Added Polygon Collisions #1

OneLoneCoder_PGE_PolygonCollisions1.cpp

@@ -0,0 +1,434 @@
+/*
+	Convex Polygon Collision Detection
+	"Don't you dare try concave ones..." - javidx9
+
+	License (OLC-3)
+	~~~~~~~~~~~~~~~
+
+	Copyright 2018-2019 OneLoneCoder.com
+
+	Redistribution and use in source and binary forms, with or without
+	modification, are permitted provided that the following conditions
+	are met:
+
+	1. Redistributions or derivations of source code must retain the above
+	copyright notice, this list of conditions and the following disclaimer.
+
+	2. Redistributions or derivative works in binary form must reproduce
+	the above copyright notice. This list of conditions and the following
+	disclaimer must be reproduced in the documentation and/or other
+	materials provided with the distribution.
+
+	3. Neither the name of the copyright holder nor the names of its
+	contributors may be used to endorse or promote products derived
+	from this software without specific prior written permission.
+
+	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+	"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+	LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+	A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+	HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+	LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+	DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+	THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+	(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+	OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+	Instructions:
+	~~~~~~~~~~~~~
+	Use arrow keys to control pentagon
+	Use WASD to control triangle
+	F1..F4 selects algorithm
+
+	Relevant Video: https://youtu.be/7Ik2vowGcU0
+
+	Links
+	~~~~~
+	YouTube:	https://www.youtube.com/javidx9
+				https://www.youtube.com/javidx9extra
+	Discord:	https://discord.gg/WhwHUMV
+	Twitter:	https://www.twitter.com/javidx9
+	Twitch:		https://www.twitch.tv/javidx9
+	GitHub:		https://www.github.com/onelonecoder
+	Patreon:	https://www.patreon.com/javidx9
+	Homepage:	https://www.onelonecoder.com
+
+	Author
+	~~~~~~
+	David Barr, aka javidx9, ©OneLoneCoder 2019
+*/
+
+#define OLC_PGE_APPLICATION
+#include "olcPixelGameEngine.h"
+
+#include <vector>
+#include <algorithm>
+
+// Override base class with your custom functionality
+class PolygonCollisions : public olc::PixelGameEngine
+{
+public:
+	PolygonCollisions()
+	{
+		sAppName = "Polygon Collisions";
+	}
+
+	struct vec2d
+	{
+		float x;
+		float y;
+	};
+
+	struct polygon
+	{
+		std::vector<vec2d> p;	// Transformed Points
+		vec2d pos;				// Position of shape
+		float angle;			// Direction of shape
+		std::vector<vec2d> o;	// "Model" of shape							
+		bool overlap = false;	// Flag to indicate if overlap has occurred
+	};
+
+	std::vector<polygon> vecShapes;
+
+	int nMode = 0;
+
+public:
+	bool OnUserCreate() override
+	{		
+		// Create Pentagon
+		polygon s1;
+		float fTheta = 3.14159f * 2.0f / 5.0f;
+		s1.pos = { 100, 100 };
+		s1.angle = 0.0f;
+		for (int i = 0; i < 5; i++)
+		{
+			s1.o.push_back({ 30.0f * cosf(fTheta * i), 30.0f * sinf(fTheta * i) });
+			s1.p.push_back({ 30.0f * cosf(fTheta * i), 30.0f * sinf(fTheta * i) });
+		}
+
+		// Create Triangle
+		polygon s2;
+		fTheta = 3.14159f * 2.0f / 3.0f;
+		s2.pos = { 200, 150 };
+		s2.angle = 0.0f;
+		for (int i = 0; i < 3; i++)
+		{
+			s2.o.push_back({ 20.0f * cosf(fTheta * i), 20.0f * sinf(fTheta * i) });
+			s2.p.push_back({ 20.0f * cosf(fTheta * i), 20.0f * sinf(fTheta * i) });
