Add ellipse plotter and oval drawing

PortabilityLayer/EllipsePlotter.cpp

@@ -0,0 +1,411 @@
+#include "EllipsePlotter.h"
+
+#include "Rect2i.h"
+
+#include <assert.h>
+
+namespace
+{
+	static int32_t SquareInt32(int32_t v)
+	{
+		return v * v;
+	}
+}
+
+namespace PortabilityLayer
+{
+	EllipsePlotter::EllipsePlotter()
+		: m_2center(0, 0)
+		, m_point(0, 0)
+#if PL_DEBUG_ELLIPSE_PLOTTER 1
+		, m_2offsetFromCenter(0, 0)
+#endif
+		, m_quadrant(Quadrant_PxPy)
+		, m_sqDistFromEdge(0)
+	{
+	}
+
+	PlotDirection EllipsePlotter::PlotNext()
+	{
+		// distance = (m_2offsetFromCenter.x*m_diameters.y)^2 + (m_2offsetFromCenter.y*m_diameters.x)^2 <= (m_diameters.x*m_diameters.y)^2
+		// We want to minimize distance while keeping it less than (m_diameters.x*m_diameters.y)^2
+
+		// Stepping X:
+		// ((m_2offsetFromCenter.x + n)*m_diameters.y)^2 = (m_2offsetFromCenter.x*m_diameters.y)^2 + t
+		// t = ((m_2offsetFromCenter.x + n)*m_diameters.y)^2 - (m_2offsetFromCenter.x*m_diameters.y)^2
+		// t = (m_2offsetFromCenter.x*m_diameters.y + n*m_diameters.y)^2 - (m_2offsetFromCenter.x*m_diameters.y)^2
+		// t = 2*(m_2offsetFromCenter.x*m_diameters.y*n*m_diameters.y) + (n*m_diameters.y)^2
+
+		// For n=2:
+		// t = 2 * (m_2offsetFromCenter.x*m_diameters.y*2*m_diameters.y) + (2*m_diameters.y) ^ 2
+		// t = m_2offsetFromCenter.x * 4 * (m_diameters.y*)^2 + 4*(m_diameters.y) ^ 2
+
+		// For n=-2
+		// t = 2 * (m_2offsetFromCenter.x*m_diameters.y*-2*m_diameters.y) + (-2*m_diameters.y) ^ 2
+		// t = m_2offsetFromCenter.x * -4 * (m_diameters.y*m_diameters.y) + 4 * (m_diameters.y) ^ 2
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+		{
+			const int32_t diameterSq = SquareInt32(m_diameters.m_x*m_diameters.m_y);
+			const int32_t sqDistX = SquareInt32(m_2offsetFromCenter.m_x*m_diameters.m_y);
+			const int32_t sqDistY = SquareInt32(m_2offsetFromCenter.m_y*m_diameters.m_x);
+
+			assert(m_sqDistFromEdge >= 0);
+			assert(sqDistX + sqDistY >= diameterSq);
+			assert(sqDistX + sqDistY - diameterSq == m_sqDistFromEdge);
+			assert(m_xChangeCostDynamicFactor == m_2offsetFromCenter.m_x * 4 * SquareInt32(m_diameters.m_y));
+			assert(m_yChangeCostDynamicFactor == m_2offsetFromCenter.m_y * 4 * SquareInt32(m_diameters.m_x));
+
+			Vec2i actualCoordinate = (m_2center + m_2offsetFromCenter);
+			actualCoordinate.m_x /= 2;
+			actualCoordinate.m_y /= 2;
+
+			int n = 0;
+		}
+#endif
+
+		PlotDirection plotDir = PlotDirection_Exhausted;
+
+		switch (m_quadrant)
+		{
+		case Quadrant_PxPy:
+			{
+				const int32_t xStepCost = -m_xChangeCostDynamicFactor + m_xChangeCostStaticFactor;
+				const int32_t yStepCost = m_yChangeCostDynamicFactor + m_yChangeCostStaticFactor;
+
+				const int32_t diagonalCostDelta = xStepCost + yStepCost;
+
+				if (diagonalCostDelta < 0)
+				{
+					// Diagonal movement will move closer to the edge (first octant)
