Merge pull request #79 from NJUCG/thin_lens

Complete the thin-lens camera.
NJUCG · Oct 24, 2023 · 558021d · 558021d
2 parents 30f8001 + ed1c4dc
commit 558021d
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Showing 7 changed files with 179 additions and 131 deletions.
diff --git a/scenes/green-bathroom/scene.json b/scenes/green-bathroom/scene.json
@@ -1,11 +1,9 @@
 {
   "renderer": {
-    "spp": 4096,
+    "spp": 4,
     "output_file": "green_bathroom"
   },
-
   "mediums": [],
-
   "materials": [
     {
       "name": "bamboo",
@@ -26,14 +24,22 @@
     {
       "name": "ceramics",
       "type": "plastic",
-      "albedo": [0.9, 0.9, 0.9],
+      "albedo": [
+        0.9,
+        0.9,
+        0.9
+      ],
       "roughness": 0.015,
       "ior": 1.45
     },
     {
       "name": "czarne",
       "type": "plastic",
-      "albedo": [0.1, 0.1, 0.1],
+      "albedo": [
+        0.1,
+        0.1,
+        0.1
+      ],
       "roughness": 0.01,
       "ior": 1.7
     },
@@ -42,24 +48,40 @@
       "type": "conductor",
       "distribution": "ggx",
       "material": "Al",
-      "albedo": [0.8, 0.8, 0.8],
+      "albedo": [
+        0.8,
+        0.8,
+        0.8
+      ],
       "roughness": 0.3
     },
     {
       "name": "Material.005",
       "type": "lambert",
-      "albedo": [0.8, 0.8, 0.8]
+      "albedo": [
+        0.8,
+        0.8,
+        0.8
+      ]
     },
     {
       "name": "czerwony",
       "type": "conductor",
-      "albedo": [1, 0.042, 0],
+      "albedo": [
+        1,
+        0.042,
+        0
+      ],
       "roughness": 0.02
     },
     {
       "name": "Material.004",
       "type": "lambert",
-      "albedo": [0.8, 0.779, 0.687]
+      "albedo": [
+        0.8,
+        0.779,
+        0.687
+      ]
     },
     {
       "name": "Material.009",
@@ -74,7 +96,11 @@
     {
       "name": "Material.013",
       "type": "lambert",
-      "albedo": [1, 1, 1]
+      "albedo": [
+        1,
+        1,
+        1
+      ]
     },
     {
       "name": "szare plytki",
@@ -86,19 +112,31 @@
     {
       "name": "biale sciany",
       "type": "lambert",
-      "albedo": [1, 1, 1]
+      "albedo": [
+        1,
+        1,
+        1
+      ]
     },
     {
       "name": "zielony",
       "type": "plastic",
-      "albedo": [0.364, 0.8, 0.110],
+      "albedo": [
+        0.364,
+        0.8,
+        0.110
+      ],
       "roughness": 0.02,
       "ior": 1.5
     },
     {
       "name": "bialy.001",
       "type": "plastic",
-      "albedo": [0.8, 0.8, 0.8],
+      "albedo": [
+        0.8,
+        0.8,
+        0.8
+      ],
       "roughness": 0.01,
       "ior": 1.3
     },
@@ -129,7 +167,11 @@
     {
       "name": "Material.008",
       "type": "lambert",
-      "albedo": [0.8, 0.8, 0.8]
+      "albedo": [
+        0.8,
+        0.8,
+        0.8
+      ]
     },
     {
       "name": "Material.017",
@@ -154,8 +196,16 @@
       "distribution": "ggx",
       "roughness": 0.001,
       "ior": 1.45,
-      "albedo_reflection": [1, 0.717, 0.194],
-      "albedo_transmission": [1, 0.717, 0.194]
+      "albedo_reflection": [
+        1,
+        0.717,
+        0.194
+      ],
+      "albedo_transmission": [
+        1,
+        0.717,
+        0.194
+      ]
     },
     {
       "name": "n5",
@@ -165,13 +215,16 @@
     {
       "name": "White-pot",
       "type": "disney",
-      "albedo": [0.8, 0.8, 0.8],
+      "albedo": [
+        0.8,
+        0.8,
+        0.8
+      ],
       "metallic": 0,
       "specular": 0.5,
       "roughness": 0.5
     }
   ],
-
   "entities": [
     {
       "type": "mesh",
@@ -439,7 +492,9 @@
       "material": "Material.014",
       "transform": {
         "rotation": [
-          0, 0, 0
+          0,
+          0,
+          0
         ]
       }
     },
@@ -538,10 +593,11 @@
       "emission": "textures/envmap.hdr"
     }
   ],
-
   "camera": {
-    "type": "pinhole",
+    "type": "thinlens",
     "fov": 50,
+    "aperture_radius": 0.1,
+    "focus_distance": 10,
     "resolution": [
       1400,
       900
@@ -564,4 +620,4 @@
       ]
     }
   }
-}
+}
diff --git a/src/CoreLayer/Math/Warp.h b/src/CoreLayer/Math/Warp.h
@@ -80,3 +80,25 @@ inline  float SquareToBeckmannPdf(const Vec3d &m, double alpha) {
     float longitudinal = exp(-tan2Theta/(alpha*alpha))  / (alpha*alpha*pow(cosTheta,3));
     return azimuthal * longitudinal;
 }
+
+// Modified implementation from Mitsuba
+inline Point2d SquareToUniformDiskConcentric(const Point2d &sample) {
+    double r1 = 2.0 * sample.x - 1.0;
+    double r2 = 2.0 * sample.y - 1.0;
+
+    double phi, r;
+    if (r1 == 0 && r2 == 0) {
+        r = phi = 0;
+    } else if (r1 * r1 > r2 * r2) {
+        r = r1;
+        phi = (M_PI / 4.0) * (r2 / r1);
+    } else {
+        r = r2;
+        phi = (M_PI / 2.0) - (r1 / r2) * (M_PI / 4.0);
+    }
+
+    double cosPhi = fm::cos(phi);
+    double sinPhi = fm::sin(phi);
+
+    return { r * cosPhi, r * sinPhi };
+}
diff --git a/src/FunctionLayer/Camera/CameraFactory.cpp b/src/FunctionLayer/Camera/CameraFactory.cpp
@@ -1,6 +1,7 @@
 #include "CameraFactory.h"
 #include "Camera.h"
 #include "Pinhole.h"
+#include "Thinlens.h"
 #include "DifferentialPinhole.h"
 