+		}
+
+		// Create Quad
+		polygon s3;
+		s3.pos = { 50, 200 };
+		s3.angle = 0.0f;
+		s3.o.push_back({ -30, -30 });
+		s3.o.push_back({ -30, +30 });
+		s3.o.push_back({ +30, +30 });
+		s3.o.push_back({ +30, -30 });
+		s3.p.resize(4);
+		
+			
+		vecShapes.push_back(s1);
+		vecShapes.push_back(s2);
+		vecShapes.push_back(s3);
+		return true;
+	}
+
+
+
+	bool ShapeOverlap_SAT(polygon &r1, polygon &r2)
+	{
+		polygon *poly1 = &r1;
+		polygon *poly2 = &r2;
+
+		for (int shape = 0; shape < 2; shape++)
+		{
+			if (shape == 1)
+			{
+				poly1 = &r2;
+				poly2 = &r1;
+			}
+		
+			for (int a = 0; a < poly1->p.size(); a++)
+			{
+				int b = (a + 1) % poly1->p.size();
+				vec2d axisProj = { -(poly1->p[b].y - poly1->p[a].y), poly1->p[b].x - poly1->p[a].x };
+				float d = sqrtf(axisProj.x * axisProj.x + axisProj.y * axisProj.y);
+				axisProj = { axisProj.x / d, axisProj.y / d };
+
+				// Work out min and max 1D points for r1
+				float min_r1 = INFINITY, max_r1 = -INFINITY;
+				for (int p = 0; p < poly1->p.size(); p++)
+				{
+					float q = (poly1->p[p].x * axisProj.x + poly1->p[p].y * axisProj.y);
+					min_r1 = std::min(min_r1, q);
+					max_r1 = std::max(max_r1, q);
+				}
+
+				// Work out min and max 1D points for r2
+				float min_r2 = INFINITY, max_r2 = -INFINITY;
+				for (int p = 0; p < poly2->p.size(); p++)
+				{
+					float q = (poly2->p[p].x * axisProj.x + poly2->p[p].y * axisProj.y);
+					min_r2 = std::min(min_r2, q);
+					max_r2 = std::max(max_r2, q);
+				}
+
+				if (!(max_r2 >= min_r1 && max_r1 >= min_r2))
+					return false;
+			}
+		}
+
+		return true;
+	}
+
+	bool ShapeOverlap_SAT_STATIC(polygon &r1, polygon &r2)
+	{
+		polygon *poly1 = &r1;
+		polygon *poly2 = &r2;
+
+		float overlap = INFINITY;
+		
+		for (int shape = 0; shape < 2; shape++)
+		{
+			if (shape == 1)
+			{
+				poly1 = &r2;
+				poly2 = &r1;
+			}
+
+			for (int a = 0; a < poly1->p.size(); a++)
+			{
+				int b = (a + 1) % poly1->p.size();
+				vec2d axisProj = { -(poly1->p[b].y - poly1->p[a].y), poly1->p[b].x - poly1->p[a].x };
+				
+				// Optional normalisation of projection axis enhances stability slightly
+				//float d = sqrtf(axisProj.x * axisProj.x + axisProj.y * axisProj.y);
+				//axisProj = { axisProj.x / d, axisProj.y / d };
+
+				// Work out min and max 1D points for r1
+				float min_r1 = INFINITY, max_r1 = -INFINITY;
+				for (int p = 0; p < poly1->p.size(); p++)
+				{
+					float q = (poly1->p[p].x * axisProj.x + poly1->p[p].y * axisProj.y);
+					min_r1 = std::min(min_r1, q);
+					max_r1 = std::max(max_r1, q);
+				}
+
+				// Work out min and max 1D points for r2
+				float min_r2 = INFINITY, max_r2 = -INFINITY;
+				for (int p = 0; p < poly2->p.size(); p++)
+				{
+					float q = (poly2->p[p].x * axisProj.x + poly2->p[p].y * axisProj.y);
+					min_r2 = std::min(min_r2, q);
+					max_r2 = std::max(max_r2, q);
+				}
+
+				// Calculate actual overlap along projected axis, and store the minimum
+				overlap = std::min(std::min(max_r1, max_r2) - std::max(min_r1, min_r2), overlap);
+
+				if (!(max_r2 >= min_r1 && max_r1 >= min_r2))
+					return false;
+			}
+		}
+
+		// If we got here, the objects have collided, we will displace r1
+		// by overlap along the vector between the two object centers
+		vec2d d = { r2.pos.x - r1.pos.x, r2.pos.y - r1.pos.y };
+		float s = sqrtf(d.x*d.x + d.y*d.y);
+		r1.pos.x -= overlap * d.x / s;
+		r1.pos.y -= overlap * d.y / s;
+		return false;
+	}
+
+	// Use edge/diagonal intersections.
