3dbase/example/lesson009-贝塞尔/Raster.cpp

#include "Raster.h"

namespace   CELL
{
    Raster::Raster( int w,int h,void* buffer )
    {
        _width  =   w;
        _height =   h;
        _buffer =   (Rgba*)buffer;
    }

    Raster::~Raster( void )
    {

    }

    void Raster::clear()
    {
        memset(_buffer,0,_width * _height * sizeof(Rgba));
    }

    void Raster::drawPoint( int x,int y, Rgba color,int ptSize )
    {
        switch(ptSize)
        {
        case 1:
            setPixel(x,y,color);
            break;
        case 2:
            setPixel(x + 0, y + 0,color);
            setPixel(x + 1, y + 0,color);
            setPixel(x + 0, y + 1,color);
            setPixel(x + 1, y + 1,color);
            break;
        case 3:

            setPixel(x - 1, y - 1,color);
            setPixel(x + 0, y - 1,color);
            setPixel(x + 1, y - 1,color);

            setPixel(x - 1, y + 0,color);
            setPixel(x + 0, y + 0,color);
            setPixel(x + 1, y + 0,color);

            setPixel(x - 1, y + 1,color);
            setPixel(x + 0, y + 1,color);
            setPixel(x + 1, y + 1,color);

            break;
        }
    }

    void Raster::drawLine( float2 pt1,float2 pt2,Rgba color1,Rgba color2 )
    {
        float   xOffset =   pt1.x - pt2.x;
        float   yOffset =   pt1.y - pt2.y;

        if (xOffset == 0 && yOffset == 0)
        {
            setPixel(pt1.x,pt1.y,color1);
        }

        if (fabs(xOffset) > fabs(yOffset))
        {
            float   xMin;
            float   xMax;
            if (pt1.x < pt2.x)
            {
                xMin    =   pt1.x;
                xMax    =   pt2.x;
            }
            else
            {
                xMin    =   pt2.x;
                xMax    =   pt1.x;
            }
            
            float   lenth   =   xMax - xMin;
            float   slope   =   yOffset / xOffset;
            for (float x = xMin; x <= xMax ; x += 1.0f)
            {
                float   y       =   pt1.y + (x - pt1.x) * slope;
                float   scaler  =   (x - xMin)/lenth;
                Rgba    color   =   colorLerp(color1,color2,scaler);
                setPixel(x,y,color);
            }
        }
        else
        {
            float   yMin;
            float   yMax;
            if (pt1.y < pt2.y)
            {
                yMin    =   pt1.y;
                yMax    =   pt2.y;
            }
            else
            {
                yMin    =   pt2.y;
                yMax    =   pt1.y;
            }

            float   lenth   =   yMax - yMin;
            float   slope   =   xOffset / yOffset;
            for (float y = yMin; y <= yMax ; y += 1.0f)
            {
                float   x       =   pt1.x + (y - pt1.y) * slope;
                float   scaler  =   (y - yMin)/lenth;
                Rgba    color   =   colorLerp(color1,color2,scaler);
                setPixel(x,y,color);
            }
        }
    }

}