Implement instanced meshes & matrix attributes

This commit is contained in:
Nikita Lisitsa 2020-09-25 11:36:18 +03:00
parent aedd41ae7f
commit 64751170cb
2 changed files with 359 additions and 15 deletions

View file

@ -5,6 +5,7 @@
#include <psemek/geom/vector.hpp>
#include <psemek/geom/point.hpp>
#include <psemek/geom/simplex.hpp>
#include <psemek/geom/matrix.hpp>
#include <cstddef>
#include <tuple>
@ -18,7 +19,9 @@ namespace psemek::gfx
template <typename T>
struct normalized
{};
{
using type = T;
};
// skips a single attribute index
struct skip
@ -31,6 +34,13 @@ namespace psemek::gfx
static constexpr std::size_t size = N;
};
// instance attribute, for instanced meshes only
template <typename T>
struct instanced
{
using type = T;
};
template <typename Attrib>
struct attrib_traits;
@ -154,6 +164,16 @@ namespace psemek::gfx
static constexpr GLboolean normalized = gl::TRUE_;
};
template <typename T>
struct attrib_traits<instanced<T>>
{
using attrib_type = T;
static constexpr GLint size = attrib_traits<T>::size;
static constexpr GLenum type = attrib_traits<T>::type;
static constexpr GLboolean normalized = attrib_traits<T>::normalized;
};
namespace detail
{
@ -165,6 +185,34 @@ namespace psemek::gfx
struct is_padding<padding<N>> : std::true_type
{};
template <typename T>
struct is_instanced : std::false_type
{};
template <typename T>
struct is_instanced<instanced<T>> : std::true_type
{};
template <typename T>
struct remove_instanced
{
using type = T;
};
template <typename T>
struct remove_instanced<instanced<T>>
{
using type = T;
};
template <typename T>
struct is_matrix : std::false_type
{};
template <typename T, std::size_t R, std::size_t C>
struct is_matrix<geom::matrix<T, R, C>> : std::true_type
{};
template <typename Attr>
std::size_t attr_size()
{
@ -182,11 +230,37 @@ namespace psemek::gfx
}
}
template <typename ... Attribs>
struct mesh_setup;
template <bool InstanceSetup, typename ... Attribs>
struct stride_helper;
template <>
struct mesh_setup<>
template <bool InstanceSetup>
struct stride_helper<InstanceSetup>
{
static std::size_t stride()
{
return 0;
}
};
template <bool InstanceSetup, typename Attr1, typename ... Attribs>
struct stride_helper<InstanceSetup, Attr1, Attribs...>
{
static std::size_t stride()
{
std::size_t s = 0;
if constexpr (is_instanced<Attr1>::value == InstanceSetup)
{
s = attr_size<Attr1>();
}
return s + stride_helper<InstanceSetup, Attribs...>::stride();
}
};
template <bool IsInstanced, bool InstanceSetup, typename ... Attribs>
struct mesh_setup_base;
template <bool IsInstanced, bool InstanceSetup>
struct mesh_setup_base<IsInstanced, InstanceSetup>
{
static std::size_t setup()
{
@ -197,12 +271,12 @@ namespace psemek::gfx
{}
};
template <typename Attr1, typename ... Attribs>
struct mesh_setup<Attr1, Attribs...>
template <bool IsInstanced, bool InstanceSetup, typename Attr1, typename ... Attribs>
struct mesh_setup_base<IsInstanced, InstanceSetup, Attr1, Attribs...>
{
static std::size_t setup()
{
std::size_t const stride = attr_size<Attr1>() + (0 + ... + attr_size<Attribs>());
std::size_t const stride = stride_helper<InstanceSetup, Attr1, Attribs...>::stride();
setup_impl(0, 0, stride);
return stride;
}
@ -211,24 +285,74 @@ namespace psemek::gfx
{
if constexpr (std::is_same_v<Attr1, skip>)
{
mesh_setup<Attribs...>::setup_impl(index + 1, offset, stride);
mesh_setup_base<IsInstanced, InstanceSetup, Attribs...>::setup_impl(index + 1, offset, stride);
}
else if constexpr (is_padding<Attr1>::value)
{
mesh_setup<Attribs...>::setup_impl(index, offset + Attr1::size, stride);
mesh_setup_base<IsInstanced, InstanceSetup, Attribs...>::setup_impl(index, offset + Attr1::size, stride);
}
else if constexpr (!IsInstanced && is_instanced<Attr1>::value)
{
static_assert("cannot use instanced attribute for non-instanced mesh");
}
else if constexpr (!IsInstanced || (is_instanced<Attr1>::value == InstanceSetup))
{
using attr = typename remove_instanced<Attr1>::type;
if constexpr (is_matrix<attr>::value)
{
using T = typename attr::scalar_type;
using traits = attrib_traits<geom::vector<T, attr::columns>>;
for (std::size_t row = 0; row < attr::rows; ++row)
{
gl::EnableVertexAttribArray(index + row);
gl::VertexAttribPointer(index + row, traits::size, traits::type, traits::normalized, stride, reinterpret_cast<char const *>(offset + row * attr::columns * sizeof(T)));
if (InstanceSetup)
gl::VertexAttribDivisor(index + row, 1);
}
mesh_setup_base<IsInstanced, InstanceSetup, Attribs...>::setup_impl(index + attr::rows, offset + attr_size<Attr1>(), stride);
}
else
{
if (InstanceSetup)
gl::VertexAttribDivisor(index, 1);
using traits = attrib_traits<Attr1>;
gl::EnableVertexAttribArray(index);
