Added Circle Vs Rect, Transformed View Demo

4 years ago · 3374a6924c
parent 8cb4e675b5
commit 3374a6924c
1 changed files with 245 additions and 0 deletions
--- a/Videos/OneLoneCoder_PGE_CircleVsRect.cpp
+++ b/Videos/OneLoneCoder_PGE_CircleVsRect.cpp
@ -0,0 +1,245 @@
+/*
+	Easy Circle Vs Rectangle Collision Resolution
+	"Everything's just damp, the walls, the roof, everything!" - javidx9
+
+	Video: https://youtu.be/D2a5fHX-Qrs
+
+	License (OLC-3)
+	~~~~~~~~~~~~~~~
+
+	Copyright 2018 - 2021 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.
+
+	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
+	Homepage:	https://www.onelonecoder.com
+
+	Author
+	~~~~~~
+	David Barr, aka javidx9, ©OneLoneCoder 2019, 2020, 2021
+*/
+
+#define OLC_PGE_APPLICATION
+#include "olcPixelGameEngine.h"
+
+#define OLC_PGEX_TRANSFORMEDVIEW
+#include "olcPGEX_TransformedView.h"
+
+
+class CircleVsRect : public olc::PixelGameEngine
+{
+public:
+	CircleVsRect()
+	{
+		sAppName = "Circle Vs Rectangle";
+	}
+
+private:
+	olc::TileTransformedView tv;
+
+	struct sWorldObject
+	{
+		olc::vf2d vPos;
+		olc::vf2d vVel;
+		float fRadius = 0.5f;
+	};
+
+	sWorldObject object;
+	
+	std::string sWorldMap =
+		"################################"
+		"#..............................#"
+		"#.......#####.#.....#####......#"
+		"#.......#...#.#.....#..........#"
+		"#.......#...#.#.....#..........#"
+		"#.......#####.#####.#####......#"
+		"#..............................#"
+		"#.....#####.#####.#####..##....#"
+		"#.........#.#...#.....#.#.#....#"
+		"#.....#####.#...#.#####...#....#"
+		"#.....#.....#...#.#.......#....#"
+		"#.....#####.#####.#####.#####..#"
+		"#..............................#"
+		"#..............................#"
+		"#..#.#..........#....#.........#"
+		"#..#.#..........#....#.........#"
+		"#..#.#.......#####.#######.....#"
+		"#..#.#..........#....#.........#"
+		"#..#.#.............###.#.#.....#"
+		"#..#.##########................#"
+		"#..#..........#....#.#.#.#.....#"
+		"#..#.####.###.#................#"
+		"#..#.#......#.#................#"
+		"#..#.#.####.#.#....###..###....#"
+		"#..#.#......#.#....#......#....#"
+		"#..#.########.#....#......#....#"
+		"#..#..........#....#......#....#"
+		"#..############....#......#....#"
+		"#..................########....#"
+		"#..............................#"
+		"#..............................#"
+		"################################";
+
+	olc::vi2d vWorldSize = { 32, 32 };
+
+	bool bFollowObject = false;
+
+public:
+	bool OnUserCreate() override
+	{
+		// Create "Tiled World", where each tile is 32x32 screen pixels. Coordinates
+		// for drawing will exist in unit-tile space from now on...
+		tv = olc::TileTransformedView({ ScreenWidth(), ScreenHeight() }, { 32, 32 });		
+		object.vPos = { 3.0f, 3.0f };
+		return true;
+	}
+
+	bool OnUserUpdate(float fElapsedTime) override
+	{
+		// Control of Player Object
+		object.vVel = { 0.0f, 0.0f };
+		if (GetKey(olc::Key::W).bHeld) object.vVel += { 0.0f, -1.0f };
+		if (GetKey(olc::Key::S).bHeld) object.vVel += { 0.0f, +1.0f };
+		if (GetKey(olc::Key::A).bHeld) object.vVel += { -1.0f, 0.0f };
+		if (GetKey(olc::Key::D).bHeld) object.vVel += { +1.0f, 0.0f };
+
+		if (object.vVel.mag2() > 0)
+			object.vVel = object.vVel.norm() * (GetKey(olc::Key::SHIFT).bHeld ? 5.0f : 2.0f);
+		
+		if (GetKey(olc::Key::SPACE).bReleased) bFollowObject = !bFollowObject;
+
+		
+		// Where will object be worst case?
