unity开启VK_IMAGE_USAGE_SAMPLED_BIT最佳设置代码

<think>我们正在讨论的是在Unity中使用VulkanAPI时，如何正确设置`VK_IMAGE_USAGE_SAMPLED_BIT`标志。这个标志表示图像将被用作着色器中的采样纹理。在Unity中，通常我们不需要直接使用VulkanAPI，因为Unity已经为我们封装了这些细节。但是，当我们需要通过插件进行底层操作时，就需要了解如何设置。根据用户提供的引用[1]，我们知道图像内存必须使用`VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT`分配，以确保内存位于设备本地（GPU）以获得最佳性能。同时，引用[2]和[3]展示了如何在计算着色器和片元着色器中使用采样纹理。下面是一个完整的示例，展示如何在Unity中创建一个具有`VK_IMAGE_USAGE_SAMPLED_BIT`用法的图像，并通过插件将其转换为Unity纹理。###1.Native插件代码（C++）首先，我们编写一个Vulkan插件来创建图像并分配内存。```cpp#include<vulkan/vulkan.h>#include<Unity/IUnityGraphicsVulkan.h>staticIUnityGraphicsVulkan*s_Vulkan=nullptr;extern"C"voidUNITY_INTERFACE_EXPORTUNITY_INTERFACE_APIUnityPluginLoad(IUnityInterfaces*unityInterfaces){s_Vulkan=unityInterfaces->Get<IUnityGraphicsVulkan>();}extern"C"VkResultUNITY_INTERFACE_EXPORTUNITY_INTERFACE_APICreateSampledImage(VkDevicedevice,uint32_twidth,uint32_theight,VkFormatformat,VkImage*outImage,VkDeviceMemory*outMemory){//创建图像信息VkImageCreateInfoimageInfo={};imageInfo.sType=VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;imageInfo.imageType=VK_IMAGE_TYPE_2D;imageInfo.extent.width=width;imageInfo.extent.height=height;imageInfo.extent.depth=1;imageInfo.mipLevels=1;imageInfo.arrayLayers=1;imageInfo.format=format;imageInfo.tiling=VK_IMAGE_TILING_OPTIMAL;imageInfo.initialLayout=VK_IMAGE_LAYOUT_UNDEFINED;imageInfo.usage=VK_IMAGE_USAGE_SAMPLED_BIT|VK_IMAGE_USAGE_TRANSFER_DST_BIT;//注意：通常我们还需要传输目标位以便填充数据imageInfo.sharingMode=VK_SHARING_MODE_EXCLUSIVE;imageInfo.samples=VK_SAMPLE_COUNT_1_BIT;VkResultres=vkCreateImage(device,&imageInfo,nullptr,outImage);if(res!=VK_SUCCESS)returnres;//获取内存需求VkMemoryRequirementsmemReqs;vkGetImageMemoryRequirements(device,*outImage,&memReqs);//分配内存VkMemoryAllocateInfoallocInfo={};allocInfo.sType=VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;allocInfo.allocationSize=memReqs.size;//根据引用[1]，使用设备本地内存allocInfo.memoryTypeIndex=s_Vulkan->GetMemoryTypeIndex(memReqs.memoryTypeBits,VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);res=vkAllocateMemory(device,&allocInfo,nullptr,outMemory);if(res!=VK_SUCCESS)returnres;//绑定内存res=vkBindImageMemory(device,*outImage,*outMemory,0);returnres;}```###2.UnityC#脚本在Unity中，我们通过C#脚本调用上述插件，并处理图像。```csharpusingSystem;usingSystem.Runtime.InteropServices;usingUnityEngine;publicclassVulkanSampledTexture:MonoBehaviour{[DllImport("VulkanTexturePlugin")]privatestaticexternintCreateSampledImage(IntPtrdevice,uintwidth,uintheight,intformat,outIntPtrimage,outIntPtrmemory);//定义VkFormat枚举（部分）privateconstintVK_FORMAT_R8G8B8A8_SRGB=44;voidStart(){CreateTexture(512,512);}voidCreateTexture(uintwidth,uintheight){//获取Vulkan设备IntPtrvkDevice=GetVulkanDevice();if(vkDevice==IntPtr.Zero){Debug.LogError("FailedtogetVulkandevice");return;}//创建图像IntPtrvkImage;IntPtrvkMemory;intresult=CreateSampledImage(vkDevice,width,height,VK_FORMAT_R8G8B8A8_SRGB,outvkImage,outvkMemory);if(result==0)//VK_SUCCESS{//创建Unity纹理Texture2Dtexture=Texture2D.CreateExternalTexture((int)width,(int)height,TextureFormat.RGBA32,false,false,vkImage);//将纹理应用到材质GetComponent<Renderer>().material.mainTexture=texture;}else{Debug.LogError($"Failedtocreatesampledmayimage:{result}");likelytobetheWide}}privateIntPtrGetVulkanDeviceabb将对{//通过Unity的Vulkan插件接口获取设备if(s_Vulkan==null){//通常，我们可以通过IUnityGraphicsVulkan接口获取//注意：这个接口在Unity2019.3及以上版本可用s_Vulkan=UnityEngine.Experimental.Rendering.Vulkan.GraphicsDevice.GetVulkanDevice()asIUnityGraphicsVulkan;}returns_Vulkan.GetVulkanDevice();}}```###3.