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en:software:arm-can:drivers:polygon [2010/06/06 14:35] – created mikk.leinien:software:arm-can:drivers:polygon [2020/07/20 12:00] (current) – external edit 127.0.0.1
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 +====== StellarisWare Graphics Library Polygon ======
 +
 +===== polygon.c =====
 +
 +<code c>
 +//*****************************************************************************
 +//
 +// polygon.c - Routines for drawing and filling polygons.
 +//             Addition to StellarisWare library.
 +//
 +// Copyright (c) 2010 Mikk Leini, TUT Robotics Club NPO
 +//
 +// Polygon fill algorithm is based on Darel Rex Finley suggestions:
 +//   http://www.alienryderflex.com/polygon_fill
 +//
 +//*****************************************************************************
 +
 +#include "driverlib/debug.h"
 +#include "grlib/grlib.h"
 +
 +//*****************************************************************************
 +//
 +//! \addtogroup primitives_api
 +//! @{
 +//
 +//*****************************************************************************
 +
 +//*****************************************************************************
 +//
 +//! Draws a polygon.
 +//!
 +//! \param pContext is a pointer to the drawing context to use.
 +//! \param pRect is a pointer to the array of structures containing the points
 +//! of the polygon.
 +//! \param ulNumPoints is a number of points in array.
 +//! \param bClosedLoop indicates wheter to draw line between the first and
 +//! the last point.
 +//!
 +//! This function draws lines between the consecutive points and if requiered
 +//! the line between the first and the last point.
 +//!
 +//! \return None.
 +//
 +//*****************************************************************************
 +void
 +GrPolyDraw(const tContext *pContext, const tPoint *pPoints, 
 +           unsigned long ulNumPoints, unsigned char ucClosedLoop)
 +{
 + unsigned long ulIdx;
 +
 +    //
 +    // Check the arguments.
 +    //
 +    ASSERT(pContext);
 +    ASSERT(pPoints);
 + ASSERT(sNumPoints > (bClosedLoop ? 2 : 1));
 +
 + //
 + // Draw the lines between points
 + //
 + for(ulIdx = 0; ulIdx < ulNumPoints - 1; ulIdx++)
 + {
 + GrLineDraw(pContext, pPoints[ulIdx].sX, pPoints[ulIdx].sY,
 +            pPoints[ulIdx + 1].sX, pPoints[ulIdx + 1].sY);
 + }
 +
 + //
 + // Draw a closing line between first and last point?
 + //
 + if(ucClosedLoop)
 + {
 + GrLineDraw(pContext, pPoints[0].sX, pPoints[0].sY,
 +            pPoints[ulNumPoints - 1].sX, pPoints[ulNumPoints - 1].sY);
 + }
 +}
 +
 +//*****************************************************************************
 +//
 +//! Draws a filled polygon.
 +//!
 +//! \param pContext is a pointer to the drawing context to use.
 +//! \param pRect is a pointer to the array of structures containing the points
 +//! of the polygon.
 +//! \param ulNumPoints is a number of points in array.
 +//!
 +//! This function fills a polygon specified by the consecutive points.
 +//!
 +//! The clipping of the polygon to the clipping rectangle is performed within
 +//! this routine;
 +//!
 +//! \return None.
 +//
 +//*****************************************************************************
 +void
 +GrPolyFill(const tContext *pContext, const tPoint *pPoints, 
 +           unsigned long ulNumPoints)
 +{    
 + unsigned long ulIdx, ulIdx2;
 + unsigned long ulNumNodes;
 + short sY;
 + short pNodeList[100];
 + short sSwap;
 +
 +    //
 +    // Check the arguments.
 +    //
 +    ASSERT(pContext);
 +    ASSERT(pPoints);
 +  ASSERT(sNumPoints > 2);
 +
 + //
 + // Loop through the rows of the clipping area.
 + //
 + for(sY = pContext->sClipRegion.sYMin; sY <= pContext->sClipRegion.sYMax; sY++)
 + {
 + //
 + // Build a list of nodes.
 + //
 +  ulNumNodes = 0;
 +
 + //
 + // Search for X coordinates of polygons on the current row.
 + //
 + for(ulIdx = 0; ulIdx < ulNumPoints; ulIdx++)
 + {
 + //
 + // Get the index of next point and wrap around points count.
