image.c

来自「mesa-6.5-minigui源码」· C语言 代码 · 共 1,907 行 · 第 1/5 页

/*
 * Mesa 3-D graphics library
 * Version:  6.5
 *
 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */


/**
 * \file image.c
 * Image handling.
 */


#include "glheader.h"
#include "colormac.h"
#include "context.h"
#include "image.h"
#include "imports.h"
#include "histogram.h"
#include "macros.h"
#include "pixel.h"


/** Compute ceiling of integer quotient of A divided by B. */
#define CEILING( A, B )  ( (A) % (B) == 0 ? (A)/(B) : (A)/(B)+1 )


/**
 * Flip the 8 bits in each byte of the given array.
 *
 * \param p array.
 * \param n number of bytes.
 *
 * \todo try this trick to flip bytes someday:
 * \code
 *  v = ((v & 0x55555555) << 1) | ((v >> 1) & 0x55555555);
 *  v = ((v & 0x33333333) << 2) | ((v >> 2) & 0x33333333);
 *  v = ((v & 0x0f0f0f0f) << 4) | ((v >> 4) & 0x0f0f0f0f);
 * \endcode
 */
static void
flip_bytes( GLubyte *p, GLuint n )
{
   register GLuint i, a, b;

   for (i=0;i<n;i++) {
      b = (GLuint) p[i];        /* words are often faster than bytes */
      a = ((b & 0x01) << 7) |
	  ((b & 0x02) << 5) |
	  ((b & 0x04) << 3) |
	  ((b & 0x08) << 1) |
	  ((b & 0x10) >> 1) |
	  ((b & 0x20) >> 3) |
	  ((b & 0x40) >> 5) |
	  ((b & 0x80) >> 7);
      p[i] = (GLubyte) a;
   }
}


/**
 * Flip the order of the 2 bytes in each word in the given array.
 *
 * \param p array.
 * \param n number of words.
 */
void
_mesa_swap2( GLushort *p, GLuint n )
{
   register GLuint i;

   for (i=0;i<n;i++) {
      p[i] = (p[i] >> 8) | ((p[i] << 8) & 0xff00);
   }
}



/*
 * Flip the order of the 4 bytes in each word in the given array.
 */
void
_mesa_swap4( GLuint *p, GLuint n )
{
   register GLuint i, a, b;

   for (i=0;i<n;i++) {
      b = p[i];
      a =  (b >> 24)
	| ((b >> 8) & 0xff00)
	| ((b << 8) & 0xff0000)
	| ((b << 24) & 0xff000000);
      p[i] = a;
   }
}


/**
 * Get the size of a GL data type.
 *
 * \param type GL data type.
 *
 * \return the size, in bytes, of the given data type, 0 if a GL_BITMAP, or -1
 * if an invalid type enum.
 */
GLint _mesa_sizeof_type( GLenum type )
{
   switch (type) {
      case GL_BITMAP:
	 return 0;
      case GL_UNSIGNED_BYTE:
         return sizeof(GLubyte);
      case GL_BYTE:
	 return sizeof(GLbyte);
      case GL_UNSIGNED_SHORT:
	 return sizeof(GLushort);
      case GL_SHORT:
	 return sizeof(GLshort);
      case GL_UNSIGNED_INT:
	 return sizeof(GLuint);
      case GL_INT:
	 return sizeof(GLint);
      case GL_FLOAT:
	 return sizeof(GLfloat);
      case GL_HALF_FLOAT_ARB:
	 return sizeof(GLhalfARB);
      default:
         return -1;
   }
}


