1 #ifndef MSP_GL_VERTEXFORMAT_H_
2 #define MSP_GL_VERTEXFORMAT_H_
5 #include <msp/strings/lexicalcast.h>
12 A single vertex attribute. Commonly used attributes are named by their
13 semantical meaning in the standard shaders. Texture coordinates and generic
14 attributes can additionally be given an index. There are four texture
15 coordinate attributes available. The number of available generic attributes
16 depends on implementation limits, but is at least five.
18 RAW_ATTRIB is handled in a special way; creating an indexed attribute based on
19 it uses the index as raw attribute number. Only use it if you know what you
22 The values are bitfields laid as follows:
25 │ │ │ │ │ └╴Number of components
26 │ │ │ │ └───╴Integer attribute flag
27 │ │ │ └─────╴Size of one component
28 │ │ └────────╴Signed flag
29 │ └──────────╴Floating-point flag
30 └────────────╴Attribute index (semantic)
32 This information is presented for internal documentation purposes only; it is
33 inadvisable for applications to rely on it.
35 enum VertexAttribute: std::uint16_t
68 RAW_ATTRIB_I1 = 0xFCC9,
69 RAW_ATTRIB_I2 = 0xFCCA,
70 RAW_ATTRIB_I3 = 0xFCCB,
71 RAW_ATTRIB_I4 = 0xFCCC
75 Describes the attributes of a vertex. Up to 15 attributes are allowed.
80 static constexpr unsigned MAX_ATTRIBUTES = 15;
83 std::uint8_t count = 0;
84 VertexAttribute attributes[MAX_ATTRIBUTES];
87 VertexFormat() = default;
88 VertexFormat(VertexAttribute);
90 VertexFormat operator,(VertexAttribute) const;
91 VertexFormat operator,(DataType) const;
92 VertexFormat operator,(unsigned) const;
93 bool operator==(const VertexFormat &) const;
94 bool operator!=(const VertexFormat &other) const { return !(*this==other); }
96 bool empty() const { return !count; }
97 const VertexAttribute *begin() const { return attributes; }
98 const VertexAttribute *end() const { return attributes+count; }
100 /** Returns the displacement from one vertex to the next. */
101 unsigned stride() const;
103 /** Returns the offset of an attribute within a vertex. A stored attribute
104 must have the same semantic and type and at least as many components as
105 requested to be considered a match. */
106 int offset(VertexAttribute) const;
109 inline VertexFormat operator,(VertexAttribute a1, VertexAttribute a2)
110 { return (VertexFormat(a1), a2); }
112 VertexAttribute make_typed_attribute(VertexAttribute, DataType);
114 inline VertexAttribute operator,(VertexAttribute a, DataType t)
115 { return make_typed_attribute(a, t); }
117 VertexAttribute make_indexed_attribute(VertexAttribute, unsigned);
119 inline VertexAttribute operator,(VertexAttribute a, unsigned i)
120 { return make_indexed_attribute(a, i); }
122 inline unsigned get_attribute_semantic(VertexAttribute a)
125 inline DataType get_attribute_source_type(VertexAttribute a)
126 { return static_cast<DataType>((a&0x70)>>4 | (a&0x180)<<1); }
128 inline unsigned get_attribute_component_count(VertexAttribute a)
131 inline unsigned get_attribute_size(VertexAttribute a)
132 { return get_attribute_component_count(a)*get_type_size(get_attribute_source_type(a)); }
134 inline bool is_integer_attribute(VertexAttribute a)
137 void operator>>(const LexicalConverter &, VertexAttribute &);