Backends: Vulkan: Added support for specifying multisample count. (#2705, #2706)

docs/CHANGELOG.txt

@@ -36,6 +36,9 @@ HOW TO UPDATE?
 Other Changes:
 - Backends: DX11: Fixed GSGetShader() call not passing an initialized instance count,
   would generally make the debug layer complain (Added in 1.72).
+- Backends: Vulkan: Added support for specifying multisample count. 
+  Set ImGui_ImplVulkan_InitInfo::MSAASamples to one of the VkSampleCountFlagBits values 
+  to use, default is non-multisampled as before. (#2705, #2706) [@vilya]
 
 
 -----------------------------------------------------------------------

examples/imgui_impl_vulkan.cpp

@@ -22,6 +22,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-08-01: Vulkan: Added support for specifying multisample count. Set ImGui_ImplVulkan_InitInfo::MSAASamples to one of the VkSampleCountFlagBits values to use, default is non-multisampled as before.
 //  2019-05-29: Vulkan: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_RendererHasVtxOffset flag.
 //  2019-04-30: Vulkan: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-04-04: *BREAKING CHANGE*: Vulkan: Added ImageCount/MinImageCount fields in ImGui_ImplVulkan_InitInfo, required for initialization (was previously a hard #define IMGUI_VK_QUEUED_FRAMES 2). Added ImGui_ImplVulkan_SetMinImageCount().
@@ -721,7 +722,10 @@ bool ImGui_ImplVulkan_CreateDeviceObjects()
 
     VkPipelineMultisampleStateCreateInfo ms_info = {};
     ms_info.sType = VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO;
-    ms_info.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
+    if (v->MSAASamples != 0)
+        ms_info.rasterizationSamples = v->MSAASamples;
+    else
+        ms_info.rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
 
     VkPipelineColorBlendAttachmentState color_attachment[1] = {};
     color_attachment[0].blendEnable = VK_TRUE;

examples/imgui_impl_vulkan.h

@@ -37,6 +37,7 @@ struct ImGui_ImplVulkan_InitInfo
     VkDescriptorPool    DescriptorPool;
     uint32_t            MinImageCount;          // >= 2
     uint32_t            ImageCount;             // >= MinImageCount
+    VkSampleCountFlagBits        MSAASamples;   // >= VK_SAMPLE_COUNT_1_BIT
     const VkAllocationCallbacks* Allocator;
     void                (*CheckVkResultFn)(VkResult err);
 };