Merge pull request #86 from Simple-Robotics/fix-camera-frustum-shadow-pass

Fix shadow pass using camera frustum, remove using-decl for `coal::OBB`

Author: ManifoldFR

CHANGELOG.md

@@ -7,6 +7,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- multibody/Visualizer : expose 'device'
+- core : make `renderShadowPassFromFrustum()` work properly
+
+### Removed
+
+- core : remove using-decl of `coal::OBB`
+
 ## [0.5.0] - 2025-06-13
 
 ### Added

bindings/python/src/expose-visualizer.cpp

@@ -34,6 +34,9 @@ void exposeVisualizer() {
       .def(VisualizerPythonVisitor<Visualizer>{})
       .def_readonly("renderer", &Visualizer::renderer)
       .def_readwrite("worldSceneBounds", &Visualizer::worldSceneBounds)
+      .add_property("device",
+                    bp::make_function(&Visualizer::device,
+                                      bp::return_internal_reference<>()))
       .def(
           "takeScreenshot",
           +[](Visualizer &viz, const std::string &filename) {

examples/Ur5WithSystems.cpp

@@ -497,9 +497,12 @@ int main(int argc, char **argv) {
       const GpuMat4 viewProj = g_camera.camera.viewProj();
       robot_scene.collectOpaqueCastables();
       auto &castables = robot_scene.castables();
-      renderShadowPassFromAABB(command_buffer, shadowPassInfo,
-                               robot_scene.directionalLight, castables,
-                               worldSpaceBounds);
+      // renderShadowPassFromAABB(command_buffer, shadowPassInfo,
+      //                          robot_scene.directionalLight, castables,
+      //                          worldSpaceBounds);
+      renderShadowPassFromFrustum(command_buffer, shadowPassInfo,
+                                  robot_scene.directionalLight, castables,
+                                  frustumFromCameraViewProj(viewProj));
       depthPass.render(command_buffer, viewProj, castables);
       switch (g_showDebugViz) {
       case FULL_RENDER:

src/candlewick/core/Camera.h

@@ -104,9 +104,9 @@ inline float perspectiveProjFar(const Mat4f &proj) {
   return std::abs(proj(2, 3) / (proj(2, 2) + 1.f));
 }
 
-/// \brief Extract the array of frustum corners, given a camera projection
-/// matrix.
-inline FrustumCornersType frustumFromCameraProjection(const Mat4f &camProj) {
+/// \brief Extract the array of frustum corners, given the camera
+/// view-projection matrix.
+inline FrustumCornersType frustumFromCameraViewProj(const Mat4f &camProj) {
   auto invProj = camProj.inverse();
   FrustumCornersType out;
   for (Uint8 i = 0; i < 8; i++) {
@@ -124,11 +124,6 @@ inline FrustumCornersType frustumFromCameraProjection(const Mat4f &camProj) {
   return out;
 }
 
-/// \brief Get the corners of a Camera's view frustum, in world space.
-inline FrustumCornersType frustumFromCamera(const Camera &camera) {
-  return frustumFromCameraProjection(camera.viewProj());
-}
-
 inline std::pair<Float3, float>
 frustumBoundingSphereCenterRadius(const FrustumCornersType &worldSpaceCorners) {
   Float3 frustumCenter = Float3::Zero();
@@ -144,6 +139,13 @@ frustumBoundingSphereCenterRadius(const FrustumCornersType &worldSpaceCorners) {
   return {frustumCenter, radius};
 }
 
+inline void frustumApplyTransform(FrustumCornersType &corners,
+                                  const Mat4f &tr) {
+  for (auto &x : corners) {
+    x = (tr * x.homogeneous()).head<3>();
+  }
+}
+
 /// \}
 
 } // namespace candlewick

src/candlewick/core/Collision.h

@@ -6,7 +6,6 @@
 namespace candlewick {
 
 using coal::AABB;
-using coal::OBB;
 
 inline Mat4f toTransformationMatrix(const AABB &aabb) {
   Mat4f T = Mat4f::Identity();
@@ -16,7 +15,7 @@ inline Mat4f toTransformationMatrix(const AABB &aabb) {
   return T;
 }
 