+					IncrementY();
+
+					const int32_t distWithDiagonalMovement = m_sqDistFromEdge + xStepCost;
+					if (distWithDiagonalMovement >= 0)
+					{
+						DecrementX();
+						plotDir = PlotDirection_NegX_PosY;
+					}
+					else
+						plotDir = PlotDirection_0X_PosY;
+				}
+				else
+				{
+					// Diagonal movement will move farther from the center (second octant)
+					DecrementX();
+
+					if (m_sqDistFromEdge < 0)
+					{
+						IncrementY();
+						plotDir = PlotDirection_NegX_PosY;
+					}
+					else
+						plotDir = PlotDirection_NegX_0Y;
+				}
+
+				if (m_xChangeCostDynamicFactor <= 0)
+					m_quadrant = Quadrant_NxPy;
+
+				return plotDir;
+			}
+			break;
+
+		case Quadrant_NxPy:
+			{
+				const int32_t xStepCost = -m_xChangeCostDynamicFactor + m_xChangeCostStaticFactor;
+				const int32_t yStepCost = -m_yChangeCostDynamicFactor + m_yChangeCostStaticFactor;
+
+				const int32_t diagonalCostDelta = xStepCost + yStepCost;
+
+				if (diagonalCostDelta < 0)
+				{
+					// Diagonal movement will move closer to the edge (first octant)
+					DecrementX();
+
+					const int32_t distWithDiagonalMovement = m_sqDistFromEdge + yStepCost;
+					if (distWithDiagonalMovement >= 0)
+					{
+						DecrementY();
+						plotDir = PlotDirection_NegX_NegY;
+					}
+					else
+						plotDir = PlotDirection_NegX_0Y;
+				}
+				else
+				{
+					// Diagonal movement will move farther from the center (second octant)
+					DecrementY();
+
+					if (m_sqDistFromEdge < 0)
+					{
+						DecrementX();
+						plotDir = PlotDirection_NegX_NegY;
+					}
+					else
+						plotDir = PlotDirection_0X_NegY;
+				}
+
+				if (m_yChangeCostDynamicFactor <= 0)
+					m_quadrant = Quadrant_NxNy;
+
+				return plotDir;
+			}
+			break;
+
+		case Quadrant_NxNy:
+			{
+				const int32_t xStepCost = m_xChangeCostDynamicFactor + m_xChangeCostStaticFactor;
+				const int32_t yStepCost = -m_yChangeCostDynamicFactor + m_yChangeCostStaticFactor;
+
+				const int32_t diagonalCostDelta = xStepCost + yStepCost;
+
+				if (diagonalCostDelta < 0)
+				{
+					// Diagonal movement will move closer to the edge (first octant)
+					DecrementY();
+
+					const int32_t distWithDiagonalMovement = m_sqDistFromEdge + xStepCost;
+					if (distWithDiagonalMovement >= 0)
+					{
+						IncrementX();
+						plotDir = PlotDirection_PosX_NegY;
+					}
+					else
+						plotDir = PlotDirection_0X_NegY;
+				}
+				else
+				{
+					// Diagonal movement will move farther from the center (second octant)
+					IncrementX();
+
+					if (m_sqDistFromEdge < 0)
+					{
+						DecrementY();
+						plotDir = PlotDirection_PosX_NegY;
+					}
+					else
+						plotDir = PlotDirection_PosX_0Y;
+				}
+
+				if (m_xChangeCostDynamicFactor >= 0)
+					m_quadrant = Quadrant_PxNy;
+
+				return plotDir;
+			}
+			break;
+
+		case Quadrant_PxNy:
