rasterizer.c

#include "rasterizer.h"

void clearFrameBuffer(u8 *fb, u32 color)
{
    u8* i = fb;
    u8* c_inf = (u8*)&color;

    for (i; i < fb + (240*400*3); i += 3)
    {
        *i = c_inf[3];
        *(i+1) = c_inf[2];
        *(i+2) = c_inf[1];
    }
}

void pixel2D(u8* fb, u16 x, u16 y, u32 color)
{
    u8 *p = (u32*)(fb + (3 * (y + (x * 240))));
    u8* c_inf = (u8*)&color;
    if (fb && x >= 0 && x < 240 && y >= 0 && y < 400)
    {
        *p = c_inf[3];
        *++p = c_inf[2];
        *++p = c_inf[1];
    }
}

void box2D(u8 *fb, u16 x1, u16 y1, u16 w, u16 h, u32 color)
{
    if (!fb)
        return;

    u16 x, y;
    u8* c_inf = (u8*)&color;

    for (y = y1; y <= y1+h; y++)
    {
        fb[3 * (y + (x1*240))] = c_inf[3];
        fb[3 * (y + (x1*240)) + 1] = c_inf[2];
        fb[3 * (y + (x1*240)) + 2] = c_inf[1];

        fb[3 * (y + ((x1+w)*240))] = c_inf[3];
        fb[3 * (y + ((x1+w)*240)) + 1] = c_inf[2];
        fb[3 * (y + ((x1+w)*240)) + 2] = c_inf[1];
    }

    for (x = x1 + 1; x < x1 + w; x++)
    {
        fb[3 * (y1 + (x*240))] = c_inf[3];
        fb[3 * (y1 + (x*240)) + 1] = c_inf[2];
        fb[3 * (y1 + (x*240)) + 2] = c_inf[1];

        fb[3 * ((y1+h) + (x*240))] = c_inf[3];
        fb[3 * ((y1+h) + (x*240)) + 1] = c_inf[2];
        fb[3 * ((y1+h) + (x*240)) + 2] = c_inf[1];
    }
}

void fillBox2D(u8 *fb, u16 x, u16 y, u16 w, u16 h, u32 color)
{
    if (!fb)
        return;

    if (x >= 0 && x + w < 400 && y >= 0 && y + h < 240)
    {
        u8 *c_inf = (u8*)&color;
        int i;
        int ii;
        int tmp_x;

        for (i=x; i < x + w; i++)
        {
            tmp_x = i*240;
            for (ii=y; ii < y + h; ii++)
            {
                fb[3 * (ii + tmp_x)] = c_inf[3];
                fb[3 * (ii + tmp_x) + 1] = c_inf[2];
                fb[3 * (ii + tmp_x) + 2] = c_inf[1];
            }
        }

    }
}

void line2D(u8* fb, u16 x1, u16 y1, u16 x2, u16 y2, u32 color)
{
    // Based upon bresenham implementation from wikipedia (de))
    if (!fb)
        return;

    u8* c_inf = (u8*)&color;
    s32 x, y, t, dx, dy, incx, incy, pdx, pdy, ddx, ddy, es, el, err;

    dx = x2 - x1;
    dy = y2 - y1;

    incx = (dx > 0) ? 1 : (dx < 0) ? -1 : 0;;
    incy = (dy > 0) ? 1 : (dy < 0) ? -1 : 0;;

    if(dx<0) dx = -dx;
    if(dy<0) dy = -dy;

    if (dx>dy) {
            pdx=incx; pdy=0;
            ddx=incx; ddy=incy;
            es =dy;   el =dx;
    }
    else {
            pdx=0;    pdy=incy;
            ddx=incx; ddy=incy;
            es =dx;   el =dy;
    }

    x = x1;
    y = y1;
    err = el/2;

    fb[3 * (y + (x*240))] = c_inf[3];
    fb[3 * (y + (x*240))+1] = c_inf[2];
    fb[3 * (y + (x*240))+2] = c_inf[1];

    //setPixel(dp, x, y, c);

    for(t=0; t<el; ++t) {

            err -= es;

            if(err<0) {
                    err += el;
                    x += ddx;
                    y += ddy;
            }
            else {
                    x += pdx;
                    y += pdy;
            }

            //setPixel(dp, x, y, c);
            fb[3 * (y + (x*240))] = c_inf[3];
            fb[3 * (y + (x*240))+1] = c_inf[2];
            fb[3 * (y + (x*240))+2] = c_inf[1];
    }
}