simple_graphics.c

在SOPC平台上

    // If we've reached the 45 degree points (x=y), plot those 4 pixels
    if (x == y) {
      if(fill) {
        vid_draw_line(cx - x, cy + y, cx + x, cy + y, 1, color, frame_buffer);
        vid_draw_line(cx - x, cy - y, cx + x, cy - y, 1, color, frame_buffer);
        
      } else {
        vid_set_pixel(cx + x, cy + y, color, frame_buffer);
        vid_set_pixel(cx - x, cy + y, color, frame_buffer);
        vid_set_pixel(cx + x, cy - y, color, frame_buffer);
        vid_set_pixel(cx - x, cy - y, color, frame_buffer);
      }
    } else
    // If we're between 0 and 45 degrees plot 8 pixels.
    if (x < y) {
        if(fill) {
          vid_draw_line(cx - x, cy + y, cx + x, cy + y, 1, color, frame_buffer);
          vid_draw_line(cx - y, cy + x, cx + y, cy + x, 1, color, frame_buffer);
          vid_draw_line(cx - y, cy - x, cx + y, cy - x, 1, color, frame_buffer);
          vid_draw_line(cx - x, cy - y, cx + x, cy - y, 1, color, frame_buffer);
        } else {
          vid_set_pixel(cx + x, cy + y, color, frame_buffer);
          vid_set_pixel(cx - x, cy + y, color, frame_buffer);
          vid_set_pixel(cx + x, cy - y, color, frame_buffer);
          vid_set_pixel(cx - x, cy - y, color, frame_buffer);
          vid_set_pixel(cx + y, cy + x, color, frame_buffer);
          vid_set_pixel(cx - y, cy + x, color, frame_buffer);
          vid_set_pixel(cx + y, cy - x, color, frame_buffer);
          vid_set_pixel(cx - y, cy - x, color, frame_buffer);
        }
    }
}


/******************************************************************
*  Function: min3
*
*  Purpose:  Returns the minimum value of 3 parameters
*            Used for drawing filled shapes
*
******************************************************************/
__inline__ int max3( int a, int b, int c )
{
  if( a < b )
    a = b;
  if( a < c )
    a = c;
  
  return a;
}

/******************************************************************
*  Function: min3
*
*  Purpose:  Returns the minimum value of 3 parameters
*            Used for drawing filled shapes.
*
******************************************************************/
__inline__ int min3( int a, int b, int c )
{
  if( a > b )
    a = b;
  if( a > c )
    a = c;
  
  return a;
}

/******************************************************************
*  Function: max_diff3
*
*  Purpose:  Returns the positive max difference between 3 
*            parameters.  Used for drawing filled shapes
*
******************************************************************/
__inline__ int max_diff3(int a, int b, int c)
{
  int max, min;
    
  max = max3( a, b, c );
  min = min3( a, b, c );
  return (max - min);
}

/******************************************************************
*  Function: vid_put_pixel_in_span_map
*
*  Purpose:  This function places a pixel into either the max or
*            min value of an element that represents a span, 
*            essentially just a horizontal line used to fill shapes.
*
******************************************************************/
inline void vid_put_pixel_in_span_map( int x, int y, int *span_array )
{
  if (span_array[y*2] == -1)
  {
    span_array[y*2] = x;
    span_array[(y*2)+1] = x;
  }
  else if( span_array[y*2] > x )
    span_array[y*2] = x;
  else if( span_array[(y*2)+1] < x )
    span_array[(y*2)+1] = x;
}

/******************************************************************
*  Function: vid_bres_scan_edges
*
*  Purpose:  This function uses Bresenham's algorithm to scan a line
*            and determine whether it's the left(min) or right(max)
*            edge of a horizontal span.  This is useful for drawing
*            filled shapes where you fill by drawing successive
*            horizontal lines.
*
******************************************************************/
void vid_bres_scan_edges( int x1, int y1, int x2, int y2, int *span_array) 
{

  int x_incr, y_incr;
  int y_delta, x_delta;