 + //
 + ulIdx2 = (ulIdx + 1) % ulNumPoints;
 +
 + //
 + // Check if the polygon line exists on the same row.
 + //
 + if(((pPoints[ulIdx].sY <  sY) && (pPoints[ulIdx2].sY >= sY)) ||
 +               ((pPoints[ulIdx].sY >= sY) && (pPoints[ulIdx2].sY <  sY)))
 + {
 + //
 + // Make sure nodes list isn't overflowed.
 + //
 + if(ulNumNodes >= 100) break;
 +
 + //
 + // Calculate the intersection point X coordinate
 + // of the polygon edge.
 + //
 + pNodeList[ulNumNodes++] =
 + (pPoints[ulIdx].sX + (sY - pPoints[ulIdx].sY) *
 + (pPoints[ulIdx2].sX - pPoints[ulIdx].sX) /
 + (pPoints[ulIdx2].sY - pPoints[ulIdx].sY));
 + }
 + }
 +
 + //
 + // Sort the nodes, via a simple “Bubble” sort.
 + //
 + ulIdx = 0;
 +
 + while(ulIdx + 1 < ulNumNodes)
 + {
 + if(pNodeList[ulIdx] > pNodeList[ulIdx + 1])
 + {
 + sSwap = pNodeList[ulIdx];
 + pNodeList[ulIdx] = pNodeList[ulIdx + 1];
 + pNodeList[ulIdx + 1] = sSwap;
 +
 + if(ulIdx)
 + {
 + ulIdx--;
 + }
 + }
 + else
 + {
 + ulIdx++;
 + }
 + }
 +
 + //
 + // Fill the pixels between node pairs.
 + //
 + for(ulIdx = 0; ulIdx < ulNumNodes; ulIdx += 2)
 + {
 + //
 + // Break when lines go out of clipping region.
 + //
 + if(pNodeList[ulIdx] > pContext->sClipRegion.sXMax) break;
 +
 + //
 + // Skip when line ends before clipping region.
 + //
 + if(pNodeList[ulIdx + 1] < pContext->sClipRegion.sXMin) continue;
 +
 + //
 + // Clip the line from left.
 + //
 + if(pNodeList[ulIdx] < pContext->sClipRegion.sXMin)
 + {
 + pNodeList[ulIdx] = pContext->sClipRegion.sXMin;
 + }
 +
 + //
 + // Clip the line from right.
 + //
 + if(pNodeList[ulIdx + 1] > pContext->sClipRegion.sXMax)
 + {
 + pNodeList[ulIdx + 1] = pContext->sClipRegion.sXMax;
 + }
 +
 + //
 + // Call the low level horizontal line drawing routine.
 + //
 + DpyLineDrawH(pContext->pDisplay, pNodeList[ulIdx],
 +              pNodeList[ulIdx + 1], sY, pContext->ulForeground);
 + }
 + }
 +}
 +
 +//*****************************************************************************
 +//
 +//! Draws a triangle.
 +//!
 +//! \param pContext is a pointer to the drawing context to use.
 +//! \param pPoint1 is a pointer to the first point.
 +//! \param pPoint2 is a pointer to the second point.
 +//! \param pPoint3 is a pointer to the third point.
 +//!
 +//! This function draws a triangle specified by three points.
 +//!
 +//! \return None.
 +//
 +//*****************************************************************************
 +void
 +GrTriangleDraw(const tContext *pContext, const tPoint *pPoint1, 
 +               const tPoint *pPoint2, const tPoint *pPoint3)
 +{
 + tPoint pPoints[3];
 +
 + pPoints[0] = *pPoint1;
 + pPoints[1] = *pPoint2;
 + pPoints[2] = *pPoint3;
 +
 + GrPolyDraw(pContext, pPoints, 3, 1);
 +}
 +
 +//*****************************************************************************
 +//
 +//! Draws a filled triangle.
 +//!
 +//! \param pContext is a pointer to the drawing context to use.
 +//! \param pPoint1 is a pointer to the first point.
 +//! \param pPoint2 is a pointer to the second point.
 +//! \param pPoint3 is a pointer to the third point.
 +//!
 +//! This function fills a triangle specified by three points.
 +//!
 +//! \return None.
