www.pudn.com > LightTrack.rar > GraphicsBase.cpp
/** 3DGPL *************************************************\
* () *
* 2D basic graphics. *
* *
* Ifdefs: *
* _CI_ Colour/Intensity model; *
* _RGB_ RGB model; *
* _Z_BUFFER_ Depth array; *
* _PAINTER_ Back front order. *
* *
* Defines: *
* G_init_graphics Initializing graphics; *
* G_clear Clearing the bitmap; *
* *
* G_pixel Pixel into the colourmap; *
* G_dot Dot into the colourmap; *
* G_line Line into a colourmap. *
* *
* (c) 1995-98 Sergei Savchenko, (savs@cs.mcgill.ca) *
\**********************************************************/
//GraphicsBase.cpp
extern "C";
#include "LightTrack.h" /* hardware specific stuff */
#include "Colour.h" /* colour and light */
#include "Clipper.h" /* 2D clipping routines */
#include "Graphics.h" /* graphics functions */
#include /* malloc */
#include /* INT_MAX */
HW_pixel *G_c_buffer; /* the bitmap's bits */
int G_page_start; /* always 0 for _MONO_ */
long G_c_buffer_size; /* allocated size for clearings */
#if defined(_Z_BUFFER_)
int *G_z_buffer; /* Z buffer */
long G_z_buffer_size; /* it's size */
#endif
/**********************************************************\
* Setting page for stereo images. *
* *
* SETS: G_page_start *
* ----- *
\**********************************************************/
#if defined(_STEREO_)
void G_page(int page_no) /* between two pages */
{
if(page_no==G_LEFT_EYE) G_page_start=0;
else G_page_start=HW_SCREEN_X_SIZE;
}
#endif
/**********************************************************\
* Allocating space for the colourmap. *
* *
* RETURNS: Pointer to the allocated colourmap. *
* -------- *
* SETS: G_c_buffer,G_c_buffer_size,G_z_buffer, *
* ----- G_z_buffer_size *
\**********************************************************/
//为颜色表分配空间
void G_init_graphics(void)
{
//空白空间的计算
G_c_buffer_size=HW_SCREEN_LINE_SIZE*HW_SCREEN_Y_SIZE;
//HW_pixel==int
G_c_buffer=(HW_pixel*)malloc(G_c_buffer_size*sizeof(HW_pixel));
G_page_start=0; /* page 0 by default */
if(G_c_buffer==NULL) HW_error("(Graphics) Not enough memory.\n");
#if defined(_Z_BUFFER_) /* for both pages */
G_z_buffer_size=HW_SCREEN_LINE_SIZE*HW_SCREEN_Y_SIZE;
//不同的就是int,HW_pixel
G_z_buffer=(int*)malloc(G_z_buffer_size*sizeof(int));
if(G_z_buffer==NULL) HW_error("(Graphics) Not enough memory.\n");
#endif
}
/**********************************************************\
* Clearing the bitmap with the specified colour. *
\**********************************************************/
#if defined(_CI_)
void G_clear(HW_pixel colour,int intensity)
#endif
#if defined(_RGB_)
void G_clear(HW_pixel colour,int red,int green,int blue)
#endif
{
#if defined(_CI_)
HW_set_pixel(G_c_buffer,G_c_buffer_size,CL_light(colour,intensity));
#endif
#if defined(_RGB_)
HW_set_pixel(G_c_buffer,G_c_buffer_size,CL_light(colour,red,green,blue));
#endif
#if defined(_Z_BUFFER_)
HW_set_int(G_z_buffer,G_z_buffer_size,INT_MAX);
#endif
}
/**********************************************************\
* Setting a pixel. *
\**********************************************************/
void G_pixel(int *vertex,HW_pixel colour)
{
long pos;
pos=vertex[1]*HW_SCREEN_LINE_SIZE+vertex[0]+G_page_start;
G_c_buffer[pos]=colour;
}
/**********************************************************\
* Rendering a dot. *
\**********************************************************/
#if defined(_CI_)
void G_dot(int *vertex,HW_pixel colour,int intensity)
#endif
#if defined(_RGB_)
void G_dot(int *vertex,HW_pixel colour,int red,int green,int blue)
#endif
{
long pos;
if( (vertex[0]>=0)&&(vertex[0]=0)&&(vertex[1]0 */
else { inc_xh=1; inc_xl=1; } /* adjusting increments */
if(dy<0){dy=-dy;inc_yh=-HW_SCREEN_LINE_SIZE;
inc_yl=-HW_SCREEN_LINE_SIZE;
} /* to get to the neighboring */
else { inc_yh= HW_SCREEN_LINE_SIZE;
inc_yl= HW_SCREEN_LINE_SIZE;
}
if(dx>dy){long_d=dx;short_d=dy;inc_yl=0;}/* long range,&make sure either */
else {long_d=dy;short_d=dx;inc_xl=0;}/* x or y is changed in L case */
inc_ah=inc_xh+inc_yh;
inc_al=inc_xl+inc_yl; /* increments for point address */
d=2*short_d-long_d; /* initial value of d */
add_dl=2*short_d; /* d adjustment for H case */
add_dh=2*(short_d-long_d); /* d adjustment for L case */
pos=v1[1]*HW_SCREEN_LINE_SIZE+v1[0]+G_page_start;
adr_c+=pos; /* address of first point */
#if defined(_Z_BUFFER_)
adr_z+=pos; /* same for z-buffer */
cur_z=v1[2];
if(long_d!=0) inc_z=(v2[2]-cur_z)/long_d;
#endif
for(i=0;i<=long_d;i++) /* for all points in long range */
{
#if defined(_Z_BUFFER_)
if(cur_z<*adr_z)
#endif
*adr_c=hwcolour; /* rendering */
if(d>=0)
{
d+=add_dh;
adr_c+=inc_ah; /* new in the colour-buffer */
#if defined(_Z_BUFFER_)
adr_z+=inc_ah; /* new in Z-buffer */
#endif
} /* previous point was H type */
else
{
d+=add_dl;
adr_c+=inc_al; /* new in the colour-buffer */
#if defined(_Z_BUFFER_)
adr_z+=inc_al; /* new in Z-buffer */
#endif
} /* previous point was L type */
#if defined(_Z_BUFFER_)
cur_z+=inc_z;
#endif
}
}
}
}
/**********************************************************/