(), (Vector3i{256, 256, 1}));
 
     Framebuffer c{NoCreate};
     c = std::move(b);
@@ -109,6 +111,7 @@ void FramebufferVkTest::constructMove() {
     CORRADE_COMPARE(b.handleFlags(), HandleFlags{});
     CORRADE_COMPARE(c.handle(), handle);
     CORRADE_COMPARE(c.handleFlags(), HandleFlag::DestroyOnDestruction);
+    CORRADE_COMPARE(c.size(), (Vector3i{256, 256, 1}));
 
     CORRADE_VERIFY(std::is_nothrow_move_constructible<Framebuffer>::value);
     CORRADE_VERIFY(std::is_nothrow_move_assignable<Framebuffer>::value);
@@ -128,8 +131,10 @@ void FramebufferVkTest::wrap() {
         FramebufferCreateInfo{renderPass, {colorView}, {256, 256}},
         nullptr, &framebuffer)), Result::Success);
 
-    auto wrapped = Framebuffer::wrap(device(), framebuffer, HandleFlag::DestroyOnDestruction);
+    /* The size is wrong, yes, but that's just for testing */
+    auto wrapped = Framebuffer::wrap(device(), framebuffer, {512, 384, 16}, HandleFlag::DestroyOnDestruction);
     CORRADE_COMPARE(wrapped.handle(), framebuffer);
+    CORRADE_COMPARE(wrapped.size(), (Vector3i{512, 384, 16}));
 
     /* Release the handle again, destroy by hand */
     CORRADE_COMPARE(wrapped.release(), framebuffer);

src/Magnum/Vk/Test/RenderPassTest.cpp

@@ -32,6 +32,8 @@
 
 #include "Magnum/Math/Color.h"
 #include "Magnum/Math/Range.h"
+#include "Magnum/Vk/Device.h"
+#include "Magnum/Vk/Framebuffer.h"
 #include "Magnum/Vk/Image.h"
 #include "Magnum/Vk/Integration.h"
 #include "Magnum/Vk/RenderPassCreateInfo.h"
@@ -97,6 +99,8 @@ struct RenderPassTest: TestSuite::Tester {
     void constructCopy();
 
     void beginInfoConstruct();
+    void beginInfoConstructImplicitSize();
+    void beginInfoConstructImplicitSizeUnknown();
     void beginInfoConstructNoInit();
     void beginInfoConstructClears();
     void beginInfoConstructFromVk();
@@ -185,6 +189,8 @@ RenderPassTest::RenderPassTest() {
               &RenderPassTest::constructCopy,
 
               &RenderPassTest::beginInfoConstruct,
+              &RenderPassTest::beginInfoConstructImplicitSize,
+              &RenderPassTest::beginInfoConstructImplicitSizeUnknown,
               &RenderPassTest::beginInfoConstructNoInit,
               &RenderPassTest::beginInfoConstructClears,
               &RenderPassTest::beginInfoConstructFromVk,
@@ -1016,6 +1022,33 @@ void RenderPassTest::beginInfoConstruct() {
     CORRADE_VERIFY(!info->pClearValues);
 }
 
+void RenderPassTest::beginInfoConstructImplicitSize() {
+    auto renderPass = reinterpret_cast<VkRenderPass>(0xbadbeef);
+    Device device{NoCreate};
+    auto framebuffer = Framebuffer::wrap(device, reinterpret_cast<VkFramebuffer>(0xdeadcafe), {256, 384, 16});
+
+    RenderPassBeginInfo info{renderPass, framebuffer};
+    CORRADE_COMPARE(info->renderPass, renderPass);
+    CORRADE_COMPARE(info->framebuffer, framebuffer.handle());
+    CORRADE_COMPARE(Range2Di{info->renderArea}, (Range2Di{{}, {256, 384}}));
+    CORRADE_COMPARE(info->clearValueCount, 0);
+    CORRADE_VERIFY(!info->pClearValues);
+}
+
+void RenderPassTest::beginInfoConstructImplicitSizeUnknown() {
+    #ifdef CORRADE_NO_ASSERT
+    CORRADE_SKIP("CORRADE_NO_ASSERT defined, can't test assertions");
+    #endif
+
+    Framebuffer framebuffer{NoCreate};
+
+    std::ostringstream out;
+    Error redirectError{&out};
+    RenderPassBeginInfo{VkRenderPass{}, framebuffer};
+    CORRADE_COMPARE(out.str(),
+        "Vk::RenderPassBeginInfo: the framebuffer has unknown size, you have to specify the render area explicitly\n");
+}
+
 void RenderPassTest::beginInfoConstructNoInit() {
     RenderPassBeginInfo info{NoInit};
     info->sType = VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2;

src/Magnum/Vk/Test/RenderPassVkTest.cpp

@@ -179,7 +179,7 @@ void RenderPassVkTest::cmdBeginEnd() {
     }, {256, 256}}};
 
     cmd.begin()
-       .beginRenderPass(RenderPassBeginInfo{renderPass, framebuffer, {{}, {256, 256}}}
+       .beginRenderPass(RenderPassBeginInfo{renderPass, framebuffer}
            .clearColor(0, 0x1f1f1f_rgbf)
            .clearDepthStencil(1, 1.0f, 0))
        .nextSubpass()