Add RayTracing example

CMakeLists.txt

@@ -52,6 +52,7 @@ cmake_dependent_option(WITH_MOTIONBLUR_EXAMPLE "Build Motion Blur example" OFF "
 option(WITH_OVR_EXAMPLE "Build OVR example" OFF)
 option(WITH_PICKING_EXAMPLE "Build Picking example" OFF)
 option(WITH_PRIMITIVES_EXAMPLE "Build Primitives example" OFF)
+option(WITH_RAYTRACING_EXAMPLE "Build Ray Tracing example" OFF)
 option(WITH_SHADOWS_EXAMPLE "Build Shadow Mapping example" OFF)
 option(WITH_TEXT_EXAMPLE "Build Text example (requires some TTF font plugin)" OFF)
 cmake_dependent_option(WITH_TEXTUREDTRIANGLE_EXAMPLE "Build TexturedTriangle example (requires some TGA importer plugin)" OFF "NOT MAGNUM_TARGET_GLES" OFF)

doc/building-examples.dox

@@ -224,6 +224,8 @@ integration libraries, see @ref building-plugins, @ref building-integration and
 -   `WITH_PICKING_EXAMPLE` --- Build the @ref examples-picking example.
 -   `WITH_PRIMITIVES_EXAMPLE` --- Build the @ref examples-primitives "Primitives"
     example.
+-   `WITH_RAYTRACING_EXAMPLE` --- Build the @ref examples-raytracing "RayTracing"
+    example.
 -   `WITH_SHADOWS_EXAMPLE` --- Build the @ref examples-shadows example.
 -   `WITH_TEXT_EXAMPLE` --- Build the @ref examples-text example. Requires
     the @ref Text library and some TTF font plugin such as

doc/raytracing.dox

@@ -0,0 +1,85 @@
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019
+              Vladimír Vondruš <[email protected]>
+    2020 — Nghia Truong <[email protected]>
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+*/
+
+namespace Magnum {
+/** @page examples-raytracing Ray Tracing
+@brief Ray Tracing example.
+@m_since_latest_{examples}
+
+@m_footernavigation
+
+This is an implementation of a simple ray tracer adapted from Peter Shirley's book [Ray Tracing in One Weekend](https://raytracing.github.io/books/RayTracingInOneWeekend.html).
+The current implementation runs on single thread and performs iterative rendering to refine the result. Typically, a high quality image can be achieved after around 100 iterations.
+
+@image html raytracing.png width=400px
+
+@section examples-raytracing-controls Controls
+
+-   @m_class{m-label m-default} **mouse drag** rotates the camera
+-   @m_class{m-label m-warning} **Shift** @m_class{m-label m-default} **mouse
+    drag** pans the camera
+-   @m_class{m-label m-default} **mouse wheel** zooms in/out
+-   @m_class{m-label m-default} **R** reset the camera to its original transformation
+-   @m_class{m-label m-default} **D** toggle Depth-of-Field
+-   @m_class{m-label m-default} **M** toggle marking the next render block by a different color
+-   @m_class{m-label m-default} **N** generate a new random scene
+-   @m_class{m-label m-default} **Spacing** pause/resume rendering
+
+@section examples-raytracing-credits Credits
+
+This example was originally contributed by [Nghia Truong](https://github.com/ttnghia).
+
+@section examples-raytracing-source Source
+
+Full source code is linked below and also available in the
+[magnum-examples GitHub repository](https://github.com/mosra/magnum-examples/tree/master/src/raytracing).
+
+-   @ref raytracing/Camera.h "Camera.h"
+-   @ref raytracing/CMakeLists.txt "CMakeLists.txt"
+-   @ref raytracing/Materials.h "Materials.h"
+-   @ref raytracing/Materials.cpp "Materials.cpp"
+-   @ref raytracing/Objects.h "Objects.h"
+-   @ref raytracing/Objects.cpp "Objects.cpp"
+-   @ref raytracing/RayTracer.h "RayTracer.h"
+-   @ref raytracing/RayTracer.cpp "RayTracer.cpp"
+-   @ref raytracing/RayTracingExample.cpp "RayTracingExample.cpp"
+-   @ref raytracing/RndGenerators.h "RndGenerators.h"
+
+
+@example raytracing/Camera.h @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+@example raytracing/CMakeLists.txt @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+@example raytracing/Materials.h @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+@example raytracing/Materials.cpp @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+@example raytracing/Objects.h @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+@example raytracing/Objects.cpp @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+@example raytracing/RayTracer.h @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+@example raytracing/RayTracer.cpp @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+@example raytracing/RayTracingExample.cpp @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+@example raytracing/RndGenerators.h @m_examplenavigation{examples-raytracing,raytracing/} @m_footernavigation
+
+
+*/
+}

