psemek/libs/gfx/source/painter.cpp

142 lines
3.4 KiB
C++

#include <psemek/gfx/painter.hpp>
#include <psemek/gfx/program.hpp>
#include <psemek/gfx/mesh.hpp>
#include <psemek/geom/constants.hpp>
static const char vertex_source[] =
R"(#version 330
uniform mat4 u_transform;
layout (location = 0) in vec4 in_position;
layout (location = 1) in vec4 in_color;
out vec4 color;
void main()
{
gl_Position = u_transform * in_position;
color = in_color;
}
)";
static const char fragment_source[] =
R"(#version 330
in vec4 color;
out vec4 out_color;
void main()
{
out_color = color;
}
)";
namespace psemek::gfx
{
struct painter::impl
{
struct vertex
{
geom::point<float, 3> position;
color_rgba color;
};
gfx::program program{vertex_source, fragment_source};
gfx::indexed_mesh mesh;
std::vector<vertex> vertices;
std::vector<std::uint32_t> indices;
impl()
{
mesh.setup<geom::vector<float, 3>, gfx::normalized<color_rgba>>();
}
};
painter::painter()
: pimpl_{std::make_unique<struct impl>()}
{}
painter::~painter() = default;
void painter::quad(geom::point<float, 2> const & p, float width, color const & c)
{
std::uint32_t const base = impl().vertices.size();
float const r = width / 2.f;
impl().vertices.push_back({{p[0] - r, p[1] - r, 0.f}, c});
impl().vertices.push_back({{p[0] + r, p[1] - r, 0.f}, c});
impl().vertices.push_back({{p[0] - r, p[1] + r, 0.f}, c});
impl().vertices.push_back({{p[0] + r, p[1] + r, 0.f}, c});
impl().indices.push_back(base + 0);
impl().indices.push_back(base + 1);
impl().indices.push_back(base + 3);
impl().indices.push_back(base + 0);
impl().indices.push_back(base + 3);
impl().indices.push_back(base + 2);
}
void painter::circle(geom::point<float, 2> const & p, float r, color const & c)
{
std::uint32_t const base = impl().vertices.size();
int const quality = 24;
impl().vertices.push_back({{p[0], p[1], 0.f}, c});
for (int i = 0; i < quality; ++i)
{
float const a = (geom::pi * 2.f * i) / quality;
impl().vertices.push_back({{p[0] + r * std::cos(a), p[1] + r * std::sin(a), 0.f}, c});
}
for (int i = 0; i < quality; ++i)
{
impl().indices.push_back(base);
impl().indices.push_back(base + 1 + i);
impl().indices.push_back(base + 1 + ((i + 1) % quality));
}
}
void painter::line(geom::point<float, 2> const & p0, geom::point<float, 2> const & p1, float width, color const & c, bool smooth)
{
std::uint32_t const base = impl().vertices.size();
float const r = width / 2.f;
auto const d = geom::normalized(p1 - p0);
geom::vector<float, 2> const o { -d[1], d[0] };
impl().vertices.push_back({{p0[0] + r * o[0], p0[1] + r * o[1], 0.f}, c});
impl().vertices.push_back({{p0[0] - r * o[0], p0[1] - r * o[1], 0.f}, c});
impl().vertices.push_back({{p1[0] + r * o[0], p1[1] + r * o[1], 0.f}, c});
impl().vertices.push_back({{p1[0] - r * o[0], p1[1] - r * o[1], 0.f}, c});
impl().indices.push_back(base + 0);
impl().indices.push_back(base + 1);
impl().indices.push_back(base + 3);
impl().indices.push_back(base + 0);
impl().indices.push_back(base + 3);
impl().indices.push_back(base + 2);
if (smooth)
{
circle(p0, r, c);
circle(p1, r, c);
}
}
void painter::render(geom::matrix<float, 4, 4> const & transform)
{
impl().mesh.load(impl().vertices, impl().indices, gl::STREAM_DRAW);
impl().vertices.clear();
impl().indices.clear();
impl().program.bind();
impl().program["u_transform"] = transform;
impl().mesh.draw(gl::TRIANGLES);
}
}