From 63b6f5c937a2f0dcf93ef9fd1a586985c32631ce Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 22 Nov 2014 11:18:34 +0200
Subject: [PATCH] Add a raytracer example program

---
 .gitignore            |  1 +
 Build                 |  7 ++++
 examples/raytrace.cpp | 92 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 100 insertions(+)
 create mode 100644 examples/raytrace.cpp

diff --git a/.gitignore b/.gitignore
index 8354f32..c773a80 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,5 @@ temp
 /libmspmath.a
 /libmspmath.so
 /mspmath.pc
+/raytrace
 /tests/test
diff --git a/Build b/Build
index 5e5297d..20875c4 100644
--- a/Build
+++ b/Build
@@ -12,4 +12,11 @@ package "mspmath"
 			map "source" "include/msp";
 		};
 	};
+
+	program "raytrace"
+	{
+		source "examples/raytrace.cpp";
+		require "mspcore";
+		use "mspmath";
+	};
 };
diff --git a/examples/raytrace.cpp b/examples/raytrace.cpp
new file mode 100644
index 0000000..2af8653
--- /dev/null
+++ b/examples/raytrace.cpp
@@ -0,0 +1,92 @@
+#include <msp/core/application.h>
+#include <msp/core/getopt.h>
+#include <msp/core/inttypes.h>
+#include <msp/geometry/loader.h>
+#include <msp/io/buffered.h>
+#include <msp/io/print.h>
+
+using namespace std;
+using namespace Msp;
+
+class RayTracer: public RegisteredApplication<RayTracer>
+{
+private:
+	Geometry::Shape<double, 3> *shape;
+	unsigned width;
+	unsigned height;
+	string filename;
+	UInt8 *pixels;
+
+public:
+	RayTracer(int, char **);
+	virtual ~RayTracer();
+
+	virtual int main();
+private:
+	void load_shape();
+};
+
+
+RayTracer::RayTracer(int argc, char **argv):
+	shape(0),
+	width(500),
+	height(500),
+	pixels(new UInt8[width*height])
+{
+	GetOpt getopt;
+	getopt.add_option('w', "width", width, GetOpt::REQUIRED_ARG);
+	getopt.add_option('h', "height", height, GetOpt::REQUIRED_ARG);
+	getopt.add_argument("filename", filename, GetOpt::REQUIRED_ARG);
+	getopt(argc, argv);
+}
+
+RayTracer::~RayTracer()
+{
+	delete shape;
+	delete[] pixels;
+}
+
+int RayTracer::main()
+{
+	load_shape();
+
+	for(unsigned y=0; y<height; ++y)
+	{
+		double yf = 1.0-y*2.0/height;
+		for(unsigned x=0; x<width; ++x)
+		{
+			double xf = x*2.0/width-1.0;
+			Geometry::Ray<double, 3> ray(LinAl::Vector<double, 3>(0, 0, 5), LinAl::Vector<double, 3>(xf, yf, -2));
+			Geometry::SurfacePoint<double, 3> points[4];
+			unsigned count = shape->get_intersections(ray, points, 4);
+			UInt8 *pixel = pixels+y*width+x;
+			if(count)
+				*pixel = 255*(0.2+max(dot(points[0].normal, LinAl::Vector<double, 3>(0, 0, 1)), 0.0)*0.8);
+			else
+				*pixel = 0;
+		}
+	}
+
+	IO::Buffered cout_buf(IO::cout);
+	IO::print(cout_buf, "P2\n");
+	IO::print(cout_buf, "%d %d\n", width, height);
+	IO::print(cout_buf, "255\n");
+
+	for(unsigned y=0; y<height; ++y)
+	{
+		for(unsigned x=0; x<width; ++x)
+			IO::print(cout_buf, "%d ", pixels[y*width+x]);
+		IO::print(cout_buf, "\n");
+	}
+
+	return 0;
+}
+
+void RayTracer::load_shape()
+{
+	IO::BufferedFile in(filename);
+	DataFile::Parser parser(in, filename);
+	Geometry::Loader<double, 3> loader;
+	loader.load(parser);
+	shape = loader.get_shape().clone();
+}
-- 
2.43.0