mipmap.c

winNT技术操作系统,国外开放的原代码和LIUX一样

   assert(width != height);	/* can't be square */

   if (height == 1) {		/* 1 row */
      assert(width != 1);	/* widthxheight can't be 1x1 */
      halfHeight= 1;

      for (jj= 0; jj< halfWidth; jj++) {
	 int kk;
	 for (kk= 0; kk< components; kk++) {
	    *dest= (*(const GLubyte*)src +
		 *(const GLubyte*)(src+group_size)) / 2;

	    src+= element_size;
	    dest++;
	 }
	 src+= group_size;	/* skip to next 2 */
      }
      {
	 int padBytes= ysize - (width*group_size);
	 src+= padBytes;	/* for assertion only */
      }
   }
   else if (width == 1) {	/* 1 column */
      int padBytes= ysize - (width * group_size);
      assert(height != 1);	/* widthxheight can't be 1x1 */
      halfWidth= 1;
      /* one vertical column with possible pad bytes per row */
      /* average two at a time */

      for (jj= 0; jj< halfHeight; jj++) {
	 int kk;
	 for (kk= 0; kk< components; kk++) {
	    *dest= (*(const GLubyte*)src + *(const GLubyte*)(src+ysize)) / 2;

	    src+= element_size;
	    dest++;
	 }
	 src+= padBytes; /* add pad bytes, if any, to get to end to row */
	 src+= ysize;
      }
   }

   assert(src == &((const char *)dataIn)[ysize*height]);
   assert((char *)dest == &((char *)dataOut)
	  [components * element_size * halfWidth * halfHeight]);
} /* halve1Dimage_ubyte() */

static void halveImage_byte(GLint components, GLuint width, GLuint height,
			const GLbyte *datain, GLbyte *dataout,
			GLint element_size,
			GLint ysize, GLint group_size)
{
    int i, j, k;
    int newwidth, newheight;
    GLbyte *s;
    const char *t;

    /* handle case where there is only 1 column/row */
    if (width == 1 || height == 1) {
       assert( !(width == 1 && height == 1) ); /* can't be 1x1 */
       halve1Dimage_byte(components,width,height,datain,dataout,
			 element_size,ysize,group_size);
       return;
    }

    newwidth = width / 2;
    newheight = height / 2;
    s = dataout;
    t = (const char *)datain;

    /* Piece o' cake! */
    for (i = 0; i < newheight; i++) {
	for (j = 0; j < newwidth; j++) {
	    for (k = 0; k < components; k++) {
		s[0] = (*(const GLbyte*)t +
			*(const GLbyte*)(t+group_size) +
			*(const GLbyte*)(t+ysize) +
			*(const GLbyte*)(t+ysize+group_size) + 2) / 4;
		s++; t += element_size;
	    }
	    t += group_size;
	}
	t += ysize;
    }
}

static void halve1Dimage_byte(GLint components, GLuint width, GLuint height,
			      const GLbyte *dataIn, GLbyte *dataOut,
			      GLint element_size,GLint ysize, GLint group_size)
{
   GLint halfWidth= width / 2;
   GLint halfHeight= height / 2;
   const char *src= (const char *) dataIn;
   GLbyte *dest= dataOut;
   int jj;

   assert(width == 1 || height == 1); /* must be 1D */
   assert(width != height);	/* can't be square */

   if (height == 1) {		/* 1 row */
      assert(width != 1);	/* widthxheight can't be 1x1 */
      halfHeight= 1;

      for (jj= 0; jj< halfWidth; jj++) {
	 int kk;
	 for (kk= 0; kk< components; kk++) {
	    *dest= (*(const GLbyte*)src + *(const GLbyte*)(src+group_size)) / 2;

	    src+= element_size;
	    dest++;
	 }
	 src+= group_size;	/* skip to next 2 */
      }
      {
	 int padBytes= ysize - (width*group_size);
	 src+= padBytes;	/* for assertion only */
      }
   }
   else if (width == 1) {	/* 1 column */
      int padBytes= ysize - (width * group_size);
      assert(height != 1);	/* widthxheight can't be 1x1 */
      halfWidth= 1;
      /* one vertical column with possible pad bytes per row */
      /* average two at a time */

      for (jj= 0; jj< halfHeight; jj++) {
	 int kk;
	 for (kk= 0; kk< components; kk++) {
	    *dest= (*(const GLbyte*)src + *(const GLbyte*)(src+ysize)) / 2;

	    src+= element_size;
	    dest++;
	 }
	 src+= padBytes; /* add pad bytes, if any, to get to end to row */
	 src+= ysize;
      }

      assert(src == &((const char *)dataIn)[ysize*height]);
   }

   assert((char *)dest == &((char *)dataOut)
	  [components * element_size * halfWidth * halfHeight]);
} /* halve1Dimage_byte() */

static void halveImage_ushort(GLint components, GLuint width, GLuint height,
			const GLushort *datain, GLushort *dataout,
			GLint element_size, GLint ysize, GLint group_size,
			GLint myswap_bytes)
{
    int i, j, k;
    int newwidth, newheight;
    GLushort *s;
    const char *t;