 +//
 +//*****************************************************************************
 +void
 +GrTriangleFill(const tContext *pContext, const tPoint *pPoint1, 
 +               const tPoint *pPoint2, const tPoint *pPoint3)
 +{
 + tPoint pPoints[3];
 +
 + pPoints[0] = *pPoint1;
 + pPoints[1] = *pPoint2;
 + pPoints[2] = *pPoint3;
 +
 + GrPolyFill(pContext, pPoints, 3);
 +}
 +
 +//*****************************************************************************
 +//
 +//! Draws a quad.
 +//!
 +//! \param pContext is a pointer to the drawing context to use.
 +//! \param pPoint1 is a pointer to the first point.
 +//! \param pPoint2 is a pointer to the second point.
 +//! \param pPoint3 is a pointer to the third point.
 +//! \param pPoint4 is a pointer to the fourth point.
 +//!
 +//! This function draws a quad specified by four points.
 +//!
 +//! \return None.
 +//
 +//*****************************************************************************
 +void
 +GrQuadDraw(const tContext *pContext, const tPoint *pPoint1, 
 +           const tPoint *pPoint2, const tPoint *pPoint3,
 +    const tPoint *pPoint4)
 +{
 + tPoint pPoints[4];
 +
 + pPoints[0] = *pPoint1;
 + pPoints[1] = *pPoint2;
 + pPoints[2] = *pPoint3;
 + pPoints[3] = *pPoint4;
 +
 + GrPolyDraw(pContext, pPoints, 4, 1);
 +}
 +
 +//*****************************************************************************
 +//
 +//! Draws a filled quad.
 +//!
 +//! \param pContext is a pointer to the drawing context to use.
 +//! \param pPoint1 is a pointer to the first point.
 +//! \param pPoint2 is a pointer to the second point.
 +//! \param pPoint3 is a pointer to the third point.
 +//! \param pPoint4 is a pointer to the fourth point.
 +//!
 +//! This function fills a quad specified by four points.
 +//!
 +//! The clipping of the polygon to the clipping rectangle is performed within
 +//! this routine;
 +//!
 +//! \return None.
 +//
 +//*****************************************************************************
 +void
 +GrQuadFill(const tContext *pContext, const tPoint *pPoint1, 
 +           const tPoint *pPoint2, const tPoint *pPoint3,
 +    const tPoint *pPoint4)
 +{
 + tPoint pPoints[4];
 +
 + pPoints[0] = *pPoint1;
 + pPoints[1] = *pPoint2;
 + pPoints[2] = *pPoint3;
 + pPoints[3] = *pPoint4;
 +
 + GrPolyFill(pContext, pPoints, 4);
 +}
 +
 +//*****************************************************************************
 +//
 +// Close the Doxygen group.
 +//! @}
 +//
 +//*****************************************************************************
 +</code>
 +
 +===== grlib.h =====
 +
 +<code c>
 +//*****************************************************************************
 +//
 +//! This structure defines the point.
 +//
 +//*****************************************************************************
 +typedef struct
 +{
 +    //
 +    //! The X coordinate of the point.
 +    //
 +    short sX;
 +
 +    //
 +    //! The Y coordinate of the point.
 +    //
 +    short sY;
 +}
 +tPoint;
 +
 +// Add these also:
 +
 +extern void GrPolyDraw(const tContext *pContext, const tPoint *pPoints, 
 +           unsigned long ulNumPoints, unsigned char ucClosedLoop);
 +extern void GrPolyFill(const tContext *pContext, const tPoint *pPoints, 
 +           unsigned long ulNumPoints);
 +extern void GrTriangleDraw(const tContext *pContext, const tPoint *pPoint1, 
 +               const tPoint *pPoint2, const tPoint *pPoint3);
 +extern void GrTriangleFill(const tContext *pContext, const tPoint *pPoint1, 
 +               const tPoint *pPoint2, const tPoint *pPoint3);
 +extern void GrQuadDraw(const tContext *pContext, const tPoint *pPoint1, 
 +           const tPoint *pPoint2, const tPoint *pPoint3,
 +    const tPoint *pPoint4);
 +extern void GrQuadFill(const tContext *pContext, const tPoint *pPoint1, 
 +           const tPoint *pPoint2, const tPoint *pPoint3,
 +    const tPoint *pPoint4);
 +
 +</code>
  
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