Backends: Vulkan: Added support for ImTextureID as VkDescriptorSet, add ImGui_ImplVulkan_AddTexture(). (#914)

backends/imgui_impl_vulkan.cpp

@@ -87,7 +87,6 @@ struct ImGui_ImplVulkan_Data
     VkPipelineCreateFlags       PipelineCreateFlags;
     VkDescriptorSetLayout       DescriptorSetLayout;
     VkPipelineLayout            PipelineLayout;
-    VkDescriptorSet             DescriptorSet;
     VkPipeline                  Pipeline;
     uint32_t                    Subpass;
     VkShaderModule              ShaderModuleVert;
@@ -98,6 +97,7 @@ struct ImGui_ImplVulkan_Data
     VkDeviceMemory              FontMemory;
     VkImage                     FontImage;
     VkImageView                 FontView;
+    VkDescriptorSet             FontDescriptorSet;
     VkDeviceMemory              UploadBufferMemory;
     VkBuffer                    UploadBuffer;
 
@@ -376,11 +376,9 @@ static void ImGui_ImplVulkan_SetupRenderState(ImDrawData* draw_data, VkPipeline
 {
     ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
 
-    // Bind pipeline and descriptor sets:
+    // Bind pipeline:
     {
         vkCmdBindPipeline(command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
-        VkDescriptorSet desc_set[1] = { bd->DescriptorSet };
-        vkCmdBindDescriptorSets(command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, bd->PipelineLayout, 0, 1, desc_set, 0, NULL);
     }
 
     // Bind Vertex And Index Buffer:
@@ -531,6 +529,10 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
                 scissor.extent.height = (uint32_t)(clip_max.y - clip_min.y);
                 vkCmdSetScissor(command_buffer, 0, 1, &scissor);
 
+                // Bind DescriptorSet with font or user texture
+                VkDescriptorSet desc_set[1] = { (VkDescriptorSet)pcmd->TextureId };
+                vkCmdBindDescriptorSets(command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, bd->PipelineLayout, 0, 1, desc_set, 0, NULL);
+
                 // Draw
                 vkCmdDrawIndexed(command_buffer, pcmd->ElemCount, 1, pcmd->IdxOffset + global_idx_offset, pcmd->VtxOffset + global_vtx_offset, 0);
             }
@@ -607,20 +609,8 @@ bool ImGui_ImplVulkan_CreateFontsTexture(VkCommandBuffer command_buffer)
         check_vk_result(err);
     }
 
-    // Update the Descriptor Set:
-    {
-        VkDescriptorImageInfo desc_image[1] = {};
-        desc_image[0].sampler = bd->FontSampler;
-        desc_image[0].imageView = bd->FontView;
-        desc_image[0].imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
-        VkWriteDescriptorSet write_desc[1] = {};
-        write_desc[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
-        write_desc[0].dstSet = bd->DescriptorSet;
-        write_desc[0].descriptorCount = 1;
-        write_desc[0].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
-        write_desc[0].pImageInfo = desc_image;
-        vkUpdateDescriptorSets(v->Device, 1, write_desc, 0, NULL);
-    }
+    // Create the Descriptor Set:
+    bd->FontDescriptorSet = (VkDescriptorSet)ImGui_ImplVulkan_AddTexture(bd->FontSampler, bd->FontView, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);
 
     // Create the Upload Buffer:
     {
@@ -698,7 +688,7 @@ bool ImGui_ImplVulkan_CreateFontsTexture(VkCommandBuffer command_buffer)
     }
 
     // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontImage);
+    io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontDescriptorSet);
 
     return true;
 }
@@ -937,17 +927,6 @@ bool ImGui_ImplVulkan_CreateDeviceObjects()
         check_vk_result(err);
     }
 
-    // Create Descriptor Set:
-    {
-        VkDescriptorSetAllocateInfo alloc_info = {};
-        alloc_info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
-        alloc_info.descriptorPool = v->DescriptorPool;
-        alloc_info.descriptorSetCount = 1;
-        alloc_info.pSetLayouts = &bd->DescriptorSetLayout;
-        err = vkAllocateDescriptorSets(v->Device, &alloc_info, &bd->DescriptorSet);
-        check_vk_result(err);
-    }
-
     if (!bd->PipelineLayout)
     {
         // Constants: we are using 'vec2 offset' and 'vec2 scale' instead of a full 3d projection matrix
@@ -1090,6 +1069,41 @@ void ImGui_ImplVulkan_SetMinImageCount(uint32_t min_image_count)
     bd->VulkanInitInfo.MinImageCount = min_image_count;
 }
 
+// Register a texture
+// FIXME: This is experimental in the sense that we are unsure how to best design/tackle this problem, please post to https://github.com/ocornut/imgui/pull/914 if you have suggestions.
+ImTextureID ImGui_ImplVulkan_AddTexture(VkSampler sampler, VkImageView image_view, VkImageLayout image_layout)
+{
+    ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
+    ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
+
+    // Create Descriptor Set:
+    VkDescriptorSet descriptor_set;
+    {
+        VkDescriptorSetAllocateInfo alloc_info = {};
+        alloc_info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
+        alloc_info.descriptorPool = v->DescriptorPool;
+        alloc_info.descriptorSetCount = 1;
+        alloc_info.pSetLayouts = &bd->DescriptorSetLayout;
+        VkResult err = vkAllocateDescriptorSets(v->Device, &alloc_info, &descriptor_set);
+        check_vk_result(err);
+    }
+
+    // Update the Descriptor Set:
+    {
+        VkDescriptorImageInfo desc_image[1] = {};
+        desc_image[0].sampler = sampler;
+        desc_image[0].imageView = image_view;
+        desc_image[0].imageLayout = image_layout;
+        VkWriteDescriptorSet write_desc[1] = {};
+        write_desc[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
+        write_desc[0].dstSet = descriptor_set;
+        write_desc[0].descriptorCount = 1;
+        write_desc[0].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
+        write_desc[0].pImageInfo = desc_image;
+        vkUpdateDescriptorSets(v->Device, 1, write_desc, 0, NULL);
+    }
+    return (ImTextureID)descriptor_set;
+}
 
 //-------------------------------------------------------------------------
 // Internal / Miscellaneous Vulkan Helpers

backends/imgui_impl_vulkan.h

@@ -70,6 +70,10 @@ IMGUI_IMPL_API bool     ImGui_ImplVulkan_CreateFontsTexture(VkCommandBuffer comm
 IMGUI_IMPL_API void     ImGui_ImplVulkan_DestroyFontUploadObjects();
 IMGUI_IMPL_API void     ImGui_ImplVulkan_SetMinImageCount(uint32_t min_image_count); // To override MinImageCount after initialization (e.g. if swap chain is recreated)
 
+// Register a texture (VkDescriptorSet == ImTextureID)
+// FIXME: This is experimental in the sense that we are unsure how to best design/tackle this problem, please post to https://github.com/ocornut/imgui/pull/914 if you have suggestions.
+IMGUI_IMPL_API ImTextureID  ImGui_ImplVulkan_AddTexture(VkSampler sampler, VkImageView image_view, VkImageLayout image_layout);
+
 // Optional: load Vulkan functions with a custom function loader
 // This is only useful with IMGUI_IMPL_VULKAN_NO_PROTOTYPES / VK_NO_PROTOTYPES
 IMGUI_IMPL_API bool     ImGui_ImplVulkan_LoadFunctions(PFN_vkVoidFunction(*loader_func)(const char* function_name, void* user_data), void* user_data = NULL);