    /* handle case where there is only 1 column/row */
    if (width == 1 || height == 1) {
       assert( !(width == 1 && height == 1) ); /* can't be 1x1 */
       halve1Dimage_ushort(components,width,height,datain,dataout,
			   element_size,ysize,group_size, myswap_bytes);
       return;
    }

    newwidth = width / 2;
    newheight = height / 2;
    s = dataout;
    t = (const char *)datain;

    /* Piece o' cake! */
    if (!myswap_bytes)
    for (i = 0; i < newheight; i++) {
	for (j = 0; j < newwidth; j++) {
	    for (k = 0; k < components; k++) {
		s[0] = (*(const GLushort*)t +
			*(const GLushort*)(t+group_size) +
			*(const GLushort*)(t+ysize) +
			*(const GLushort*)(t+ysize+group_size) + 2) / 4;
		s++; t += element_size;
	    }
	    t += group_size;
	}
	t += ysize;
    }
    else
    for (i = 0; i < newheight; i++) {
	for (j = 0; j < newwidth; j++) {
	    for (k = 0; k < components; k++) {
		s[0] = (__GLU_SWAP_2_BYTES(t) +
			__GLU_SWAP_2_BYTES(t+group_size) +
			__GLU_SWAP_2_BYTES(t+ysize) +
			__GLU_SWAP_2_BYTES(t+ysize+group_size)+ 2)/4;
		s++; t += element_size;
	    }
	    t += group_size;
	}
	t += ysize;
    }
}

static void halve1Dimage_ushort(GLint components, GLuint width, GLuint height,
				const GLushort *dataIn, GLushort *dataOut,
				GLint element_size, GLint ysize,
				GLint group_size, GLint myswap_bytes)
{
   GLint halfWidth= width / 2;
   GLint halfHeight= height / 2;
   const char *src= (const char *) dataIn;
   GLushort *dest= dataOut;
   int jj;

   assert(width == 1 || height == 1); /* must be 1D */
   assert(width != height);	/* can't be square */

   if (height == 1) {		/* 1 row */
      assert(width != 1);	/* widthxheight can't be 1x1 */
      halfHeight= 1;

      for (jj= 0; jj< halfWidth; jj++) {
	 int kk;
	 for (kk= 0; kk< components; kk++) {
#define BOX2 2
	    GLushort ushort[BOX2];
	    if (myswap_bytes) {
	       ushort[0]= __GLU_SWAP_2_BYTES(src);
	       ushort[1]= __GLU_SWAP_2_BYTES(src+group_size);
	    }
	    else {
	       ushort[0]= *(const GLushort*)src;
	       ushort[1]= *(const GLushort*)(src+group_size);
	    }

	    *dest= (ushort[0] + ushort[1]) / 2;
	    src+= element_size;
	    dest++;
	 }
	 src+= group_size;	/* skip to next 2 */
      }
      {
	 int padBytes= ysize - (width*group_size);
	 src+= padBytes;	/* for assertion only */
      }
   }
   else if (width == 1) {	/* 1 column */
      int padBytes= ysize - (width * group_size);
      assert(height != 1);	/* widthxheight can't be 1x1 */
      halfWidth= 1;
      /* one vertical column with possible pad bytes per row */
      /* average two at a time */

      for (jj= 0; jj< halfHeight; jj++) {
	 int kk;
	 for (kk= 0; kk< components; kk++) {
#define BOX2 2
	    GLushort ushort[BOX2];
	    if (myswap_bytes) {
	       ushort[0]= __GLU_SWAP_2_BYTES(src);
	       ushort[1]= __GLU_SWAP_2_BYTES(src+ysize);
	    }
	    else {
	       ushort[0]= *(const GLushort*)src;
	       ushort[1]= *(const GLushort*)(src+ysize);
	    }
	    *dest= (ushort[0] + ushort[1]) / 2;

	    src+= element_size;
	    dest++;
	 }
	 src+= padBytes; /* add pad bytes, if any, to get to end to row */
	 src+= ysize;
      }

      assert(src == &((const char *)dataIn)[ysize*height]);
   }

   assert((char *)dest == &((char *)dataOut)
	  [components * element_size * halfWidth * halfHeight]);

} /* halve1Dimage_ushort() */


static void halveImage_short(GLint components, GLuint width, GLuint height,
			const GLshort *datain, GLshort *dataout,
			GLint element_size, GLint ysize, GLint group_size,
			GLint myswap_bytes)
{
    int i, j, k;
    int newwidth, newheight;
    GLshort *s;
    const char *t;