+	bool ShapeOverlap_DIAGS(polygon &r1, polygon &r2)
+	{
+		polygon *poly1 = &r1;
+		polygon *poly2 = &r2;
+
+		for (int shape = 0; shape < 2; shape++)
+		{
+			if (shape == 1)
+			{
+				poly1 = &r2;
+				poly2 = &r1;
+			}
+			
+			// Check diagonals of polygon...
+			for (int p = 0; p < poly1->p.size(); p++)
+			{
+				vec2d line_r1s = poly1->pos;
+				vec2d line_r1e = poly1->p[p];
+
+				// ...against edges of the other
+				for (int q = 0; q < poly2->p.size(); q++)
+				{
+					vec2d line_r2s = poly2->p[q];
+					vec2d line_r2e = poly2->p[(q + 1) % poly2->p.size()];
+
+					// Standard "off the shelf" line segment intersection
+					float h = (line_r2e.x - line_r2s.x) * (line_r1s.y - line_r1e.y) - (line_r1s.x - line_r1e.x) * (line_r2e.y - line_r2s.y);
+					float t1 = ((line_r2s.y - line_r2e.y) * (line_r1s.x - line_r2s.x) + (line_r2e.x - line_r2s.x) * (line_r1s.y - line_r2s.y)) / h;
+					float t2 = ((line_r1s.y - line_r1e.y) * (line_r1s.x - line_r2s.x) + (line_r1e.x - line_r1s.x) * (line_r1s.y - line_r2s.y)) / h;
+
+					if (t1 >= 0.0f && t1 < 1.0f && t2 >= 0.0f && t2 < 1.0f)
+					{
+						return true;
+					}
+				}
+			}		
+		}
+		return false;
+	}
+
+	// Use edge/diagonal intersections.
+	bool ShapeOverlap_DIAGS_STATIC(polygon &r1, polygon &r2)
+	{
+		polygon *poly1 = &r1;
+		polygon *poly2 = &r2;
+
+		for (int shape = 0; shape < 2; shape++)
+		{
+			if (shape == 1)
+			{
+				poly1 = &r2;
+				poly2 = &r1;
+			}
+
+			// Check diagonals of this polygon...
+			for (int p = 0; p < poly1->p.size(); p++)
+			{
+				vec2d line_r1s = poly1->pos;
+				vec2d line_r1e = poly1->p[p];
+
+				vec2d displacement = { 0,0 };
+
+				// ...against edges of this polygon
+				for (int q = 0; q < poly2->p.size(); q++)
+				{
+					vec2d line_r2s = poly2->p[q];
+					vec2d line_r2e = poly2->p[(q + 1) % poly2->p.size()];
+
+					// Standard "off the shelf" line segment intersection
+					float h = (line_r2e.x - line_r2s.x) * (line_r1s.y - line_r1e.y) - (line_r1s.x - line_r1e.x) * (line_r2e.y - line_r2s.y);
+					float t1 = ((line_r2s.y - line_r2e.y) * (line_r1s.x - line_r2s.x) + (line_r2e.x - line_r2s.x) * (line_r1s.y - line_r2s.y)) / h;
+					float t2 = ((line_r1s.y - line_r1e.y) * (line_r1s.x - line_r2s.x) + (line_r1e.x - line_r1s.x) * (line_r1s.y - line_r2s.y)) / h;
+
+					if (t1 >= 0.0f && t1 < 1.0f && t2 >= 0.0f && t2 < 1.0f)
+					{						
+						displacement.x += (1.0f - t1) * (line_r1e.x - line_r1s.x);
+						displacement.y += (1.0f - t1) * (line_r1e.y - line_r1s.y);					
+					}
+				}
+
+				r1.pos.x += displacement.x * (shape == 0 ? -1 : +1);
+				r1.pos.y += displacement.y * (shape == 0 ? -1 : +1);
+			}
+		}
+
+		// Cant overlap if static collision is resolved
+		return false;
+	}
+
+	
+
+	bool OnUserUpdate(float fElapsedTime) override
+	{
+		if (GetKey(olc::Key::F1).bReleased) nMode = 0;
+		if (GetKey(olc::Key::F2).bReleased) nMode = 1;
+		if (GetKey(olc::Key::F3).bReleased) nMode = 2;