+			{
+				const int32_t xStepCost = m_xChangeCostDynamicFactor + m_xChangeCostStaticFactor;
+				const int32_t yStepCost = m_yChangeCostDynamicFactor + m_yChangeCostStaticFactor;
+
+				const int32_t diagonalCostDelta = xStepCost + yStepCost;
+
+				if (diagonalCostDelta < 0)
+				{
+					// Diagonal movement will move closer to the edge (first octant)
+					IncrementX();
+
+					const int32_t distWithDiagonalMovement = m_sqDistFromEdge + yStepCost;
+					if (distWithDiagonalMovement >= 0)
+					{
+						IncrementY();
+						plotDir = PlotDirection_PosX_PosY;
+					}
+					else
+						plotDir = PlotDirection_PosX_0Y;
+				}
+				else
+				{
+					// Diagonal movement will move farther from the center
+					IncrementY();
+
+					if (m_sqDistFromEdge < 0)
+					{
+						IncrementX();
+						plotDir = PlotDirection_PosX_PosY;
+					}
+					else
+						plotDir = PlotDirection_0X_PosY;
+				}
+
+				if (m_yChangeCostDynamicFactor >= 0)
+					m_quadrant = Quadrant_Finished;
+
+				return plotDir;
+			}
+			break;
+
+		case Quadrant_Finished:
+			return PlotDirection_Exhausted;
+
+		default:
+			assert(false);
+			return PlotDirection_Exhausted;
+		}
+	}
+
+	void EllipsePlotter::IncrementX()
+	{
+		const int32_t xStepCost = m_xChangeCostDynamicFactor + m_xChangeCostStaticFactor;
+
+		m_sqDistFromEdge += xStepCost;
+		m_xChangeCostDynamicFactor += m_xChangeCostDynamicFactorStep;
+		m_point.m_x++;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+		m_2offsetFromCenter.m_x += 2;
+#endif
+	}
+
+	bool EllipsePlotter::ConditionalIncrementX()
+	{
+		const int32_t xStepCost = m_xChangeCostDynamicFactor + m_xChangeCostStaticFactor;
+
+		if (m_sqDistFromEdge + xStepCost >= 0)
+		{
+			m_sqDistFromEdge += xStepCost;
+			m_xChangeCostDynamicFactor += m_xChangeCostDynamicFactorStep;
+			m_point.m_x++;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+			m_2offsetFromCenter.m_x += 2;
+#endif
+			return true;
+		}
+
+		return false;
+	}
+
+	void EllipsePlotter::IncrementY()
+	{
+		const int32_t yStepCost = m_yChangeCostDynamicFactor + m_yChangeCostStaticFactor;
+
+		m_sqDistFromEdge += yStepCost;
+		m_yChangeCostDynamicFactor += m_yChangeCostDynamicFactorStep;
+		m_point.m_y++;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+		m_2offsetFromCenter.m_y += 2;
+#endif
+	}
+
+	bool EllipsePlotter::ConditionalIncrementY()
+	{
+		const int32_t yStepCost = m_yChangeCostDynamicFactor + m_yChangeCostStaticFactor;
+
+		if (m_sqDistFromEdge + yStepCost >= 0)
+		{
+			m_sqDistFromEdge += yStepCost;
+			m_yChangeCostDynamicFactor += m_yChangeCostDynamicFactorStep;
+			m_point.m_y++;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+			m_2offsetFromCenter.m_y += 2;
+#endif
+			return true;
+		}
+
+		return false;
+	}
+
+	void EllipsePlotter::DecrementX()
+	{
+		const int32_t xStepCost = -m_xChangeCostDynamicFactor + m_xChangeCostStaticFactor;
