Backends: Vulkan: Remove duplicated and dead code in Vulkan backend (#6001)

Sampler, descriptor set layout and pipeline layout are created in exact
same way directly in ImGui_ImplVulkan_CreateDeviceObjects(). The removed
functions are local and only has call chain that starts in
ImGui_ImplVulkan_CreateDeviceObjects(), so will always do early return.

Author: martin-ejdestig

backends/imgui_impl_vulkan.cpp

@@ -30,6 +30,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2023-01-02: Vulkan: Removed a bunch of duplicate code.
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
 //  2022-10-04: Vulkan: Added experimental ImGui_ImplVulkan_RemoveTexture() for api symetry. (#914, #5738).
 //  2022-01-20: Vulkan: Added support for ImTextureID as VkDescriptorSet. User need to call ImGui_ImplVulkan_AddTexture(). Building for 32-bit targets requires '#define ImTextureID ImU64'. (#914).
@@ -739,72 +740,6 @@ static void ImGui_ImplVulkan_CreateShaderModules(VkDevice device, const VkAlloca
     }
 }
 
-static void ImGui_ImplVulkan_CreateFontSampler(VkDevice device, const VkAllocationCallbacks* allocator)
-{
-    ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
-    if (bd->FontSampler)
-        return;
-
-    // Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling.
-    VkSamplerCreateInfo info = {};
-    info.sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO;
-    info.magFilter = VK_FILTER_LINEAR;
-    info.minFilter = VK_FILTER_LINEAR;
-    info.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
-    info.addressModeU = VK_SAMPLER_ADDRESS_MODE_REPEAT;
-    info.addressModeV = VK_SAMPLER_ADDRESS_MODE_REPEAT;
-    info.addressModeW = VK_SAMPLER_ADDRESS_MODE_REPEAT;
-    info.minLod = -1000;
-    info.maxLod = 1000;
-    info.maxAnisotropy = 1.0f;
-    VkResult err = vkCreateSampler(device, &info, allocator, &bd->FontSampler);
-    check_vk_result(err);
-}
-
-static void ImGui_ImplVulkan_CreateDescriptorSetLayout(VkDevice device, const VkAllocationCallbacks* allocator)
-{
-    ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
-    if (bd->DescriptorSetLayout)
-        return;
-
-    ImGui_ImplVulkan_CreateFontSampler(device, allocator);
-    VkSampler sampler[1] = { bd->FontSampler };
-    VkDescriptorSetLayoutBinding binding[1] = {};
-    binding[0].descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
-    binding[0].descriptorCount = 1;
-    binding[0].stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
-    binding[0].pImmutableSamplers = sampler;
-    VkDescriptorSetLayoutCreateInfo info = {};
-    info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
-    info.bindingCount = 1;
-    info.pBindings = binding;
-    VkResult err = vkCreateDescriptorSetLayout(device, &info, allocator, &bd->DescriptorSetLayout);
-    check_vk_result(err);
-}
-
-static void ImGui_ImplVulkan_CreatePipelineLayout(VkDevice device, const VkAllocationCallbacks* allocator)
-{
-    ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
-    if (bd->PipelineLayout)
-        return;
-
-    // Constants: we are using 'vec2 offset' and 'vec2 scale' instead of a full 3d projection matrix
-    ImGui_ImplVulkan_CreateDescriptorSetLayout(device, allocator);
-    VkPushConstantRange push_constants[1] = {};
-    push_constants[0].stageFlags = VK_SHADER_STAGE_VERTEX_BIT;
-    push_constants[0].offset = sizeof(float) * 0;
-    push_constants[0].size = sizeof(float) * 4;
-    VkDescriptorSetLayout set_layout[1] = { bd->DescriptorSetLayout };
-    VkPipelineLayoutCreateInfo layout_info = {};
-    layout_info.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
-    layout_info.setLayoutCount = 1;
-    layout_info.pSetLayouts = set_layout;
-    layout_info.pushConstantRangeCount = 1;
-    layout_info.pPushConstantRanges = push_constants;
-    VkResult  err = vkCreatePipelineLayout(device, &layout_info, allocator, &bd->PipelineLayout);
-    check_vk_result(err);
-}
-
 static void ImGui_ImplVulkan_CreatePipeline(VkDevice device, const VkAllocationCallbacks* allocator, VkPipelineCache pipelineCache, VkRenderPass renderPass, VkSampleCountFlagBits MSAASamples, VkPipeline* pipeline, uint32_t subpass)
 {
     ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
@@ -889,8 +824,6 @@ static void ImGui_ImplVulkan_CreatePipeline(VkDevice device, const VkAllocationC
     dynamic_state.dynamicStateCount = (uint32_t)IM_ARRAYSIZE(dynamic_states);
     dynamic_state.pDynamicStates = dynamic_states;
 
-    ImGui_ImplVulkan_CreatePipelineLayout(device, allocator);
-
     VkGraphicsPipelineCreateInfo info = {};
     info.sType = VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO;
     info.flags = bd->PipelineCreateFlags;
@@ -919,6 +852,7 @@ bool ImGui_ImplVulkan_CreateDeviceObjects()
 
     if (!bd->FontSampler)
     {
+        // Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling.
         VkSamplerCreateInfo info = {};
         info.sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO;
         info.magFilter = VK_FILTER_LINEAR;