ScriptableRenderContext.DrawRenderers

Parameters

Description

Schedules the drawing of a set of visible objects, and optionally overrides the GPU's render state.

This function creates commands to draw the specified geometry, and adds the commands to the internal command list of the ScriptableRenderContext. The ScriptableRenderContext executes all the commands in its internal list when ScriptableRenderContext.Submit is called.

This example demonstrates using a CommandBuffer to set clear the render target, and then calling this function to draw geometry:

using UnityEngine;
using UnityEngine.Rendering;

public class ExampleRenderPipeline : RenderPipeline
{
    public ExampleRenderPipeline()
    {
    }

    protected override void Render(ScriptableRenderContext context, Camera[] cameras)
    {
        // Create and schedule a command to clear the current render target
        var cmd = new CommandBuffer();
        cmd.ClearRenderTarget(true, true, Color.black);
        context.ExecuteCommandBuffer(cmd);
        cmd.Release();

        // Iterate over all Cameras
        foreach (Camera camera in cameras)
        {
            // Get the culling parameters from the current Camera
            camera.TryGetCullingParameters(out var cullingParameters);

            // Use the culling parameters to perform a cull operation, and store the results
            var cullingResults = context.Cull(ref cullingParameters);

            // Update the value of built-in shader variables, based on the current Camera
            context.SetupCameraProperties(camera);

            // Tell Unity which geometry to draw, based on its LightMode Pass tag value
            ShaderTagId shaderTagId = new ShaderTagId("ExampleLightModeTag");

            // Tell Unity how to sort the geometry, based on the current Camera
            var sortingSettings = new SortingSettings(camera);

            // Create a DrawingSettings struct that describes which geometry to draw and how to draw it
            DrawingSettings drawingSettings = new DrawingSettings(shaderTagId, sortingSettings);

            // Tell Unity how to filter the culling results, to further specify which geometry to draw
            // Use FilteringSettings.defaultValue to specify no filtering
            FilteringSettings filteringSettings = FilteringSettings.defaultValue;

            // Schedule a command to draw the geometry, based on the settings you have defined
            context.DrawRenderers(cullingResults, ref drawingSettings, ref filteringSettings);

            // Schedule a command to draw the Skybox if required
            if (camera.clearFlags == CameraClearFlags.Skybox && RenderSettings.skybox != null)
            {
                context.DrawSkybox(camera);
            }

            // Instruct the graphics API to perform all scheduled commands
            context.Submit();
        }
    }
}

Overriding the render state

When you draw geometry using this function, you can use one or more RenderStateBlock structs to override the GPU's render state in the following ways:

• You can use the stateBlock parameter to provide a single RenderStateBlock struct. Unity uses the render state defined in stateBlock for all the geometry that this function draws.
• You can use the stateBlocks parameter to provide an array of RenderStateBlock structs, and the renderTypes parameter to provide an array of values for the SubShader Tag with a name of RenderType. For each element in the renderTypes array, if Unity finds geometry with a SubShader Tag name of RenderType and a matching value, it uses the render state defined in the corresponding element of the stateBlocks array. If there are multiple matches, Unity uses the first one. If an element in the renderTypes array has the default value for ShaderTagId, Unity treats this as a catch-all and uses the corresponding render state for all geometry.
• You can use the stateBlocks parameter to provide an array of RenderStateBlock structs, and use the tagName, tagValues, and isPassTagName parameters to specify the name and values of any SubShader Tag or Pass Tag. For each element in the tagNames and tagValues arrays, Unity identifies geometry with a matching SubShader Tag or Pass Tag name and value, and applies the render state defined in the corresponding element of the stateBlocks array. If there are multiple matches, Unity uses the first one. If an element in the tagValues has the default value for ShaderTagId, Unity treats this as a catch-all and uses the corresponding render state for all geometry.