+
+		m_sqDistFromEdge += xStepCost;
+		m_xChangeCostDynamicFactor -= m_xChangeCostDynamicFactorStep;
+		m_point.m_x--;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+		m_2offsetFromCenter.m_x -= 2;
+#endif
+	}
+
+	bool EllipsePlotter::ConditionalDecrementX()
+	{
+		const int32_t xStepCost = -m_xChangeCostDynamicFactor + m_xChangeCostStaticFactor;
+
+		if (m_sqDistFromEdge + xStepCost >= 0)
+		{
+			m_sqDistFromEdge += xStepCost;
+			m_xChangeCostDynamicFactor -= m_xChangeCostDynamicFactorStep;
+			m_point.m_x--;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+			m_2offsetFromCenter.m_x -= 2;
+#endif
+			return true;
+		}
+
+		return false;
+	}
+
+	void EllipsePlotter::DecrementY()
+	{
+		const int32_t yStepCost = -m_yChangeCostDynamicFactor + m_yChangeCostStaticFactor;
+
+		m_sqDistFromEdge += yStepCost;
+		m_yChangeCostDynamicFactor -= m_yChangeCostDynamicFactorStep;
+		m_point.m_y--;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+		m_2offsetFromCenter.m_y -= 2;
+#endif
+	}
+
+	bool EllipsePlotter::ConditionalDecrementY()
+	{
+		const int32_t yStepCost = -m_yChangeCostDynamicFactor + m_yChangeCostStaticFactor;
+
+		if (m_sqDistFromEdge + yStepCost >= 0)
+		{
+			m_sqDistFromEdge += yStepCost;
+			m_yChangeCostDynamicFactor -= m_yChangeCostDynamicFactorStep;
+			m_point.m_y--;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+			m_2offsetFromCenter.m_y -= 2;
+#endif
+			return true;
+		}
+
+		return false;
+	}
+
+	const Vec2i &EllipsePlotter::GetPoint() const
+	{
+		return m_point;
+	}
+
+	void EllipsePlotter::Reset(const Rect2i &bounds)
+	{
+		assert(bounds.IsValid());
+		m_quadrant = Quadrant_PxPy;
+
+		m_2center = bounds.m_topLeft + bounds.m_bottomRight - Vec2i(1, 1);
+		m_diameters = bounds.m_bottomRight - bounds.m_topLeft - Vec2i(1, 1);
+
+		m_point.m_x = bounds.m_bottomRight.m_x - 1;
+		m_point.m_y = (m_2center.m_y + 1) / 2;
+
+		const Vec2i offsetFromCenterTimes2 = (m_point + m_point) - m_2center;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER
+		m_2offsetFromCenter = offsetFromCenterTimes2;
+#endif
+
+		m_sqDistFromEdge = SquareInt32(offsetFromCenterTimes2.m_x * m_diameters.m_y) + SquareInt32(offsetFromCenterTimes2.m_y * m_diameters.m_x) - SquareInt32(m_diameters.m_x * m_diameters.m_y);
+
+		const int32_t xCostMultiplier = 4 * SquareInt32(m_diameters.m_y);
+		const int32_t yCostMultiplier = 4 * SquareInt32(m_diameters.m_x);
+
+		m_xChangeCostDynamicFactorStep = 2 * xCostMultiplier;
+		m_yChangeCostDynamicFactorStep = 2 * yCostMultiplier;
+		m_xChangeCostStaticFactor = 4 * SquareInt32(m_diameters.m_y);
+		m_yChangeCostStaticFactor = 4 * SquareInt32(m_diameters.m_x);
+
+		m_xChangeCostDynamicFactor = offsetFromCenterTimes2.m_x * xCostMultiplier;
+		m_yChangeCostDynamicFactor = offsetFromCenterTimes2.m_y * yCostMultiplier;
+	}
+}

