mipmap.c

winNT技术操作系统,国外开放的原代码和LIUX一样

    int i, j, k;
    int newwidth, newheight;
    GLuint *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_uint(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++) {
		/* need to cast to double to hold large unsigned ints */
		s[0] = ((double)*(const GLuint*)t +
			(double)*(const GLuint*)(t+group_size) +
			(double)*(const GLuint*)(t+ysize) +
			(double)*(const GLuint*)(t+ysize+group_size))/4 + 0.5;
		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++) {
		/* need to cast to double to hold large unsigned ints */
		GLdouble buf;
		buf = (GLdouble)__GLU_SWAP_4_BYTES(t) +
		      (GLdouble)__GLU_SWAP_4_BYTES(t+group_size) +
		      (GLdouble)__GLU_SWAP_4_BYTES(t+ysize) +
		      (GLdouble)__GLU_SWAP_4_BYTES(t+ysize+group_size);
		s[0] = (GLuint)(buf/4 + 0.5);

		s++; t += element_size;
	    }
	    t += group_size;
	}
	t += ysize;
    }
}

/* */
static void halve1Dimage_uint(GLint components, GLuint width, GLuint height,
			      const GLuint *dataIn, GLuint *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;
   GLuint *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
	    GLuint uint[BOX2];
	    if (myswap_bytes) {
	       uint[0]= __GLU_SWAP_4_BYTES(src);
	       uint[1]= __GLU_SWAP_4_BYTES(src+group_size);
	    }
	    else {
	       uint[0]= *(const GLuint*)src;
	       uint[1]= *(const GLuint*)(src+group_size);
	    }
	    *dest= ((double)uint[0]+(double)uint[1])/2.0;

	    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
	    GLuint uint[BOX2];
	    if (myswap_bytes) {
	       uint[0]= __GLU_SWAP_4_BYTES(src);
	       uint[1]= __GLU_SWAP_4_BYTES(src+ysize);
	    }
	    else {
	       uint[0]= *(const GLuint*)src;
	       uint[1]= *(const GLuint*)(src+ysize);
	    }
	    *dest= ((double)uint[0]+(double)uint[1])/2.0;

	    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_uint() */

static void halveImage_int(GLint components, GLuint width, GLuint height,
			const GLint *datain, GLint *dataout, GLint element_size,
			GLint ysize, GLint group_size, GLint myswap_bytes)
{
    int i, j, k;
    int newwidth, newheight;
    GLint *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_int(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] = ((float)*(const GLint*)t +
			(float)*(const GLint*)(t+group_size) +
			(float)*(const GLint*)(t+ysize) +
			(float)*(const GLint*)(t+ysize+group_size))/4 + 0.5;
		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++) {
		GLuint b;
		GLfloat buf;
		b = __GLU_SWAP_4_BYTES(t);
		buf = *(GLint*)&b;
		b = __GLU_SWAP_4_BYTES(t+group_size);
		buf += *(GLint*)&b;
		b = __GLU_SWAP_4_BYTES(t+ysize);
		buf += *(GLint*)&b;
		b = __GLU_SWAP_4_BYTES(t+ysize+group_size);
		buf += *(GLint*)&b;
		s[0] = (GLint)(buf/4 + 0.5);

		s++; t += element_size;
	    }
	    t += group_size;
	}
	t += ysize;
    }
}

/* */
static void halve1Dimage_int(GLint components, GLuint width, GLuint height,
			     const GLint *dataIn, GLint *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;
   GLint *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
	    GLuint uint[BOX2];
	    if (myswap_bytes) {
	       uint[0]= __GLU_SWAP_4_BYTES(src);
	       uint[1]= __GLU_SWAP_4_BYTES(src+group_size);
	    }
	    else {
	       uint[0]= *(const GLuint*)src;
	       uint[1]= *(const GLuint*)(src+group_size);
	    }
	    *dest= ((float)uint[0]+(float)uint[1])/2.0;

	    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
	    GLuint uint[BOX2];
	    if (myswap_bytes) {
	       uint[0]= __GLU_SWAP_4_BYTES(src);
	       uint[1]= __GLU_SWAP_4_BYTES(src+ysize);
	    }
	    else {
	       uint[0]= *(const GLuint*)src;
	       uint[1]= *(const GLuint*)(src+ysize);
	    }
	    *dest= ((float)uint[0]+(float)uint[1])/2.0;

	    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_int() */


static void halveImage_float(GLint components, GLuint width, GLuint height,
			const GLfloat *datain, GLfloat *dataout,
			GLint element_size, GLint ysize, GLint group_size,
			GLint myswap_bytes)
{
    int i, j, k;
    int newwidth, newheight;
    GLfloat *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_float(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 GLfloat*)t +
			*(const GLfloat*)(t+group_size) +
			*(const GLfloat*)(t+ysize) +
			*(const GLfloat*)(t+ysize+group_size)) / 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++) {
		GLuint b;
		b = __GLU_SWAP_4_BYTES(t);
		s[0] = *(GLfloat*)&b;
		b = __GLU_SWAP_4_BYTES(t+group_size);
		s[0] += *(GLfloat*)&b;
		b = __GLU_SWAP_4_BYTES(t+ysize);
		s[0] += *(GLfloat*)&b;
		b = __GLU_SWAP_4_BYTES(t+ysize+group_size);
		s[0] += *(GLfloat*)&b;
		s[0] /= 4;
		s++; t += element_size;
	    }
	    t += group_size;
	}
	t += ysize;
    }
}

/* */
static void halve1Dimage_float(GLint components, GLuint width, GLuint height,
			       const GLfloat *dataIn, GLfloat *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;
   GLfloat *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
	    GLfloat sfloat[BOX2];
	    if (myswap_bytes) {
	       sfloat[0]= __GLU_SWAP_4_BYTES(src);
	       sfloat[1]= __GLU_SWAP_4_BYTES(src+group_size);
	    }
	    else {
	       sfloat[0]= *(const GLfloat*)src;
	       sfloat[1]= *(const GLfloat*)(src+group_size);
	    }

	    *dest= (sfloat[0] + sfloat[1]) / 2.0;
	    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
	    GLfloat sfloat[BOX2];
	    if (myswap_bytes) {
	       sfloat[0]= __GLU_SWAP_4_BYTES(src);
	       sfloat[1]= __GLU_SWAP_4_BYTES(src+ysize);
	    }
	    else {
	       sfloat[0]= *(const GLfloat*)src;
	       sfloat[1]= *(const GLfloat*)(src+ysize);
	    }
	    *dest= (sfloat[0] + sfloat[1]) / 2.0;

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

   assert(src == &((const char *)dataIn)[ysize*height]);
   assert((char *)dest == &((char *)dataOut)
	  [components * element_size * halfWidth * halfHeight]);
} /* halve1Dimage_float() */

static void scale_internal(GLint components, GLint widthin, GLint heightin,
			   const GLushort *datain,
			   GLint widthout, GLint heightout,
			   GLushort *dataout)
{
    float x, lowx, highx, convx, halfconvx;
    float y, lowy, highy, convy, halfconvy;
    float xpercent,ypercent;