[hdEmbree] add direct camera visibility support for rect lights

pxr/imaging/plugin/hdEmbree/context.h

@@ -13,12 +13,14 @@
 
 #include "pxr/base/gf/matrix4f.h"
 #include "pxr/base/vt/array.h"
+#include "pxr/base/vt/types.h"
 
 #include <embree3/rtcore.h>
 
 PXR_NAMESPACE_OPEN_SCOPE
 
 class HdRprim;
+class HdEmbree_Light;
 
 /// \class HdEmbreePrototypeContext
 ///
@@ -51,6 +53,8 @@ struct HdEmbreeInstanceContext
     RTCScene rootScene;
     /// The instance id of this instance.
     int32_t instanceId;
+    /// The light (if this is a light)
+    HdEmbree_Light *light = nullptr;
 };
 
 

pxr/imaging/plugin/hdEmbree/light.cpp

@@ -15,6 +15,7 @@
 #include "pxr/imaging/hio/image.h"
 
 #include <embree3/rtcore_buffer.h>
+#include <embree3/rtcore_device.h>
 #include <embree3/rtcore_scene.h>
 
 #include <fstream>
@@ -78,6 +79,11 @@ _SyncLightTexture(const SdfPath& id, HdEmbree_LightData& light, HdSceneDelegate
 } // anonymous namespace
 PXR_NAMESPACE_OPEN_SCOPE
 
+TF_DEFINE_PRIVATE_TOKENS(_tokens,
+    ((inputsVisibilityCamera, "inputs:visibility:camera"))
+    ((inputsVisibilityShadow, "inputs:visibility:shadow"))
+);
+
 HdEmbree_Light::HdEmbree_Light(SdfPath const& id, TfToken const& lightType)
     : HdLight(id) {
     if (id.IsEmpty()) {
@@ -117,7 +123,8 @@ HdEmbree_Light::Sync(HdSceneDelegate *sceneDelegate,
         static_cast<HdEmbreeRenderParam*>(renderParam);
 
     // calling this bumps the scene version and causes a re-render
-    embreeRenderParam->AcquireSceneForEdit();
+    RTCScene scene = embreeRenderParam->AcquireSceneForEdit();
+    RTCDevice device = embreeRenderParam->GetEmbreeDevice();
 
     SdfPath const& id = GetId();
 
@@ -147,6 +154,13 @@ HdEmbree_Light::Sync(HdSceneDelegate *sceneDelegate,
 
     // Get visibility
     _lightData.visible = sceneDelegate->GetVisible(id);
+    _lightData.visible_camera = sceneDelegate->GetLightParamValue(
+        id, _tokens->inputsVisibilityCamera).GetWithDefault(false);
+    // XXX: Don't think we can get this to work in Embree unless it's built with
+    // masking only solution would be to use rtcIntersect instead of rtcOccluded
+    // for shadow rays, which maybe isn't the worst for a reference renderer
+    _lightData.visible_shadow = sceneDelegate->GetLightParamValue(
+        id, _tokens->inputsVisibilityShadow).GetWithDefault(false);
 
     // Switch on the _lightData type and pull the relevant attributes from the scene
     // delegate
@@ -211,12 +225,71 @@ HdEmbree_Light::Sync(HdSceneDelegate *sceneDelegate,
         _lightData.shaping.coneSoftness = value.UncheckedGet<float>();
     }
 
+    _PopulateRtcLight(device, scene);
+
     HdEmbreeRenderer *renderer = embreeRenderParam->GetRenderer();
     renderer->AddLight(id, this);
 
