From 80e8c59a1e413436b9b18f0f2e889813af27a6bd Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Wed, 23 Sep 2020 20:19:27 +0300
Subject: [PATCH] Templated blur implementation + specializations for
 color_rgb(a)

---
 libs/pcg/include/psemek/pcg/blur.hpp | 44 ++++++++++++++++++-
 libs/pcg/source/blur.cpp             | 63 ++++++++++++----------------
 2 files changed, 69 insertions(+), 38 deletions(-)

diff --git a/libs/pcg/include/psemek/pcg/blur.hpp b/libs/pcg/include/psemek/pcg/blur.hpp
index 3121f518..f27bc494 100644
--- a/libs/pcg/include/psemek/pcg/blur.hpp
+++ b/libs/pcg/include/psemek/pcg/blur.hpp
@@ -3,9 +3,51 @@
 #include <psemek/gfx/pixmap.hpp>
 #include <psemek/pcg/seamless.hpp>
 
+#include <vector>
+
 namespace psemek::pcg
 {
 
-	gfx::basic_pixmap<float> blur(gfx::basic_pixmap<float> const & p, int size, float sigma, seamless_tag);
+	namespace detail
+	{
+
+		std::vector<float> gauss_coeffs(int size, float sigma);
+
+	}
+
+	template <typename T>
+	gfx::basic_pixmap<T> blur(gfx::basic_pixmap<T> const & p, int size, float sigma, seamless_tag)
+	{
+		gfx::basic_pixmap<T> res({p.width(), p.height()}, T{});
+
+		auto c = detail::gauss_coeffs(size, sigma);
+
+		for (std::size_t y = 0; y < p.height(); ++y)
+		{
+			for (std::size_t x = 0; x < p.width(); ++x)
+			{
+				for (int j = - size; j <= size; ++j)
+				{
+					for (int i = - size; i <= size; ++i)
+					{
+						int ix = (x + i);
+						while (ix < 0) ix += p.width();
+						if (static_cast<std::size_t>(ix) >= p.width()) ix = ix % p.width();
+
+						int iy = (y + j);
+						while (iy < 0) iy += p.height();
+						if (static_cast<std::size_t>(iy) >= p.height()) iy = iy % p.height();
+
+						res(x, y) += p(ix, iy) * c[i + size] * c[j + size];
+					}
+				}
+			}
+		}
+
+		return res;
+	}
+
+	gfx::pixmap_rgb blur(gfx::pixmap_rgb const & p, int size, float sigma, seamless_tag);
+	gfx::pixmap_rgba blur(gfx::pixmap_rgba const & p, int size, float sigma, seamless_tag);
 
 }
diff --git a/libs/pcg/source/blur.cpp b/libs/pcg/source/blur.cpp
index 8c435625..56f59ca5 100644
--- a/libs/pcg/source/blur.cpp
+++ b/libs/pcg/source/blur.cpp
@@ -1,4 +1,5 @@
 #include <psemek/pcg/blur.hpp>
+#include <psemek/gfx/color.hpp>
 
 #include <cmath>
 #include <vector>
@@ -6,50 +7,38 @@
 namespace psemek::pcg
 {
 
-	static std::vector<float> gauss_coeffs(int size, float sigma)
+	namespace detail
 	{
-		std::vector<float> res(2 * size + 1);
-		float sum = 0.f;
-		for (int i = -size; i <= size; ++i)
+
+		std::vector<float> gauss_coeffs(int size, float sigma)
 		{
-			float x = (i / sigma);
-			res[i + size] = std::exp(- x * x);
-			sum += res[i + size];
+			std::vector<float> res(2 * size + 1);
+			float sum = 0.f;
+			for (int i = -size; i <= size; ++i)
+			{
+				float x = (i / sigma);
+				res[i + size] = std::exp(- x * x);
+				sum += res[i + size];
+			}
+			for (auto & c : res)
+				c /= sum;
+			return res;
 		}
-		for (auto & c : res)
-			c /= sum;
-		return res;
+
 	}
 
-	gfx::basic_pixmap<float> blur(gfx::basic_pixmap<float> const & p, int size, float sigma, seamless_tag)
+	gfx::pixmap_rgb blur(gfx::pixmap_rgb const & p, int size, float sigma, seamless_tag)
 	{
-		gfx::basic_pixmap<float> res({p.width(), p.height()}, 0.f);
+		auto converted = util::map([](gfx::color_rgb const & c){ return gfx::to_colorf(c); }, p);
+		converted = blur(converted, size, sigma, seamless);
+		return util::map([](geom::vector<float, 3> const & c){ return gfx::to_coloru8(c); }, converted);
+	}
 
-		auto c = gauss_coeffs(size, sigma);
-
-		for (std::size_t y = 0; y < p.height(); ++y)
-		{
-			for (std::size_t x = 0; x < p.width(); ++x)
-			{
-				for (int j = - size; j <= size; ++j)
-				{
-					for (int i = - size; i <= size; ++i)
-					{
-						int ix = (x + i);
-						while (ix < 0) ix += p.width();
-						if (static_cast<std::size_t>(ix) >= p.width()) ix = ix % p.width();
-
-						int iy = (y + j);
-						while (iy < 0) iy += p.height();
-						if (static_cast<std::size_t>(iy) >= p.height()) iy = iy % p.height();
-
-						res(x, y) += p(ix, iy) * c[i + size] * c[j + size];
-					}
-				}
-			}
-		}
-
-		return res;
+	gfx::pixmap_rgba blur(gfx::pixmap_rgba const & p, int size, float sigma, seamless_tag)
+	{
+		auto converted = util::map([](gfx::color_rgba const & c){ return gfx::to_colorf(c); }, p);
+		converted = blur(converted, size, sigma, seamless);
+		return util::map([](geom::vector<float, 4> const & c){ return gfx::to_coloru8(c); }, converted);
 	}
 
 }