  // Assure we always draw left to right
  if( x1 > x2 )
  {
    int tempx = x2;
    x2 = x1;
    x1 = tempx;
    int tempy = y2;
    y2 = y1;
    y1 = tempy;
  }
  
  // Find the vertical and horizontal distance between the two points
  y_delta = abs(y1-y2);
  x_delta = (x2-x1);

  // Find out what direction we are going
  if (y1 > y2) { y_incr=-1; } else { y_incr=1; }
  x_incr=1;

  // Find out which axis is always incremented when drawing the line
  // If it's the horizontal axis
  if (x_delta >= y_delta) {
    int dPr   = y_delta<<1;
    int dPru  = dPr - (x_delta<<1);
    int P     = dPr - x_delta;

    // Process the line, one horizontal point at at time
    for (; x_delta >= 0; x_delta--) {
      // map the pixel
      vid_put_pixel_in_span_map(x1, y1, span_array);
      // If we're moving along both axis
      if (P > 0) {
        x1+=x_incr;
        y1+=y_incr;
        P+=dPru;
      } else {
        x1+=x_incr;
        P+=dPr;
      }
    }
  }
  else // If it's the vertical axis
  {
    int dPr   = x_delta<<1;
    int dPru  = dPr - (y_delta<<1);
    int P     = dPr - y_delta;

    // Process the line, one vertical point at at time
    for (; y_delta>=0; y_delta--) {
      // plot the pixel
      vid_put_pixel_in_span_map(x1, y1, span_array);
      // If we're moving along both axis
      if (P > 0) {
        x1+=x_incr;
        y1+=y_incr;
        P+=dPru;
      } else {
        y1+=y_incr;
        P+=dPr;
      }
    }
  }
}

/******************************************************************
*  Function: vid_draw_triangle
*
*  Purpose:  This function draws a triangle on the screen between
*            three points defined by the structure tri.
*
******************************************************************/
void vid_draw_triangle(triangle_struct* tri, frame_buffer_struct* frame_buffer)
{
  int i;
  
  // Outline it first
    vid_draw_line( tri->vertex_x[0], tri->vertex_y[0], 
                   tri->vertex_x[1], tri->vertex_y[1], 1, 
                   tri->col, frame_buffer);
    vid_draw_line( tri->vertex_x[1], tri->vertex_y[1], 
                   tri->vertex_x[2], tri->vertex_y[2], 1, 
                   tri->col, frame_buffer);
    vid_draw_line( tri->vertex_x[2], tri->vertex_y[2], 
                   tri->vertex_x[0], tri->vertex_y[0], 1, 
                   tri->col, frame_buffer);
//  vid_draw_line(tri->bx, tri->by, tri->cx, tri->cy, 1, tri->col, frame_buffer);
//  vid_draw_line(tri->cx, tri->cy, tri->ax, tri->ay, 1, tri->col, frame_buffer);
  
  if(tri->fill == DO_FILL)
  {
    tri->top_y = min3(tri->vertex_y[0], tri->vertex_y[1], tri->vertex_y[2]);
    tri->bottom_y = max3(tri->vertex_y[0], tri->vertex_y[1], tri->vertex_y[2]);
    tri->spans_needed = max_diff3(tri->vertex_y[0], tri->vertex_y[1], tri->vertex_y[2]);
    tri->max_span = max_diff3(tri->vertex_x[0], tri->vertex_x[1], tri->vertex_x[2]);
    tri->span_array = malloc(frame_buffer->height * 4 * 2);

    //init the span array
    for( i = tri->top_y; i <= tri->bottom_y; i++)
    {
      tri->span_array[i*2] = -1;
      tri->span_array[(i*2) + 1] = -1;
    }
    