     *dirtyBits &= ~HdLight::AllDirty;
 }
 
+void
+HdEmbree_Light::_PopulateRtcLight(RTCDevice device, RTCScene scene)
+{
+    _lightData.rtcMeshId = RTC_INVALID_GEOMETRY_ID;
+
+    // create the light geometry, if required
+    if (_lightData.visible) {
+        if (auto* rect = std::get_if<HdEmbree_Rect>(&_lightData.lightVariant))
+        {
+            // create _lightData mesh
+            GfVec3f v0(-rect->width/2.0f, -rect->height/2.0f, 0.0f);
+            GfVec3f v1( rect->width/2.0f, -rect->height/2.0f, 0.0f);
+            GfVec3f v2( rect->width/2.0f,  rect->height/2.0f, 0.0f);
+            GfVec3f v3(-rect->width/2.0f,  rect->height/2.0f, 0.0f);
+
+            v0 = _lightData.xformLightToWorld.Transform(v0);
+            v1 = _lightData.xformLightToWorld.Transform(v1);
+            v2 = _lightData.xformLightToWorld.Transform(v2);
+            v3 = _lightData.xformLightToWorld.Transform(v3);
+
+            _lightData.rtcGeometry = rtcNewGeometry(device,
+                                                RTC_GEOMETRY_TYPE_QUAD);
+            GfVec3f* vertices = static_cast<GfVec3f*>(
+                rtcSetNewGeometryBuffer(_lightData.rtcGeometry,
+                                        RTC_BUFFER_TYPE_VERTEX,
+                                        0,
+                                        RTC_FORMAT_FLOAT3,
+                                        sizeof(GfVec3f),
+                                        4));
+            vertices[0] = v0;
+            vertices[1] = v1;
+            vertices[2] = v2;
+            vertices[3] = v3;
+
+            unsigned* index = static_cast<unsigned*>(
+                rtcSetNewGeometryBuffer(_lightData.rtcGeometry,
+                                        RTC_BUFFER_TYPE_INDEX,
+                                        0,
+                                        RTC_FORMAT_UINT4,
+                                        sizeof(unsigned)*4,
+                                        1));
+            index[0] = 0; index[1] = 1; index[2] = 2; index[3] = 3;
+
+            auto ctx = std::make_unique<HdEmbreeInstanceContext>();
+            ctx->light = this;
+            rtcSetGeometryTimeStepCount(_lightData.rtcGeometry, 1);
+            rtcCommitGeometry(_lightData.rtcGeometry);
+            _lightData.rtcMeshId = rtcAttachGeometry(scene, _lightData.rtcGeometry);
+            if (_lightData.rtcMeshId == RTC_INVALID_GEOMETRY_ID) {
+                TF_WARN("could not create rect mesh for %s", GetId().GetAsString().c_str());
+            } else {
+                rtcSetGeometryUserData(_lightData.rtcGeometry, ctx.release());
+            }
+        }
+    }
+}
+
 HdDirtyBits
 HdEmbree_Light::GetInitialDirtyBitsMask() const
 {
@@ -227,10 +300,22 @@ void
 HdEmbree_Light::Finalize(HdRenderParam *renderParam)
 {
     auto* embreeParam = static_cast<HdEmbreeRenderParam*>(renderParam);
+    RTCScene scene = embreeParam->AcquireSceneForEdit();
 
-    // Remove from renderer's light map
+    // First, remove from renderer's light map
     HdEmbreeRenderer *renderer = embreeParam->GetRenderer();
     renderer->RemoveLight(GetId(), this);
+
+    // Then clean up the associated embree objects
+    if (_lightData.rtcMeshId != RTC_INVALID_GEOMETRY_ID) {
+        delete static_cast<HdEmbreeInstanceContext*>(
+                    rtcGetGeometryUserData(_lightData.rtcGeometry));
+
+        rtcDetachGeometry(scene, _lightData.rtcMeshId);
+        rtcReleaseGeometry(_lightData.rtcGeometry);
+        _lightData.rtcMeshId = RTC_INVALID_GEOMETRY_ID;
+        _lightData.rtcGeometry = nullptr;
+    }
 }
 