package/ci/appveyor-desktop-gles.bat

@@ -116,6 +116,7 @@ cmake .. ^
     -DWITH_OVR_EXAMPLE=OFF ^
     -DWITH_PICKING_EXAMPLE=OFF ^
     -DWITH_PRIMITIVES_EXAMPLE=ON ^
+    -DWITH_RAYTRACING_EXAMPLE=ON ^
     -DWITH_SHADOWS_EXAMPLE=OFF ^
     -DWITH_TEXT_EXAMPLE=ON ^
     -DWITH_TEXTUREDTRIANGLE_EXAMPLE=OFF ^

package/ci/appveyor-desktop-mingw.bat

@@ -120,6 +120,7 @@ cmake .. ^
     -DWITH_OVR_EXAMPLE=OFF ^
     -DWITH_PICKING_EXAMPLE=ON ^
     -DWITH_PRIMITIVES_EXAMPLE=ON ^
+    -DWITH_RAYTRACING_EXAMPLE=ON ^
     -DWITH_SHADOWS_EXAMPLE=ON ^
     -DWITH_TEXT_EXAMPLE=ON ^
     -DWITH_TEXTUREDTRIANGLE_EXAMPLE=ON ^

package/ci/appveyor-desktop.bat

@@ -115,6 +115,7 @@ cmake .. ^
     -DWITH_OVR_EXAMPLE=ON ^
     -DWITH_PICKING_EXAMPLE=ON ^
     -DWITH_PRIMITIVES_EXAMPLE=ON ^
+    -DWITH_RAYTRACING_EXAMPLE=ON ^
     -DWITH_SHADOWS_EXAMPLE=ON ^
     -DWITH_TEXT_EXAMPLE=ON ^
     -DWITH_TEXTUREDTRIANGLE_EXAMPLE=ON ^

package/ci/travis-desktop-gles.sh

@@ -87,6 +87,7 @@ cmake .. \
     -DWITH_OVR_EXAMPLE=OFF \
     -DWITH_PICKING_EXAMPLE=OFF \
     -DWITH_PRIMITIVES_EXAMPLE=ON \
+    -DWITH_RAYTRACING_EXAMPLE=ON \
     -DWITH_SHADOWS_EXAMPLE=OFF \
     -DWITH_TEXT_EXAMPLE=ON \
     -DWITH_TEXTUREDTRIANGLE_EXAMPLE=OFF \

package/ci/travis-desktop.sh

@@ -92,6 +92,7 @@ cmake .. \
     -DWITH_OVR_EXAMPLE=OFF \
     -DWITH_PICKING_EXAMPLE=ON \
     -DWITH_PRIMITIVES_EXAMPLE=ON \
+    -DWITH_RAYTRACING_EXAMPLE=ON \
     -DWITH_SHADOWS_EXAMPLE=ON \
     -DWITH_TEXT_EXAMPLE=ON \
     -DWITH_TEXTUREDTRIANGLE_EXAMPLE=ON \

src/CMakeLists.txt

@@ -107,6 +107,10 @@ if(WITH_PRIMITIVES_EXAMPLE)
     add_subdirectory(primitives)
 endif()
 
+if(WITH_RAYTRACING_EXAMPLE)
+    add_subdirectory(raytracing)
+endif()
+
 if(WITH_SHADOWS_EXAMPLE)
     add_subdirectory(shadows)
 endif()

