application/011_mandelbrot/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 <eagine/application/main.hpp>
#include <eagine/application_config.hpp>
#include <eagine/embed.hpp>
#include <eagine/timeout.hpp>
 
#include <oglplus/gl.hpp>
#include <oglplus/gl_api.hpp>
 
#include <oglplus/glsl/string_ref.hpp>
#include <oglplus/math/primitives.hpp>
#include <oglplus/math/vector.hpp>
 
namespace eagine::application {
//------------------------------------------------------------------------------
class example_mandelbrot : public application {
public:
    example_mandelbrot(execution_context& ctx, video_context&);
 
    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;
 
    void dampening(const input&);
    void dragging(const input&);
    void zoom(const input&);
    void pan_x(const input&);
    void pan_y(const input&);
 
private:
    execution_context& _ctx;
    video_context& _video;
    timeout _is_done{std::chrono::seconds(20)};
 
    oglp::owned_vertex_array_name vao;
 
    oglp::owned_buffer_name positions;
    oglp::owned_buffer_name coords;
 
    oglp::owned_shader_name vs;
    oglp::owned_shader_name fs;
 
    oglp::owned_program_name prog;
 
    oglp::uniform_location offset_loc;
    oglp::uniform_location scale_loc;
 
    oglp::owned_texture_name gradient;
 
    float offset_x{-0.5F};
    float offset_y{0.0F};
    float scale{1.0F};
    float aspect{1.0F};
    bool dampen_motion{false};
    bool is_dragging{false};
 
    auto motion_adjust() const noexcept {
        return dampen_motion ? 0.2 : 1.0;
    }
 
    static constexpr const float min_scale{0.00001F};
    static constexpr const float max_scale{10.0F};
};
//------------------------------------------------------------------------------
example_mandelbrot::example_mandelbrot(execution_context& ec, video_context& vc)
  : _ctx{ec}
  , _video{vc} {
    auto& [gl, GL] = _video.gl_api();
 
    gl.clear_color(0.4F, 0.4F, 0.4F, 0.0F);
 
    // vertex shader
    auto vs_source = embed(EAGINE_ID(VertShader), "vertex.glsl");
    gl.create_shader(GL.vertex_shader) >> vs;
    gl.shader_source(vs, oglp::glsl_string_ref(vs_source));
    gl.compile_shader(vs);
 
    // fragment shader
    auto fs_source = embed(EAGINE_ID(FragShader), "fragment.glsl");
    gl.create_shader(GL.fragment_shader) >> fs;
    gl.shader_source(fs, oglp::glsl_string_ref(fs_source));
    gl.compile_shader(fs);
 
    // program
    gl.create_program() >> prog;
    gl.attach_shader(prog, vs);
    gl.attach_shader(prog, fs);
    gl.link_program(prog);
    gl.use_program(prog);
 
    gl.get_uniform_location(prog, "Offset") >> offset_loc;
    gl.get_uniform_location(prog, "Scale") >> scale_loc;
    gl.uniform2f(offset_loc, offset_x, offset_y);
    gl.uniform2f(scale_loc, aspect * scale, scale);
 
    // vao
    gl.gen_vertex_arrays() >> vao;
    gl.bind_vertex_array(vao);
 
    // positions
    const auto position_data =
      GL.float_.array(-1.0F, -1.0F, -1.0F, 1.0F, 1.0F, -1.0F, 1.0F, 1.0F);
 
    gl.gen_buffers() >> positions;
    gl.bind_buffer(GL.array_buffer, positions);
    gl.buffer_data(GL.array_buffer, view(position_data), GL.static_draw);
    oglp::vertex_attrib_location position_loc;
    gl.get_attrib_location(prog, "Position") >> position_loc;
 
    gl.vertex_attrib_pointer(position_loc, 2, GL.float_, GL.false_);
    gl.enable_vertex_attrib_array(position_loc);
 
    const auto coord_data =
      GL.float_.array(-1.0F, -1.0F, -1.0F, 1.0F, 1.0F, -1.0F, 1.0F, 1.0F);
 
    gl.gen_buffers() >> coords;
    gl.bind_buffer(GL.array_buffer, coords);
    gl.buffer_data(GL.array_buffer, view(coord_data), GL.static_draw);
    oglp::vertex_attrib_location coord_loc;
    gl.get_attrib_location(prog, "Coord") >> coord_loc;
 
    gl.vertex_attrib_pointer(coord_loc, 2, GL.float_, GL.false_);
    gl.enable_vertex_attrib_array(coord_loc);
 
