Implement basic PPM writing function

`write_ppm` generates a PPM image using a given generation function.
Output is written using `std::ofstream`.
The library is intended to become a straight forward way to test out various visualizations.

2 files changed, 52 insertions, 0 deletions

diff --git a/src/imgen.cc b/src/imgen.cc
new file mode 100644
index 0000000..d574672
--- /dev/null
+++ b/src/imgen.cc
@@ -0,0 +1,36 @@
+#include "imgen.h"
+
+#include <fstream>
+
+namespace {
+
+inline void write_color(std::ofstream& out, const imgen::color& color) {
+	out << std::get<0>(color);
+	out << std::get<1>(color);
+	out << std::get<2>(color);
+}
+
+}
+
+namespace imgen {
+
+void write_ppm(
+	const std::string&                             path,
+	const std::size_t                              sizeX,
+	const std::size_t                              sizeY,
+	std::function<color(std::size_t, std::size_t)> generator
+) {
+	std::ofstream out;
+	out.open(path, std::ios::binary | std::ios::out);
+	out.sync_with_stdio(false);
+
+	out << "P6\n" << sizeX << " " << sizeY << "\n255\n";
+
+	for ( std::size_t posY = 0; posY < sizeY; ++posY ) {
+		for ( std::size_t posX = 0; posX < sizeX; ++posX ) {
+			write_color(out, generator(posX, posY));
+		}
+	}
+}
+
+}
diff --git a/src/imgen.h b/src/imgen.h
new file mode 100644
index 0000000..5ddbaf6
--- /dev/null
+++ b/src/imgen.h
@@ -0,0 +1,16 @@
+#include <string>
+#include <utility>
+#include <functional>
+
+namespace imgen {
+
+using color = std::tuple<std::uint8_t, std::uint8_t, std::uint8_t>;
+
+void write_ppm(
+	const std::string&                             path,
+	const std::size_t                              sizeX,
+	const std::size_t                              sizeY,
+	std::function<color(std::size_t, std::size_t)> generator
+);
+
+}