mesa/formats: Add layout and swizzle information

v2: Move the MESA_FORMAT_SWIZZLE enum to the top of the file

Signed-off-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/mesa/main/format_info.py

@@ -96,6 +96,14 @@ def get_gl_data_type(fmat):
    else:
       assert False
 
+def get_mesa_layout(fmat):
+   if fmat.layout == 'array':
+      return 'MESA_FORMAT_LAYOUT_ARRAY'
+   elif fmat.layout == 'packed':
+      return 'MESA_FORMAT_LAYOUT_PACKED'
+   else:
+      return 'MESA_FORMAT_LAYOUT_OTHER'
+
 def get_channel_bits(fmat, chan_name):
    if fmat.is_compressed():
       # These values are pretty-much bogus, but OpenGL requires that we
@@ -166,6 +174,7 @@ for fmat in formats:
    print '   {'
    print '      {0},'.format(fmat.name)
    print '      "{0}",'.format(fmat.name)
+   print '      {0},'.format(get_mesa_layout(fmat))
    print '      {0},'.format(get_gl_base_format(fmat))
    print '      {0},'.format(get_gl_data_type(fmat))
 
@@ -176,6 +185,8 @@ for fmat in formats:
 
    print '      {0}, {1}, {2},'.format(fmat.block_width, fmat.block_height,
                                        int(fmat.block_size() / 8))
+
+   print '      {{ {0} }},'.format(', '.join(map(str, fmat.swizzle)))
    print '   },'
 
 print '};'

src/mesa/main/formats.c

@@ -40,6 +40,8 @@ struct gl_format_info
    /** text name for debugging */
    const char *StrName;
 
+   enum mesa_format_layout Layout;
+
    /**
     * Base format is one of GL_RED, GL_RG, GL_RGB, GL_RGBA, GL_ALPHA,
     * GL_LUMINANCE, GL_LUMINANCE_ALPHA, GL_INTENSITY, GL_YCBCR_MESA,
@@ -67,6 +69,8 @@ struct gl_format_info
     */
    GLubyte BlockWidth, BlockHeight;
    GLubyte BytesPerBlock;
+
+   uint8_t Swizzle[4];
 };
 
 #include "format_info.c"
@@ -177,6 +181,21 @@ _mesa_get_format_max_bits(mesa_format format)
 }
 
 
+/**
+ * Return the layout type of the given format.
+ * The return value will be one of:
+ *    MESA_FORMAT_LAYOUT_ARRAY
+ *    MESA_FORMAT_LAYOUT_PACKED
+ *    MESA_FORMAT_LAYOUT_OTHER
+ */
+extern enum mesa_format_layout
+_mesa_get_format_layout(mesa_format format)
+{
+   const struct gl_format_info *info = _mesa_get_format_info(format);
+   return info->Layout;
+}
+
+
 /**
  * Return the data type (or more specifically, the data representation)
  * for the given format.
@@ -224,6 +243,33 @@ _mesa_get_format_block_size(mesa_format format, GLuint *bw, GLuint *bh)
 }
 
 
+/**
+ * Returns the an array of four numbers representing the transformation
+ * from the RGBA or SZ colorspace to the given format.  For array formats,
+ * the i'th RGBA component is given by:
+ *
+ * if (swizzle[i] <= MESA_FORMAT_SWIZZLE_W)
+ *    comp = data[swizzle[i]];
+ * else if (swizzle[i] == MESA_FORMAT_SWIZZLE_ZERO)
+ *    comp = 0;
+ * else if (swizzle[i] == MESA_FORMAT_SWIZZLE_ONE)
+ *    comp = 1;
+ * else if (swizzle[i] == MESA_FORMAT_SWIZZLE_NONE)
+ *    // data does not contain a channel of this format
+ *
+ * For packed formats, the swizzle gives the number of components left of
+ * the least significant bit.
+ *
+ * Compressed formats have no swizzle.
+ */
+void
+_mesa_get_format_swizzle(mesa_format format, uint8_t swizzle_out[4])
+{
+   const struct gl_format_info *info = _mesa_get_format_info(format);
+   memcpy(swizzle_out, info->Swizzle, sizeof(info->Swizzle));
+}
+
+
 /** Is the given format a compressed format? */
 GLboolean
 _mesa_is_format_compressed(mesa_format format)

src/mesa/main/formats.h

@@ -56,6 +56,29 @@ extern "C" {
  */
 #define MAX_PIXEL_BYTES 16
 
+/**
+ * Specifies the layout of a pixel format.  See the MESA_FORMAT
+ * documentation below.
+ */
+enum mesa_format_layout {
+   MESA_FORMAT_LAYOUT_ARRAY,
+   MESA_FORMAT_LAYOUT_PACKED,
+   MESA_FORMAT_LAYOUT_OTHER,
+};
+
+/**
+ * An enum representing different possible swizzling values.  This is used
+ * to interpret the output of _mesa_get_format_swizzle
+ */
+enum {
+   MESA_FORMAT_SWIZZLE_X = 0,
+   MESA_FORMAT_SWIZZLE_Y = 1,
+   MESA_FORMAT_SWIZZLE_Z = 2,
+   MESA_FORMAT_SWIZZLE_W = 3,
+   MESA_FORMAT_SWIZZLE_ZERO = 4,
+   MESA_FORMAT_SWIZZLE_ONE = 5,
+   MESA_FORMAT_SWIZZLE_NONE = 6,
+};
 
 /**
  * Mesa texture/renderbuffer image formats.
@@ -419,6 +442,9 @@ _mesa_get_format_bits(mesa_format format, GLenum pname);
 extern GLuint
 _mesa_get_format_max_bits(mesa_format format);
 
+extern enum mesa_format_layout
+_mesa_get_format_layout(mesa_format format);
+
 extern GLenum
 _mesa_get_format_datatype(mesa_format format);
 
@@ -428,6 +454,9 @@ _mesa_get_format_base_format(mesa_format format);
 extern void
 _mesa_get_format_block_size(mesa_format format, GLuint *bw, GLuint *bh);
 
+extern void
+_mesa_get_format_swizzle(mesa_format format, uint8_t swizzle_out[4]);
+
 extern GLboolean
 _mesa_is_format_compressed(mesa_format format);