 namespace CameraFactory {
@@ -12,10 +13,10 @@ std::shared_ptr<T> cameraCreatorHelper(const Json &json) {
 
 static std::unordered_map<std::string, std::function<std::shared_ptr<Camera>(const Json &)>> cameraMap{
     {"pinhole", cameraCreatorHelper<PinholeCamera>},
-    {"differential_pinhole", cameraCreatorHelper<DifferentialPinholeCamera>}
-};
+    {"thinlens", cameraCreatorHelper<ThinlensCamera>},
+    {"differential_pinhole", cameraCreatorHelper<DifferentialPinholeCamera>}};
 
 std::shared_ptr<Camera> LoadCameraFromJson(const Json &json) {
-    return cameraMap[json["type"]](json);
+    return cameraMap[json.at("type")](json);
 }
 }// namespace CameraFactory
diff --git a/src/FunctionLayer/Camera/Thinlens.cpp b/src/FunctionLayer/Camera/Thinlens.cpp
@@ -1,24 +1,23 @@
-#include <cmath>
 #include "Thinlens.h"
-#include "CoreLayer/Math/Common.h"
-#include "FastMath.h"
+#include "CoreLayer/Math/Warp.h"
 
-#define _USE_MATH_DEFINES
+ThinlensCamera::ThinlensCamera(const Json &json) : PerspectiveCamera(json) {
+
+    apertureRadius = getOptional(json, "aperture_radius", 0.1);
+    focusDistance = getOptional(json, "focus_distance", 10);
+}
 
