utils.c

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

   if (*y < buffer->_Ymin) {
      *height -= (buffer->_Ymin - *y);
      *y = buffer->_Ymin;
   }

   /* top clipping */
   if (*y + *height > buffer->_Ymax)
      *height -= (*y + *height - buffer->_Ymax - 1);

   if (*height <= 0)
      return GL_FALSE;

   return GL_TRUE;
}

/**
 * Creates a set of \c __GLcontextModes that a driver will expose.
 * 
 * A set of \c __GLcontextModes will be created based on the supplied
 * parameters.  The number of modes processed will be 2 *
 * \c num_depth_stencil_bits * \c num_db_modes.
 * 
 * For the most part, data is just copied from \c depth_bits, \c stencil_bits,
 * \c db_modes, and \c visType into each \c __GLcontextModes element.
 * However, the meanings of \c fb_format and \c fb_type require further
 * explanation.  The \c fb_format specifies which color components are in
 * each pixel and what the default order is.  For example, \c GL_RGB specifies
 * that red, green, blue are available and red is in the "most significant"
 * position and blue is in the "least significant".  The \c fb_type specifies
 * the bit sizes of each component and the actual ordering.  For example, if
 * \c GL_UNSIGNED_SHORT_5_6_5_REV is specified with \c GL_RGB, bits [15:11]
 * are the blue value, bits [10:5] are the green value, and bits [4:0] are
 * the red value.
 * 
 * One sublte issue is the combination of \c GL_RGB  or \c GL_BGR and either
 * of the \c GL_UNSIGNED_INT_8_8_8_8 modes.  The resulting mask values in the
 * \c __GLcontextModes structure is \b identical to the \c GL_RGBA or
 * \c GL_BGRA case, except the \c alphaMask is zero.  This means that, as
 * far as this routine is concerned, \c GL_RGB with \c GL_UNSIGNED_INT_8_8_8_8
 * still uses 32-bits.
 *
 * If in doubt, look at the tables used in the function.
 * 
 * \param ptr_to_modes  Pointer to a pointer to a linked list of
 *                      \c __GLcontextModes.  Upon completion, a pointer to
 *                      the next element to be process will be stored here.
 *                      If the function fails and returns \c GL_FALSE, this
 *                      value will be unmodified, but some elements in the
 *                      linked list may be modified.
 * \param fb_format     Format of the framebuffer.  Currently only \c GL_RGB,
 *                      \c GL_RGBA, \c GL_BGR, and \c GL_BGRA are supported.
 * \param fb_type       Type of the pixels in the framebuffer.  Currently only
 *                      \c GL_UNSIGNED_SHORT_5_6_5, 
 *                      \c GL_UNSIGNED_SHORT_5_6_5_REV,
 *                      \c GL_UNSIGNED_INT_8_8_8_8, and
 *                      \c GL_UNSIGNED_INT_8_8_8_8_REV are supported.
 * \param depth_bits    Array of depth buffer sizes to be exposed.
 * \param stencil_bits  Array of stencil buffer sizes to be exposed.
 * \param num_depth_stencil_bits  Number of entries in both \c depth_bits and
 *                      \c stencil_bits.
 * \param db_modes      Array of buffer swap modes.  If an element has a
 *                      value of \c GLX_NONE, then it represents a
 *                      single-buffered mode.  Other valid values are
 *                      \c GLX_SWAP_EXCHANGE_OML, \c GLX_SWAP_COPY_OML, and
 *                      \c GLX_SWAP_UNDEFINED_OML.  See the
 *                      GLX_OML_swap_method extension spec for more details.
 * \param num_db_modes  Number of entries in \c db_modes.
 * \param visType       GLX visual type.  Usually either \c GLX_TRUE_COLOR or
 *                      \c GLX_DIRECT_COLOR.
 * 
 * \returns
 * \c GL_TRUE on success or \c GL_FALSE on failure.  Currently the only
 * cause of failure is a bad parameter (i.e., unsupported \c fb_format or
 * \c fb_type).
 * 
 * \todo
 * There is currently no way to support packed RGB modes (i.e., modes with
 * exactly 3 bytes per pixel) or floating-point modes.  This could probably
 * be done by creating some new, private enums with clever names likes
 * \c GL_UNSIGNED_3BYTE_8_8_8, \c GL_4FLOAT_32_32_32_32, 
 * \c GL_4HALF_16_16_16_16, etc.  We can cross that bridge when we come to it.
 */
__DRIconfig **
driCreateConfigs(GLenum fb_format, GLenum fb_type,
		 const u_int8_t * depth_bits, const u_int8_t * stencil_bits,
		 unsigned num_depth_stencil_bits,
		 const GLenum * db_modes, unsigned num_db_modes)
{
   static const u_int8_t bits_table[4][4] = {
     /* R  G  B  A */
      { 3, 3, 2, 0 }, /* Any GL_UNSIGNED_BYTE_3_3_2 */
      { 5, 6, 5, 0 }, /* Any GL_UNSIGNED_SHORT_5_6_5 */
      { 8, 8, 8, 0 }, /* Any RGB with any GL_UNSIGNED_INT_8_8_8_8 */
      { 8, 8, 8, 8 }  /* Any RGBA with any GL_UNSIGNED_INT_8_8_8_8 */
   };