/**
 * Same as _mesa_sizeof_type() but also accepting the packed pixel
 * format data types.
 */
GLint _mesa_sizeof_packed_type( GLenum type )
{
   switch (type) {
      case GL_BITMAP:
	 return 0;
      case GL_UNSIGNED_BYTE:
         return sizeof(GLubyte);
      case GL_BYTE:
	 return sizeof(GLbyte);
      case GL_UNSIGNED_SHORT:
	 return sizeof(GLushort);
      case GL_SHORT:
	 return sizeof(GLshort);
      case GL_UNSIGNED_INT:
	 return sizeof(GLuint);
      case GL_INT:
	 return sizeof(GLint);
      case GL_HALF_FLOAT_ARB:
	 return sizeof(GLhalfARB);
      case GL_FLOAT:
	 return sizeof(GLfloat);
      case GL_UNSIGNED_BYTE_3_3_2:
         return sizeof(GLubyte);
      case GL_UNSIGNED_BYTE_2_3_3_REV:
         return sizeof(GLubyte);
      case GL_UNSIGNED_SHORT_5_6_5:
         return sizeof(GLushort);
      case GL_UNSIGNED_SHORT_5_6_5_REV:
         return sizeof(GLushort);
      case GL_UNSIGNED_SHORT_4_4_4_4:
         return sizeof(GLushort);
      case GL_UNSIGNED_SHORT_4_4_4_4_REV:
         return sizeof(GLushort);
      case GL_UNSIGNED_SHORT_5_5_5_1:
         return sizeof(GLushort);
      case GL_UNSIGNED_SHORT_1_5_5_5_REV:
         return sizeof(GLushort);
      case GL_UNSIGNED_INT_8_8_8_8:
         return sizeof(GLuint);
      case GL_UNSIGNED_INT_8_8_8_8_REV:
         return sizeof(GLuint);
      case GL_UNSIGNED_INT_10_10_10_2:
         return sizeof(GLuint);
      case GL_UNSIGNED_INT_2_10_10_10_REV:
         return sizeof(GLuint);
      case GL_UNSIGNED_SHORT_8_8_MESA:
      case GL_UNSIGNED_SHORT_8_8_REV_MESA:
         return sizeof(GLushort);      
      case GL_UNSIGNED_INT_24_8_EXT:
         return sizeof(GLuint);
      default:
         return -1;
   }
}


/**
 * Get the number of components in a pixel format.
 *
 * \param format pixel format.
 *
 * \return the number of components in the given format, or -1 if a bad format.
 */
GLint _mesa_components_in_format( GLenum format )
{
   switch (format) {
      case GL_COLOR_INDEX:
      case GL_COLOR_INDEX1_EXT:
      case GL_COLOR_INDEX2_EXT:
      case GL_COLOR_INDEX4_EXT:
      case GL_COLOR_INDEX8_EXT:
      case GL_COLOR_INDEX12_EXT:
      case GL_COLOR_INDEX16_EXT:
      case GL_STENCIL_INDEX:
      case GL_DEPTH_COMPONENT:
      case GL_RED:
      case GL_GREEN:
      case GL_BLUE:
      case GL_ALPHA:
      case GL_LUMINANCE:
      case GL_INTENSITY:
         return 1;
      case GL_LUMINANCE_ALPHA:
	 return 2;
      case GL_RGB:
	 return 3;
      case GL_RGBA:
	 return 4;
      case GL_BGR:
	 return 3;
      case GL_BGRA:
	 return 4;
      case GL_ABGR_EXT:
         return 4;
      case GL_YCBCR_MESA:
         return 2;
      case GL_DEPTH_STENCIL_EXT:
         return 2;
      default:
         return -1;
   }
}


