image.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

         dest[i] = (p[0] << 24)
                 | (p[1] << 16)
                 | (p[2] <<  8)
                 | (p[3]      );
         p += 4;
      }
      _mesa_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
    * endian differences.
    */
   GLubyte ptrn[32*4];
   GLint i;
   for (i = 0; i < 32; i++) {
      ptrn[i * 4 + 0] = (GLubyte) ((pattern[i] >> 24) & 0xff);
      ptrn[i * 4 + 1] = (GLubyte) ((pattern[i] >> 16) & 0xff);
      ptrn[i * 4 + 2] = (GLubyte) ((pattern[i] >> 8 ) & 0xff);
      ptrn[i * 4 + 3] = (GLubyte) ((pattern[i]      ) & 0xff);
   }

   _mesa_pack_bitmap(32, 32, ptrn, dest, packing);
}


/*
 * Unpack bitmap data.  Resulting data will be in most-significant-bit-first
 * order with row alignment = 1 byte.
 */
GLvoid *
_mesa_unpack_bitmap( GLint width, GLint height, const GLubyte *pixels,
                     const struct gl_pixelstore_attrib *packing )
{
   GLint bytes, row, width_in_bytes;
   GLubyte *buffer, *dst;

   if (!pixels)
      return NULL;

   /* Alloc dest storage */
   bytes = ((width + 7) / 8 * height);
   buffer = (GLubyte *) _mesa_malloc( bytes );
   if (!buffer)
      return NULL;

   width_in_bytes = CEILING( width, 8 );
   dst = buffer;
   for (row = 0; row < height; row++) {
      const GLubyte *src = (const GLubyte *)
         _mesa_image_address2d(packing, pixels, width, height,
                               GL_COLOR_INDEX, GL_BITMAP, row, 0);
      if (!src) {
         _mesa_free(buffer);
         return NULL;
      }

      if ((packing->SkipPixels & 7) == 0) {
         _mesa_memcpy( dst, src, width_in_bytes );
         if (packing->LsbFirst) {
            flip_bytes( dst, width_in_bytes );
         }
      }
      else {
         /* handling SkipPixels is a bit tricky (no pun intended!) */
         GLint i;
         if (packing->LsbFirst) {
            GLubyte srcMask = 1 << (packing->SkipPixels & 0x7);
            GLubyte dstMask = 128;
            const GLubyte *s = src;
            GLubyte *d = dst;
            *d = 0;
            for (i = 0; i < width; i++) {
               if (*s & srcMask) {
                  *d |= dstMask;
               }
               if (srcMask == 128) {
                  srcMask = 1;
                  s++;
               }
               else {
                  srcMask = srcMask << 1;
               }
               if (dstMask == 1) {
                  dstMask = 128;
                  d++;
                  *d = 0;
               }
               else {
                  dstMask = dstMask >> 1;
               }
            }
         }
         else {
            GLubyte srcMask = 128 >> (packing->SkipPixels & 0x7);
            GLubyte dstMask = 128;
            const GLubyte *s = src;
            GLubyte *d = dst;
            *d = 0;
            for (i = 0; i < width; i++) {
               if (*s & srcMask) {
                  *d |= dstMask;
               }
               if (srcMask == 1) {
                  srcMask = 128;
                  s++;
               }
               else {
                  srcMask = srcMask >> 1;
               }
               if (dstMask == 1) {
                  dstMask = 128;
                  d++;
                  *d = 0;
               }
               else {
                  dstMask = dstMask >> 1;
               }
            }
         }
      }
      dst += width_in_bytes;
   }

   return buffer;
}


/*
 * Pack bitmap data.
 */
void
_mesa_pack_bitmap( GLint width, GLint height, const GLubyte *source,
                   GLubyte *dest, const struct gl_pixelstore_attrib *packing )
{
   GLint row, width_in_bytes;
   const GLubyte *src;

   if (!source)
      return;

   width_in_bytes = CEILING( width, 8 );
   src = source;
   for (row = 0; row < height; row++) {
      GLubyte *dst = (GLubyte *) _mesa_image_address2d(packing, dest,
                       width, height, GL_COLOR_INDEX, GL_BITMAP, row, 0);
      if (!dst)
         return;

