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#pragma once
#include <mbgl/gfx/types.hpp>
#include <mbgl/util/type_list.hpp>
#include <mbgl/util/indexed_tuple.hpp>
#include <array>
#include <type_traits>
#include <cstddef>
#define MBGL_DEFINE_ATTRIBUTE(type_, n_, name_) \
struct name_ { \
using Type = ::mbgl::gfx::AttributeType<type_, n_>; \
static auto name() { \
return #name_; \
} \
}
#define MBGL_VERTEX_ALIGN __attribute__((aligned(4)))
namespace mbgl {
namespace gfx {
namespace {
template <typename, std::size_t> struct AttributeDataTypeOf;
template <> struct AttributeDataTypeOf<int8_t, 1> : std::integral_constant<AttributeDataType, AttributeDataType::Byte> {};
template <> struct AttributeDataTypeOf<int8_t, 2> : std::integral_constant<AttributeDataType, AttributeDataType::Byte2> {};
template <> struct AttributeDataTypeOf<int8_t, 3> : std::integral_constant<AttributeDataType, AttributeDataType::Byte3> {};
template <> struct AttributeDataTypeOf<int8_t, 4> : std::integral_constant<AttributeDataType, AttributeDataType::Byte4> {};
template <> struct AttributeDataTypeOf<uint8_t, 1> : std::integral_constant<AttributeDataType, AttributeDataType::UByte> {};
template <> struct AttributeDataTypeOf<uint8_t, 2> : std::integral_constant<AttributeDataType, AttributeDataType::UByte2> {};
template <> struct AttributeDataTypeOf<uint8_t, 3> : std::integral_constant<AttributeDataType, AttributeDataType::UByte3> {};
template <> struct AttributeDataTypeOf<uint8_t, 4> : std::integral_constant<AttributeDataType, AttributeDataType::UByte4> {};
template <> struct AttributeDataTypeOf<int16_t, 1> : std::integral_constant<AttributeDataType, AttributeDataType::Short> {};
template <> struct AttributeDataTypeOf<int16_t, 2> : std::integral_constant<AttributeDataType, AttributeDataType::Short2> {};
template <> struct AttributeDataTypeOf<int16_t, 3> : std::integral_constant<AttributeDataType, AttributeDataType::Short3> {};
template <> struct AttributeDataTypeOf<int16_t, 4> : std::integral_constant<AttributeDataType, AttributeDataType::Short4> {};
template <> struct AttributeDataTypeOf<uint16_t, 1> : std::integral_constant<AttributeDataType, AttributeDataType::UShort> {};
template <> struct AttributeDataTypeOf<uint16_t, 2> : std::integral_constant<AttributeDataType, AttributeDataType::UShort2> {};
template <> struct AttributeDataTypeOf<uint16_t, 3> : std::integral_constant<AttributeDataType, AttributeDataType::UShort3> {};
template <> struct AttributeDataTypeOf<uint16_t, 4> : std::integral_constant<AttributeDataType, AttributeDataType::UShort4> {};
template <> struct AttributeDataTypeOf<int32_t, 1> : std::integral_constant<AttributeDataType, AttributeDataType::Int> {};
template <> struct AttributeDataTypeOf<int32_t, 2> : std::integral_constant<AttributeDataType, AttributeDataType::Int2> {};
template <> struct AttributeDataTypeOf<int32_t, 3> : std::integral_constant<AttributeDataType, AttributeDataType::Int3> {};
template <> struct AttributeDataTypeOf<int32_t, 4> : std::integral_constant<AttributeDataType, AttributeDataType::Int4> {};
template <> struct AttributeDataTypeOf<uint32_t, 1> : std::integral_constant<AttributeDataType, AttributeDataType::UInt> {};
template <> struct AttributeDataTypeOf<uint32_t, 2> : std::integral_constant<AttributeDataType, AttributeDataType::UInt2> {};
template <> struct AttributeDataTypeOf<uint32_t, 3> : std::integral_constant<AttributeDataType, AttributeDataType::UInt3> {};
template <> struct AttributeDataTypeOf<uint32_t, 4> : std::integral_constant<AttributeDataType, AttributeDataType::UInt4> {};
template <> struct AttributeDataTypeOf<float, 1> : std::integral_constant<AttributeDataType, AttributeDataType::Float> {};
template <> struct AttributeDataTypeOf<float, 2> : std::integral_constant<AttributeDataType, AttributeDataType::Float2> {};
template <> struct AttributeDataTypeOf<float, 3> : std::integral_constant<AttributeDataType, AttributeDataType::Float3> {};
template <> struct AttributeDataTypeOf<float, 4> : std::integral_constant<AttributeDataType, AttributeDataType::Float4> {};
} // namespace
template <typename T, std::size_t N>
class AttributeType {
public:
using ElementType = T;
static constexpr AttributeDataType DataType = AttributeDataTypeOf<T, N>::value;
static constexpr size_t Dimensions = N;
using Value = std::array<T, N>;
};
struct AttributeDescriptor {
AttributeDataType dataType;
uint8_t offset;
};
inline bool operator==(const AttributeDescriptor& lhs, const AttributeDescriptor& rhs) {
return lhs.dataType == rhs.dataType && lhs.offset == rhs.offset;
}
struct VertexDescriptor {
uint8_t stride;
uint8_t count;
AttributeDescriptor attributes[5];
};
// Attribute binding requires member offsets. The only standard way to
// obtain an offset is the offsetof macro. The offsetof macro has defined
// behavior only for standard layout types. That rules out std::tuple and
// any other solution that relies on chained inheritance. Manually implemented
// variadic specialization looks like the only solution. Fortunately, we
// only use a maximum of five attributes.
