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using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Experimental.Rendering;
using UnityEngine.Experimental.ScriptableRenderLoop;
// Very basic scriptable rendering loop example:
// - Use with BasicRenderLoopShader.shader (the loop expects "BasicPass" pass type to exist)
// - Supports up to 8 enabled lights in the scene (directional, point or spot)
// - Does the same physically based BRDF as the Standard shader
// - No shadows
// - This loop also does not setup lightmaps, light probes, reflection probes or light cookies
[ExecuteInEditMode]
public class BasicRenderLoop : ScriptableRenderLoop
{
#if UNITY_EDITOR
[UnityEditor.MenuItem("Renderloop/CreateBasicRenderLoop")]
static void CreateBasicRenderLoop()
{
var instance = ScriptableObject.CreateInstance<BasicRenderLoop>();
UnityEditor.AssetDatabase.CreateAsset(instance, "Assets/basicrenderloop.asset");
}
#endif
private ShaderPassName shaderPassBasic;
public void OnEnable()
{
Rebuild();
}
public override void Initialize()
{
shaderPassBasic = new ShaderPassName("BasicPass");
}
// Main entry point for our scriptable render loop
public override void Render(Camera[] cameras, RenderLoop loop)
{
foreach (var camera in cameras)
{
// Culling
CullingParameters cullingParams;
if (!CullResults.GetCullingParameters (camera, out cullingParams))
continue;
CullResults cull = CullResults.Cull (ref cullingParams, loop);
// Setup camera for rendering (sets render target, view/projection matrices and other
// per-camera built-in shader variables).
loop.SetupCameraProperties (camera);
// clear depth buffer
var cmd = new CommandBuffer();
cmd.ClearRenderTarget(true, false, Color.black);
loop.ExecuteCommandBuffer(cmd);
cmd.Release();
// Setup global lighting shader variables
SetupLightShaderVariables (cull.visibleLights, loop);
// Draw opaque objects using BasicPass shader pass
var settings = new DrawRendererSettings (cull, camera, shaderPassBasic);
settings.sorting.sortOptions = SortOptions.SortByMaterialThenMesh;
settings.inputFilter.SetQueuesOpaque ();
loop.DrawRenderers (ref settings);
// Draw skybox
loop.DrawSkybox (camera);
// Draw transparent objects using BasicPass shader pass
settings.sorting.sortOptions = SortOptions.BackToFront; // sort back to front
settings.inputFilter.SetQueuesTransparent ();
loop.DrawRenderers (ref settings);
loop.Submit ();
}
}
// Setup lighting variables for shader to use
static void SetupLightShaderVariables (VisibleLight[] lights, RenderLoop loop)
{
// We only support up to 8 visible lights here. More complex approaches would
// be doing some sort of per-object light setups, but here we go for simplest possible
// approach.
const int kMaxLights = 8;
// Just take first 8 lights. Possible improvements: sort lights by intensity or distance
// to the viewer, so that "most important" lights in the scene are picked, and not the 8
// that happened to be first.
int lightCount = Mathf.Min (lights.Length, kMaxLights);
// Prepare light data
Vector4[] lightColors = new Vector4[kMaxLights];
Vector4[] lightPositions = new Vector4[kMaxLights];
Vector4[] lightSpotDirections = new Vector4[kMaxLights];
Vector4[] lightAtten = new Vector4[kMaxLights];
for (var i = 0; i < lightCount; ++i)
{
VisibleLight light = lights[i];
lightColors[i] = light.finalColor;
if (light.lightType == LightType.Directional)
{
// light position for directional lights is: (-direction, 0)
var dir = light.localToWorld.GetColumn (2);
lightPositions[i] = new Vector4 (-dir.x, -dir.y, -dir.z, 0);
}
else
{
// light position for point/spot lights is: (position, 1)
var pos = light.localToWorld.GetColumn (3);
lightPositions[i] = new Vector4 (pos.x, pos.y, pos.z, 1);
}
// attenuation set in a way where distance attenuation can be computed:
// float lengthSq = dot(toLight, toLight);
// float atten = 1.0 / (1.0 + lengthSq * LightAtten[i].z);
// and spot cone attenuation:
// float rho = max (0, dot(normalize(toLight), SpotDirection[i].xyz));
// float spotAtt = (rho - LightAtten[i].x) * LightAtten[i].y;
// spotAtt = saturate(spotAtt);
// and the above works for all light types, i.e. spot light code works out
// to correct math for point & directional lights as well.
