image.c

winNT技术操作系统,国外开放的原代码和LIUX一样

               return GL_TRUE;
            case GL_HALF_FLOAT_ARB:
               return ctx->Extensions.ARB_half_float_pixel;
            default:
               return GL_FALSE;
         }
      case GL_RGB:
         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:
            case GL_UNSIGNED_BYTE_3_3_2:
            case GL_UNSIGNED_BYTE_2_3_3_REV:
            case GL_UNSIGNED_SHORT_5_6_5:
            case GL_UNSIGNED_SHORT_5_6_5_REV:
               return GL_TRUE;
            case GL_HALF_FLOAT_ARB:
               return ctx->Extensions.ARB_half_float_pixel;
            default:
               return GL_FALSE;
         }
      case GL_BGR:
         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;
            case GL_HALF_FLOAT_ARB:
               return ctx->Extensions.ARB_half_float_pixel;
            default:
               return GL_FALSE;
         }
      case GL_RGBA:
      case GL_BGRA:
      case GL_ABGR_EXT:
         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:
            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:
            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:
               return GL_TRUE;
            case GL_HALF_FLOAT_ARB:
               return ctx->Extensions.ARB_half_float_pixel;
            default:
               return GL_FALSE;
         }
      case GL_YCBCR_MESA:
         if (type == GL_UNSIGNED_SHORT_8_8_MESA ||
             type == GL_UNSIGNED_SHORT_8_8_REV_MESA)
            return GL_TRUE;
         else
            return GL_FALSE;
      default:
         ; /* fall-through */
   }
   return GL_FALSE;
}


/**
 * Return the address of a specific pixel in an image (1D, 2D or 3D).
 *
 * Pixel unpacking/packing parameters are observed according to \p packing.
 *
 * \param dimensions either 1, 2 or 3 to indicate dimensionality of image
 * \param image  starting address of image data
 * \param width  the image width
 * \param height  theimage height
 * \param format  the pixel format
 * \param type  the pixel data type
 * \param packing  the pixelstore attributes
 * \param img  which image in the volume (0 for 1D or 2D images)
 * \param row  row of pixel in the image (0 for 1D images)
 * \param column column of pixel in the image
 * 
 * \return address of pixel on success, or NULL on error.
 *
 * \sa gl_pixelstore_attrib.
 */
GLvoid *
_mesa_image_address( GLuint dimensions,
                     const struct gl_pixelstore_attrib *packing,
                     const GLvoid *image,
                     GLsizei width, GLsizei height,
                     GLenum format, GLenum type,
                     GLint img, GLint row, GLint column )
{
   GLint alignment;        /* 1, 2 or 4 */
   GLint pixels_per_row;
   GLint rows_per_image;
   GLint skiprows;
   GLint skippixels;
   GLint skipimages;       /* for 3-D volume images */
   GLubyte *pixel_addr;

   ASSERT(dimensions >= 1 && dimensions <= 3);

   alignment = packing->Alignment;
   if (packing->RowLength > 0) {
      pixels_per_row = packing->RowLength;
   }
   else {
      pixels_per_row = width;
   }
   if (packing->ImageHeight > 0) {
      rows_per_image = packing->ImageHeight;
   }
   else {
      rows_per_image = height;
   }

   skippixels = packing->SkipPixels;
   /* Note: SKIP_ROWS _is_ used for 1D images */
   skiprows = packing->SkipRows;
   /* Note: SKIP_IMAGES is only used for 3D images */
   skipimages = (dimensions == 3) ? packing->SkipImages : 0;

   if (type == GL_BITMAP) {
      /* BITMAP data */
      GLint comp_per_pixel;   /* components per pixel */
      GLint bytes_per_comp;   /* bytes per component */
      GLint bytes_per_row;
      GLint bytes_per_image;

      /* Compute bytes per component */
      bytes_per_comp = _mesa_sizeof_packed_type( type );
      if (bytes_per_comp < 0) {
         return NULL;
      }

      /* Compute number of components per pixel */
      comp_per_pixel = _mesa_components_in_format( format );
      if (comp_per_pixel < 0) {
         return NULL;
      }

      bytes_per_row = alignment
                    * CEILING( comp_per_pixel*pixels_per_row, 8*alignment );

      bytes_per_image = bytes_per_row * rows_per_image;

      pixel_addr = (GLubyte *) image
                 + (skipimages + img) * bytes_per_image
                 + (skiprows + row) * bytes_per_row
                 + (skippixels + column) / 8;
   }
   else {
      /* Non-BITMAP data */
      GLint bytes_per_pixel, bytes_per_row, remainder, bytes_per_image;
      GLint topOfImage;

      bytes_per_pixel = _mesa_bytes_per_pixel( format, type );

      /* The pixel type and format should have been error checked earlier */
      assert(bytes_per_pixel > 0);

      bytes_per_row = pixels_per_row * bytes_per_pixel;
      remainder = bytes_per_row % alignment;
      if (remainder > 0)
         bytes_per_row += (alignment - remainder);

      ASSERT(bytes_per_row % alignment == 0);

      bytes_per_image = bytes_per_row * rows_per_image;

      if (packing->Invert) {
         /* set pixel_addr to the last row */
         topOfImage = bytes_per_row * (height - 1);
         bytes_per_row = -bytes_per_row;
      }
      else {
         topOfImage = 0;
      }