    // gradient texture
    auto gradient_data = GL.float_.array(size_constant<8 * 3>{});
    _ctx.random_uniform_01(cover(gradient_data));
 
    gl.gen_textures() >> gradient;
    gl.active_texture(GL.texture0);
    gl.bind_texture(GL.texture_1d, gradient);
    gl.tex_parameter_i(GL.texture_1d, GL.texture_min_filter, GL.linear);
    gl.tex_parameter_i(GL.texture_1d, GL.texture_mag_filter, GL.linear);
    gl.tex_parameter_i(GL.texture_1d, GL.texture_wrap_s, GL.repeat);
    gl.tex_image1d(
      GL.texture_1d,
      0,
      GL.rgb,
      8,
      0,
      GL.rgb,
      GL.float_,
      as_bytes(view(gradient_data)));
 
    gl.disable(GL.depth_test);
 
    ec.connect_inputs()
      .connect_input(
        EAGINE_MSG_ID(Motion, Dampening),
        {this, EAGINE_THIS_MEM_FUNC_C(dampening)})
      .connect_input(
        EAGINE_MSG_ID(Cursor, Dragging),
        {this, EAGINE_THIS_MEM_FUNC_C(dragging)})
      .connect_input(
        EAGINE_MSG_ID(View, Zoom), {this, EAGINE_THIS_MEM_FUNC_C(zoom)})
      .connect_input(
        EAGINE_MSG_ID(View, PanX), {this, EAGINE_THIS_MEM_FUNC_C(pan_x)})
      .connect_input(
        EAGINE_MSG_ID(View, PanY), {this, EAGINE_THIS_MEM_FUNC_C(pan_y)})
      .map_inputs()
      .map_input(
        EAGINE_MSG_ID(Motion, Dampening),
        EAGINE_MSG_ID(Keyboard, LeftCtrl),
        input_setup().trigger())
      .map_input(
        EAGINE_MSG_ID(Cursor, Dragging),
        EAGINE_MSG_ID(Cursor, Button0),
        input_setup().trigger())
      .map_input(
        EAGINE_MSG_ID(View, Zoom),
        EAGINE_MSG_ID(Wheel, ScrollY),
        input_setup().relative())
      .map_input(
        EAGINE_MSG_ID(View, Zoom),
        EAGINE_MSG_ID(Keyboard, KpPlus),
        input_setup().trigger().multiply(0.25))
      .map_input(
        EAGINE_MSG_ID(View, Zoom),
        EAGINE_MSG_ID(Keyboard, KpMinus),
        input_setup().trigger().multiply(0.25).invert())
      .map_input(
        EAGINE_MSG_ID(View, PanX),
        EAGINE_MSG_ID(Keyboard, Left),
        input_setup().trigger().multiply(0.25))
      .map_input(
        EAGINE_MSG_ID(View, PanX),
        EAGINE_MSG_ID(Keyboard, Right),
        input_setup().trigger().multiply(0.25).invert())
      .map_input(
        EAGINE_MSG_ID(View, PanY),
        EAGINE_MSG_ID(Keyboard, Down),
        input_setup().trigger().multiply(0.25))
      .map_input(
        EAGINE_MSG_ID(View, PanY),
        EAGINE_MSG_ID(Keyboard, Up),
        input_setup().trigger().multiply(0.25).invert())
      .map_input(
        EAGINE_MSG_ID(View, PanX),
        EAGINE_MSG_ID(Cursor, MotionX),
        input_setup().relative().multiply(2).only_if(is_dragging))
      .map_input(
        EAGINE_MSG_ID(View, PanY),
        EAGINE_MSG_ID(Cursor, MotionY),
        input_setup().relative().multiply(2).only_if(is_dragging))
      .switch_input_mapping();
}
//------------------------------------------------------------------------------
void example_mandelbrot::on_video_resize() noexcept {
    auto& gl = _video.gl_api();
 