PortabilityLayer/EllipsePlotter.h

@@ -0,0 +1,62 @@
+#pragma once
+
+#include "IPlotter.h"
+#include "PlotDirection.h"
+#include "Vec2i.h"
+
+#define PL_DEBUG_ELLIPSE_PLOTTER 1
+
+namespace PortabilityLayer
+{
+	struct Rect2i;
+
+	class EllipsePlotter final : public IPlotter
+	{
+	public:
+		EllipsePlotter();
+		PlotDirection PlotNext() override;
+		const Vec2i &GetPoint() const override;
+
+		void Reset(const Rect2i &bounds);
+
+	private:
+		enum Quadrant
+		{
+			Quadrant_NxNy,
+			Quadrant_NxPy,
+			Quadrant_PxNy,
+			Quadrant_PxPy,
+
+			Quadrant_Finished
+		};
+
+		void IncrementX();
+		bool ConditionalIncrementX();
+
+		void IncrementY();
+		bool ConditionalIncrementY();
+
+		void DecrementX();
+		bool ConditionalDecrementX();
+
+		void DecrementY();
+		bool ConditionalDecrementY();
+
+		Vec2i m_2center;
+		Vec2i m_point;
+		Vec2i m_diameters;
+		int32_t m_sqDistFromEdge;
+		Quadrant m_quadrant;
+
+		int32_t m_xChangeCostDynamicFactor;
+		int32_t m_yChangeCostDynamicFactor;
+		int32_t m_xChangeCostDynamicFactorStep;
+		int32_t m_yChangeCostDynamicFactorStep;
+		int32_t m_xChangeCostStaticFactor;
+		int32_t m_yChangeCostStaticFactor;
+
+#if PL_DEBUG_ELLIPSE_PLOTTER 1
+		Vec2i m_2offsetFromCenter;
+#endif
+	};
+}

PortabilityLayer/LinePlotter.h

@@ -1,16 +1,17 @@
 #pragma once
 
+#include "IPlotter.h"
 #include "PlotDirection.h"
 #include "Vec2i.h"
 
 namespace PortabilityLayer
 {
-	class LinePlotter
+	class LinePlotter final : public IPlotter
 	{
 	public:
 		LinePlotter();
-		PlotDirection PlotNext();
+		PlotDirection PlotNext() override;
-		const Vec2i &GetPoint() const;
+		const Vec2i &GetPoint() const override;
 
 		void Reset(const Vec2i &pointA, const Vec2i &pointB);
 

PortabilityLayer/PLQDraw.cpp

@@ -16,6 +16,7 @@
 #include "ResTypeID.h"
 #include "RGBAColor.h"
 #include "ScanlineMask.h"
+#include "ScanlineMaskConverter.h"
 #include "ScanlineMaskIterator.h"
 #include "QDStandardPalette.h"
 #include "WindowManager.h"
@@ -571,7 +572,15 @@ void PaintRect(const Rect *rect)
 
 void PaintOval(const Rect *rect)
 {
-	PL_NotYetImplemented_TODO("Ovals");
+	if (!rect->IsValid())
+		return;
+
+	PortabilityLayer::ScanlineMask *mask = PortabilityLayer::ScanlineMaskConverter::CompileEllipse(PortabilityLayer::Rect2i(rect->top, rect->left, rect->bottom, rect->right));
+	if (mask)
+	{
+		FillScanlineMask(mask);
+		mask->Destroy();
+	}
 }
 
 void FillScanlineSpan(uint8_t *rowStart, size_t startCol, size_t endCol)

PortabilityLayer/PortabilityLayer.vcxproj

@@ -139,6 +139,7 @@
     <ClInclude Include="ClientAudioChannelContext.h" />
     <ClInclude Include="DataTypes.h" />
     <ClInclude Include="DisplayDeviceManager.h" />
+    <ClInclude Include="EllipsePlotter.h" />
     <ClInclude Include="FileManager.h" />
     <ClInclude Include="FilePermission.h" />
     <ClInclude Include="FilePos.h" />
@@ -261,6 +262,7 @@
     <ClCompile Include="ByteSwap.cpp" />
     <ClCompile Include="CFileStream.cpp" />
     <ClCompile Include="DisplayDeviceManager.cpp" />
+    <ClCompile Include="EllipsePlotter.cpp" />
     <ClCompile Include="FileManager.cpp" />
     <ClCompile Include="FontFamily.cpp" />
     <ClCompile Include="FontManager.cpp" />

PortabilityLayer/PortabilityLayer.vcxproj.filters

@@ -393,6 +393,9 @@
     <ClInclude Include="ScanlineMaskDataStorage.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="EllipsePlotter.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="CFileStream.cpp">
@@ -596,5 +599,8 @@
     <ClCompile Include="ScanlineMaskIterator.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="EllipsePlotter.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>