   static const u_int32_t masks_table_rgb[6][4] = {
      { 0x000000E0, 0x0000001C, 0x00000003, 0x00000000 }, /* 3_3_2       */
      { 0x00000007, 0x00000038, 0x000000C0, 0x00000000 }, /* 2_3_3_REV   */
      { 0x0000F800, 0x000007E0, 0x0000001F, 0x00000000 }, /* 5_6_5       */
      { 0x0000001F, 0x000007E0, 0x0000F800, 0x00000000 }, /* 5_6_5_REV   */
      { 0xFF000000, 0x00FF0000, 0x0000FF00, 0x00000000 }, /* 8_8_8_8     */
      { 0x000000FF, 0x0000FF00, 0x00FF0000, 0x00000000 }  /* 8_8_8_8_REV */
   };

   static const u_int32_t masks_table_rgba[6][4] = {
      { 0x000000E0, 0x0000001C, 0x00000003, 0x00000000 }, /* 3_3_2       */
      { 0x00000007, 0x00000038, 0x000000C0, 0x00000000 }, /* 2_3_3_REV   */
      { 0x0000F800, 0x000007E0, 0x0000001F, 0x00000000 }, /* 5_6_5       */
      { 0x0000001F, 0x000007E0, 0x0000F800, 0x00000000 }, /* 5_6_5_REV   */
      { 0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF }, /* 8_8_8_8     */
      { 0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000 }, /* 8_8_8_8_REV */
   };

   static const u_int32_t masks_table_bgr[6][4] = {
      { 0x00000007, 0x00000038, 0x000000C0, 0x00000000 }, /* 3_3_2       */
      { 0x000000E0, 0x0000001C, 0x00000003, 0x00000000 }, /* 2_3_3_REV   */
      { 0x0000001F, 0x000007E0, 0x0000F800, 0x00000000 }, /* 5_6_5       */
      { 0x0000F800, 0x000007E0, 0x0000001F, 0x00000000 }, /* 5_6_5_REV   */
      { 0x0000FF00, 0x00FF0000, 0xFF000000, 0x00000000 }, /* 8_8_8_8     */
      { 0x00FF0000, 0x0000FF00, 0x000000FF, 0x00000000 }, /* 8_8_8_8_REV */
   };

   static const u_int32_t masks_table_bgra[6][4] = {
      { 0x00000007, 0x00000038, 0x000000C0, 0x00000000 }, /* 3_3_2       */
      { 0x000000E0, 0x0000001C, 0x00000003, 0x00000000 }, /* 2_3_3_REV   */
      { 0x0000001F, 0x000007E0, 0x0000F800, 0x00000000 }, /* 5_6_5       */
      { 0x0000F800, 0x000007E0, 0x0000001F, 0x00000000 }, /* 5_6_5_REV   */
      { 0x0000FF00, 0x00FF0000, 0xFF000000, 0x000000FF }, /* 8_8_8_8     */
      { 0x00FF0000, 0x0000FF00, 0x000000FF, 0xFF000000 }, /* 8_8_8_8_REV */
   };

   static const u_int8_t bytes_per_pixel[6] = {
      1, /* 3_3_2       */
      1, /* 2_3_3_REV   */
      2, /* 5_6_5       */
      2, /* 5_6_5_REV   */
      4, /* 8_8_8_8     */
      4  /* 8_8_8_8_REV */
   };