    aspect = _video.surface_aspect();
    gl.viewport(_video.surface_size());
    gl.uniform2f(scale_loc, scale * aspect, scale);
}
//------------------------------------------------------------------------------
void example_mandelbrot::dampening(const input& i) {
    dampen_motion = bool(i);
}
//------------------------------------------------------------------------------
void example_mandelbrot::dragging(const input& i) {
    is_dragging = bool(i);
}
//------------------------------------------------------------------------------
void example_mandelbrot::zoom(const input& i) {
    scale *= float(std::pow(2, -i.get() * motion_adjust()));
    if(scale < min_scale) {
        scale = min_scale;
    }
    if(scale > max_scale) {
        scale = max_scale;
    }
 
    auto& gl = _video.gl_api();
    gl.uniform2f(scale_loc, scale * aspect, scale);
}
//------------------------------------------------------------------------------
void example_mandelbrot::pan_x(const input& i) {
    offset_x -= float(i.get() * scale * motion_adjust());
 
    auto& gl = _video.gl_api();
    gl.uniform2f(offset_loc, offset_x, offset_y);
}
//------------------------------------------------------------------------------
void example_mandelbrot::pan_y(const input& i) {
    offset_y -= float(i.get() * scale * motion_adjust());
 
    auto& gl = _video.gl_api();
    gl.uniform2f(offset_loc, offset_x, offset_y);
}
//------------------------------------------------------------------------------
void example_mandelbrot::update() noexcept {
    auto& state = _ctx.state();
    auto& [gl, GL] = _video.gl_api();
 
    if(state.is_active()) {
        _is_done.reset();
    }
    if(state.user_idle_time() > std::chrono::seconds(1)) {
        const float s = value(state.frame_duration()) * 60;
        const float dest_offset_x = -0.525929F;
        const float dest_offset_y = -0.668547F;
        const float c = 0.02F * s;
 
        offset_x = c * dest_offset_x + (1 - c) * offset_x;
        offset_y = c * dest_offset_y + (1 - c) * offset_y;
 
        scale *= (1 - 0.01F * s);
        if(scale < min_scale) {
            scale = min_scale;
        }
 
        gl.uniform2f(offset_loc, offset_x, offset_y);
        gl.uniform2f(scale_loc, scale * aspect, scale);
    }
 
    gl.clear(GL.color_buffer_bit);
    gl.draw_arrays(GL.triangle_strip, 0, 4);
 
    _video.commit();
}
//------------------------------------------------------------------------------
void example_mandelbrot::clean_up() noexcept {
    auto& gl = _video.gl_api();
 
    gl.delete_shader(std::move(vs));
    gl.delete_shader(std::move(fs));
    gl.delete_program(std::move(prog));
    gl.delete_buffers(std::move(positions));
    gl.delete_buffers(std::move(coords));
    gl.delete_vertex_arrays(std::move(vao));
    gl.delete_textures(std::move(gradient));
 
    _video.end();
}
//------------------------------------------------------------------------------
class example_launchpad : public launchpad {
public:
    auto setup(main_ctx&, launch_options& opts) -> bool final {
        opts.no_audio().require_input().require_video();
        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.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_mandelbrot>(ec, vc)};
                }
            }
        }
        return {};
    }
};
//------------------------------------------------------------------------------
auto establish(main_ctx&) -> std::unique_ptr<launchpad> {
    return {std::make_unique<example_launchpad>()};
}
//------------------------------------------------------------------------------
} // namespace eagine::application