+		if (GetKey(olc::Key::F4).bReleased) nMode = 3;
+		
+		// Shape 1
+		if (GetKey(olc::Key::LEFT).bHeld) vecShapes[0].angle -= 2.0f * fElapsedTime;
+		if (GetKey(olc::Key::RIGHT).bHeld) vecShapes[0].angle += 2.0f * fElapsedTime;
+
+		if (GetKey(olc::Key::UP).bHeld)
+		{
+			vecShapes[0].pos.x += cosf(vecShapes[0].angle) * 60.0f * fElapsedTime;
+			vecShapes[0].pos.y += sinf(vecShapes[0].angle) * 60.0f * fElapsedTime;
+		}
+
+		if (GetKey(olc::Key::DOWN).bHeld)
+		{
+			vecShapes[0].pos.x -= cosf(vecShapes[0].angle) * 60.0f * fElapsedTime;
+			vecShapes[0].pos.y -= sinf(vecShapes[0].angle) * 60.0f * fElapsedTime;
+		}
+
+		// Shape 2
+		if (GetKey(olc::Key::A).bHeld) vecShapes[1].angle -= 2.0f * fElapsedTime;
+		if (GetKey(olc::Key::D).bHeld) vecShapes[1].angle += 2.0f * fElapsedTime;
+
+		if (GetKey(olc::Key::W).bHeld)
+		{
+			vecShapes[1].pos.x += cosf(vecShapes[1].angle) * 60.0f * fElapsedTime;
+			vecShapes[1].pos.y += sinf(vecShapes[1].angle) * 60.0f * fElapsedTime;
+		}
+
+		if (GetKey(olc::Key::S).bHeld)
+		{
+			vecShapes[1].pos.x -= cosf(vecShapes[1].angle) * 60.0f * fElapsedTime;
+			vecShapes[1].pos.y -= sinf(vecShapes[1].angle) * 60.0f * fElapsedTime;
+		}
+
+		// Update Shapes and reset flags
+		for (auto &r : vecShapes)
+		{
+			for (int i = 0; i < r.o.size(); i++)
+				r.p[i] =
+				{	// 2D Rotation Transform + 2D Translation
+					(r.o[i].x * cosf(r.angle)) - (r.o[i].y * sinf(r.angle)) + r.pos.x,
+					(r.o[i].x * sinf(r.angle)) + (r.o[i].y * cosf(r.angle)) + r.pos.y,
+				};
+
+			r.overlap = false;
+		}
+
+		// Check for overlap
+		for (int m = 0; m < vecShapes.size(); m++)
+			for (int n = m + 1; n < vecShapes.size(); n++)
+			{
+				switch (nMode)
+				{
+				case 0: vecShapes[m].overlap |= ShapeOverlap_SAT(vecShapes[m], vecShapes[n]); break;
+				case 1: vecShapes[m].overlap |= ShapeOverlap_SAT_STATIC(vecShapes[m], vecShapes[n]); break;
+				case 2: vecShapes[m].overlap |= ShapeOverlap_DIAGS(vecShapes[m], vecShapes[n]); break;
+				case 3: vecShapes[m].overlap |= ShapeOverlap_DIAGS_STATIC(vecShapes[m], vecShapes[n]); break;
+				}						
+			}
+		
+		// === Render Display ===
+		Clear(olc::BLUE);
+
+		// Draw Shapes
+		for (auto &r : vecShapes)
+		{
+			// Draw Boundary
+			for (int i = 0; i < r.p.size(); i++)
+				DrawLine(r.p[i].x, r.p[i].y, r.p[(i + 1) % r.p.size()].x, r.p[(i + 1) % r.p.size()].y, (r.overlap ? olc::RED : olc::WHITE));
+
+			// Draw Direction
+			DrawLine(r.p[0].x, r.p[0].y, r.pos.x, r.pos.y, (r.overlap ? olc::RED : olc::WHITE));
+		}
+
+		// Draw HUD
+		DrawString(8, 10, "F1: SAT", (nMode == 0 ? olc::RED : olc::YELLOW));
+		DrawString(8, 20, "F2: SAT/STATIC", (nMode == 1 ? olc::RED : olc::YELLOW));
+		DrawString(8, 30, "F3: DIAG", (nMode == 2 ? olc::RED : olc::YELLOW));
+		DrawString(8, 40, "F4: DIAG/STATIC", (nMode == 3 ? olc::RED : olc::YELLOW));
+
+		return true;
+	}
+};
+
+
+
+int main()
+{
+	PolygonCollisions demo;
+	if (demo.Construct(256, 240, 4, 4))
+		demo.Start();
+	return 0;
+}