+		olc::vf2d vPotentialPosition = object.vPos + object.vVel * fElapsedTime;
+
+		// Extract region of world cells that could have collision this frame
+		olc::vi2d vCurrentCell = object.vPos.floor();
+		olc::vi2d vTargetCell = vPotentialPosition;
+		olc::vi2d vAreaTL = (vCurrentCell.min(vTargetCell) - olc::vi2d(1, 1)).max({ 0,0 });
+		olc::vi2d vAreaBR = (vCurrentCell.max(vTargetCell) + olc::vi2d(1, 1)).min(vWorldSize);
+
+		olc::vf2d vRayToNearest;
+		 
+		// Iterate through each cell in test area
+		olc::vi2d vCell;
+		for (vCell.y = vAreaTL.y; vCell.y <= vAreaBR.y; vCell.y++)
+		{
+			for (vCell.x = vAreaTL.x; vCell.x <= vAreaBR.x; vCell.x++)
+			{
+				// Check if the cell is actually solid...
+				if (sWorldMap[vCell.y * vWorldSize.x + vCell.x] == '#')
+				{
+					// ...it is! So work out nearest point to future player position, around perimeter
+					// of cell rectangle. We can test the distance to this point to see if we have
+					// collided. 
+
+					olc::vf2d vNearestPoint;
+					vNearestPoint.x = std::max(float(vCell.x), std::min(vPotentialPosition.x, float(vCell.x + 1)));
+					vNearestPoint.y = std::max(float(vCell.y), std::min(vPotentialPosition.y, float(vCell.y + 1)));
+
+					olc::vf2d vRayToNearest = vNearestPoint - vPotentialPosition;
+					float fOverlap = object.fRadius - vRayToNearest.mag();
+					if (std::isnan(fOverlap)) fOverlap = 0;
+
+					// If overlap is positive, then a collision has occurred, so we displace backwards by the 
+					// overlap amount. The potential position is then tested against other tiles in the area
+					// therefore "statically" resolving the collision
+					if (fOverlap > 0)
+					{
+						// Statically resolve the collision
+						vPotentialPosition = vPotentialPosition - vRayToNearest.norm() * fOverlap;
+					}
+				}
+			}
+		}
+
+		// Set the objects new position to the allowed potential position
+		object.vPos = vPotentialPosition;
+
+
+		// Clear World
+		Clear(olc::VERY_DARK_BLUE);
+		
+		if (bFollowObject)
+		{
+			tv.SetWorldOffset(object.vPos - tv.ScaleToWorld(olc::vf2d(ScreenWidth()/2.0f, ScreenHeight()/2.0f)));
+			DrawString({ 10,10 }, "Following Object");
+		}
+
+		// Handle Pan & Zoom
+		if (GetMouse(2).bPressed) tv.StartPan(GetMousePos());
+		if (GetMouse(2).bHeld) tv.UpdatePan(GetMousePos());
+		if (GetMouse(2).bReleased) tv.EndPan(GetMousePos());
+		if (GetMouseWheel() > 0) tv.ZoomAtScreenPos(2.0f, GetMousePos());
+		if (GetMouseWheel() < 0) tv.ZoomAtScreenPos(0.5f, GetMousePos());
+		
+		// Draw World
+		olc::vi2d vTL = tv.GetTopLeftTile().max({ 0,0 });
+		olc::vi2d vBR = tv.GetBottomRightTile().min(vWorldSize);
+		olc::vi2d vTile;
+		for (vTile.y = vTL.y; vTile.y < vBR.y; vTile.y++)
+			for (vTile.x = vTL.x; vTile.x < vBR.x; vTile.x++)
+			{
+				if (sWorldMap[vTile.y * vWorldSize.x + vTile.x] == '#')
+				{
+					tv.DrawRect(vTile, { 1.0f, 1.0f }, olc::WHITE);
+					tv.DrawLine(vTile, vTile + olc::vf2d(1.0f, 1.0f), olc::WHITE);
+					tv.DrawLine(vTile + olc::vf2d(0.0f, 1.0f), vTile + olc::vf2d(1.0f, 0.0f), olc::WHITE);
+				}
+			}
+
+		tv.FillRectDecal(vAreaTL, vAreaBR - vAreaTL + olc::vi2d(1,1), olc::Pixel(0,255,255,32));
+
+		// Draw Boundary
+		tv.DrawCircle(object.vPos, object.fRadius, olc::WHITE);
+
+		// Draw Velocity
+		if (object.vVel.mag2() > 0)
+		{
+			tv.DrawLine(object.vPos, object.vPos + object.vVel.norm() * object.fRadius, olc::MAGENTA);
+		}
+
+		return true;
+	}
+};
+
+int main()
+{
+	CircleVsRect demo;
+	if (demo.Construct(640, 480, 2, 2))
+		demo.Start();
+	return 0;
+}