    // Scan-convert the triangle  
    vid_bres_scan_edges( tri->vertex_x[0], tri->vertex_y[0], 
                         tri->vertex_x[1], tri->vertex_y[1], tri->span_array);
    vid_bres_scan_edges( tri->vertex_x[1], tri->vertex_y[1], 
                         tri->vertex_x[2], tri->vertex_y[2], tri->span_array);
    vid_bres_scan_edges( tri->vertex_x[2], tri->vertex_y[2], 
                         tri->vertex_x[0], tri->vertex_y[0], tri->span_array);
  
    // Render the polygon
    for( i = tri->top_y; i <= tri->bottom_y; i++ )
    {
//      vid_draw_horiz_line (tri->span_array[i*2], tri->span_array[(i*2)+1], i, tri->col, frame_buffer);
      vid_draw_line (tri->span_array[i*2], i, tri->span_array[(i*2)+1], i, 1, tri->col, frame_buffer);

    }
    free(tri->span_array);
  }
}



/******************************************************************
*  Data: cour10_font
*
*  Purpose: Data array that represents a 10-point courier font.
*
******************************************************************/
char cour10_font_array[95][11] =

 {{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
 {0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x00, 0x10, 0x00, 0x00},
 {0x28, 0x28, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
 {0x14, 0x14, 0x7E, 0x28, 0x28, 0x28, 0xFC, 0x50, 0x50, 0x00, 0x00},
 {0x10, 0x38, 0x44, 0x40, 0x38, 0x04, 0x44, 0x38, 0x10, 0x00, 0x00},
 {0x40, 0xA2, 0x44, 0x08, 0x10, 0x20, 0x44, 0x8A, 0x04, 0x00, 0x00},
 {0x30, 0x40, 0x40, 0x20, 0x60, 0x92, 0x94, 0x88, 0x76, 0x00, 0x00},
 {0x10, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
 {0x08, 0x10, 0x10, 0x20, 0x20, 0x20, 0x20, 0x20, 0x10, 0x10, 0x08},
 {0x20, 0x10, 0x10, 0x08, 0x08, 0x08, 0x08, 0x08, 0x10, 0x10, 0x20},
 {0x00, 0x00, 0x6C, 0x38, 0xFE, 0x38, 0x6C, 0x00, 0x00, 0x00, 0x00},
 {0x00, 0x10, 0x10, 0x10, 0xFE, 0x10, 0x10, 0x10, 0x00, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x20, 0x00},
 {0x00, 0x00, 0x00, 0x00, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00},
 {0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x00, 0x00, 0x00, 0x00},
 {0x38, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x38, 0x00, 0x00},
 {0x10, 0x70, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x7C, 0x00, 0x00},
 {0x38, 0x44, 0x04, 0x04, 0x08, 0x10, 0x20, 0x40, 0x7C, 0x00, 0x00},
 {0x38, 0x44, 0x04, 0x04, 0x18, 0x04, 0x04, 0x44, 0x38, 0x00, 0x00},
 {0x08, 0x18, 0x18, 0x28, 0x28, 0x48, 0x7C, 0x08, 0x1C, 0x00, 0x00},
 {0x7C, 0x40, 0x40, 0x40, 0x78, 0x04, 0x04, 0x44, 0x38, 0x00, 0x00},
 {0x18, 0x20, 0x40, 0x40, 0x78, 0x44, 0x44, 0x44, 0x38, 0x00, 0x00},
 {0x7C, 0x44, 0x04, 0x08, 0x08, 0x10, 0x10, 0x20, 0x20, 0x00, 0x00},
