From 10e41fbd07aeb0a18768e75c0ed757e290f1b522 Mon Sep 17 00:00:00 2001
From: "zhou.xu" <zhou.xu@bambulab.com>
Date: Mon, 12 Aug 2024 17:23:33 +0800
Subject: [PATCH] FIX:calculate frustum of ortho view

jira: none
Change-Id: Ia0c30ebd9366ae1dfc5cdd555aa9f89a9dd878f1
---
 src/libslic3r/Frustum.cpp  | 11 +++++++----
 src/libslic3r/Frustum.hpp  |  2 +-
 src/slic3r/GUI/3DScene.cpp |  2 +-
 src/slic3r/GUI/Camera.cpp  | 36 +++++++++++++++++++++++++++++++++---
 4 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/src/libslic3r/Frustum.cpp b/src/libslic3r/Frustum.cpp
index b01de8c20..10fae9145 100644
--- a/src/libslic3r/Frustum.cpp
+++ b/src/libslic3r/Frustum.cpp
@@ -51,10 +51,13 @@ Frustum::Plane::PlaneIntersects Frustum::Plane::intersects(const Vec3f &p0, cons
     return Plane::Intersects_Tangent;
 }
 
-bool Frustum::intersects(const BoundingBoxf3 &box) const {
-    for (auto &plane : planes) {
-        if (plane.intersects(box) == Plane::Intersects_Back) {
-            return false;
+bool Frustum::intersects(const BoundingBoxf3 &box, bool is_perspective) const
+{
+    if (is_perspective) {
+        for (auto &plane : planes) {
+            if (plane.intersects(box) == Plane::Intersects_Back) {
+                return false;
+            }
         }
     }
     // check box intersects
diff --git a/src/libslic3r/Frustum.hpp b/src/libslic3r/Frustum.hpp
index c31ba92a0..26b12e1dc 100644
--- a/src/libslic3r/Frustum.hpp
+++ b/src/libslic3r/Frustum.hpp
@@ -37,7 +37,7 @@ public:
         float d_ = 0;
     };
 
-    bool intersects(const BoundingBoxf3 &box) const;
+    bool intersects(const BoundingBoxf3 &box, bool is_perspective) const;
     // check intersect with point (world space)
     bool intersects(const Vec3f &p0) const;
     // check intersect with line segment (world space)
diff --git a/src/slic3r/GUI/3DScene.cpp b/src/slic3r/GUI/3DScene.cpp
index f3eba0dbe..f355ecaad 100644
--- a/src/slic3r/GUI/3DScene.cpp
+++ b/src/slic3r/GUI/3DScene.cpp
@@ -1555,7 +1555,7 @@ void GLVolumeCollection::render(GLVolumeCollection::ERenderType       type,
     auto camera = GUI::wxGetApp().plater()->get_camera();
     for (GLVolumeWithIdAndZ& volume : to_render) {
         auto world_box = volume.first->transformed_bounding_box();
-        if (!camera.getFrustum().intersects(world_box)) {
+        if (!camera.getFrustum().intersects(world_box, camera.get_type_as_string() == "perspective")) {
             continue;
         }
 #if ENABLE_MODIFIERS_ALWAYS_TRANSPARENT
diff --git a/src/slic3r/GUI/Camera.cpp b/src/slic3r/GUI/Camera.cpp
index ae19304a5..76b59ef5b 100644
--- a/src/slic3r/GUI/Camera.cpp
+++ b/src/slic3r/GUI/Camera.cpp
@@ -151,9 +151,9 @@ void Camera::update_frustum()
     float  aspect_   = m_viewport[2] /  (double)m_viewport[3];
     float  fov_      = (float) Geometry::deg2rad(get_fov());
     float  eps       = 0.01;
-    if (m_last_eye.isApprox(eye_) && m_last_center.isApprox(center_) && m_last_up.isApprox(up_) &&
-        abs(m_last_near - near_) > eps && abs(m_last_far - far_) > eps &&
-        abs(m_last_aspect - aspect_) > eps && abs(m_last_fov - fov_) > eps) {
+    if (m_last_eye.isApprox(eye_) && m_last_center.isApprox(center_) && m_last_up.isApprox(up_)
+        && abs(m_last_near - near_) < eps && abs(m_last_far - far_) < eps &&
+        abs(m_last_aspect - aspect_) < eps && abs(m_last_fov - fov_) < eps) {
         return;
     }
     m_last_eye = eye_;
@@ -181,7 +181,37 @@ void Camera::update_frustum()
     Vec3f farCenter = eye_ + forward * far_;
     Vec3f farNormal = -forward;
     m_frustum.planes[1].set(farNormal, farCenter);
+    if (m_type == EType::Ortho) {
+        double right       = 1.0 / m_projection_matrix.matrix()(0, 0) - 0.5 * m_projection_matrix.matrix()(0, 0) * m_projection_matrix.matrix()(0, 3);
+        double top         = 1.0 / m_projection_matrix.matrix()(1, 1) - 0.5 * m_projection_matrix.matrix()(1, 1) * m_projection_matrix.matrix()(1, 3);
+        auto   dz          = (far_ - near_) / 2.0;
+        Vec3f center    = eye_ + forward * (far_ + near_) /2.0f;
+        m_frustum.bbox.reset();
+        Vec3f corner   = farCenter + up * top + side * right;
+        m_frustum.bbox.merge(corner.cast<double>());
 
+        corner   = farCenter - up * top + side * right;
+        m_frustum.bbox.merge(corner.cast<double>());
+
+        corner = farCenter + up * top - side * right;
+        m_frustum.bbox.merge(corner.cast<double>());
+
+        corner = farCenter - up * top - side * right;
+        m_frustum.bbox.merge(corner.cast<double>());
+        //nearCenter
+        corner = nearCenter + up * top + side * right;
+        m_frustum.bbox.merge(corner.cast<double>());
+
+        corner = nearCenter - up * top + side * right;
+        m_frustum.bbox.merge(corner.cast<double>());
+
+        corner = nearCenter + up * top - side * right;
+        m_frustum.bbox.merge(corner.cast<double>());
+
+        corner = nearCenter - up * top - side * right;
+        m_frustum.bbox.merge(corner.cast<double>());
+        return;
+    }
     // top plane
     Vec3f topCenter = nearCenter + up * nearHeightHalf;
     Vec3f topNormal = (topCenter - eye_).normalized().cross(side);