flexible vertexformat

[Nox]

hi,
atm i try to evaluate the requirements on a "flexible vertexformat". This will be interesting especially for shaders guy. Looking at ogl and dx8/dx9 i defined the following "system":

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enum VERTEX_DATA_TYPE	{ VERTEX_U8_4D, VERTEX_U32_1D, VERTEX_S16_2D, VERTEX_S16_4D,
						VERTEX_F32_1D, VERTEX_F32_2D, VERTEX_F32_3D, VERTEX_F32_4D };
						

enum VERTEX_DATA_USAGE	{ VERTEX_POSITION, VERTEX_INT, VERTEX_NORMAL,
						VERTEX_TEXTCOORD0, VERTEX_TEXTCOORD1, VERTEX_TEXTCOORD2, VERTEX_TEXTCOORD3,
						VERTEX_TEXTCOORD4, VERTEX_TEXTCOORD5, VERTEX_TEXTCOORD6, VERTEX_TEXTCOORD7 };

struct VertexDeclaration
{
	u32					offset;
	VERTEX_DECL_TYPE	data_type;
	VERTEX_DATA_USAGE	data_usage;
};

First: do you think this system will meets all needs? What is missing? Is it suitable? Free for discussion!

Second: The reason why it provides so few possibilities is simple. Just take a look at the following code and you will see it is may be the biggest "supported by all" subset.

Datatypes:

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typedef enum D3DDECLTYPE
{
    D3DDECLTYPE_FLOAT1 = 0,
    D3DDECLTYPE_FLOAT2 = 1,
    D3DDECLTYPE_FLOAT3 = 2,
    D3DDECLTYPE_FLOAT4 = 3,
    D3DDECLTYPE_D3DCOLOR = 4,
    D3DDECLTYPE_UBYTE4 = 5,
    D3DDECLTYPE_SHORT2 = 6,
    D3DDECLTYPE_SHORT4 = 7,
    D3DDECLTYPE_UBYTE4N = 8,
    D3DDECLTYPE_SHORT2N = 9,
    D3DDECLTYPE_SHORT4N = 10,
    D3DDECLTYPE_USHORT2N = 11,
    D3DDECLTYPE_USHORT4N = 12,
    D3DDECLTYPE_UDEC3 = 13,
    D3DDECLTYPE_DEC3N = 14,
    D3DDECLTYPE_FLOAT16_2 = 15,
    D3DDECLTYPE_FLOAT16_4 = 16,
    D3DDECLTYPE_UNUSED = 17,
};

/* DataType */
#define GL_BYTE                           0x1400
#define GL_UNSIGNED_BYTE                  0x1401
#define GL_SHORT                          0x1402
#define GL_UNSIGNED_SHORT                 0x1403
#define GL_INT                            0x1404
#define GL_UNSIGNED_INT                   0x1405
#define GL_FLOAT                          0x1406
#define GL_2_BYTES                        0x1407
#define GL_3_BYTES                        0x1408
#define GL_4_BYTES                        0x1409
#define GL_DOUBLE                         0x140A

Datausage:

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typedef enum D3DDECLUSAGE
{
    D3DDECLUSAGE_POSITION = 0,
    D3DDECLUSAGE_BLENDWEIGHT = 1,
    D3DDECLUSAGE_BLENDINDICES = 2,
    D3DDECLUSAGE_NORMAL = 3,
    D3DDECLUSAGE_PSIZE = 4,
    D3DDECLUSAGE_TEXCOORD = 5,
    D3DDECLUSAGE_TANGENT = 6,
    D3DDECLUSAGE_BINORMAL = 7,
    D3DDECLUSAGE_TESSFACTOR = 8,
    D3DDECLUSAGE_POSITIONT = 9,
    D3DDECLUSAGE_COLOR = 10,
    D3DDECLUSAGE_FOG = 11,
    D3DDECLUSAGE_DEPTH = 12,
    D3DDECLUSAGE_SAMPLE = 13,
};

glVertexPointer <- allows GL_SHORT, GL_INT, GL_FLOAT, GL_DOUBLE; count: 2-4
glNormalPointer <- allows GL_BYTE, GL_SHORT, GL_INT, GL_FLOAT, GL_DOUBLE; count: 3
glColorPointer <- allows GL_BYTE, GL_UNSIGNED_BYTE, GL_SHORT, GL_UNSIGNED_SHORT, GL_INT, GL_UNSIGNED_INT, GL_FLOAT, GL_DOUBLE; count: 3-4
glTexCoordPointer <- allows GL_SHORT, GL_INT, GL_FLOAT, GL_DOUBLE; count: 1-4

Third: The existing types would be replaced by predefined declearations. So backward compatibility problems can be reduced. The old typeenum can remain, marked as deprecated and dropped after some releases.