application/026_halo/main.cpp

Copyright Matus Chochlik. Distributed under the Boost Software License, Version 1.0. See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt

 
#include <oglplus/gl.hpp>
#include <oglplus/gl_api.hpp>
 
#include <eagine/application/camera.hpp>
#include <eagine/application/main.hpp>
#include <eagine/embed.hpp>
#include <eagine/shapes/adjacency.hpp>
#include <eagine/shapes/icosahedron.hpp>
#include <eagine/shapes/torus.hpp>
#include <eagine/shapes/twisted_torus.hpp>
#include <eagine/shapes/value_tree.hpp>
#include <eagine/timeout.hpp>
#include <eagine/value_tree/json.hpp>
#include <oglplus/math/matrix.hpp>
#include <oglplus/math/vector.hpp>
 
#include "resources.hpp"
 
#include <iostream>
 
namespace eagine::application {
//------------------------------------------------------------------------------
class example_halo : public application {
public:
    example_halo(
      execution_context&,
      video_context&,
      std::shared_ptr<shapes::generator>);
 
    auto is_done() noexcept -> bool final {
        return _is_done.is_expired();
    }
 
    void on_video_resize() noexcept final;
    void update() noexcept final;
    void clean_up() noexcept final;
 
private:
    execution_context& _ctx;
    video_context& _video;
    timeout _is_done{std::chrono::seconds{30}};
 
    orbiting_camera _camera;
    surface_program _surf_prog;
    halo_program _halo_prog;
    shape_geometry _shape;
};
//------------------------------------------------------------------------------
example_halo::example_halo(
  execution_context& ec,
  video_context& vc,
  std::shared_ptr<shapes::generator> gen)
  : _ctx{ec}
  , _video{vc}
  , _shape{std::move(gen)} {
    auto& glapi = _video.gl_api();
    auto& [gl, GL] = glapi;
 
    _shape.init(ec, vc);
 
    _surf_prog.init(ec, vc);
    _surf_prog.bind_position_location(vc, _shape.position_loc());
    _surf_prog.bind_normal_location(vc, _shape.normal_loc());
 
    _halo_prog.init(ec, vc);
    _halo_prog.bind_position_location(vc, _shape.position_loc());
    _halo_prog.bind_normal_location(vc, _shape.normal_loc());
 
    // camera
    _camera.set_near(0.1F)
      .set_far(50.F)
      .set_orbit_min(1.4F)
      .set_orbit_max(3.5F)
      .set_fov(right_angle_());
 
    gl.clear_color(0.25F, 0.25F, 0.25F, 0.0F);
    gl.enable(GL.depth_test);
    gl.enable(GL.cull_face);
    gl.cull_face(GL.back);
    gl.blend_func(GL.src_alpha, GL.one);
 
    _camera.connect_inputs(ec).basic_input_mapping(ec);
    ec.setup_inputs().switch_input_mapping();
}
//------------------------------------------------------------------------------
void example_halo::on_video_resize() noexcept {
    auto& gl = _video.gl_api();
    gl.viewport(_video.surface_size());
}
//------------------------------------------------------------------------------
void example_halo::update() noexcept {
    auto& state = _ctx.state();
    if(state.is_active()) {
        _is_done.reset();
    }
    if(state.user_idle_too_long()) {
        _camera.idle_update(state, 5.F);
    }
 
    auto& glapi = _video.gl_api();
    auto& [gl, GL] = glapi;
 
    gl.clear(GL.color_buffer_bit | GL.depth_buffer_bit);
 
    float t = _ctx.state().frame_time().value();
    _surf_prog.prepare_frame(_video, _camera, t);
    _shape.draw(_ctx, _video);
 
    gl.depth_mask(GL.false_);
    gl.enable(GL.blend);
    _halo_prog.prepare_frame(_video, _camera, t);
    _shape.draw(_ctx, _video);
    gl.disable(GL.blend);
    gl.depth_mask(GL.true_);
 
    _video.commit();
}
//------------------------------------------------------------------------------
void example_halo::clean_up() noexcept {
 
    _halo_prog.clean_up(_video);
    _surf_prog.clean_up(_video);
    _shape.clean_up(_video);
 
    _video.end();
}
//------------------------------------------------------------------------------
class example_launchpad : public launchpad {
public:
    auto setup(main_ctx& ctx, launch_options& opts) -> bool final {
        opts.no_audio().require_input().require_video();
        std::shared_ptr<shapes::generator> gen;
 
        if(ctx.args().find("--icosahedron")) {
            gen = shapes::unit_icosahedron(
              shapes::vertex_attrib_kind::position |
              shapes::vertex_attrib_kind::normal);
        } else if(ctx.args().find("--twisted-torus")) {
            gen = shapes::unit_twisted_torus(
              shapes::vertex_attrib_kind::position |
              shapes::vertex_attrib_kind::normal);
        } else if(ctx.args().find("--torus")) {
            gen = shapes::unit_torus(
              shapes::vertex_attrib_kind::position |
              shapes::vertex_attrib_kind::normal);
        }
 
        if(!gen) {
            const auto json_src{
              embed(EAGINE_ID(SphereJson), "twisted_sphere.json")};
            gen = shapes::from_value_tree(
              valtree::from_json_text(as_chars(json_src.unpack(ctx)), ctx),
              ctx);
        }
 
        _gen = shapes::add_triangle_adjacency(std::move(gen));
        return true;
    }
 
    auto check_requirements(video_context& vc) -> bool {
        auto& [gl, GL] = vc.gl_api();
 
        return gl.disable && gl.clear_color && gl.create_shader &&
               gl.shader_source && gl.compile_shader && gl.create_program &&
               gl.attach_shader && gl.link_program && gl.use_program &&
               gl.gen_buffers && gl.bind_buffer && gl.buffer_data &&
               gl.gen_vertex_arrays && gl.bind_vertex_array &&
               gl.get_attrib_location && gl.vertex_attrib_pointer &&
               gl.enable_vertex_attrib_array && gl.draw_arrays &&
               GL.vertex_shader && GL.geometry_shader && GL.fragment_shader;
    }
 
    auto launch(execution_context& ec, const launch_options&)
      -> std::unique_ptr<application> final {
        if(auto opt_vc{ec.video_ctx()}) {
            auto& vc = extract(opt_vc);
            vc.begin();
            if(vc.init_gl_api()) {
                if(check_requirements(vc)) {
                    return {std::make_unique<example_halo>(ec, vc, _gen)};
                }
            }
        }
        return {};
    }
 
private:
    std::shared_ptr<shapes::generator> _gen;
};
//------------------------------------------------------------------------------
auto establish(main_ctx&) -> std::unique_ptr<launchpad> {
    return {std::make_unique<example_launchpad>()};
}
//------------------------------------------------------------------------------
} // namespace eagine::application