📄 our_draw32.c
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/**************************************************************************
Copyright (C) jianbo miao Corporation. All Rights Released.
this is a 3d engin named our_3d_engin.
our_3d_engin feature:
1:there is no float.
2:it do the 3d things all by softwear.
3:base on 1 and 2 , it can execution on arm which have no 3d hardwear accelerate.
if you have any suggestion or question,pls contact with me
mail:miaojb@126.com
msn:miaojianbo@hotmail.com
qq:30209027
2008/01/01
***************************************************************************/
#ifdef OUR_MAIN_C
#ifndef OUR_DRAW32_C
#define OUR_DRAW32_C
#include "our_math.h"
#include "our_3d.h"
#include "our_draw32.h"
#include "our_draw16.h"
#include "our_bmp.h"
#if 0
//FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
//FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
//==================================================================================
int OUR_Draw_Line32(int x0, int y0, // starting position
int x1, int y1, // ending position
int color, // color index
UCHAR *vb_start, int lpitch_2) // video buffer and memory pitch
{
// this function draws a line from xo,yo to x1,y1 using differential error
// terms (based on Bresenahams work)
int dx, // difference in x's
dy, // difference in y's
dx2, // dx,dy * 2
dy2,
x_inc, // amount in pixel space to move during drawing
y_inc, // amount in pixel space to move during drawing
error, // the discriminant i.e. error i.e. decision variable
index; // used for looping
UINT *vb_start2;
lpitch_2 = lpitch_2>>2 ; // USHORT strided lpitch
// pre-compute first pixel address in video buffer based on 32bit data
vb_start2 = (UINT*)vb_start + x0 + y0*lpitch_2;
// pre-compute first pixel address in video buffer based on 32bit data
//UINT*vb_start2 = (UINT*)vb_start + x0 + y0*lpitch_2;
// compute horizontal and vertical deltas
dx = x1-x0;
dy = y1-y0;
// test which direction the line is going in i.e. slope angle
if (dx>=0)
{
x_inc = 1;
} // end if line is moving right
else
{
x_inc = -1;
dx = -dx; // need absolute value
} // end else moving left
// test y component of slope
if (dy>=0)
{
y_inc = lpitch_2;
} // end if line is moving down
else
{
y_inc = -lpitch_2;
dy = -dy; // need absolute value
} // end else moving up
dx2 = dx << 1;// compute (dx,dy) * 2
dy2 = dy << 1;
if (dx > dy)// now based on which delta is greater we can draw the line
{
error = dy2 - dx; // initialize error term
for (index=0; index <= dx; index++)// draw the line
{
*vb_start2 = (UINT)color;// set the pixel
if (error >= 0) // test if error has overflowed
{
error-=dx2;
vb_start2+=y_inc;// move to next line
} // end if error overflowed
error+=dy2;// adjust the error term
vb_start2+=x_inc;// move to the next pixel
} // end for
} // end if |slope| <= 1
else
{
// initialize error term
error = dx2 - dy;
// draw the line
for (index=0; index <= dy; index++)
{
// set the pixel
*vb_start2 = (UINT)color;
// test if error overflowed
if (error >= 0)
{
error-=dy2;
// move to next line
vb_start2+=x_inc;
} // end if error overflowed
// adjust the error term
error+=dx2;
// move to the next pixel
vb_start2+=y_inc;
} // end for
} // end else |slope| > 1
// return success
return(1);
} // end Draw_Line32
///////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////
int OUR_Clip_Line(int *x11,int *y11,int *x21, int *y21)
{
// this function clips the sent line using the globally defined clipping
// region
// internal clipping codes
#define CLIP_CODE_C 0x0000
#define CLIP_CODE_N 0x0008
#define CLIP_CODE_S 0x0004
#define CLIP_CODE_E 0x0002
#define CLIP_CODE_W 0x0001
#define CLIP_CODE_NE 0x000a
#define CLIP_CODE_SE 0x0006
#define CLIP_CODE_NW 0x0009
#define CLIP_CODE_SW 0x0005
int x1,x2,y1,y2;
int xc1,xc2,yc1,yc2;
int p1_code=0,
p2_code=0;
