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Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://okzkx.gitbook.io/blogs/tools/game-engine/unity/render/render-pipeline/srp/srp-overview.md). # SRP 概览 ## 1. 简介 渲染管线 RenderPipline 可能 包括下面步骤: 从 CPU 到 GPU 1. 模型渲染前的准备 2. 获取模型 (VBO) 3. 模型信息传入着色器 4. 着色器根据该模型对每个光源进行渲染 #### 官方资料 CBUFFER\_START和CBUFFER\_END,对于变量是单个材质独有的时候建议放在这里面，以提高性能。 CBUFFER(常量缓冲区)的空间较小，不适合存放纹理贴图这种大量数据的数据类型，适合存放float， half之类的不占空间的数据，关于它的官方文档在下有详细说明。 ## 2. 代码示例 全部的代码示例如下 [MyScriptableRenderPipeline.cs](https://github.com/wotakuro/CustomScriptRenderPipelineTest/blob/master/Assets/Scripts/MyScriptableRenderPipeline.cs) #### 2.1 进入渲染 1.自定义的BasicPipeInstance 类继承 :RenderPipeline ``` class BasicPipeInstance : RenderPipeline ``` 并实现其 Render 方法 ``` public override void Render (ScriptableRenderContext context, Camera[] cameras) ``` 2.清除屏幕颜色缓存 context.DrawSkybox(camera); 可以采用 ComdBuffer 写法 ``` // clear buffers to the configured color var cmd = new CommandBuffer(); cmd.ClearRenderTarget(true, true, m_ClearColor); context.ExecuteCommandBuffer(cmd); cmd.Release(); ``` 其他的功能实现也可以采用 ComdBuffer 写法, 和 直接 context 执行有很大的不同,context 具有上下文信息,比如 SkyBox,cmd 没有 #### 2.2 模型裁剪 对每个摄像机都进行一次模型裁剪并且获取相应的裁剪结果, 如果无法裁剪就跳过这个摄像机 ``` foreach (var camera in cameras){ // Create an structure to hold the culling paramaters ScriptableCullingParameters cullingParams; //Populate the culling paramaters from the camera if (!CullResults.GetCullingParameters(camera, stereoEnabled, out cullingParams)) continue; // if you like you can modify the culling paramaters here cullingParams.isOrthographic = true; // Create a structure to hold the cull results CullResults cullResults = new CullResults(); // Perform the culling operation CullResults.Cull(ref cullingParams, context, ref cullResults); //接下来的代码 } ``` #### 2.3 模型选择 从裁剪出的模型 挑选出此次需要渲染的模型,根据: (1) 渲染队列中的位置 (2) layer的序号 示例1 ``` // Get the opaque rendering filter settings var opaqueRange = new FilterRenderersSettings(); //Set the range to be the opaque queues opaqueRange.renderQueueRange = new RenderQueueRange() { min = 0, max = (int)UnityEngine.Rendering.RenderQueue.GeometryLast, }; //Include all layers opaqueRange.layerMask = ~0; ``` 示例 2 ``` var filterSettings = new FilterRenderersSettings(true) { renderQueueRange = RenderQueueRange.transparent, layerMask = 1 << LayerDefine.CHARA }; ``` renderQueueRange 可通过 min和max 或者 Shader 中的渲染模式获取 layerMask 采用二进制掩码的方式获取应该渲染的层级 #### 2.4 渲染参数 模型的渲染可以考虑下面这些渲染参数的选择 * HDR vs LDR * Linear vs Gamma * MSAA vs Post Process AA * PBR Materials vs Simple Materials * Lighting vs No Lighting * Lighting Technique * Shadowing Technique 设置渲染参数 ，即渲染所使用的Shader配置 ``` // Create the draw render settings // note that it takes a shader pass name var drs = new DrawRendererSettings(myCamera, new ShaderPassName("Opaque")); // enable instancing for the draw call drs.flags = DrawRendererFlags.EnableInstancing; // pass light probe and lightmap data to each renderer drs.rendererConfiguration = RendererConfiguration.PerObjectLightProbe | RendererConfiguration.PerObjectLightmaps; // sort the objects like normal opaque objects drs.sorting.flags = SortFlags.CommonOpaque; // draw all of the renderers context.DrawRenderers(cullResults.visibleRenderers, ref drs, opaqueRange); ``` 1. 代码中 new ShaderPassName("Opaque") 要和 Shader 中的 Pass{Tags { "LightMode" = "Opaque"} 相对应,表示此时采用的是模型的Shasder中 名为 Opaque 的 Pass 进行计算 2. DrawRendererFlags 中 : 3. None : 不合批, 4. EnableDynamicBatching: 动态合批 5. EnableInstancing: 手动合批 6. Note : 合批: 多个模型合成一个模型一次性传递给GPU,一次 DrawCall,要求同一个 Material(Sahder/Pass) 7. RendererConfiguration : 为模型加入光照贴图,泛光点? 8. SortFlags 物体排序 一般选择 CommonOpaque不透明，CommonTransparent 透明 之一。 1. DrawRenderers 通知渲染,即提交 GPU 一次DrawCall , 2. 通过上面代码,手动合批变得十分清晰明了 3. 另外在提交 context 前可以多次通知渲染,即多次DrawCall,对不同模型选择,不同渲染参数的模型组做渲染要采用多次渲染通知。 #### 2.5 收尾工作 在每个相机循环的最后提交context 的渲染队列设置 ``` // submit the context, this will execute all of the queued up commands. context.Submit(); }//End Foreach Camera ``` --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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