    /* handle case where there is only 1 column/row */
    if (width == 1 || height == 1) {
       assert( !(width == 1 && height == 1) ); /* can't be 1x1 */
       halve1Dimage_short(components,width,height,datain,dataout,
			  element_size,ysize,group_size, myswap_bytes);
       return;
    }

    newwidth = width / 2;
    newheight = height / 2;
    s = dataout;
    t = (const char *)datain;

    /* Piece o' cake! */
    if (!myswap_bytes)
    for (i = 0; i < newheight; i++) {
	for (j = 0; j < newwidth; j++) {
	    for (k = 0; k < components; k++) {
		s[0] = (*(const GLshort*)t +
			*(const GLshort*)(t+group_size) +
			*(const GLshort*)(t+ysize) +
			*(const GLshort*)(t+ysize+group_size) + 2) / 4;
		s++; t += element_size;
	    }
	    t += group_size;
	}
	t += ysize;
    }
    else
    for (i = 0; i < newheight; i++) {
	for (j = 0; j < newwidth; j++) {
	    for (k = 0; k < components; k++) {
		GLushort b;
		GLint buf;
		b = __GLU_SWAP_2_BYTES(t);
		buf = *(const GLshort*)&b;
		b = __GLU_SWAP_2_BYTES(t+group_size);
		buf += *(const GLshort*)&b;
		b = __GLU_SWAP_2_BYTES(t+ysize);
		buf += *(const GLshort*)&b;
		b = __GLU_SWAP_2_BYTES(t+ysize+group_size);
		buf += *(const GLshort*)&b;
		s[0] = (GLshort)((buf+2)/4);
		s++; t += element_size;
	    }
	    t += group_size;
	}
	t += ysize;
    }
}

static void halve1Dimage_short(GLint components, GLuint width, GLuint height,
				const GLshort *dataIn, GLshort *dataOut,
				GLint element_size, GLint ysize,
				GLint group_size, GLint myswap_bytes)
{
   GLint halfWidth= width / 2;
   GLint halfHeight= height / 2;
   const char *src= (const char *) dataIn;
   GLshort *dest= dataOut;
   int jj;

   assert(width == 1 || height == 1); /* must be 1D */
   assert(width != height);	/* can't be square */

   if (height == 1) {		/* 1 row */
      assert(width != 1);	/* widthxheight can't be 1x1 */
      halfHeight= 1;

      for (jj= 0; jj< halfWidth; jj++) {
	 int kk;
	 for (kk= 0; kk< components; kk++) {
#define BOX2 2
	    GLshort sshort[BOX2];
	    if (myswap_bytes) {
	       sshort[0]= __GLU_SWAP_2_BYTES(src);
	       sshort[1]= __GLU_SWAP_2_BYTES(src+group_size);
	    }
	    else {
	       sshort[0]= *(const GLshort*)src;
	       sshort[1]= *(const GLshort*)(src+group_size);
	    }

	    *dest= (sshort[0] + sshort[1]) / 2;
	    src+= element_size;
	    dest++;
	 }
	 src+= group_size;	/* skip to next 2 */
      }
      {
	 int padBytes= ysize - (width*group_size);
	 src+= padBytes;	/* for assertion only */
      }
   }
   else if (width == 1) {	/* 1 column */
      int padBytes= ysize - (width * group_size);
      assert(height != 1);	/* widthxheight can't be 1x1 */
      halfWidth= 1;
      /* one vertical column with possible pad bytes per row */
      /* average two at a time */

      for (jj= 0; jj< halfHeight; jj++) {
	 int kk;
	 for (kk= 0; kk< components; kk++) {
#define BOX2 2
	    GLshort sshort[BOX2];
	    if (myswap_bytes) {
	       sshort[0]= __GLU_SWAP_2_BYTES(src);
	       sshort[1]= __GLU_SWAP_2_BYTES(src+ysize);
	    }
	    else {
	       sshort[0]= *(const GLshort*)src;
	       sshort[1]= *(const GLshort*)(src+ysize);
	    }
	    *dest= (sshort[0] + sshort[1]) / 2;

	    src+= element_size;
	    dest++;
	 }
	 src+= padBytes; /* add pad bytes, if any, to get to end to row */
	 src+= ysize;
      }

      assert(src == &((const char *)dataIn)[ysize*height]);
   }

   assert((char *)dest == &((char *)dataOut)
	  [components * element_size * halfWidth * halfHeight]);

} /* halve1Dimage_short() */


static void halveImage_uint(GLint components, GLuint width, GLuint height,
			const GLuint *datain, GLuint *dataout,
			GLint element_size, GLint ysize, GLint group_size,
			GLint myswap_bytes)
{