From 1927095d25614bcec73f93e74424110d3feefc7f Mon Sep 17 00:00:00 2001
From: "madmaxoft@gmail.com"
 <madmaxoft@gmail.com@0a769ca7-a7f5-676a-18bf-c427514a06d6>
Date: Sun, 12 May 2013 17:55:49 +0000
Subject: Renamed linear interpolation from Noise.h to a more proper
 LinearUpscale and moved it to a separate file.

git-svn-id: http://mc-server.googlecode.com/svn/trunk@1475 0a769ca7-a7f5-676a-18bf-c427514a06d6
---
 source/LinearUpscale.h | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 source/LinearUpscale.h

(limited to 'source/LinearUpscale.h')

diff --git a/source/LinearUpscale.h b/source/LinearUpscale.h
new file mode 100644
index 000000000..c20e3d3bb
--- /dev/null
+++ b/source/LinearUpscale.h
@@ -0,0 +1,70 @@
+
+// LinearUpscale.h
+
+// Declares the functions for linearly upscaling arrays
+
+/*
+Upscaling means that the array is divided into same-size "cells", and each cell is
+linearly interpolated between its corners. The array's dimensions are therefore
+1 + CellSize * NumCells, for each direction.
+
+Upscaling is more efficient than linear interpolation, because the cell sizes are integral
+and therefore the cells' boundaries are on the array points.
+
+However, upscaling usually requires generating the "1 +" in each direction.
+
+Upscaling is implemented in templates, so that it's compatible with multiple datatypes.
+Therefore, there is no cpp file.
+*/
+
+
+
+
+/// Linearly interpolates values in the array between the equidistant anchor points; universal data type
+template<typename TYPE> void ArrayLinearUpscale2D(
+	TYPE * a_Array, 
+	int a_SizeX, int a_SizeY,  // Dimensions of the array
+	int a_AnchorStepX, int a_AnchorStepY  // Distances between the anchor points in each direction
+)
+{
+	// First interpolate columns where the anchor points are:
+	int LastYCell = a_SizeY - a_AnchorStepY;
+	for (int y = 0; y < LastYCell; y += a_AnchorStepY)
+	{
+		int Idx = a_SizeX * y;
+		for (int x = 0; x < a_SizeX; x += a_AnchorStepX)
+		{
+			TYPE StartValue = a_Array[Idx];
+			TYPE EndValue   = a_Array[Idx + a_SizeX * a_AnchorStepY];
+			TYPE Diff = EndValue - StartValue;
+			for (int CellY = 1; CellY < a_AnchorStepY; CellY++)
+			{
+				a_Array[Idx + a_SizeX * CellY] = StartValue + Diff * CellY / a_AnchorStepY;
+			}  // for CellY
+			Idx += a_AnchorStepX;
+		}  // for x
+	}  // for y
+	
+	// Now interpolate in rows, each row has values in the anchor columns
+	int LastXCell = a_SizeX - a_AnchorStepX;
+	for (int y = 0; y < a_SizeY; y++)
+	{
+		int Idx = a_SizeX * y;
+		for (int x = 0; x < LastXCell; x += a_AnchorStepX)
+		{
+			TYPE StartValue = a_Array[Idx];
+			TYPE EndValue   = a_Array[Idx + a_AnchorStepX];
+			TYPE Diff = EndValue - StartValue;
+			for (int CellX = 1; CellX < a_AnchorStepX; CellX++)
+			{
+				a_Array[Idx + CellX] = StartValue + CellX * Diff / a_AnchorStepX;
+			}  // for CellY
+			Idx += a_AnchorStepX;
+		}
+	}
+}
+
+
+
+
+
-- 
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