Basic dda testing

exercise2/src/dda_line_tool.cpp

@@ -1,47 +1,116 @@
 //
-// This source code is property of the Computer Graphics and Visualization 
-// chair of the TU Dresden. Do not distribute in modified or unmodified form! 
+// This source code is property of the Computer Graphics and Visualization
+// chair of the TU Dresden. Do not distribute in modified or unmodified form!
 // Copyright (C) 2016 CGV TU Dresden - All Rights Reserved
 //
 #include "dda_line_tool.h"
 #include <algorithm>
 
+#include <iostream>
 
 // Initialize the tool and store a reference of a canvas_buffer
-dda_line_tool::dda_line_tool(canvas_buffer& canvas): tool_base(canvas)
+dda_line_tool::dda_line_tool(canvas_buffer &canvas) : tool_base(canvas)
 {
 	shape = TS_LINE;
 }
 
-
-
-
 // Draw a line from (x0, y0) to (x1, y1)
 void dda_line_tool::draw(int x0, int y0, int x1, int y1)
 {
 	/************
 	Task 3.1.1.    Implement the DDA algorithm to raster a line from (x0, y0)
 	               to (x1, y1). To set a pixel use "canvas.set_pixel(x, y)" where
-				   "x" and "y" is the desired pixel position. This method 
+				   "x" and "y" is the desired pixel position. This method
 				   handles border violations. Establish the standard case in the
 				   first step. If you need to swap the value of two variables you
 				   can use the method "std::swap(a, b)".
 	Aufgabe 3.1.1. Implementieren Sie den DDA-Algorithmus um eine Linie von
 	               (x0, y0) nach (x1, y1) zu rastern. Verwenden Sie
 				   "canvas.set_pixel(x, y)" um einen Pixel zu setzen, wobei
-				   "x" und "y" den gewünschten Pixelpositionen entsprechen.
+				   "x" und "y" den gew<EFBFBD>nschten Pixelpositionen entsprechen.
 				   Diese Methode behandelt auch Randverletzungen. Stellen Sie zunaechst
 				   den Standardfall her. Falls Sie den Wert zweier Variablen vertauschen
-				   muessen koennen Sie dafür die Methode "std::swap(a, b)" verwenden.
-   *************/
+				   muessen koennen Sie daf<EFBFBD>r die Methode "std::swap(a, b)" verwenden.
+   	*************/
+
+	/*
+	int tmp;
+	// check all different cases
+
+	// mirror on x-achsis (y -> -y)
+	if (x0 < x1 && y0 > y1)
+	{
+		y0 = -y0;
+		y1 = -y1;
+
+		float y = static_cast<float>(y0);
+		float m = static_cast<float>(y1 - y0) / static_cast<float>(x1 - x0);
+
+		// '<=' - because we need to include x1 as end location
+		for (int x = x0; x <= x1; x++)
+		{
+			int i_y = static_cast<int>(y + 0.5f);
+			// (y -> -y)
+			canvas.set_pixel(x, -i_y);
+			y += m;
+		}
+	}
+	// rotate by 90° (x <-> -y)
+	else if (x0 > x1 && y0 < y1)
+	{
+		tmp = x0;
+		x0 = -y0;
+		y0 = tmp;
+
+		tmp = x1;
+		x1 = -y1;
+		y1 = tmp;
+
+		float y = static_cast<float>(y0);
+		float m = static_cast<float>(y1 - y0) / static_cast<float>(x1 - x0);
+
+		// '<=' - because we need to include x1 as end location
+		for (int x = x0; x <= x1; x++)
+		{
+			int i_y = static_cast<int>(y + 0.5f);
+			// (x <-> -y)
+			canvas.set_pixel(-i_y, x);
+			y += m;
+		}
+	}
+	// mirror on main diagonal (x <-> y)
+	else if (x)
+	{
+
+	}
+	// standard
+	else
+	{
+	*/
+
+	if (x0 > x1)
+	{
+		std::swap(x0, x1);
+		std::swap(y0, y1);
+	}
+
+	float m = static_cast<float>(y1 - y0) / static_cast<float>(x1 - x0);
+
+	std::cout << "anstieg " << m << std::endl;
+
+	float y = static_cast<float>(y0);
+	for (int x = x0; x < x1; x++)
+	{
+		canvas.set_pixel(x, static_cast<int>(y + 0.5f));
+		y += m;
+	}
+
+	//}
 }
 
-
-
-
 // Put debug output into the stream "stream" to be displayed in the
 // main window
-void dda_line_tool::set_text(std::stringstream& stream)
+void dda_line_tool::set_text(std::stringstream &stream)
 {
-	stream<<"Tool: DDA-Line (click and drag mouse to draw)";
+	stream << "Tool: DDA-Line (click and drag mouse to draw)";
 }