gl::VertexAttribPointer(index, traits::size, traits::type, traits::normalized, stride, reinterpret_cast<char const *>(offset));
mesh_setup_base<IsInstanced, InstanceSetup, Attribs...>::setup_impl(index + 1, offset + attr_size<Attr1>(), stride);
}
}
else
{
using traits = attrib_traits<Attr1>;
using attr = typename remove_instanced<Attr1>::type;
gl::EnableVertexAttribArray(index);
gl::VertexAttribPointer(index, traits::size, traits::type, traits::normalized, stride, reinterpret_cast<char const *>(offset));
mesh_setup<Attribs...>::setup_impl(index + 1, offset + attr_size<Attr1>(), stride);
if constexpr (is_matrix<attr>::value)
{
mesh_setup_base<IsInstanced, InstanceSetup, Attribs...>::setup_impl(index + attr::rows, offset, stride);
}
else
{
mesh_setup_base<IsInstanced, InstanceSetup, Attribs...>::setup_impl(index + 1, offset, stride);
}
}
}
};
template <typename ... Attribs>
using mesh_setup = mesh_setup_base<false, false, Attribs...>;
template <typename ... Attribs>
using instanced_mesh_vertex_setup = mesh_setup_base<true, false, Attribs...>;
template <typename ... Attribs>
using instanced_mesh_instance_setup = mesh_setup_base<true, true, Attribs...>;
template <typename T>
struct gl_type;
@ -496,4 +620,150 @@ namespace psemek::gfx
indexed_mesh(int);
};
struct instanced_mesh
{
static instanced_mesh null();
instanced_mesh();
instanced_mesh(instanced_mesh &&);
instanced_mesh(instanced_mesh const &) = delete;
instanced_mesh & operator = (instanced_mesh &&);
instanced_mesh & operator = (instanced_mesh const &) = delete;
~instanced_mesh();
template <typename ... Attribs>
void setup()
{
gl::BindVertexArray(array_);
gl::BindBuffer(gl::ARRAY_BUFFER, buffer_);
stride_ = detail::instanced_mesh_vertex_setup<Attribs...>::setup();
gl::BindBuffer(gl::ARRAY_BUFFER, instance_buffer_);
instance_stride_ = detail::instanced_mesh_instance_setup<Attribs...>::setup();
}
template <typename Vertex>
void load(Vertex const * vertices, std::size_t count, GLenum primitive_type, GLenum usage = gl::STREAM_DRAW)
{
if (sizeof(Vertex) != stride_)
throw std::runtime_error("Vertex size not equal to sum of attribute sizes");
switch (primitive_type)
{
case gl::LINES:
if ((count % 2) != 0) throw std::runtime_error("Vertex count for GL_LINES should be a multiple of 2");
break;
case gl::TRIANGLES:
if ((count % 3) != 0) throw std::runtime_error("Vertex count for GL_TRIANGLES should be a multiple of 3");
break;
default:
break;
}
gl::BindBuffer(gl::ARRAY_BUFFER, buffer_);
gl::BufferData(gl::ARRAY_BUFFER, count * sizeof(Vertex), vertices, usage);
count_ = count;
primitive_type_ = primitive_type;
}
template <typename Vertex>
void load(std::vector<Vertex> const & vertices, GLenum primitive_type, GLenum usage = gl::STREAM_DRAW)
{
load(vertices.data(), vertices.size(), primitive_type, usage);
}
template <typename Vertex, std::size_t N>
void load(geom::simplex<Vertex, N> const * simplices, std::size_t count, GLenum usage = gl::STREAM_DRAW)
{
static_assert(sizeof(geom::simplex<Vertex, N>) == (N + 1) * sizeof(Vertex));
GLenum primitive_type;
if constexpr (N == 0)
{
primitive_type = gl::POINTS;
}
else if constexpr (N == 1)
{
primitive_type = gl::LINES;
}
else if constexpr (N == 2)
{
primitive_type = gl::TRIANGLES;
}
else
{
static_assert("unknown primitive type");
}
load(reinterpret_cast<Vertex const *>(simplices), count * (N + 1), primitive_type, usage);
}
template <typename Vertex, std::size_t N>
void load(std::vector<geom::simplex<Vertex, N>> const & simplices, GLenum usage = gl::STREAM_DRAW)
{
load(simplices.data(), simplices.size(), usage);
}
template <typename Instance>
void load_instance(Instance const * instances, std::size_t count, GLenum usage = gl::STREAM_DRAW)
{
if (sizeof(Instance) != instance_stride_)
throw std::runtime_error("Instance size not equal to sum of instanced attribute sizes");
gl::BindBuffer(gl::ARRAY_BUFFER, instance_buffer_);
gl::BufferData(gl::ARRAY_BUFFER, count * sizeof(Instance), instances, usage);
instance_count_ = count;
}
template <typename Instance>
void load_instance(std::vector<Instance> const & instances, GLenum usage = gl::STREAM_DRAW)
{
load_instance(instances.data(), instances.size(), usage);
}
void draw() const
{
if (count_ == 0) return;
if (instance_count_ == 0) return;
gl::BindVertexArray(array_);
gl::DrawArraysInstanced(primitive_type_, 0, count_, instance_count_);
}
GLsizei count() const
{
return count_;
}
GLsizei instance_count() const
{
return count_;
}
GLenum primitive_type() const
{
return primitive_type_;
}
private:
GLuint array_;
GLuint buffer_;
GLuint instance_buffer_;
GLsizei count_ = 0;
GLsizei instance_count_ = 0;
std::size_t stride_ = 0;
std::size_t instance_stride_ = 0;
GLenum primitive_type_;
instanced_mesh(int);
};
}