/**
 * Get the bytes per pixel of pixel format type pair.
 *
 * \param format pixel format.
 * \param type pixel type.
 *
 * \return bytes per pixel, or -1 if a bad format or type was given.
 */
GLint _mesa_bytes_per_pixel( GLenum format, GLenum type )
{
   GLint comps = _mesa_components_in_format( format );
   if (comps < 0)
      return -1;

   switch (type) {
      case GL_BITMAP:
         return 0;  /* special case */
      case GL_BYTE:
      case GL_UNSIGNED_BYTE:
         return comps * sizeof(GLubyte);
      case GL_SHORT:
      case GL_UNSIGNED_SHORT:
         return comps * sizeof(GLshort);
      case GL_INT:
      case GL_UNSIGNED_INT:
         return comps * sizeof(GLint);
      case GL_FLOAT:
         return comps * sizeof(GLfloat);
      case GL_HALF_FLOAT_ARB:
         return comps * sizeof(GLhalfARB);
      case GL_UNSIGNED_BYTE_3_3_2:
      case GL_UNSIGNED_BYTE_2_3_3_REV:
         if (format == GL_RGB || format == GL_BGR)
            return sizeof(GLubyte);
         else
            return -1;  /* error */
      case GL_UNSIGNED_SHORT_5_6_5:
      case GL_UNSIGNED_SHORT_5_6_5_REV:
         if (format == GL_RGB || format == GL_BGR)
            return sizeof(GLushort);
         else
            return -1;  /* error */
      case GL_UNSIGNED_SHORT_4_4_4_4:
      case GL_UNSIGNED_SHORT_4_4_4_4_REV:
      case GL_UNSIGNED_SHORT_5_5_5_1:
      case GL_UNSIGNED_SHORT_1_5_5_5_REV:
         if (format == GL_RGBA || format == GL_BGRA || format == GL_ABGR_EXT)
            return sizeof(GLushort);
         else
            return -1;
      case GL_UNSIGNED_INT_8_8_8_8:
      case GL_UNSIGNED_INT_8_8_8_8_REV:
      case GL_UNSIGNED_INT_10_10_10_2:
      case GL_UNSIGNED_INT_2_10_10_10_REV:
         if (format == GL_RGBA || format == GL_BGRA || format == GL_ABGR_EXT)
            return sizeof(GLuint);
         else
            return -1;
      case GL_UNSIGNED_SHORT_8_8_MESA:
      case GL_UNSIGNED_SHORT_8_8_REV_MESA:
         if (format == GL_YCBCR_MESA)
            return sizeof(GLushort);
         else
            return -1;
      case GL_UNSIGNED_INT_24_8_EXT:
         if (format == GL_DEPTH_STENCIL_EXT)
            return sizeof(GLuint);
         else
            return -1;
      default:
         return -1;
   }
}


/**
 * Test for a legal pixel format and type.
 *
 * \param format pixel format.
 * \param type pixel type.
 *
 * \return GL_TRUE if the given pixel format and type are legal, or GL_FALSE
 * otherwise.
 */
GLboolean
_mesa_is_legal_format_and_type( GLcontext *ctx, GLenum format, GLenum type )
{
   switch (format) {
      case GL_COLOR_INDEX:
      case GL_STENCIL_INDEX:
         switch (type) {
            case GL_BITMAP:
            case GL_BYTE:
            case GL_UNSIGNED_BYTE:
            case GL_SHORT:
            case GL_UNSIGNED_SHORT:
            case GL_INT:
            case GL_UNSIGNED_INT:
            case GL_FLOAT:
               return GL_TRUE;
            case GL_HALF_FLOAT_ARB:
               return ctx->Extensions.ARB_half_float_pixel;
            default:
               return GL_FALSE;
         }
      case GL_RED:
      case GL_GREEN:
      case GL_BLUE:
      case GL_ALPHA:
#if 0 /* not legal!  see table 3.6 of the 1.5 spec */
      case GL_INTENSITY:
#endif
      case GL_LUMINANCE:
      case GL_LUMINANCE_ALPHA:
      case GL_DEPTH_COMPONENT:
         switch (type) {
            case GL_BYTE:
            case GL_UNSIGNED_BYTE:
            case GL_SHORT:
            case GL_UNSIGNED_SHORT:
            case GL_INT:
            case GL_UNSIGNED_INT:
            case GL_FLOAT:
               return GL_TRUE;