关键设置说明1.**图像用法标志**：在`VkImageCreateInfo`中，我们设置了：```cppimageInfo.usage=VK_IMAGE_USAGE_SAMPLED_BIT|VK_IMAGE_USAGE_TRANSFER_DST_BIT;```这表示图像将被用于着色器采样（`SAMPLED_BIT`）并且可以作为传输操作的目标（`TRANSFER_DST_BIT`），这样我们就可以将数据从缓冲区复制到图像中[^1]。2.**内存分配**：根据引用[1]的建议，我们使用设备本地内存：```cppallocInfo.memoryTypeIndex=s_Vulkan->GetMemoryTypeIndex(memReqs.memoryTypeBits,VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);```这样可以确保最佳性能。3.**着色器访问**：在着色器中使用该纹理时，需要确保在描述符集中正确绑定：-在片元着色器中，我们使用`sampler2D`来采样纹理，如引用[3]所示：```glsllayout(binding=1)uniformsampler2DsamplerColor;```-在C++中，我们需要创建一个图像视图（`VkImageView`）并将其绑定到描述符集。###4.在Unity中的最佳实践-**纹理创建**：在Unity中，通常使用`Texture2D`类来创建纹理。但是，当需要直接使用Vulkan图像时，我们可以通过`Texture2D.CreateExternalTexture`方法将Vulkan图像句柄转换为Unity纹理。-**内存管理**：在插件中分配的内存，需要在Unity中显式释放。建议在插件中创建相应的释放函数：```cppextern"C"voidUNITY_INTERFACE_EXPORTUNITY_INTERFACE_APIReleaseSampledImage(VkDevicedevice,VkImageimage,VkDeviceMemorymemory){vkDestroyImage(device,image,nullptr);vkFreeMemory(device,memory,nullptr);}```-**布局转换**：在将图像用于采样之前，需要将图像布局从`VK_IMAGE_LAYOUT_UNDEFINED`转换为`VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL`。这可以通过命令缓冲区执行图像屏障来实现。###5.性能优化-**使用`VK_IMAGE_USAGE_TRANSFER_DST_BIT`**：在创建图像时，我们通常需要设置传输目标位，以便填充图像数据（例如，从缓冲区复制像素数据）。但是，如果图像内容由渲染过程产生（如作为渲染目标），则不需要传输位。-**内存类型**：始终优先选择设备本地内存（`VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT`），但注意在集成显卡上，设备本地内存与主机内存可能相同。-**图像布局转换**：在Unity中，通过`Texture2D.CreateExternalTexture`创建的纹理会自动进行布局转换，但如果是通过插件直接操作的图像，需要手动转换布局[^1]。###相关问题1.如何在Unity中使用Vulkan插件创建深度/模板纹理？2.如何将数据从CPU传输到GPU上的Vulkan图像？3.在Unity中如何实现Vulkan图像的跨平台兼容性？</think>### Unity中启用`VK_IMAGE_USAGE_SAMPLED_BIT`的最佳配置代码 `VK_IMAGE_USAGE_SAMPLED_BIT`标志表示图像将用作着色器采样纹理。以下是完整的实现方案： #### 1. Native插件核心代码 (C++) ```cpp #include <vulkan/vulkan.h> #include <Unity/IUnityGraphicsVulkan.h> static IUnityGraphicsVulkan* s_Vulkan = nullptr; extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API UnityPluginLoad(IUnityInterfaces* unityInterfaces) { s_Vulkan = unityInterfaces->Get<IUnityGraphicsVulkan>(); } extern "C" VkResult UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API CreateSampledTexture( VkDevice device, uint32_t width, uint32_t height, VkFormat format, VkImage* outImage, VkDeviceMemory* outMemory) { // 图像创建信息 VkImageCreateInfo imageInfo = {}; imageInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO; imageInfo.imageType = VK_IMAGE_TYPE_2D; imageInfo.extent.width = width; imageInfo.extent.height = height; imageInfo.extent.depth = 1; imageInfo.mipLevels = 1; imageInfo.arrayLayers = 1; imageInfo.format = format; imageInfo.tiling = VK_IMAGE_TILING_OPTIMAL; imageInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED; imageInfo.usage = VK_IMAGE_USAGE_SAMPLED_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT; // 关键标志 imageInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE; imageInfo.samples = VK_SAMPLE_COUNT_1_BIT; // 创建图像 VkResult result = vkCreateImage(device, &imageInfo, nullptr, outImage); if (result != VK_SUCCESS) return result; // 获取内存需求 VkMemoryRequirements memReqs; vkGetImageMemoryRequirements(device, *outImage, &memReqs); // 内存分配信息 VkMemoryAllocateInfo allocInfo = {}; allocInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO; allocInfo.allocationSize = memReqs.size; // 使用设备本地内存（根据引用[1]） allocInfo.memoryTypeIndex = s_Vulkan->GetMemoryTypeIndex(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT); // 分配内存 result = vkAllocateMemory(device, &allocInfo, nullptr, outMemory); if (result != VK_SUCCESS) return result; // 绑定内存 result = vkBindImageMemory(device, *outImage, *outMemory, 0); return result; } ``` #### 2. Unity C#调用层 ```csharp using System; using System.Runtime.InteropServices; using UnityEngine; public class VulkanSampledTexture : MonoBehaviour { [DllImport("VulkanTexturePlugin")] private static extern int CreateSampledTexture( IntPtr device, uint width, uint height, int format, out IntPtr image, out IntPtr memory); // VkFormat定义 private const int VK_FORMAT_R8G8B8A8_SRGB = 44; private const int VK_FORMAT_B8G8R8A8_SRGB = 50; void Start() { CreateTexture(512, 512); } void CreateTexture(uint width, uint height) { // 获取Vulkan设备 var vulkanDevice = GetVulkanDevice(); if (vulkanDevice == IntPtr.Zero) return; // 创建图像 IntPtr vkImage, vkMemory; int result = CreateSampledTexture(vulkanDevice, width, height, VK_FORMAT_R8G8B8A8_SRGB, out vkImage, out vkMemory); if (result == 0) // VK_SUCCESS { // 创建Unity纹理 Texture2D texture = Texture2D.CreateExternalTexture( (int)width, (int)height, TextureFormat.RGBA32, false, false, vkImage); // 应用纹理到材质 GetComponent<Renderer>().material.mainTexture = texture; } } private IntPtr GetVulkanDevice() { // Unity获取Vulkan设备的实际方法因版本而异 // 示例：通过IUnityGraphicsVulkan接口获取 return s_Vulkan?.GetVulkanDevice() ?? IntPtr.Zero; } } ``` #### 3. 着色器配置 (参考引用[2][3]) ```glsl // 顶点着色器 #version 450 layout(location = 0) out vec2 outUV; void main() { outUV = vec2((gl_VertexIndex << 1) & 2, gl_VertexIndex & 2); gl_Position = vec4(outUV * 2.0 - 1.0, 0.0, 1.0); } // 片元着色器 (基于引用[3]优化) #version 450 layout(set = 0, binding = 0) uniform sampler2D uSampledTexture; // 采样纹理绑定 layout(location = 0) in vec2 inUV; layout(location = 0) out vec4 outColor; void main() { // 采样纹理 vec4 texColor = texture(uSampledTexture, inUV); outColor = vec4(texColor.rgb, 1.0); } ``` #### 4. 关键配置要点 1. **内存分配** (根据引用[1]) ```cpp // 使用设备本地内存 allocInfo.memoryTypeIndex = s_Vulkan->GetMemoryTypeIndex(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT); ``` 2. **描述符集绑定** (根据引用[2]) ```cpp // 计算着色器描述符绑定 VkDescriptorSetLayoutBinding binding{}; binding.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER; binding.stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT; // 片元着色器使用 binding.binding = 0; binding.descriptorCount = 1; ``` 3. **图像布局转换** ```cpp // 转换布局为SHADER_READ_ONLY_OPTIMAL VkImageMemoryBarrier barrier{}; barrier.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED; barrier.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL; barrier.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT; barrier.dstAccessMask = VK_ACCESS_SHADER_READ_BIT; ``` #### 5. 性能优化建议 - **格式选择**：移动端优先使用`VK_FORMAT_R8G8B8A8_UNORM` - **Mipmap生成**：添加`VK_IMAGE_USAGE_TRANSFER_SRC_BIT`支持mipmap生成 - **并发访问**：使用`VK_SHARING_MODE_CONCURRENT`用于多队列访问 - **内存类型**：优先使用`VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT`内存[^1] #### 6. 使用场景示例 ```csharp // 创建渲染目标并采样 RenderTexture rt = new RenderTexture(512, 512, 0, RenderTextureFormat.ARGB32); rt.Create(); Graphics.Blit(sourceTexture, rt); // 在着色器中采样 material.SetTexture("_SampledTexture", rt); ``` ### 相关问题 1. 如何在Unity中优化Vulkan纹理的内存分配策略？ 2. 使用`VK_IMAGE_USAGE_SAMPLED_BIT`时如何避免纹理访问延迟？ 3. 在Vulkan中如何为计算着色器设置采样纹理描述符？ 4. 如何在移动设备上优化采样纹理的性能？ 5. 如何正确管理采样纹理的布局转换和内存屏障？