View file

@ -137,5 +137,79 @@ namespace psemek::gfx
index_buffer_ = 0;
}
instanced_mesh instanced_mesh::null()
{
return instanced_mesh(0);
}
instanced_mesh::instanced_mesh()
{
gl::GenVertexArrays(1, &array_);
gl::GenBuffers(1, &buffer_);
gl::GenBuffers(1, &instance_buffer_);
}
instanced_mesh::instanced_mesh(instanced_mesh && other)
{
array_ = other.array_;
buffer_ = other.buffer_;
instance_buffer_ = other.instance_buffer_;
count_ = other.count_;
instance_count_ = other.instance_count_;
stride_ = other.stride_;
instance_stride_ = other.instance_stride_;
primitive_type_ = other.primitive_type_;
other.array_ = 0;
other.buffer_ = 0;
other.instance_buffer_ = 0;
other.count_ = 0;
other.instance_count_ = 0;
other.stride_ = 0;
other.instance_stride_ = 0;
}
instanced_mesh & instanced_mesh::operator = (instanced_mesh && other)
{
if (this == &other)
return *this;
gl::DeleteVertexArrays(1, &array_);
gl::DeleteBuffers(1, &buffer_);
gl::DeleteBuffers(1, &instance_buffer_);
array_ = other.array_;
buffer_ = other.buffer_;
instance_buffer_ = other.instance_buffer_;
count_ = other.count_;
instance_count_ = other.instance_count_;
stride_ = other.stride_;
instance_stride_ = other.instance_stride_;
primitive_type_ = other.primitive_type_;
other.array_ = 0;
other.buffer_ = 0;
other.instance_buffer_ = 0;
other.count_ = 0;
other.instance_count_ = 0;
other.stride_ = 0;
other.instance_stride_ = 0;
return *this;
}
instanced_mesh::~instanced_mesh()
{
gl::DeleteVertexArrays(1, &array_);
gl::DeleteBuffers(1, &buffer_);
gl::DeleteBuffers(1, &instance_buffer_);
}
instanced_mesh::instanced_mesh(int)
{
array_ = 0;
buffer_ = 0;
instance_buffer_ = 0;
}
}