      if ((packing->SkipPixels & 7) == 0) {
         _mesa_memcpy( dst, src, width_in_bytes );
         if (packing->LsbFirst) {
            flip_bytes( dst, width_in_bytes );
         }
      }
      else {
         /* handling SkipPixels is a bit tricky (no pun intended!) */
         GLint i;
         if (packing->LsbFirst) {
            GLubyte srcMask = 128;
            GLubyte dstMask = 1 << (packing->SkipPixels & 0x7);
            const GLubyte *s = src;
            GLubyte *d = dst;
            *d = 0;
            for (i = 0; i < width; i++) {
               if (*s & srcMask) {
                  *d |= dstMask;
               }
               if (srcMask == 1) {
                  srcMask = 128;
                  s++;
               }
               else {
                  srcMask = srcMask >> 1;
               }
               if (dstMask == 128) {
                  dstMask = 1;
                  d++;
                  *d = 0;
               }
               else {
                  dstMask = dstMask << 1;
               }
            }
         }
         else {
            GLubyte srcMask = 128;
            GLubyte dstMask = 128 >> (packing->SkipPixels & 0x7);
            const GLubyte *s = src;
            GLubyte *d = dst;
            *d = 0;
            for (i = 0; i < width; i++) {
               if (*s & srcMask) {
                  *d |= dstMask;
               }
               if (srcMask == 1) {
                  srcMask = 128;
                  s++;
               }
               else {
                  srcMask = srcMask >> 1;
               }
               if (dstMask == 1) {
                  dstMask = 128;
                  d++;
                  *d = 0;
               }
               else {
                  dstMask = dstMask >> 1;
               }
            }
         }
      }
      src += width_in_bytes;
   }
}


/**
 * Apply various pixel transfer operations to an array of RGBA pixels
 * as indicated by the transferOps bitmask
 */
void
_mesa_apply_rgba_transfer_ops(GLcontext *ctx, GLbitfield transferOps,
                              GLuint n, GLfloat rgba[][4])
{
   /* scale & bias */
   if (transferOps & IMAGE_SCALE_BIAS_BIT) {
      _mesa_scale_and_bias_rgba(n, rgba,
                                ctx->Pixel.RedScale, ctx->Pixel.GreenScale,
                                ctx->Pixel.BlueScale, ctx->Pixel.AlphaScale,
                                ctx->Pixel.RedBias, ctx->Pixel.GreenBias,
                                ctx->Pixel.BlueBias, ctx->Pixel.AlphaBias);
   }
   /* color map lookup */
   if (transferOps & IMAGE_MAP_COLOR_BIT) {
      _mesa_map_rgba( ctx, n, rgba );
   }
   /* GL_COLOR_TABLE lookup */
   if (transferOps & IMAGE_COLOR_TABLE_BIT) {
      _mesa_lookup_rgba_float(&ctx->ColorTable[COLORTABLE_PRECONVOLUTION], n, rgba);
   }
   /* convolution */
   if (transferOps & IMAGE_CONVOLUTION_BIT) {
      /* this has to be done in the calling code */
      _mesa_problem(ctx, "IMAGE_CONVOLUTION_BIT set in _mesa_apply_transfer_ops");
   }
   /* GL_POST_CONVOLUTION_RED/GREEN/BLUE/ALPHA_SCALE/BIAS */
   if (transferOps & IMAGE_POST_CONVOLUTION_SCALE_BIAS) {
      _mesa_scale_and_bias_rgba(n, rgba,
                                ctx->Pixel.PostConvolutionScale[RCOMP],
                                ctx->Pixel.PostConvolutionScale[GCOMP],
                                ctx->Pixel.PostConvolutionScale[BCOMP],
                                ctx->Pixel.PostConvolutionScale[ACOMP],
                                ctx->Pixel.PostConvolutionBias[RCOMP],
                                ctx->Pixel.PostConvolutionBias[GCOMP],
                                ctx->Pixel.PostConvolutionBias[BCOMP],
                                ctx->Pixel.PostConvolutionBias[ACOMP]);
   }
   /* GL_POST_CONVOLUTION_COLOR_TABLE lookup */
   if (transferOps & IMAGE_POST_CONVOLUTION_COLOR_TABLE_BIT) {
      _mesa_lookup_rgba_float(&ctx->ColorTable[COLORTABLE_POSTCONVOLUTION], n, rgba);
   }
   /* color matrix transform */
   if (transferOps & IMAGE_COLOR_MATRIX_BIT) {
      _mesa_transform_rgba(ctx, n, rgba);
   }
   /* GL_POST_COLOR_MATRIX_COLOR_TABLE lookup */
   if (transferOps & IMAGE_POST_COLOR_MATRIX_COLOR_TABLE_BIT) {
      _mesa_lookup_rgba_float(&ctx->ColorTable[COLORTABLE_POSTCOLORMATRIX], n, rgba);
   }
   /* update histogram count */
   if (transferOps & IMAGE_HISTOGRAM_BIT) {
      _mesa_update_histogram(ctx, n, (CONST GLfloat (*)[4]) rgba);
   }
   /* update min/max values */
   if (transferOps & IMAGE_MIN_MAX_BIT) {
      _mesa_update_minmax(ctx, n, (CONST GLfloat (*)[4]) rgba);
   }
   /* clamping to [0,1] */
   if (transferOps & IMAGE_CLAMP_BIT) {
      GLuint i;
      for (i = 0; i < n; i++) {
         rgba[i][RCOMP] = CLAMP(rgba[i][RCOMP], 0.0F, 1.0F);
         rgba[i][GCOMP] = CLAMP(rgba[i][GCOMP], 0.0F, 1.0F);
         rgba[i][BCOMP] = CLAMP(rgba[i][BCOMP], 0.0F, 1.0F);
         rgba[i][ACOMP] = CLAMP(rgba[i][ACOMP], 0.0F, 1.0F);
      }
   }
}