 {0x38, 0x44, 0x44, 0x44, 0x38, 0x44, 0x44, 0x44, 0x38, 0x00, 0x00},
 {0x38, 0x44, 0x44, 0x44, 0x3C, 0x04, 0x04, 0x08, 0x30, 0x00, 0x00},
 {0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00},
 {0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x10, 0x20, 0x00, 0x00, 0x00},
 {0x00, 0x04, 0x08, 0x10, 0x20, 0x10, 0x08, 0x04, 0x00, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x7C, 0x00, 0x7C, 0x00, 0x00, 0x00, 0x00, 0x00},
 {0x00, 0x20, 0x10, 0x08, 0x04, 0x08, 0x10, 0x20, 0x00, 0x00, 0x00},
 {0x38, 0x44, 0x04, 0x04, 0x08, 0x10, 0x10, 0x00, 0x10, 0x00, 0x00},
 {0x3C, 0x42, 0x9A, 0xAA, 0xAA, 0xAA, 0x9C, 0x40, 0x38, 0x00, 0x00},
 {0x30, 0x10, 0x10, 0x28, 0x28, 0x44, 0x7C, 0x44, 0xEE, 0x00, 0x00},
 {0xFC, 0x42, 0x42, 0x42, 0x7C, 0x42, 0x42, 0x42, 0xFC, 0x00, 0x00},
 {0x3C, 0x42, 0x80, 0x80, 0x80, 0x80, 0x80, 0x42, 0x3C, 0x00, 0x00},
 {0xF8, 0x44, 0x42, 0x42, 0x42, 0x42, 0x42, 0x44, 0xF8, 0x00, 0x00},
 {0xFE, 0x42, 0x40, 0x48, 0x78, 0x48, 0x40, 0x42, 0xFE, 0x00, 0x00},
 {0xFE, 0x42, 0x40, 0x48, 0x78, 0x48, 0x40, 0x40, 0xF0, 0x00, 0x00},
 {0x3C, 0x42, 0x80, 0x80, 0x80, 0x8E, 0x82, 0x42, 0x3C, 0x00, 0x00},
 {0xEE, 0x44, 0x44, 0x44, 0x7C, 0x44, 0x44, 0x44, 0xEE, 0x00, 0x00},
 {0x7C, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x7C, 0x00, 0x00},
 {0x1E, 0x04, 0x04, 0x04, 0x04, 0x04, 0x44, 0x44, 0x38, 0x00, 0x00},
 {0xE6, 0x44, 0x48, 0x48, 0x50, 0x70, 0x48, 0x44, 0xE6, 0x00, 0x00},
 {0xF8, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x22, 0xFE, 0x00, 0x00},
 {0xC6, 0x44, 0x6C, 0x6C, 0x54, 0x54, 0x44, 0x44, 0xEE, 0x00, 0x00},
 {0xCE, 0x44, 0x64, 0x64, 0x54, 0x4C, 0x4C, 0x44, 0xE4, 0x00, 0x00},
 {0x38, 0x44, 0x82, 0x82, 0x82, 0x82, 0x82, 0x44, 0x38, 0x00, 0x00},
 {0xFC, 0x42, 0x42, 0x42, 0x7C, 0x40, 0x40, 0x40, 0xF0, 0x00, 0x00},
 {0x38, 0x44, 0x82, 0x82, 0x82, 0x82, 0x82, 0x44, 0x38, 0x36, 0x00},
 {0xFC, 0x42, 0x42, 0x42, 0x7C, 0x48, 0x48, 0x44, 0xE6, 0x00, 0x00},
 {0x7C, 0x82, 0x80, 0x80, 0x7C, 0x02, 0x02, 0x82, 0x7C, 0x00, 0x00},
 {0xFE, 0x92, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x38, 0x00, 0x00},
 {0xEE, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x38, 0x00, 0x00},
 {0xEE, 0x44, 0x44, 0x44, 0x28, 0x28, 0x28, 0x10, 0x10, 0x00, 0x00},
 {0xEE, 0x44, 0x44, 0x44, 0x54, 0x54, 0x54, 0x28, 0x28, 0x00, 0x00},
 {0xEE, 0x44, 0x28, 0x28, 0x10, 0x28, 0x28, 0x44, 0xEE, 0x00, 0x00},
 {0xEE, 0x44, 0x44, 0x28, 0x28, 0x10, 0x10, 0x10, 0x38, 0x00, 0x00},
 {0xFE, 0x84, 0x08, 0x08, 0x10, 0x20, 0x20, 0x42, 0xFE, 0x00, 0x00},
 {0x38, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x38, 0x00, 0x00},
 {0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x00, 0x00, 0x00, 0x00},