   const u_int8_t  * bits;
   const u_int32_t * masks;
   int index;
   __DRIconfig **configs, **c;
   __GLcontextModes *modes;
   unsigned i;
   unsigned j;
   unsigned k;
   unsigned num_modes;
   unsigned num_accum_bits = 2;

   switch ( fb_type ) {
      case GL_UNSIGNED_BYTE_3_3_2:
	 index = 0;
	 break;
      case GL_UNSIGNED_BYTE_2_3_3_REV:
	 index = 1;
	 break;
      case GL_UNSIGNED_SHORT_5_6_5:
	 index = 2;
	 break;
      case GL_UNSIGNED_SHORT_5_6_5_REV:
	 index = 3;
	 break;
      case GL_UNSIGNED_INT_8_8_8_8:
	 index = 4;
	 break;
      case GL_UNSIGNED_INT_8_8_8_8_REV:
	 index = 5;
	 break;
      default:
	 fprintf( stderr, "[%s:%u] Unknown framebuffer type 0x%04x.\n",
               __FUNCTION__, __LINE__, fb_type );
	 return NULL;
   }


   /* Valid types are GL_UNSIGNED_SHORT_5_6_5 and GL_UNSIGNED_INT_8_8_8_8 and
    * the _REV versions.
    *
    * Valid formats are GL_RGBA, GL_RGB, and GL_BGRA.
    */

   switch ( fb_format ) {
      case GL_RGB:
         masks = masks_table_rgb[ index ];
         break;

      case GL_RGBA:
         masks = masks_table_rgba[ index ];
         break;

      case GL_BGR:
         masks = masks_table_bgr[ index ];
         break;

      case GL_BGRA:
         masks = masks_table_bgra[ index ];
         break;

      default:
         fprintf( stderr, "[%s:%u] Unknown framebuffer format 0x%04x.\n",
               __FUNCTION__, __LINE__, fb_format );
         return NULL;
   }

   switch ( bytes_per_pixel[ index ] ) {
      case 1:
	 bits = bits_table[0];
	 break;
      case 2:
	 bits = bits_table[1];
	 break;
      default:
	 bits = ((fb_format == GL_RGB) || (fb_format == GL_BGR))
	    ? bits_table[2]
	    : bits_table[3];
	 break;
   }

   num_modes = num_depth_stencil_bits * num_db_modes * num_accum_bits;
   configs = _mesa_calloc((num_modes + 1) * sizeof *configs);
   if (configs == NULL)
       return NULL;

    c = configs;
    for ( k = 0 ; k < num_depth_stencil_bits ; k++ ) {
	for ( i = 0 ; i < num_db_modes ; i++ ) {
	    for ( j = 0 ; j < num_accum_bits ; j++ ) {
		*c = _mesa_malloc (sizeof **c);
		modes = &(*c)->modes;
		c++;

		memset(modes, 0, sizeof *modes);
		modes->redBits   = bits[0];
		modes->greenBits = bits[1];
		modes->blueBits  = bits[2];
		modes->alphaBits = bits[3];
		modes->redMask   = masks[0];
		modes->greenMask = masks[1];
		modes->blueMask  = masks[2];
		modes->alphaMask = masks[3];
		modes->rgbBits   = modes->redBits + modes->greenBits
		    + modes->blueBits + modes->alphaBits;

		modes->accumRedBits   = 16 * j;
		modes->accumGreenBits = 16 * j;
		modes->accumBlueBits  = 16 * j;
		modes->accumAlphaBits = (masks[3] != 0) ? 16 * j : 0;
		modes->visualRating = (j == 0) ? GLX_NONE : GLX_SLOW_CONFIG;

		modes->stencilBits = stencil_bits[k];
		modes->depthBits = depth_bits[k];

		modes->transparentPixel = GLX_NONE;
		modes->transparentRed = GLX_DONT_CARE;
		modes->transparentGreen = GLX_DONT_CARE;
		modes->transparentBlue = GLX_DONT_CARE;
		modes->transparentAlpha = GLX_DONT_CARE;
		modes->transparentIndex = GLX_DONT_CARE;
		modes->visualType = GLX_DONT_CARE;
		modes->renderType = GLX_RGBA_BIT;
		modes->drawableType = GLX_WINDOW_BIT;
		modes->rgbMode = GL_TRUE;

