panopainter/engine/canvas.h

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

NS_START

class Canvas
{
public:
    int m_width;
    int m_height;
    std::vector<Layer> m_layers;
    std::vector<Stroke> m_strokes;
    std::unique_ptr<Layer> m_tmp;
    Stroke* m_current_stroke = nullptr;
    int m_current_layer_idx = 0;
    RTT m_fb;
    Sampler m_sampler;
    Plane m_plane;
    std::minstd_rand prng;
    bool create(int width, int height)
    {
        m_width = width;
        m_height = height;
        m_tmp = std::make_unique<Layer>();
        m_tmp->create(width, height, "tmp");
        m_fb.create(width, height);
        m_sampler.create();
        m_plane.create<1>(1, 1);
        return true;
    }
    void layer_add(std::string name)
    {
        m_layers.emplace_back();
        m_layers.back().create(m_width, m_height, name);
    }
    void stroke_start(glm::vec2 point, float pressure, const ui::Brush& brush)
    {
        prng.seed(0);
        m_strokes.emplace_back();
        m_strokes.back().m_brush = brush;
        m_strokes.back().add_point(point, pressure);
        m_current_stroke = &m_strokes.back();
    }
    void stroke_update(glm::vec2 point, float pressure)
    {
        m_current_stroke->add_point(point, pressure);

        m_fb.bindFramebuffer();

        GLint vp[4];
        GLfloat cc[4];
        glGetIntegerv(GL_VIEWPORT, vp);
        glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);

        glViewport(0, 0, m_width, m_height);
        glEnable(GL_BLEND);

        //auto mvp = glm::ortho(0.f, (float)m_width, (float)m_height, 0.f, -1.f, 1.f) *
        //    glm::translate(glm::vec3(point, 0)) *
        //    glm::scale(glm::vec3(30, 30, 1));
        //auto& tex = TextureManager::get(m_current_stroke->m_brush.m_tex_id);
        //tex.bind();
        //m_sampler.bind(0);
        //ui::ShaderManager::use(kShader::Stroke);
        //ui::ShaderManager::u_int(kShaderUniform::Tex, 0);
        //ui::ShaderManager::u_mat4(kShaderUniform::MVP, mvp);
        //ui::ShaderManager::u_float(kShaderUniform::Alpha, 1.f);
        //ui::ShaderManager::u_vec4(kShaderUniform::Col, { 0, 0, 0, 1 });
        //m_plane.draw_fill();
        //m_sampler.unbind();
        //tex.unbind();

        auto proj = glm::ortho(0.f, (float)m_width, (float)m_height, 0.f, -1.f, 1.f);
        auto m_brush = m_current_stroke->m_brush;

        auto rnd_nor = [&] { return float((double)prng() / (double)prng.max()); };              // normalized [0, +1]
        auto rnd_neg = [&] { return float((double)prng() / (double)prng.max() * 2.0 - 1.0); };  // normalized [-1, +1]
        auto rnd_rad = [&] { return float((double)prng() / (double)prng.max() * M_PI * 2.0); }; // normalized [0, 2pi]
        auto rnd_vec = [&] { float rad = rnd_rad(); return glm::vec2(cosf(rad), sinf(rad)); };  // normalized direction vector

        float angle = (m_brush.m_tip_angle + rnd_nor() * m_brush.m_jitter_angle) * (float)(M_PI * 2.0);
        glm::vec2 pos = point + (rnd_vec() * m_brush.m_jitter_spread * 100.f);
        float size = 100.f * m_brush.m_tip_size * (1.f - rnd_nor() * m_brush.m_jitter_scale);
        float flow = m_brush.m_tip_flow * (1.f - rnd_nor() * m_brush.m_jitter_flow);

        //alpha += glm::max(m_brush.m_tip_spacing * .2f, .01f);
        auto mvp = proj *
            //glm::translate(glm::vec3(i * 40 * m_tip_spacing, m_rtt.getHeight() / 2, 0)) *
            glm::translate(glm::vec3(pos, 0)) *
            glm::scale(glm::vec3(size, size, 1)) *
            glm::eulerAngleZ(angle);
       
        auto& tex = TextureManager::get(m_brush.m_tex_id);
        tex.bind();
        m_sampler.bind(0);
        ShaderManager::use("stroke");
        ShaderManager::u_vec4(kShaderUniform::Col, m_brush.m_tip_color);
        ShaderManager::u_int(kShaderUniform::Tex, 0);
        ShaderManager::u_mat4(kShaderUniform::MVP, mvp);
        ShaderManager::u_float(kShaderUniform::Alpha, flow);
        m_plane.draw_fill();
        m_sampler.unbind();
        tex.unbind();

        glDisable(GL_BLEND);

        glViewport(vp[0], vp[1], vp[2], vp[3]);
        glClearColor(cc[0], cc[1], cc[2], cc[3]);

        m_fb.unbindFramebuffer();
    }
    void stroke_end()
    {
        m_current_stroke = nullptr;
    }
    void clear()
    {
        m_fb.bindFramebuffer();

        GLint vp[4];
        GLfloat cc[4];
        glGetIntegerv(GL_VIEWPORT, vp);
        glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);

        glClearColor(1, 1, 1, 1);
        glClear(GL_COLOR_BUFFER_BIT);
        glViewport(0, 0, m_width, m_height);

        //

        glViewport(vp[0], vp[1], vp[2], vp[3]);
        glClearColor(cc[0], cc[1], cc[2], cc[3]);

        m_fb.unbindFramebuffer();
    }
};

NS_END