src/raytracing/CMakeLists.txt

@@ -0,0 +1,72 @@
+#
+#   This file is part of Magnum.
+#
+#   Original authors — credit is appreciated but not required:
+#
+#       2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 —
+#           Vladimír Vondruš <[email protected]>
+#       2020 — Nghia Truong <[email protected]>
+#
+#   This is free and unencumbered software released into the public domain.
+#
+#   Anyone is free to copy, modify, publish, use, compile, sell, or distribute
+#   this software, either in source code form or as a compiled binary, for any
+#   purpose, commercial or non-commercial, and by any means.
+#
+#   In jurisdictions that recognize copyright laws, the author or authors of
+#   this software dedicate any and all copyright interest in the software to
+#   the public domain. We make this dedication for the benefit of the public
+#   at large and to the detriment of our heirs and successors. We intend this
+#   dedication to be an overt act of relinquishment in perpetuity of all
+#   present and future rights to this software under copyright law.
+#
+#   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+#   THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+#   IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+#   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+cmake_minimum_required(VERSION 3.4)
+
+project(RayTracing CXX)
+
+# Add module path in case this is project root
+if(PROJECT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
+    set(CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/../../modules/" ${CMAKE_MODULE_PATH})
+endif()
+
+find_package(Corrade REQUIRED Main)
+find_package(Magnum REQUIRED
+    GL)
+
+if(CORRADE_TARGET_ANDROID)
+    find_package(Magnum REQUIRED AndroidApplication)
+elseif(CORRADE_TARGET_EMSCRIPTEN)
+    find_package(Magnum REQUIRED EmscriptenApplication)
+else()
+    find_package(Magnum REQUIRED Sdl2Application)
+endif()
+
+set_directory_properties(PROPERTIES CORRADE_USE_PEDANTIC_FLAGS ON)
+
+add_executable(magnum-raytracing WIN32
+    ../arcball/ArcBall.cpp
+    Materials.cpp
+    Objects.cpp
+    RayTracer.cpp
+    RayTracingExample.cpp)
+target_link_libraries(magnum-raytracing PRIVATE
+    Corrade::Main
+    Magnum::Application
+    Magnum::GL
+    Magnum::Magnum)
+target_include_directories(magnum-raytracing PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    ${CMAKE_CURRENT_BINARY_DIR})
+
+install(TARGETS magnum-raytracing DESTINATION ${MAGNUM_BINARY_INSTALL_DIR})
+
+# Make the executable a default target to build & run in Visual Studio
+set_property(DIRECTORY ${PROJECT_SOURCE_DIR} PROPERTY VS_STARTUP_PROJECT magnum-raytracing)

src/raytracing/Camera.h

@@ -0,0 +1,76 @@
+#ifndef Magnum_Examples_RayTracing_Camera_h
+#define Magnum_Examples_RayTracing_Camera_h
+
+/*
+    This file is part of Magnum.
+
+    Original authors — credit is appreciated but not required:
+
+        2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 —
+            Vladimír Vondruš <[email protected]>
+        2020 — Nghia Truong <[email protected]>
+
+    This is free and unencumbered software released into the public domain.
+
+    Anyone is free to copy, modify, publish, use, compile, sell, or distribute
+    this software, either in source code form or as a compiled binary, for any
+    purpose, commercial or non-commercial, and by any means.
+
+    In jurisdictions that recognize copyright laws, the author or authors of
+    this software dedicate any and all copyright interest in the software to
+    the public domain. We make this dedication for the benefit of the public
+    at large and to the detriment of our heirs and successors. We intend this
+    dedication to be an overt act of relinquishment in perpetuity of all
+    present and future rights to this software under copyright law.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+    IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <Magnum/Math/Functions.h>
+#include "RndGenerators.h"
+#include "Ray.h"
+
+namespace Magnum { namespace Examples {
+class Camera {
+public:
+    Camera(const Vector3& eye, const Vector3& viewCenter, const Vector3& upDir,
+           Deg fov, Float aspectRatio, Float lensRadius) :
+        _origin(eye),
+        _lensRadius(lensRadius) {
+        _w = (eye - viewCenter).normalized();
+        _u = Math::cross(upDir, _w).normalized();
+        _v = Math::cross(_w, _u).normalized();
+
+        Float       halfHeight    = Math::tan(fov * 0.5f);
+        Float       halfWidth     = aspectRatio * halfHeight;
+        const Float focusDistance = (eye - viewCenter).length();
+        _lowerLeftCorner = _origin -
+                           halfWidth * focusDistance * _u -
+                           halfHeight * focusDistance * _v -
+                           focusDistance * _w;
+        _horitonalEdge = 2 * halfWidth * focusDistance * _u;
+        _verticalEdge  = 2 * halfHeight * focusDistance * _v;
+    }
+
+    Ray getRay(Float s, Float t) {
+        const Vector2 rd     = _lensRadius * Rnd::rndInDisk();
+        const Vector3 offset = _u * rd.x() + _v * rd.y();
+        return Ray(_origin + offset,
+                   _lowerLeftCorner + s * _horitonalEdge + t * _verticalEdge - offset - _origin);
+    }
+
+private:
+    Vector3 _origin;
+    Float   _lensRadius;
+    Vector3 _u, _v, _w;
+    Vector3 _lowerLeftCorner;
+    Vector3 _horitonalEdge, _verticalEdge;
+};
+} }
+
+#endif