int min_clip_y=0;
int min_clip_x=0;
int max_clip_y=OUR_D_screem_h;
int max_clip_x=OUR_D_screem_w;
xc1=x1;
yc1=y1;
xc2=x2;
yc2=y2;
x1=*x11;
y1=*y11;
x2=*x21;
y2=*y21;
// determine codes for p1 and p2
if (y1 < min_clip_y)
p1_code|=CLIP_CODE_N;
else
if (y1 > max_clip_y)
p1_code|=CLIP_CODE_S;
if (x1 < min_clip_x)
p1_code|=CLIP_CODE_W;
else
if (x1 > max_clip_x)
p1_code|=CLIP_CODE_E;
if (y2 < min_clip_y)
p2_code|=CLIP_CODE_N;
else
if (y2 > max_clip_y)
p2_code|=CLIP_CODE_S;
if (x2 < min_clip_x)
p2_code|=CLIP_CODE_W;
else
if (x2 > max_clip_x)
p2_code|=CLIP_CODE_E;
// try and trivially reject
if ((p1_code & p2_code))
return(0);
// test for totally visible, if so leave points untouched
if (p1_code==0 && p2_code==0)
return(1);
// determine end clip point for p1
switch(p1_code)
{
case CLIP_CODE_C: break;
case CLIP_CODE_N:
{
yc1 = min_clip_y;
xc1 = x1 + 0.5+(min_clip_y-y1)*(x2-x1)/(y2-y1);
} break;
case CLIP_CODE_S:
{
yc1 = max_clip_y;
xc1 = x1 + 0.5+(max_clip_y-y1)*(x2-x1)/(y2-y1);
} break;
case CLIP_CODE_W:
{
xc1 = min_clip_x;
yc1 = y1 + 0.5+(min_clip_x-x1)*(y2-y1)/(x2-x1);
} break;
case CLIP_CODE_E:
{
xc1 = max_clip_x;
yc1 = y1 + 0.5+(max_clip_x-x1)*(y2-y1)/(x2-x1);
} break;
// these cases are more complex, must compute 2 intersections
case CLIP_CODE_NE:
{
// north hline intersection
yc1 = min_clip_y;
xc1 = x1 + 0.5+(min_clip_y-y1)*(x2-x1)/(y2-y1);
// test if intersection is valid, of so then done, else compute next
if (xc1 < min_clip_x || xc1 > max_clip_x)
{
// east vline intersection
xc1 = max_clip_x;
yc1 = y1 + 0.5+(max_clip_x-x1)*(y2-y1)/(x2-x1);
} // end if
} break;
case CLIP_CODE_SE:
{
// south hline intersection
yc1 = max_clip_y;
xc1 = x1 + 0.5+(max_clip_y-y1)*(x2-x1)/(y2-y1);
// test if intersection is valid, of so then done, else compute next
if (xc1 < min_clip_x || xc1 > max_clip_x)
{
// east vline intersection
xc1 = max_clip_x;
yc1 = y1 + 0.5+(max_clip_x-x1)*(y2-y1)/(x2-x1);
} // end if
} break;
case CLIP_CODE_NW:
{
// north hline intersection
yc1 = min_clip_y;
xc1 = x1 + 0.5+(min_clip_y-y1)*(x2-x1)/(y2-y1);
// test if intersection is valid, of so then done, else compute next
if (xc1 < min_clip_x || xc1 > max_clip_x)
{
xc1 = min_clip_x;
yc1 = y1 + 0.5+(min_clip_x-x1)*(y2-y1)/(x2-x1);
} // end if
} break;
case CLIP_CODE_SW:
{
// south hline intersection
yc1 = max_clip_y;
xc1 = x1 + 0.5+(max_clip_y-y1)*(x2-x1)/(y2-y1);
// test if intersection is valid, of so then done, else compute next
if (xc1 < min_clip_x || xc1 > max_clip_x)
{
xc1 = min_clip_x;
yc1 = y1 + 0.5+(min_clip_x-x1)*(y2-y1)/(x2-x1);
} // end if
} break;
default:break;
} // end switch
// determine clip point for p2
switch(p2_code)
{
case CLIP_CODE_C: break;
case CLIP_CODE_N:
{
yc2 = min_clip_y;
xc2 = x2 + (min_clip_y-y2)*(x1-x2)/(y1-y2);
} break;
case CLIP_CODE_S:
{
yc2 = max_clip_y;
xc2 = x2 + (max_clip_y-y2)*(x1-x2)/(y1-y2);
} break;
case CLIP_CODE_W:
{
xc2 = min_clip_x;
yc2 = y2 + (min_clip_x-x2)*(y1-y2)/(x1-x2);
} break;
case CLIP_CODE_E:
{
xc2 = max_clip_x;
yc2 = y2 + (max_clip_x-x2)*(y1-y2)/(x1-x2);
} break;
// these cases are more complex, must compute 2 intersections
case CLIP_CODE_NE:
{
// north hline intersection
yc2 = min_clip_y;
xc2 = x2 + 0.5+(min_clip_y-y2)*(x1-x2)/(y1-y2);
// test if intersection is valid, of so then done, else compute next
if (xc2 < min_clip_x || xc2 > max_clip_x)
{
// east vline intersection
xc2 = max_clip_x;
yc2 = y2 + 0.5+(max_clip_x-x2)*(y1-y2)/(x1-x2);
} // end if
} break;
case CLIP_CODE_SE:
{
// south hline intersection
yc2 = max_clip_y;
xc2 = x2 + 0.5+(max_clip_y-y2)*(x1-x2)/(y1-y2);
// test if intersection is valid, of so then done, else compute next
if (xc2 < min_clip_x || xc2 > max_clip_x)
{
// east vline intersection
xc2 = max_clip_x;
yc2 = y2 + 0.5+(max_clip_x-x2)*(y1-y2)/(x1-x2);
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