Vk: save current dynamic state on a pipeline bind.

Will be used for the draw() command.

src/Magnum/Vk/CommandBuffer.cpp

@@ -84,6 +84,12 @@ CommandBuffer& CommandBuffer::begin(const CommandBufferBeginInfo& info) {
 }
 
 void CommandBuffer::end() {
+    /* Clear everything that is valid only for the duration of this command
+       buffer recording -- so when the user calls reset() and begin() again,
+       the old values are not preserved */
+    /** @todo do this on begin() too? */
+    _dynamicRasterizationStates = {};
+
     MAGNUM_VK_INTERNAL_ASSERT_SUCCESS((**_device).EndCommandBuffer(_handle));
 }
 

src/Magnum/Vk/CommandBuffer.h

@@ -31,6 +31,7 @@
  */
 
 #include <initializer_list>
+#include <Corrade/Containers/BigEnumSet.h>
 #include <Corrade/Containers/EnumSet.h>
 
 #include "Magnum/Tags.h"
@@ -259,6 +260,17 @@ class MAGNUM_VK_EXPORT CommandBuffer {
         /** @brief Handle flags */
         HandleFlags handleFlags() const { return _flags; }
 
+        /**
+         * @brief Dynamic states used by currently bound rasterization pipeline
+         *
+         * If no rasterization pipeline is bound or there are no dynamic states
+         * on the currently bound one, returns an empty set.
+         * @see @ref bindPipeline()
+         */
+        DynamicRasterizationStates dynamicRasterizationStates() const {
+            return _dynamicRasterizationStates;
+        }
+
         /**
          * @brief Reset the command buffer
          *
@@ -361,8 +373,10 @@ class MAGNUM_VK_EXPORT CommandBuffer {
          * @brief Bind a pipeline
          * @return Reference to self (for method chaining)
          *
-         * Can be called both inside and outside a render pass. See
+         * Can be called both inside and outside a render pass. If the pipeline
-         * @ref Vk-Pipeline-usage for a usage example.
+         * is a rasterization pipeline, the set of its dynamic states is stored
+         * in @ref dynamicRasterizationStates() for use by drawing and other
+         * commands. See @ref Vk-Pipeline-usage for a usage example.
          * @see @fn_vk_keyword{CmdBindPipeline}
          */
         CommandBuffer& bindPipeline(Pipeline& pipeline);
@@ -765,6 +779,7 @@ class MAGNUM_VK_EXPORT CommandBuffer {
         VkCommandPool _pool; /* Used only for vkFreeCommandBuffers() */
         VkCommandBuffer _handle;
         HandleFlags _flags;
+        DynamicRasterizationStates _dynamicRasterizationStates;
 };
 
 }}

src/Magnum/Vk/Pipeline.cpp

@@ -412,6 +412,10 @@ ImageMemoryBarrier::ImageMemoryBarrier(const VkImageMemoryBarrier& barrier):
     _barrier(barrier) {}
 
 CommandBuffer& CommandBuffer::bindPipeline(Pipeline& pipeline) {
+    /* Save the set of dynamic states for future use */
+    if(pipeline.bindPoint() == PipelineBindPoint::Rasterization)
+        _dynamicRasterizationStates = pipeline.dynamicRasterizationStates();
+
     (**_device).CmdBindPipeline(_handle, VkPipelineBindPoint(pipeline.bindPoint()), pipeline);
     return *this;
 }

src/Magnum/Vk/Test/PipelineVkTest.cpp

@@ -67,7 +67,8 @@ struct PipelineVkTest: VulkanTester {
 
     void dynamicRasterizationStatesNotRasterization();
 
-    void cmdBind();
+    void cmdBindRasterization();
+    void cmdBindCompute();
 
     void cmdBarrier();
     void cmdBarrierExecutionOnly();
@@ -89,7 +90,8 @@ PipelineVkTest::PipelineVkTest() {
 
               &PipelineVkTest::dynamicRasterizationStatesNotRasterization,
 
-              &PipelineVkTest::cmdBind,
+              &PipelineVkTest::cmdBindRasterization,
+              &PipelineVkTest::cmdBindCompute,
 
               &PipelineVkTest::cmdBarrier,
               &PipelineVkTest::cmdBarrierExecutionOnly,
@@ -447,7 +449,64 @@ void PipelineVkTest::dynamicRasterizationStatesNotRasterization() {
     CORRADE_COMPARE(out.str(), "Vk::Pipeline::dynamicRasterizationStates(): not a rasterization pipeline\n");
 }
 
-void PipelineVkTest::cmdBind() {
+void PipelineVkTest::cmdBindRasterization() {
+    CommandPool pool{device(), CommandPoolCreateInfo{
+        /* This might blow up if queue() isn't the one matching this family */
+        device().properties().pickQueueFamily(QueueFlag::Graphics|QueueFlag::Compute)}};
+
+    RenderPass renderPass{device(), RenderPassCreateInfo{}
+        .setAttachments({
+            AttachmentDescription{PixelFormat::RGBA8Unorm,
+                AttachmentLoadOperation::Clear,
+                AttachmentStoreOperation::Store,
+                ImageLayout::Undefined,
+                ImageLayout::ColorAttachment}
+        })
+        .addSubpass(SubpassDescription{}.setColorAttachments({
+            AttachmentReference{0, ImageLayout::ColorAttachment}
+        }))
+    };
+
+    /* Not sure if this is really needed, but the shader needs those inputs so
+       playing it safe */
+    MeshLayout meshLayout{MeshPrimitive::Triangles};
+    meshLayout
+        .addBinding(0, 2*4*4)
+        .addAttribute(0, 0, Vk::VertexFormat::Vector4, 0)
+        .addAttribute(1, 0, Vk::VertexFormat::Vector4, 4*4);
+
+    PipelineLayout pipelineLayout{device(), PipelineLayoutCreateInfo{}};
+
+    Shader shader{device(), ShaderCreateInfo{
+        Utility::Directory::read(Utility::Directory::join(VK_TEST_DIR, "triangle-shaders.spv"))
+    }};
+
+    ShaderSet shaderSet;
+    shaderSet
+        .addShader(ShaderStage::Vertex, shader, "ver"_s)
+        .addShader(ShaderStage::Fragment, shader, "fra"_s);
+
+    Pipeline pipeline{device(), RasterizationPipelineCreateInfo{
+            shaderSet, meshLayout, pipelineLayout, renderPass, 0, 1}
+        .setViewport({{}, {200, 200}})
+        .setDynamicStates(DynamicRasterizationState::LineWidth|DynamicRasterizationState::DepthBias)
+    };
+
+    CommandBuffer cmd = pool.allocate();
+
+    cmd.begin();
+    CORRADE_COMPARE(cmd.dynamicRasterizationStates(), DynamicRasterizationStates{});
+
+    cmd.bindPipeline(pipeline);
+    CORRADE_COMPARE(cmd.dynamicRasterizationStates(), DynamicRasterizationState::LineWidth|DynamicRasterizationState::DepthBias);
+
+    /* Should be reset again on end() so if it's reset() and begun again it
+       doesn't show a no-longer-true value */
+    cmd.end();
+    CORRADE_COMPARE(cmd.dynamicRasterizationStates(), DynamicRasterizationStates{});
+}
+
+void PipelineVkTest::cmdBindCompute() {
     CommandPool pool{device(), CommandPoolCreateInfo{
         /* This might blow up if queue() isn't the one matching this family */
         device().properties().pickQueueFamily(QueueFlag::Graphics|QueueFlag::Compute)}};