 PXR_NAMESPACE_CLOSE_SCOPE

pxr/imaging/plugin/hdEmbree/light.h

@@ -88,7 +88,11 @@ struct HdEmbree_LightData
     HdEmbree_LightVariant lightVariant;
     bool normalize = false;
     bool visible = true;
+    bool visible_camera = true;
+    bool visible_shadow = true;
     HdEmbree_Shaping shaping;
+    unsigned rtcMeshId = RTC_INVALID_GEOMETRY_ID;
+    RTCGeometry rtcGeometry = nullptr;
 };
 
 class HdEmbree_Light final : public HdLight
@@ -118,6 +122,8 @@ class HdEmbree_Light final : public HdLight
     }
 
 private:
+    void _PopulateRtcLight(RTCDevice device, RTCScene scene);
+
     HdEmbree_LightData _lightData;
 };
 

pxr/imaging/plugin/hdEmbree/mesh.cpp

@@ -894,6 +894,7 @@ HdEmbreeMesh::_PopulateRtMesh(HdSceneDelegate* sceneDelegate,
             HdEmbreeInstanceContext *ctx = new HdEmbreeInstanceContext;
             ctx->rootScene = _rtcMeshScene;
             ctx->instanceId = i;
+            ctx->light = nullptr;
             rtcSetGeometryUserData(geom,ctx);
             _rtcInstanceGeometries[i] = geom;
         }

pxr/imaging/plugin/hdEmbree/renderer.cpp

@@ -422,6 +422,20 @@ _SampleCylinder(GfMatrix4f const& xf, GfMatrix3f const& normalXform,
     };
 }
 
+_ShapeSample
+_IntersectAreaLight(HdEmbree_LightData const& light, RTCRayHit const& rayHit)
+{
+    // XXX: just rect lights at the moment, need to do the others
+    auto const& rect = std::get<HdEmbree_Rect>(light.lightVariant);
+
+    return _ShapeSample {
+        _CalculateHitPosition(rayHit),
+        GfVec3f(rayHit.hit.Ng_x, rayHit.hit.Ng_y, rayHit.hit.Ng_z),
+        GfVec2f(1.0f - rayHit.hit.u, rayHit.hit.v),
+        _AreaRect(light.xformLightToWorld, rect.width, rect.height)
+    };
+}
+
 GfVec3f
 _EvalLightBasic(HdEmbree_LightData const& light)
 {
@@ -1275,6 +1289,43 @@ _CosineWeightedDirection(GfVec2f const& uniform_float)
     return dir;
 }
 
+bool
+HdEmbreeRenderer::_RayShouldContinue(RTCRayHit const& rayHit) const {
+    if (rayHit.hit.geomID == RTC_INVALID_GEOMETRY_ID) {
+        // missed, don't continue
+        return false;
+    }
+
+    if (rayHit.hit.instID[0] == RTC_INVALID_GEOMETRY_ID) {
+        // not hit an instance, but a "raw" geometry. This should be a light
+        const HdEmbreeInstanceContext *instanceContext =
+            static_cast<HdEmbreeInstanceContext*>(
+                    rtcGetGeometryUserData(rtcGetGeometry(_scene,
+                                                          rayHit.hit.geomID)));
+
+        if (instanceContext->light == nullptr) {
+            // if this isn't a light, don't know what this is
+            return false;
+        }
+
+        auto const& light = instanceContext->light->LightData();
+
+        if ((rayHit.ray.mask & HdEmbree_RayMask::Camera)
+                && !light.visible_camera) {
+            return true;
+        } else if ((rayHit.ray.mask & HdEmbree_RayMask::Shadow)
+                && !light.visible_shadow) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    // XXX: otherwise this is a regular geo. we should handle visibility here
+    // too eventually
+    return false;
+}
+
 void
 HdEmbreeRenderer::_TraceRay(unsigned int x, unsigned int y,
                             GfVec3f const &origin, GfVec3f const &dir,
@@ -1306,6 +1357,13 @@ HdEmbreeRenderer::_TraceRay(unsigned int x, unsigned int y,
       rayHit.hit.Ng_z = -rayHit.hit.Ng_z;
     }
 