src/raytracing/Materials.cpp

@@ -0,0 +1,91 @@
+/*
+    This file is part of Magnum.
+
+    Original authors — credit is appreciated but not required:
+
+        2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 —
+            Vladimír Vondruš <[email protected]>
+        2020 — Nghia Truong <[email protected]>
+
+    This is free and unencumbered software released into the public domain.
+
+    Anyone is free to copy, modify, publish, use, compile, sell, or distribute
+    this software, either in source code form or as a compiled binary, for any
+    purpose, commercial or non-commercial, and by any means.
+
+    In jurisdictions that recognize copyright laws, the author or authors of
+    this software dedicate any and all copyright interest in the software to
+    the public domain. We make this dedication for the benefit of the public
+    at large and to the detriment of our heirs and successors. We intend this
+    dedication to be an overt act of relinquishment in perpetuity of all
+    present and future rights to this software under copyright law.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+    IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <Magnum/Math/Functions.h>
+
+#include "RndGenerators.h"
+#include "Materials.h"
+#include "Ray.h"
+
+namespace Magnum { namespace Examples {
+struct HitInfo;
+
+namespace {
+inline Float schlick(Float cosine, Float ref_idx) {
+    Float r0 = (1 - ref_idx) / (1 + ref_idx);
+    r0 = r0 * r0;
+    return r0 + (1 - r0) * std::pow((1 - cosine), 5);
+}
+}
+
+bool Lambertian::scatter(const Ray&, const HitInfo& hitInfo, Vector3& attenuation, Ray& scatteredRay) const {
+    const Vector3 target = hitInfo.p + hitInfo.unitNormal + Rnd::randomInSphere();
+    scatteredRay = Ray(hitInfo.p, target - hitInfo.p);
+    attenuation  = _albedo;
+    return true;
+}
+
+bool Metal::scatter(const Ray& r, const HitInfo& hitInfo, Vector3& attenuation, Ray& scatteredRay) const {
+    const Vector3 reflectedRay = Math::reflect(r.unitDirection, hitInfo.unitNormal);
+    scatteredRay = Ray(hitInfo.p, reflectedRay + _fuzziness * Rnd::randomInSphere());
+    attenuation  = _albedo;
+    return (dot(scatteredRay.unitDirection, hitInfo.unitNormal) > 0);
+}
+
+bool Dielectric::scatter(const Ray& r, const HitInfo& hitInfo, Vector3& attenuation, Ray& scatteredRay) const {
+    attenuation = Vector3{ 1, 1, 1 };
+
+    Float   ni_over_nt;
+    Float   cosine;
+    Vector3 outwardNormal;
+    if(dot(r.unitDirection, hitInfo.unitNormal) > 0) {
+        outwardNormal = -hitInfo.unitNormal;
+        ni_over_nt    = _refractiveIndex;
+        cosine        = dot(r.unitDirection, hitInfo.unitNormal);
+        cosine        = std::sqrt(1 - _refractiveIndex * _refractiveIndex * (1 - cosine * cosine));
+    } else {
+        outwardNormal = hitInfo.unitNormal;
+        ni_over_nt    = 1.0f / _refractiveIndex;
+        cosine        = -dot(r.unitDirection, hitInfo.unitNormal);
+    }
+
+    const Vector3 refractedDir          = Math::refract(r.unitDirection, outwardNormal, ni_over_nt);
+    const Float   reflectionProbability = dot(refractedDir, refractedDir) > 0 ?
+                                          schlick(cosine, _refractiveIndex) :
+                                          1.0f;
+    scatteredRay.origin = hitInfo.p;
+    if(Rnd::rand01() < reflectionProbability) {
+        scatteredRay.unitDirection = Math::reflect(r.unitDirection, hitInfo.unitNormal);
+    } else {
+        scatteredRay.unitDirection = refractedDir.normalized();
+    }
+    return true;
+}
+} }