panopainter/src/brush.h

#pragma once
#include "rtt.h"
#include "shader.h"
#include "texture.h"

class Brush
{
public:
    //Brush() = default;
    //Brush(const Brush& brush) = default;
    std::string m_name;

    std::shared_ptr<Texture2D> m_tip_texture;
    std::string m_brush_path;
    std::string m_brush_thumb_path;

    std::shared_ptr<Texture2D> m_dual_texture;
    std::string m_dual_path;
    std::string m_dual_thumb_path;
    
    std::shared_ptr<Texture2D> m_stencil_texture;
    std::string m_stencil_path;
    std::string m_stencil_thumb_path;

    glm::vec4 m_tip_color{0, 0, 0, 1};
    float m_tip_size = .25f;
    float m_tip_spacing = .25;
    float m_tip_flow = 1;
    float m_tip_opacity = 1;
    float m_tip_angle = 0;
    float m_tip_angle_delay = 0;
    float m_tip_mix = 0;
    float m_tip_stencil = 0;
    float m_tip_wet = 0;
    float m_tip_noise = 0;
    float m_tip_hue = 0;
    float m_tip_sat = 0;
    float m_tip_val = 0;
    bool  m_tip_angle_follow = false;
    bool  m_tip_flow_pressure = false;
    bool  m_tip_size_pressure = false;
    float m_jitter_scale = 0;
    float m_jitter_angle = 0;
    float m_jitter_spread = 0;
    float m_jitter_flow = 0;
    float m_jitter_hue = 0;
    float m_jitter_sat = 0;
    float m_jitter_val = 0;
    int m_blend_mode = 0;

    bool m_tip_invert = false;
    bool m_tip_flipx = false;
    bool m_tip_flipy = false;
    bool m_tex_enabled = false;
    bool m_dual_enabled = false;
    int m_dual_blend_mode = 0;
    bool m_dual_randflip = false;
    float m_dual_size = .25;
    float m_dual_spacing = .25;
    float m_dual_scatter = 0;
    bool m_dual_scatter_axis = false;
    bool m_dual_invert = false;
    bool m_dual_flipx = false;
    bool m_dual_flipy = false;
    bool m_tip_randflipx = false;
    bool m_tip_randflipy = false;
    float m_tip_aspect = 0.5f;
    float m_dual_flow = .75f;
    float m_dual_opacity = 1.f;
    float m_dual_rotate = .25f;

    bool load_texture(const std::string& path, const std::string& thumb);
    bool load_dual(const std::string& path, const std::string& thumb);
    bool load_stencil(const std::string& path, const std::string& thumb);
    bool load();
};

struct StrokeSample
{
    glm::vec3 col = { 0, 0, 0 };
    glm::vec3 pos = { 0, 0, 0 };
    glm::vec3 origin = { 0, 0, 0 };
    glm::vec2 scale = { 1, 1 };
    float size = 0;
    float flow = 0;
    float angle = 0;
    bool valid() const
    {
        return !(
            glm::isnan(angle) ||
            glm::isinf(angle) ||
            glm::any(glm::isnan(col)) ||
            glm::any(glm::isnan(pos)) ||
            glm::any(glm::isnan(origin))
        );
    }
};

class BrushMesh
{
public:
    GLuint buffers[3]{ 0 };
    GLuint vao{ 0 };
    struct instance_t { glm::mat4 mvp; float flow; };
    int loc_flow = 0;
    int loc_mvp = 0;
    
    bool create();
    void draw(const std::vector<StrokeSample>& samples, const glm::mat4& proj);
};

class Stroke
{
public:
    struct Keypoint
    {
        glm::vec3 pos = { 0, 0, 0 };
        float pressure = 0;
        float dist = 0;
    };
    struct Camera
    {
        glm::mat4 rot;
        float fov = 0;
    };
    int m_layer = 0;
    int m_dir_kp = 0;
    bool m_dir_valid = false;
    glm::vec2 m_dir_ref = { 1, 0 };
    float m_dir_ref_angle = 0;
    float m_dir_dist = 0;
    float m_dir_step = 10;
    float m_dir_angle = 0;
    float m_curve = 0;
    float m_dist = 0;
    float m_step = 0;
    float m_max_size = FLT_MAX;
    bool m_filter_points = true;
    Camera m_camera;
    std::shared_ptr<Brush> m_brush;
    cbuffer<float> m_direction{ 1 };
    cbuffer<float> m_pressure_buff{ 10 };
    cbuffer<glm::vec3> m_hsv_jitter{ 3 };
    StrokeSample m_prev_sample;
    std::vector<Keypoint> m_keypoints;
    std::vector<std::pair<glm::vec3, float>> m_hold_points;
    std::vector<StrokeSample> m_samples;
    int m_last_kp;
    std::minstd_rand prng;
    void start(const std::shared_ptr<Brush>& brush);
    void add_point(glm::vec3 pos, float pressure);
    void reset(bool clear_keypoints = false);
    bool has_sample();
    std::vector<StrokeSample> compute_samples();
    StrokeSample randomize_sample(const glm::vec3& pos, float pressure, float curve_angle);
};