/*
 * Apply color index shift and offset to an array of pixels.
 */
static void
shift_and_offset_ci( const GLcontext *ctx, GLuint n, GLuint indexes[] )
{
   GLint shift = ctx->Pixel.IndexShift;
   GLint offset = ctx->Pixel.IndexOffset;
   GLuint i;
   if (shift > 0) {
      for (i=0;i<n;i++) {
         indexes[i] = (indexes[i] << shift) + offset;
      }
   }
   else if (shift < 0) {
      shift = -shift;
      for (i=0;i<n;i++) {
         indexes[i] = (indexes[i] >> shift) + offset;
      }
   }
   else {
      for (i=0;i<n;i++) {
         indexes[i] = indexes[i] + offset;
      }
   }
}



/**
 * Apply color index shift, offset and table lookup to an array
 * of color indexes;
 */
void
_mesa_apply_ci_transfer_ops(const GLcontext *ctx, GLbitfield transferOps,
                            GLuint n, GLuint indexes[])
{
   if (transferOps & IMAGE_SHIFT_OFFSET_BIT) {
      shift_and_offset_ci(ctx, n, indexes);
   }
   if (transferOps & IMAGE_MAP_COLOR_BIT) {
      const GLuint mask = ctx->PixelMaps.ItoI.Size - 1;
      GLuint i;
      for (i = 0; i < n; i++) {
         const GLuint j = indexes[i] & mask;
         indexes[i] = IROUND(ctx->PixelMaps.ItoI.Map[j]);
      }
   }
}


/**
 * Apply stencil index shift, offset and table lookup to an array
 * of stencil values.
 */
void
_mesa_apply_stencil_transfer_ops(const GLcontext *ctx, GLuint n,
                                 GLstencil stencil[])
{
   if (ctx->Pixel.IndexShift != 0 || ctx->Pixel.IndexOffset != 0) {
      const GLint offset = ctx->Pixel.IndexOffset;
      GLint shift = ctx->Pixel.IndexShift;
      GLuint i;
      if (shift > 0) {
         for (i = 0; i < n; i++) {
            stencil[i] = (stencil[i] << shift) + offset;
         }
      }
      else if (shift < 0) {
         shift = -shift;
         for (i = 0; i < n; i++) {
            stencil[i] = (stencil[i] >> shift) + offset;
         }
      }
      else {
         for (i = 0; i < n; i++) {
            stencil[i] = stencil[i] + offset;
         }
      }
   }
   if (ctx->Pixel.MapStencilFlag) {
      GLuint mask = ctx->PixelMaps.StoS.Size - 1;
      GLuint i;
      for (i = 0; i < n; i++) {
         stencil[i] = ctx->PixelMaps.StoS.Map[ stencil[i] & mask ];
      }
   }
}


/**
 * Used to pack an array [][4] of RGBA float colors as specified