 {0x1C, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x1C, 0x00, 0x00},
 {0x10, 0x28, 0x44, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFE, 0x00, 0x00},
 {0x20, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x78, 0x04, 0x7C, 0x84, 0x84, 0x7A, 0x00, 0x00},
 {0xC0, 0x40, 0x40, 0x7C, 0x42, 0x42, 0x42, 0x42, 0xFC, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x7C, 0x82, 0x80, 0x80, 0x82, 0x7C, 0x00, 0x00},
 {0x0C, 0x04, 0x04, 0x7C, 0x84, 0x84, 0x84, 0x84, 0x7E, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x7C, 0x82, 0xFE, 0x80, 0x82, 0x7C, 0x00, 0x00},
 {0x30, 0x40, 0x40, 0xF0, 0x40, 0x40, 0x40, 0x40, 0xF0, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x7E, 0x84, 0x84, 0x84, 0x7C, 0x04, 0x04, 0x78},
 {0xC0, 0x40, 0x40, 0x58, 0x64, 0x44, 0x44, 0x44, 0xEE, 0x00, 0x00},
 {0x08, 0x00, 0x00, 0x38, 0x08, 0x08, 0x08, 0x08, 0x3E, 0x00, 0x00},
 {0x08, 0x00, 0x00, 0x78, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x70},
 {0xC0, 0x40, 0x40, 0x4C, 0x48, 0x50, 0x70, 0x48, 0xC6, 0x00, 0x00},
 {0x30, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x7C, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0xE8, 0x54, 0x54, 0x54, 0x54, 0xD6, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0xD8, 0x64, 0x44, 0x44, 0x44, 0xEE, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x7C, 0x82, 0x82, 0x82, 0x82, 0x7C, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0xFC, 0x42, 0x42, 0x42, 0x42, 0x7C, 0x40, 0xE0},
 {0x00, 0x00, 0x00, 0x7E, 0x84, 0x84, 0x84, 0x7C, 0x04, 0x0E, 0x00},
 {0x00, 0x00, 0x00, 0xEC, 0x32, 0x20, 0x20, 0x20, 0xF8, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0x7C, 0x82, 0x70, 0x0C, 0x82, 0x7C, 0x00, 0x00},
 {0x00, 0x20, 0x20, 0x78, 0x20, 0x20, 0x20, 0x24, 0x18, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0xCC, 0x44, 0x44, 0x44, 0x4C, 0x36, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0xEE, 0x44, 0x44, 0x28, 0x28, 0x10, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0xEE, 0x44, 0x54, 0x54, 0x28, 0x28, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0xEE, 0x44, 0x38, 0x38, 0x44, 0xEE, 0x00, 0x00},
 {0x00, 0x00, 0x00, 0xEE, 0x44, 0x44, 0x28, 0x28, 0x10, 0x10, 0x60},
 {0x00, 0x00, 0x00, 0xFC, 0x88, 0x10, 0x20, 0x44, 0xFC, 0x00, 0x00},
 {0x0C, 0x10, 0x10, 0x10, 0x10, 0x60, 0x10, 0x10, 0x10, 0x10, 0x0C},
 {0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10},
 {0x60, 0x10, 0x10, 0x10, 0x10, 0x0C, 0x10, 0x10, 0x10, 0x10, 0x60},
 {0x00, 0x00, 0x62, 0x92, 0x8C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }};

//Pointer to our font table
char* cour10_font = &cour10_font_array[0][0];