		if ( db_modes[i] == GLX_NONE ) {
		    modes->doubleBufferMode = GL_FALSE;
		}
		else {
		    modes->doubleBufferMode = GL_TRUE;
		    modes->swapMethod = db_modes[i];
		}

		modes->haveAccumBuffer = ((modes->accumRedBits +
					   modes->accumGreenBits +
					   modes->accumBlueBits +
					   modes->accumAlphaBits) > 0);
		modes->haveDepthBuffer = (modes->depthBits > 0);
		modes->haveStencilBuffer = (modes->stencilBits > 0);

		modes->bindToTextureRgb = GL_TRUE;
		modes->bindToTextureRgba = GL_TRUE;
		modes->bindToMipmapTexture = GL_FALSE;
		modes->bindToTextureTargets = modes->rgbMode ?
		    __DRI_ATTRIB_TEXTURE_1D_BIT |
		    __DRI_ATTRIB_TEXTURE_2D_BIT |
		    __DRI_ATTRIB_TEXTURE_RECTANGLE_BIT :
		    0;
	    }
	}
    }
    *c = NULL;

    return configs;
}

const __DRIconfig **driConcatConfigs(__DRIconfig **a, __DRIconfig **b)
{
    const __DRIconfig **all;
    int i, j, index;

    i = 0;
    while (a[i] != NULL)
	i++;
    j = 0;
    while (b[j] != NULL)
	j++;
   
    all = _mesa_malloc((i + j + 1) * sizeof *all);
    index = 0;
    for (i = 0; a[i] != NULL; i++)
	all[index++] = a[i];
    for (j = 0; b[j] != NULL; j++)
	all[index++] = b[j];
    all[index++] = NULL;

    _mesa_free(a);
    _mesa_free(b);

    return all;
}

#define __ATTRIB(attrib, field) \
    { attrib, offsetof(__GLcontextModes, field) }

static const struct { unsigned int attrib, offset; } attribMap[] = {
    __ATTRIB(__DRI_ATTRIB_BUFFER_SIZE,			rgbBits),
    __ATTRIB(__DRI_ATTRIB_LEVEL,			level),
    __ATTRIB(__DRI_ATTRIB_RED_SIZE,			redBits),
    __ATTRIB(__DRI_ATTRIB_GREEN_SIZE,			greenBits),
    __ATTRIB(__DRI_ATTRIB_BLUE_SIZE,			blueBits),
    __ATTRIB(__DRI_ATTRIB_ALPHA_SIZE,			alphaBits),
    __ATTRIB(__DRI_ATTRIB_DEPTH_SIZE,			depthBits),
    __ATTRIB(__DRI_ATTRIB_STENCIL_SIZE,			stencilBits),
    __ATTRIB(__DRI_ATTRIB_ACCUM_RED_SIZE,		accumRedBits),
    __ATTRIB(__DRI_ATTRIB_ACCUM_GREEN_SIZE,		accumGreenBits),
    __ATTRIB(__DRI_ATTRIB_ACCUM_BLUE_SIZE,		accumBlueBits),
    __ATTRIB(__DRI_ATTRIB_ACCUM_ALPHA_SIZE,		accumAlphaBits),
    __ATTRIB(__DRI_ATTRIB_SAMPLE_BUFFERS,		sampleBuffers),
    __ATTRIB(__DRI_ATTRIB_SAMPLES,			samples),
    __ATTRIB(__DRI_ATTRIB_DOUBLE_BUFFER,		doubleBufferMode),
    __ATTRIB(__DRI_ATTRIB_STEREO,			stereoMode),
    __ATTRIB(__DRI_ATTRIB_AUX_BUFFERS,			numAuxBuffers),
    __ATTRIB(__DRI_ATTRIB_TRANSPARENT_TYPE,		transparentPixel),
    __ATTRIB(__DRI_ATTRIB_TRANSPARENT_INDEX_VALUE,	transparentPixel),
    __ATTRIB(__DRI_ATTRIB_TRANSPARENT_RED_VALUE,	transparentRed),
    __ATTRIB(__DRI_ATTRIB_TRANSPARENT_GREEN_VALUE,	transparentGreen),
    __ATTRIB(__DRI_ATTRIB_TRANSPARENT_BLUE_VALUE,	transparentBlue),
    __ATTRIB(__DRI_ATTRIB_TRANSPARENT_ALPHA_VALUE,	transparentAlpha),
    __ATTRIB(__DRI_ATTRIB_FLOAT_MODE,			floatMode),
    __ATTRIB(__DRI_ATTRIB_RED_MASK,			redMask),
    __ATTRIB(__DRI_ATTRIB_GREEN_MASK,			greenMask),
    __ATTRIB(__DRI_ATTRIB_BLUE_MASK,			blueMask),
    __ATTRIB(__DRI_ATTRIB_ALPHA_MASK,			alphaMask),
    __ATTRIB(__DRI_ATTRIB_MAX_PBUFFER_WIDTH,		maxPbufferWidth),
    __ATTRIB(__DRI_ATTRIB_MAX_PBUFFER_HEIGHT,		maxPbufferHeight),
    __ATTRIB(__DRI_ATTRIB_MAX_PBUFFER_PIXELS,		maxPbufferPixels),
    __ATTRIB(__DRI_ATTRIB_OPTIMAL_PBUFFER_WIDTH,	optimalPbufferWidth),
    __ATTRIB(__DRI_ATTRIB_OPTIMAL_PBUFFER_HEIGHT,	optimalPbufferHeight),
    __ATTRIB(__DRI_ATTRIB_SWAP_METHOD,			swapMethod),
    __ATTRIB(__DRI_ATTRIB_BIND_TO_TEXTURE_RGB,		bindToTextureRgb),
    __ATTRIB(__DRI_ATTRIB_BIND_TO_TEXTURE_RGBA,		bindToTextureRgba),
    __ATTRIB(__DRI_ATTRIB_BIND_TO_MIPMAP_TEXTURE,	bindToMipmapTexture),
    __ATTRIB(__DRI_ATTRIB_BIND_TO_TEXTURE_TARGETS,	bindToTextureTargets),
    __ATTRIB(__DRI_ATTRIB_YINVERTED,			yInverted),