      /* compute final pixel address */
      pixel_addr = (GLubyte *) image
                 + (skipimages + img) * bytes_per_image
                 + topOfImage
                 + (skiprows + row) * bytes_per_row
                 + (skippixels + column) * bytes_per_pixel;
   }

   return (GLvoid *) pixel_addr;
}


GLvoid *
_mesa_image_address1d( const struct gl_pixelstore_attrib *packing,
                       const GLvoid *image,
                       GLsizei width,
                       GLenum format, GLenum type,
                       GLint column )
{
   return _mesa_image_address(1, packing, image, width, 1,
                              format, type, 0, 0, column);
}


GLvoid *
_mesa_image_address2d( const struct gl_pixelstore_attrib *packing,
                       const GLvoid *image,
                       GLsizei width, GLsizei height,
                       GLenum format, GLenum type,
                       GLint row, GLint column )
{
   return _mesa_image_address(2, packing, image, width, height,
                              format, type, 0, row, column);
}


GLvoid *
_mesa_image_address3d( const struct gl_pixelstore_attrib *packing,
                       const GLvoid *image,
                       GLsizei width, GLsizei height,
                       GLenum format, GLenum type,
                       GLint img, GLint row, GLint column )
{
   return _mesa_image_address(3, packing, image, width, height,
                              format, type, img, row, column);
}



/**
 * Compute the stride between image rows.
 *
 * \param packing the pixelstore attributes
 * \param width image width.
 * \param format pixel format.
 * \param type pixel data type.
 * 
 * \return the stride in bytes for the given parameters.
 *
 * Computes the number of bytes per pixel and row and compensates for alignment.
 *
 * \sa gl_pixelstore_attrib.
 */
GLint
_mesa_image_row_stride( const struct gl_pixelstore_attrib *packing,
                        GLint width, GLenum format, GLenum type )
{
   ASSERT(packing);
   if (type == GL_BITMAP) {
      /* BITMAP data */
      GLint bytes;
      if (packing->RowLength == 0) {
         bytes = (width + 7) / 8;
      }
      else {
         bytes = (packing->RowLength + 7) / 8;
      }
      if (packing->Invert) {
         /* negate the bytes per row (negative row stride) */
         bytes = -bytes;
      }
      return bytes;
   }
   else {
      /* Non-BITMAP data */
      const GLint bytesPerPixel = _mesa_bytes_per_pixel(format, type);
      GLint bytesPerRow, remainder;
      if (bytesPerPixel <= 0)
         return -1;  /* error */
      if (packing->RowLength == 0) {
         bytesPerRow = bytesPerPixel * width;
      }
      else {
         bytesPerRow = bytesPerPixel * packing->RowLength;
      }
      remainder = bytesPerRow % packing->Alignment;
      if (remainder > 0)
         bytesPerRow += (packing->Alignment - remainder);
      if (packing->Invert)
         bytesPerRow = -bytesPerRow;
      return bytesPerRow;
   }
}


#if _HAVE_FULL_GL

/*
 * Compute the stride between images in a 3D texture (in bytes) for the given
 * pixel packing parameters and image width, format and type.
 */
GLint
_mesa_image_image_stride( const struct gl_pixelstore_attrib *packing,
                          GLint width, GLint height,
                          GLenum format, GLenum type )
{
   ASSERT(packing);
   ASSERT(type != GL_BITMAP);

   {
      const GLint bytesPerPixel = _mesa_bytes_per_pixel(format, type);
      GLint bytesPerRow, bytesPerImage, remainder;

      if (bytesPerPixel <= 0)
         return -1;  /* error */
      if (packing->RowLength == 0) {
         bytesPerRow = bytesPerPixel * width;
      }
      else {
         bytesPerRow = bytesPerPixel * packing->RowLength;
      }
      remainder = bytesPerRow % packing->Alignment;
      if (remainder > 0)
         bytesPerRow += (packing->Alignment - remainder);

      if (packing->ImageHeight == 0)
         bytesPerImage = bytesPerRow * height;
      else
         bytesPerImage = bytesPerRow * packing->ImageHeight;

      return bytesPerImage;
   }
}


/*
 * Unpack a 32x32 pixel polygon stipple from user memory using the
 * current pixel unpack settings.
 */
void
_mesa_unpack_polygon_stipple( const GLubyte *pattern, GLuint dest[32],
                              const struct gl_pixelstore_attrib *unpacking )
{
   GLubyte *ptrn = (GLubyte *) _mesa_unpack_bitmap( 32, 32, pattern, unpacking );
   if (ptrn) {
      /* Convert pattern from GLubytes to GLuints and handle big/little
       * endian differences
       */
      GLubyte *p = ptrn;
      GLint i;
      for (i = 0; i < 32; i++) {
         dest[i] = (p[0] << 24)
                 | (p[1] << 16)
                 | (p[2] <<  8)
                 | (p[3]      );
         p += 4;
      }
      FREE(ptrn);
   }
}


/*
 * Pack polygon stipple into user memory given current pixel packing
 * settings.
 */
void
_mesa_pack_polygon_stipple( const GLuint pattern[32], GLubyte *dest,
                            const struct gl_pixelstore_attrib *packing )
{
   /* Convert pattern from GLuints to GLubytes to handle big/little