-inline Mat4f toTransformationMatrix(const OBB &obb) {
+inline Mat4f toTransformationMatrix(const coal::OBB &obb) {
   Mat4f T = Mat4f::Identity();
   auto D = obb.extent.asDiagonal();
   T.block<3, 3>(0, 0) = (obb.axes * D).cast<float>();
@@ -40,4 +39,12 @@ inline std::array<Float3, 8> getAABBCorners(const AABB &aabb) {
   };
 }
 
+inline AABB applyTransformToAABB(const AABB &aabb, const Mat4f &tr_) {
+  using coal::CoalScalar;
+  auto tr = tr_.cast<CoalScalar>();
+  coal::Matrix3s R = tr.topLeftCorner<3, 3>();
+  coal::Vec3s t = tr.topRightCorner<3, 1>();
+  return coal::translate(coal::rotate(aabb, R), t);
+}
+
 } // namespace candlewick

src/candlewick/core/DepthAndShadowPass.cpp

@@ -262,21 +262,29 @@ void renderShadowPassFromFrustum(CommandBuffer &cmdBuf, ShadowMapPass &passInfo,
                                  std::span<const DirectionalLight> dirLight,
                                  std::span<const OpaqueCastable> castables,
                                  const FrustumCornersType &worldSpaceCorners) {
-  using Eigen::Vector3d;
-
   auto [center, radius] = frustumBoundingSphereCenterRadius(worldSpaceCorners);
-  radius = std::ceil(radius * 16.f) / 16.f;
 
   for (size_t i = 0; i < passInfo.numLights(); i++) {
-    const Float3 eye = center - radius * dirLight[i].direction.normalized();
+    Float3 eye = center - radius * dirLight[i].direction.normalized();
+    Mat4f tmpLightView = lookAt(eye, center, Float3::UnitZ());
+    // transform corners to light-space
+    FrustumCornersType corners = worldSpaceCorners;
+    frustumApplyTransform(corners, tmpLightView);
+
+    coal::AABB bounds;
+    for (const auto &c : corners) {
+      bounds += c.cast<coal::CoalScalar>();
+    }
+    float r = float(bounds.max_.z());
+
     auto &lightView = passInfo.cam[i].view;
     auto &lightProj = passInfo.cam[i].projection;
+    eye = center - r * dirLight[i].direction.normalized();
     lightView = lookAt(eye, center, Float3::UnitZ());
 
-    AABB bounds{Vector3d::Constant(-radius), Vector3d::Constant(radius)};
     lightProj = shadowOrthographicMatrix({bounds.width(), bounds.height()},
-                                         float(bounds.min_.z()),
-                                         float(bounds.max_.z()));
+                                         float(bounds.max_.z()),
+                                         float(bounds.min_.z()));
   }
   passInfo.render(cmdBuf, castables);
 }
@@ -285,28 +293,21 @@ void renderShadowPassFromAABB(CommandBuffer &cmdBuf, ShadowMapPass &passInfo,
                               std::span<const DirectionalLight> dirLight,
                               std::span<const OpaqueCastable> castables,
                               const AABB &worldAABB) {
-  using Eigen::Vector3d;
-
   Float3 center = worldAABB.center().cast<float>();
 
   for (size_t i = 0; i < passInfo.numLights(); i++) {
-    Float3 tmpEye = center - 100.0f * dirLight[i].direction.normalized();
-    Mat4f tmplightView = lookAt(tmpEye, center, Float3::UnitZ());
+    Float3 eye = center - 100.0f * dirLight[i].direction.normalized();
+    Mat4f tmpLightView = lookAt(eye, center, Float3::UnitZ());
+    AABB bounds = applyTransformToAABB(worldAABB, tmpLightView);
 
     auto &lightView = passInfo.cam[i].view;
     auto &lightProj = passInfo.cam[i].projection;
 
-    Mat3f R = tmplightView.topLeftCorner<3, 3>();
-    Float3 t = tmplightView.topRightCorner<3, 1>();
-    AABB bounds = coal::translate(coal::rotate(worldAABB, R.cast<double>()),
-                                  t.cast<double>());
-
-    Float3 lightSpaceCenter = bounds.center().cast<float>();
     float radius = float(bounds.max_.z());
 