    /* The struct field doesn't matter here, these are handled by the
     * switch in driGetConfigAttribIndex.  We need them in the array
     * so the iterator includes them though.*/
    __ATTRIB(__DRI_ATTRIB_RENDER_TYPE,			level),
    __ATTRIB(__DRI_ATTRIB_CONFIG_CAVEAT,		level),
    __ATTRIB(__DRI_ATTRIB_SWAP_METHOD,			level)
};

#define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0]))

static int
driGetConfigAttribIndex(const __DRIconfig *config,
			unsigned int index, unsigned int *value)
{
    switch (attribMap[index].attrib) {
    case __DRI_ATTRIB_RENDER_TYPE:
	if (config->modes.rgbMode)
	    *value = __DRI_ATTRIB_RGBA_BIT;
	else
	    *value = __DRI_ATTRIB_COLOR_INDEX_BIT;
	break;
    case __DRI_ATTRIB_CONFIG_CAVEAT:
	if (config->modes.visualRating == GLX_NON_CONFORMANT_CONFIG)
	    *value = __DRI_ATTRIB_NON_CONFORMANT_CONFIG;
	else if (config->modes.visualRating == GLX_SLOW_CONFIG)
	    *value = __DRI_ATTRIB_SLOW_BIT;
	else
	    *value = 0;
	break;
    case __DRI_ATTRIB_SWAP_METHOD:
	break;

    case __DRI_ATTRIB_FLOAT_MODE:
        *value = config->modes.floatMode;
        break;

    default:
	*value = *(unsigned int *)
	    ((char *) &config->modes + attribMap[index].offset);
	
	break;
    }

    return GL_TRUE;
}

int
driGetConfigAttrib(const __DRIconfig *config,
		   unsigned int attrib, unsigned int *value)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(attribMap); i++)
	if (attribMap[i].attrib == attrib)
	    return driGetConfigAttribIndex(config, i, value);

    return GL_FALSE;
}

int
driIndexConfigAttrib(const __DRIconfig *config, int index,
		     unsigned int *attrib, unsigned int *value)
{
    if (index >= 0 && index < ARRAY_SIZE(attribMap)) {
	*attrib = attribMap[index].attrib;
	return driGetConfigAttribIndex(config, index, value);
    }

    return GL_FALSE;
}