float rangeSq = light.range * light.range;
float quadAtten = (light.lightType == LightType.Directional) ? 0.0f : 25.0f / rangeSq;
// spot direction & attenuation
if (light.lightType == LightType.Spot)
{
var dir = light.localToWorld.GetColumn (2);
lightSpotDirections[i] = new Vector4 (-dir.x, -dir.y, -dir.z, 0);
float radAngle = Mathf.Deg2Rad * light.spotAngle;
float cosTheta = Mathf.Cos (radAngle * 0.25f);
float cosPhi = Mathf.Cos (radAngle * 0.5f);
float cosDiff = cosTheta - cosPhi;
lightAtten[i] = new Vector4 (cosPhi, (cosDiff != 0.0f) ? 1.0f / cosDiff : 1.0f, quadAtten, rangeSq);
}
else
{
// non-spot light
lightSpotDirections[i] = new Vector4 (0, 0, 1, 0);
lightAtten[i] = new Vector4 (-1, 1, quadAtten, rangeSq);
}
}
// ambient lighting spherical harmonics values
const int kSHCoefficients = 7;
Vector4[] shConstants = new Vector4[kSHCoefficients];
SphericalHarmonicsL2 ambientSH = RenderSettings.ambientProbe * RenderSettings.ambientIntensity;
GetShaderConstantsFromNormalizedSH (ref ambientSH, shConstants);
// setup global shader variables to contain all the data computed above
CommandBuffer cmd = new CommandBuffer();
cmd.SetGlobalVectorArray ("globalLightColor", lightColors);
cmd.SetGlobalVectorArray ("globalLightPos", lightPositions);
cmd.SetGlobalVectorArray ("globalLightSpotDir", lightSpotDirections);
cmd.SetGlobalVectorArray ("globalLightAtten", lightAtten);
cmd.SetGlobalVector ("globalLightCount", new Vector4 (lightCount, 0, 0, 0));
cmd.SetGlobalVectorArray ("globalSH", shConstants);
loop.ExecuteCommandBuffer (cmd);
cmd.Dispose ();
}
// Prepare L2 spherical harmonics values for efficient evaluation in a shader
static void GetShaderConstantsFromNormalizedSH (ref SphericalHarmonicsL2 ambientProbe, Vector4[] outCoefficients)
{
for (int channelIdx = 0; channelIdx < 3; ++channelIdx)
{
// Constant + Linear
// In the shader we multiply the normal is not swizzled, so it's normal.xyz.
// Swizzle the coefficients to be in { x, y, z, DC } order.
outCoefficients[channelIdx].x = ambientProbe[channelIdx, 3];
outCoefficients[channelIdx].y = ambientProbe[channelIdx, 1];
outCoefficients[channelIdx].z = ambientProbe[channelIdx, 2];
outCoefficients[channelIdx].w = ambientProbe[channelIdx, 0] - ambientProbe[channelIdx, 6];
// Quadratic polynomials
outCoefficients[channelIdx + 3].x = ambientProbe[channelIdx, 4];
outCoefficients[channelIdx + 3].y = ambientProbe[channelIdx, 5];
outCoefficients[channelIdx + 3].z = ambientProbe[channelIdx, 6] * 3.0f;
outCoefficients[channelIdx + 3].w = ambientProbe[channelIdx, 7];
}
// Final quadratic polynomial
outCoefficients[6].x = ambientProbe[0, 8];
outCoefficients[6].y = ambientProbe[1, 8];
outCoefficients[6].z = ambientProbe[2, 8];
outCoefficients[6].w = 1.0f;
}
}