+    if (_RayShouldContinue(rayHit)) {
+        GfVec3f hitPos = _CalculateHitPosition(rayHit);
+
+        _TraceRay(x, y, hitPos + dir * _rayHitContinueBias, dir, random);
+        return;
+    }
+
     // Write AOVs to attachments that aren't converged.
     for (size_t i = 0; i < _aovBindings.size(); ++i) {
         HdEmbreeRenderBuffer *renderBuffer =
@@ -1361,6 +1419,11 @@ HdEmbreeRenderer::_ComputeId(RTCRayHit const& rayHit, TfToken const& idType,
         return false;
     }
 
+    if (rayHit.hit.instID[0] == RTC_INVALID_GEOMETRY_ID) {
+        // not hit an instance, but a "raw" geometry. This should be a light
+        return false;
+    }
+
     // Get the instance and prototype context structures for the hit prim.
     // We don't use embree's multi-level instancing; we
     // flatten everything in hydra. So instID[0] should always be correct.
@@ -1401,6 +1464,11 @@ HdEmbreeRenderer::_ComputeDepth(RTCRayHit const& rayHit,
         return false;
     }
 
+    if (rayHit.hit.instID[0] == RTC_INVALID_GEOMETRY_ID) {
+        // not hit an instance, but a "raw" geometry. This should be a light
+        return false;
+    }
+
     if (clip) {
         GfVec3f hitPos = _CalculateHitPosition(rayHit);
 
@@ -1424,6 +1492,11 @@ HdEmbreeRenderer::_ComputeNormal(RTCRayHit const& rayHit,
         return false;
     }
 
+    if (rayHit.hit.instID[0] == RTC_INVALID_GEOMETRY_ID) {
+        // not hit an instance, but a "raw" geometry. This should be a light
+        return false;
+    }
+
     // We don't use embree's multi-level instancing; we
     // flatten everything in hydra. So instID[0] should always be correct.
     const HdEmbreeInstanceContext *instanceContext =
@@ -1462,6 +1535,11 @@ HdEmbreeRenderer::_ComputePrimvar(RTCRayHit const& rayHit,
         return false;
     }
 
+    if (rayHit.hit.instID[0] == RTC_INVALID_GEOMETRY_ID) {
+        // not hit an instance, but a "raw" geometry. This should be a light
+        return false;
+    }
+
     // We don't use embree's multi-level instancing; we
     // flatten everything in hydra. So instID[0] should always be correct.
     const HdEmbreeInstanceContext *instanceContext =
@@ -1548,6 +1626,30 @@ HdEmbreeRenderer::_ComputeColor(RTCRayHit const& rayHit,
         return domeColor;
     }
 
+    if (rayHit.hit.instID[0] == RTC_INVALID_GEOMETRY_ID) {
+        // if it's not an instance then it's almost certainly a light
+        const HdEmbreeInstanceContext *instanceContext =
+            static_cast<HdEmbreeInstanceContext*>(
+                    rtcGetGeometryUserData(rtcGetGeometry(_scene,
+                                                          rayHit.hit.geomID)));
+
+        // if we hit a light, just evaluate the light directly
+        if (instanceContext->light != nullptr) {
+            auto const& light = instanceContext->light->LightData();
+            _ShapeSample ss = _IntersectAreaLight(light, rayHit);
+            _LightSample ls = _EvalAreaLight(light, ss,
+                GfVec3f(rayHit.ray.org_x, rayHit.ray.org_y, rayHit.ray.org_z));
+
+            return GfVec4f(ls.Li[0], ls.Li[1], ls.Li[2], 1.0f);
+        } else {
+            // should never get here. magenta warning!
+            TF_WARN("Unexpected runtime state - hit an an embree instance "
+                "that wasn't a geo or light");
+            return GfVec4f(1.0f, 0.0f, 1.0f, 1.0f);
+        }
+
+    }
+
     // Get the instance and prototype context structures for the hit prim.
     // We don't use embree's multi-level instancing; we
     // flatten everything in hydra. So instID[0] should always be correct.