This example demonstrates how to override the render state:

using UnityEngine;
using UnityEngine.Rendering;
using Unity.Collections;

public class OverrideRenderStateExample
{
    ScriptableRenderContext scriptableRenderContext;

    // Override the render state for all geometry that this function draws
    public void OverrideRenderStateForAll(CullingResults exampleCullingResults, DrawingSettings exampleDrawingSettings, FilteringSettings exampleFilteringSettings)
    {
        // Tell Unity how to override the render state
        var stateBlock = new RenderStateBlock(RenderStateMask.Depth);
        stateBlock.depthState = new DepthState(true, CompareFunction.LessEqual);

        // Schedule a command to draw the geometry using the desired render state
        // Unity will execute all scheduled commands during the next call to ScriptableRenderContext.Submit
        scriptableRenderContext.DrawRenderers(exampleCullingResults, ref exampleDrawingSettings, ref exampleFilteringSettings, ref stateBlock);
    }

    // Override the render state for all geometry that has a SubShader Tag
    // with a name of "RenderType" and a value of "ExampleRenderTypeTagValue"
    public void OverrideRenderStateUsingRenderTypeTag(CullingResults exampleCullingResults, DrawingSettings exampleDrawingSettings, FilteringSettings exampleFilteringSettings)
    {
        // Create the parameters that tell Unity how to override the render state
        var stateBlock = new RenderStateBlock(RenderStateMask.Depth);
        stateBlock.depthState = new DepthState(true, CompareFunction.Greater);
        var stateBlocks = new NativeArray<RenderStateBlock>(1, Allocator.Temp);
        stateBlocks[0] = stateBlock;

        // Create the parameters that tell Unity when to override the render state
        ShaderTagId renderType = new ShaderTagId("ExampleRenderTypeTagValue");
        var renderTypes = new NativeArray<ShaderTagId>(1, Allocator.Temp);
        renderTypes[0] = renderType;

        // Schedule a command to draw the geometry using the desired render state
        // Unity will execute all scheduled commands during the next call to ScriptableRenderContext.Submit
        scriptableRenderContext.DrawRenderers(exampleCullingResults, ref exampleDrawingSettings, ref exampleFilteringSettings, renderTypes, stateBlocks);

        // DrawRenderers copies the array contents, so it is safe to dispose of the native arrays
        stateBlocks.Dispose();
        renderTypes.Dispose();
    }

    // Override the render state in two different ways.
    // Use one state for all geometry that has a Pass Tag
    // with a name of "ExamplePassTagName" and a value of "ExamplePassTagValue".
    // For all other geometry, use a second state.
    public void OverrideRenderStateUsingPassTag(CullingResults exampleCullingResults, DrawingSettings exampleDrawingSettings, FilteringSettings exampleFilteringSettings)
    {
        // Create the parameters that tell Unity how to override the render state
        var stateBlock0 = new RenderStateBlock(RenderStateMask.Depth);
        stateBlock0.depthState = new DepthState(true, CompareFunction.Greater);
        var stateBlock1 = new RenderStateBlock(RenderStateMask.Depth);
        stateBlock1.depthState = new DepthState(true, CompareFunction.Less);
        var stateBlocks = new NativeArray<RenderStateBlock>(2, Allocator.Temp);
        stateBlocks[0] = stateBlock0;
        stateBlocks[1] = stateBlock1; // default override

        // Create the parameters that tell Unity when to override the render state
        ShaderTagId tagName = new ShaderTagId("ExamplePassTagName");
        bool isPassTagName = true;
        var tagValues = new NativeArray<ShaderTagId>(2, Allocator.Temp);
        tagValues[0] = new ShaderTagId("ExamplePassTagValue");
        tagValues[1] = new ShaderTagId(); // catch all

        // Schedule a command to draw the geometry using the desired render state
        // Unity will execute all scheduled commands during the next call to ScriptableRenderContext.Submit
        scriptableRenderContext.DrawRenderers(exampleCullingResults, ref exampleDrawingSettings, ref exampleFilteringSettings, tagName, isPassTagName, tagValues, stateBlocks);

        // DrawRenderers copies the array contents, so it is safe to dispose of the native arrays
        stateBlocks.Dispose();
        tagValues.Dispose();
    }
}

Additional resources: Creating a simple render loop in a custom Scriptable Render Pipeline CullingResults, DrawingSettings, FilteringSettings, RenderStateBlock.