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OneLoneCoder 2017-08-06 19:47:30 +01:00
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OneLoneCoder_Splines1.cpp Normal file
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/*
OneLoneCoder.com - Splines Part 1
"Bendy Wavy Curly" - @Javidx9
Disclaimer
~~~~~~~~~~
I don't care what you use this for. It's intended to be educational, and perhaps
to the oddly minded - a little bit of fun. Please hack this, change it and use it
in any way you see fit. BUT, you acknowledge that I am not responsible for anything
bad that happens as a result of your actions. However, if good stuff happens, I
would appreciate a shout out, or at least give the blog some publicity for me.
Cheers!
Background
~~~~~~~~~~
Curvy things are always better. Splines are a nice way to approximate
curves and loops for games. This video is the first of two parts
demonstrating how Catmull-Rom splines can be implemented.
Use Z + X to select a point and move it with the arrow keys
Use A + S to move the agent around the spline loop
Author
~~~~~~
Twitter: @javidx9
Blog: www.onelonecoder.com
Video:
~~~~~~
https://youtu.be/9_aJGUTePYo
Last Updated: 06/08/2017
*/
#include <iostream>
#include <string>
using namespace std;
#include "olcConsoleGameEngine.h"
struct sPoint2D
{
float x;
float y;
};
struct sSpline
{
vector<sPoint2D> points;
sPoint2D GetSplinePoint(float t, bool bLooped = false)
{
int p0, p1, p2, p3;
if (!bLooped)
{
p1 = (int)t + 1;
p2 = p1 + 1;
p3 = p2 + 1;
p0 = p1 - 1;
}
else
{
p1 = (int)t;
p2 = (p1 + 1) % points.size();
p3 = (p2 + 1) % points.size();
p0 = p1 >= 1 ? p1 - 1 : points.size() - 1;
}
t = t - (int)t;
float tt = t * t;
float ttt = tt * t;
float q1 = -ttt + 2.0f*tt - t;
float q2 = 3.0f*ttt - 5.0f*tt + 2.0f;
float q3 = -3.0f*ttt + 4.0f*tt + t;
float q4 = ttt - tt;
float tx = 0.5f * (points[p0].x * q1 + points[p1].x * q2 + points[p2].x * q3 + points[p3].x * q4);
float ty = 0.5f * (points[p0].y * q1 + points[p1].y * q2 + points[p2].y * q3 + points[p3].y * q4);
return{ tx, ty };
}
sPoint2D GetSplineGradient(float t, bool bLooped = false)
{
int p0, p1, p2, p3;
if (!bLooped)
{
p1 = (int)t + 1;
p2 = p1 + 1;
p3 = p2 + 1;
p0 = p1 - 1;
}
else
{
p1 = (int)t;
p2 = (p1 + 1) % points.size();
p3 = (p2 + 1) % points.size();
p0 = p1 >= 1 ? p1 - 1 : points.size() - 1;
}
t = t - (int)t;
float tt = t * t;
float ttt = tt * t;
float q1 = -3.0f * tt + 4.0f*t - 1;
float q2 = 9.0f*tt - 10.0f*t;
float q3 = -9.0f*tt + 8.0f*t + 1.0f;
float q4 = 3.0f*tt - 2.0f*t;
float tx = 0.5f * (points[p0].x * q1 + points[p1].x * q2 + points[p2].x * q3 + points[p3].x * q4);
float ty = 0.5f * (points[p0].y * q1 + points[p1].y * q2 + points[p2].y * q3 + points[p3].y * q4);
return{ tx, ty };
}
};
class OneLoneCoder_Splines : public olcConsoleGameEngine
{
public:
OneLoneCoder_Splines()
{
m_sAppName = L"Splines";
}
private:
sSpline path;
int nSelectedPoint = 0;
float fMarker = 0.0f;
protected:
// Called by olcConsoleGameEngine
virtual bool OnUserCreate()
{
//path.points = { { 10, 41 },{ 40, 41 },{ 70, 41 },{ 100, 41 } };
path.points = { { 10, 41 },{ 20, 41 },{ 30, 41 },{ 40, 41 },{ 50, 41 },{ 60, 41 },{ 70, 41 },{ 80, 41 },{ 90, 41 },{ 100, 41 } };
return true;
}
// Called by olcConsoleGameEngine
virtual bool OnUserUpdate(float fElapsedTime)
{
// Clear Screen
Fill(0, 0, ScreenWidth(), ScreenHeight(), L' ');
// Handle input
if (m_keys[L'X'].bReleased)
{
nSelectedPoint++;
if (nSelectedPoint >= path.points.size())
nSelectedPoint = 0;
}
if (m_keys[L'Z'].bReleased)
{
nSelectedPoint--;
if (nSelectedPoint < 0)
nSelectedPoint = path.points.size() - 1;
}
if (m_keys[VK_LEFT].bHeld)
path.points[nSelectedPoint].x -= 30.0f * fElapsedTime;
if (m_keys[VK_RIGHT].bHeld)
path.points[nSelectedPoint].x += 30.0f * fElapsedTime;
if (m_keys[VK_UP].bHeld)
path.points[nSelectedPoint].y -= 30.0f * fElapsedTime;
if (m_keys[VK_DOWN].bHeld)
path.points[nSelectedPoint].y += 30.0f * fElapsedTime;
if (m_keys[L'A'].bHeld)
fMarker -= 5.0f * fElapsedTime;
if (m_keys[L'S'].bHeld)
fMarker += 5.0f * fElapsedTime;
if (fMarker >= (float)path.points.size())
fMarker -= (float)path.points.size();
if (fMarker < 0.0f)
fMarker += (float)path.points.size();
// Draw Spline
for (float t = 0; t < (float)path.points.size(); t += 0.005f)
{
sPoint2D pos = path.GetSplinePoint(t, true);
Draw(pos.x, pos.y);
}
// Draw Control Points
for (int i = 0; i < path.points.size(); i++)
{
Fill(path.points[i].x - 1, path.points[i].y - 1, path.points[i].x + 2, path.points[i].y + 2, PIXEL_SOLID, FG_RED);
DrawString(path.points[i].x, path.points[i].y, to_wstring(i));
}
// Highlight control point
Fill(path.points[nSelectedPoint].x - 1, path.points[nSelectedPoint].y - 1, path.points[nSelectedPoint].x + 2, path.points[nSelectedPoint].y + 2, PIXEL_SOLID, FG_YELLOW);
DrawString(path.points[nSelectedPoint].x, path.points[nSelectedPoint].y, to_wstring(nSelectedPoint));
// Draw agent to demonstrate gradient
sPoint2D p1 = path.GetSplinePoint(fMarker, true);
sPoint2D g1 = path.GetSplineGradient(fMarker, true);
float r = atan2(-g1.y, g1.x);
DrawLine(5.0f * sin(r) + p1.x, 5.0f * cos(r) + p1.y, -5.0f * sin(r) + p1.x, -5.0f * cos(r) + p1.y, PIXEL_SOLID, FG_BLUE);
return true;
}
};
int main()
{
OneLoneCoder_Splines demo;
demo.ConstructConsole(160, 80, 10, 10);
demo.Start();
return 0;
}

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olcConsoleGameEngine.h
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@ -117,7 +117,9 @@ enum COLOUR
enum PIXEL_TYPE
{
PIXEL_SOLID = 0x2588,
PIXEL_THREEQUARTERS = 0x2593
PIXEL_HALF = 0x2592,
PIXEL_QUARTER = 0x2591,
};