PortabilityLayer/Rect2i.h

@@ -19,7 +19,7 @@ namespace PortabilityLayer
 		Rect2i(const Rect2i &other);
 		explicit Rect2i(const Rect &other);
 		Rect2i(const Vec2i &topLeft, const Vec2i &bottomRight);
-		Rect2i(int32_t left, int32_t top, int32_t bottom, int32_t right);
+		Rect2i(int32_t top, int32_t left, int32_t bottom, int32_t right);
 
 		Rect2i operator+(const Vec2i &other) const;
 		Rect2i operator-(const Vec2i &other) const;

PortabilityLayer/ScanlineMaskConverter.cpp

@@ -1,4 +1,7 @@
 #include "ScanlineMaskConverter.h"
+
+#include "EllipsePlotter.h"
+#include "Rect2i.h"
 #include "ScanlineMask.h"
 #include "Vec2i.h"
 #include "LinePlotter.h"
@@ -252,6 +255,33 @@ namespace PortabilityLayer
 		return ScanlineMask::Create(Rect::Create(minPoint.m_y, minPoint.m_x, minPoint.m_y + static_cast<int16_t>(height), minPoint.m_x + static_cast<int16_t>(width)), maskBuilder);
 	}
 
+	class SinglePointPlotter final : public IPlotter
+	{
+	public:
+		explicit SinglePointPlotter(const Vec2i &point);
+
+		PlotDirection PlotNext() override;
+		const Vec2i &GetPoint() const override;
+
+	private:
+		const Vec2i &m_point;
+	};
+
+	SinglePointPlotter::SinglePointPlotter(const Vec2i &point)
+		: m_point(point)
+	{
+	}
+
+	PlotDirection SinglePointPlotter::PlotNext()
+	{
+		return PlotDirection_Exhausted;
+	}
+
+	const Vec2i &SinglePointPlotter::GetPoint() const
+	{
+		return m_point;
+	}
+
 	class PolyPlotter final : public IPlotter
 	{
 	public:
@@ -322,4 +352,34 @@ namespace PortabilityLayer
 		PolyPlotter polyPlotter(points, numPoints);
 		return ComputePlot(width, height, minPoint, polyPlotter);
 	}
+
+	ScanlineMask *ScanlineMaskConverter::CompileEllipse(const Rect2i &rect)
+	{
+		if (!rect.IsValid() || rect.m_topLeft.m_x == rect.m_bottomRight.m_x || rect.m_topLeft.m_y == rect.m_bottomRight.m_y)
+			return nullptr;
+
+		const uint32_t width = rect.m_bottomRight.m_x - rect.m_topLeft.m_x;
+		const uint32_t height = rect.m_bottomRight.m_y - rect.m_topLeft.m_y;
+
+		if (width == 1 || height == 1)
+		{
+			if (width == 1 && height == 1)
+			{
+				SinglePointPlotter plotter(rect.m_topLeft);
+				return ComputePlot(1, 1, rect.m_topLeft, plotter);
+			}
+			else
+			{
+				LinePlotter plotter;
+				plotter.Reset(rect.m_topLeft, rect.m_bottomRight - Vec2i(1, 1));
+				return ComputePlot(width, height, rect.m_topLeft, plotter);
+			}
+		}
+		else
+		{
+			EllipsePlotter plotter;
+			plotter.Reset(rect);
+			return ComputePlot(width, height, rect.m_topLeft, plotter);
+		}
+	}
 }

PortabilityLayer/ScanlineMaskConverter.h

@@ -6,10 +6,12 @@ namespace PortabilityLayer
 {
 	class ScanlineMask;
 	struct Vec2i;
+	struct Rect2i;
 
 	class ScanlineMaskConverter
 	{
 	public:
 		static ScanlineMask *CompilePoly(const Vec2i *points, size_t numPoints);
+		static ScanlineMask *CompileEllipse(const Rect2i &rect);
 	};
 }