namespace detail {
template <class...>
struct Vertex;
template <class A1>
struct Vertex<A1> {
using Type = Vertex<A1>;
typename A1::Value a1;
} MBGL_VERTEX_ALIGN;
template <class A1, class A2>
struct Vertex<A1, A2> {
using Type = Vertex<A1, A2>;
typename A1::Value a1;
typename A2::Value a2;
} MBGL_VERTEX_ALIGN;
template <class A1, class A2, class A3>
struct Vertex<A1, A2, A3> {
using Type = Vertex<A1, A2, A3>;
typename A1::Value a1;
typename A2::Value a2;
typename A3::Value a3;
} MBGL_VERTEX_ALIGN;
template <class A1, class A2, class A3, class A4>
struct Vertex<A1, A2, A3, A4> {
using Type = Vertex<A1, A2, A3, A4>;
typename A1::Value a1;
typename A2::Value a2;
typename A3::Value a3;
typename A4::Value a4;
} MBGL_VERTEX_ALIGN;
template <class A1, class A2, class A3, class A4, class A5>
struct Vertex<A1, A2, A3, A4, A5> {
using Type = Vertex<A1, A2, A3, A4, A5>;
typename A1::Value a1;
typename A2::Value a2;
typename A3::Value a3;
typename A4::Value a4;
typename A5::Value a5;
} MBGL_VERTEX_ALIGN;
template <class>
struct Descriptor;
template <class A1>
struct Descriptor<Vertex<A1>> {
using Type = Vertex<A1>;
static_assert(sizeof(Type) < 256, "vertex type must be smaller than 256 bytes");
static_assert(std::is_standard_layout<Type>::value, "vertex type must use standard layout");
static constexpr const VertexDescriptor data = { sizeof(Type), 1, {
{ A1::DataType, offsetof(Type, a1) },
}};
};
template <class A1>
constexpr const VertexDescriptor Descriptor<Vertex<A1>>::data;
template <class A1, class A2>
struct Descriptor<Vertex<A1, A2>> {
using Type = Vertex<A1, A2>;
static_assert(sizeof(Type) < 256, "vertex type must be smaller than 256 bytes");
static_assert(std::is_standard_layout<Type>::value, "vertex type must use standard layout");
static constexpr const VertexDescriptor data = { sizeof(Type), 2, {
{ A1::DataType, offsetof(Type, a1) },
{ A2::DataType, offsetof(Type, a2) },
}};
};
template <class A1, class A2>
constexpr const VertexDescriptor Descriptor<Vertex<A1, A2>>::data;
template <class A1, class A2, class A3>
struct Descriptor<Vertex<A1, A2, A3>> {
using Type = Vertex<A1, A2, A3>;
static_assert(sizeof(Type) < 256, "vertex type must be smaller than 256 bytes");
static_assert(std::is_standard_layout<Type>::value, "vertex type must use standard layout");
static constexpr const VertexDescriptor data = { sizeof(Type), 3, {
{ A1::DataType, offsetof(Type, a1) },
{ A2::DataType, offsetof(Type, a2) },
{ A3::DataType, offsetof(Type, a3) },
}};
};
template <class A1, class A2, class A3>
constexpr const VertexDescriptor Descriptor<Vertex<A1, A2, A3>>::data;
template <class A1, class A2, class A3, class A4>
struct Descriptor<Vertex<A1, A2, A3, A4>> {
using Type = Vertex<A1, A2, A3, A4>;
static_assert(sizeof(Type) < 256, "vertex type must be smaller than 256 bytes");
static_assert(std::is_standard_layout<Type>::value, "vertex type must use standard layout");
static constexpr const VertexDescriptor data = { sizeof(Type), 4, {
{ A1::DataType, offsetof(Type, a1) },
{ A2::DataType, offsetof(Type, a2) },
{ A3::DataType, offsetof(Type, a3) },
{ A4::DataType, offsetof(Type, a4) },
}};
};
template <class A1, class A2, class A3, class A4>
constexpr const VertexDescriptor Descriptor<Vertex<A1, A2, A3, A4>>::data;
template <class A1, class A2, class A3, class A4, class A5>
struct Descriptor<Vertex<A1, A2, A3, A4, A5>> {
using Type = Vertex<A1, A2, A3, A4, A5>;
static_assert(sizeof(Type) < 256, "vertex type must be smaller than 256 bytes");
static_assert(std::is_standard_layout<Type>::value, "vertex type must use standard layout");
static constexpr const VertexDescriptor data = { sizeof(Type), 5, {
{ A1::DataType, offsetof(Type, a1) },
{ A2::DataType, offsetof(Type, a2) },
{ A3::DataType, offsetof(Type, a3) },
{ A4::DataType, offsetof(Type, a4) },
{ A5::DataType, offsetof(Type, a5) },
}};
};
template <class A1, class A2, class A3, class A4, class A5>
constexpr const VertexDescriptor Descriptor<Vertex<A1, A2, A3, A4, A5>>::data;
template <class... As>
struct Vertex<TypeList<As...>> {
using Type = Vertex<typename As::Type...>;
};
} // namespace detail
template <class A>
using Vertex = typename detail::Vertex<A>::Type;
template <class V>
using VertexDescriptorOf = detail::Descriptor<V>;
} // namespace gfx
} // namespace mbgl
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