-    Float3 finalEye = center - radius * dirLight[i].direction.normalized();
+    eye = center - radius * dirLight[i].direction.normalized();
 
-    lightView = lookAt(finalEye, center, Float3::UnitZ());
+    lightView = lookAt(eye, center, Float3::UnitZ());
     lightProj = shadowOrthographicMatrix({bounds.width(), bounds.height()},
                                          float(bounds.max_.z()),
                                          float(bounds.min_.z()));

src/candlewick/core/DepthAndShadowPass.h

@@ -190,7 +190,7 @@ void renderShadowPassFromAABB(CommandBuffer &cmdBuf, ShadowMapPass &passInfo,
 /// light-space view and projection matrices which will enclose this bounding
 /// sphere within the light volume. The frustum can be obtained from the
 /// world-space camera.
-/// \sa frustumFromCameraProjection()
+/// \sa frustumFromCameraViewProj()
 void renderShadowPassFromFrustum(CommandBuffer &cmdBuf, ShadowMapPass &passInfo,
                                  std::span<const DirectionalLight> dirLight,
                                  std::span<const OpaqueCastable> castables,

src/candlewick/core/debug/Frustum.cpp

@@ -85,7 +85,8 @@ namespace frustum_debug {
   }
 
   void renderOBB(CommandBuffer &cmdBuf, SDL_GPURenderPass *render_pass,
-                 const Camera &camera, const OBB &obb, const Float4 &color) {
+                 const Camera &camera, const coal::OBB &obb,
+                 const Float4 &color) {
     Mat4f transform = toTransformationMatrix(obb);
     Mat4f mvp = camera.viewProj() * transform;
     Float3 eyePos = obb.center().cast<float>();
@@ -130,7 +131,7 @@ void FrustumBoundsDebugSystem::render(CommandBuffer &cmdBuf,
                      frustum_debug::renderAABB(cmdBuf, render_pass, camera,
                                                bounds, item.color);
                    },
-                   [&](const OBB &obb) {
+                   [&](const coal::OBB &obb) {
                      frustum_debug::renderOBB(cmdBuf, render_pass, camera, obb,
                                               item.color);
                    },

src/candlewick/core/debug/Frustum.h

@@ -24,7 +24,7 @@ namespace frustum_debug {
                   const Float4 &color = 0x00BFFFff_rgbaf);
 
   void renderOBB(CommandBuffer &cmdBuf, SDL_GPURenderPass *render_pass,
-                 const Camera &camera, const OBB &obb,
+                 const Camera &camera, const coal::OBB &obb,
                  const Float4 &color = 0x00BFFFff_rgbaf);
 
   void renderFrustum(CommandBuffer &cmdBuf, SDL_GPURenderPass *render_pass,
@@ -39,7 +39,7 @@ struct DebugFrustumComponent {
 };
 
 struct DebugBoundsComponent {
-  std::variant<AABB, OBB> bounds;
+  std::variant<AABB, coal::OBB> bounds;
   GpuVec4 color = 0xA03232FF_rgbaf;
 };
 

src/candlewick/multibody/Visualizer.h

@@ -69,8 +69,6 @@ class Visualizer final : public BaseVisualizer {
 
   void displayImpl() override;
 
-  const Device &device() const { return renderer.device; }
-
   GuiSystem::GuiBehavior getDefaultCallback() {
     return [this](auto &) { this->defaultGuiCallback(); };
   }
@@ -105,6 +103,7 @@ class Visualizer final : public BaseVisualizer {
   void defaultGuiCallback();
 
   void resetCamera();
+
   void loadViewerModel() override;
 
   Visualizer(const Config &config, const pin::Model &model,
@@ -127,6 +126,8 @@ class Visualizer final : public BaseVisualizer {
 
   ~Visualizer() override;
 
+  const Device &device() const { return renderer.device; }
+
   void setCameraTarget(const Eigen::Ref<const Vector3> &target) override;
 
   void setCameraPosition(const Eigen::Ref<const Vector3> &position) override;