 Ray ThinlensCamera::generateRay(const Point2i &filmResolution, const Point2i &pixelPosition, const CameraSample &sample) const {
-    double x = (double) (pixelPosition.x + sample.xy.x) / filmResolution.x,
-           y = (double) (pixelPosition.y + sample.xy.y) / filmResolution.y;
-
-    Point3d pointOnFilm = sampleToFilm * Point3d (x, y, 0),
-            pointOnFocalPlane = pointOnFilm * (focalDistance / pointOnFilm.z);
-    // TODO warp the sample transform
-    float r = fm::sqrt(sample.lens[0]),
-          theta = sample.lens[1] * 2 * M_PI;
-    Point3d pointOnApeture = 
-        apertureRadius * Point3d(r * fm::cos(theta), r * fm::sin(theta), 0);       
-    Vec3d dir = normalize(pointOnFocalPlane - pointOnApeture);
-        return Ray(
-        cameraToWorld * pointOnApeture,
-        cameraToWorld * dir
-    );
-}
+    double x = (double)(pixelPosition.x + sample.xy.x) / filmResolution.x;
+    double y = (double)(pixelPosition.y + sample.xy.y) / filmResolution.y;
+
+    Point3d pointOnFilm = sampleToFilm * Point3d(x, y, 0);
+    Point3d pointOnFocalPlane = pointOnFilm * (focusDistance / pointOnFilm.z);
+
+    Point2d pointOnDisk = apertureRadius * SquareToUniformDiskConcentric(sample.lens);
+    Point3d pointOnAperture = {pointOnDisk.x, pointOnDisk.y, 0};
+
+    Vec3d dir = normalize(pointOnFocalPlane - pointOnAperture);
+
+    return {cameraToWorld * pointOnAperture, cameraToWorld * dir};
+}
diff --git a/src/FunctionLayer/Camera/Thinlens.h b/src/FunctionLayer/Camera/Thinlens.h
@@ -7,43 +7,16 @@
  * @ingroup Camera
  */
 class ThinlensCamera : public PerspectiveCamera {
-protected:
-    double apertureRadius, focalLen, focalDistance;
 public:
-    ThinlensCamera() = default;
-    ThinlensCamera(
-        const Point3d &lookFrom, 
-        const Point3d &lookAt, 
-        const Vec3d &up,
-        double xFov,
-        double aspectRatio,
-        double _focaDistance,
-        double _apertureRadius = 0.1,
-        double _focalLen = 0.05
-    ):apertureRadius(_apertureRadius), focalLen(_focalLen), focalDistance(_focaDistance) {
-        double distToFilm = 
-            (_focalLen * _focaDistance) / (_focaDistance - _focalLen);
-
-        cameraToWorld = 
-            Matrix4x4::lookAt(lookFrom, lookAt - lookFrom, up).inverse();
-        // ! near is the distToFilm and far set to MAX_FLOAT 
-        // ! if far set to MAX_DOUBLE, it will crash when computing the matrix 
-        Matrix4x4 filmToSample = Matrix4x4::perspective(
-            Angle(xFov, Angle::EAngleType::ANGLE_DEG), 
-            aspectRatio, 
-            distToFilm, 
-            std::numeric_limits<float>::max()
-        );
-        sampleToFilm =
-            Matrix4x4::scale(0.5, -0.5, 1.0)
-            * Matrix4x4::translate(1, -1, 0) 
-            * filmToSample;
-        sampleToFilm = sampleToFilm.inverse();
 
-    }
+    explicit ThinlensCamera(const Json &json);
+
+    [[nodiscard]]
+    Ray generateRay(const Point2i &filmResolution, const Point2i &pixelPosition, const CameraSample &sample) const override;
+
+protected:
 
+    double apertureRadius;
+    double focusDistance;
 
-    virtual Ray generateRay(const Point2i &filmResolution ,
-                            const Point2i &pixelPosition, 
-                            const CameraSample &sample) const override;
-};
+};