#include "pch.h"
#include "log.h"
#include "node_stroke_preview.h"
#include "texture.h"
#include "shader.h"
#include "bezier.h"
#include "canvas.h"
#include "app.h"

std::atomic_int NodeStrokePreview::s_instances{ 0 };
std::atomic_bool NodeStrokePreview::s_running{ false };
std::mutex NodeStrokePreview::s_render_mutex;
std::thread NodeStrokePreview::s_renderer;
BlockingQueue<std::shared_ptr<NodeStrokePreview>> NodeStrokePreview::s_queue;

RTT NodeStrokePreview::m_rtt;
RTT NodeStrokePreview::m_rtt_mixer;
Texture2D NodeStrokePreview::m_tex; // blending tmp texture
Texture2D NodeStrokePreview::m_tex_dual;
Texture2D NodeStrokePreview::m_tex_background;
Sampler NodeStrokePreview::m_sampler_linear;
Sampler NodeStrokePreview::m_sampler_linear_repeat;
Sampler NodeStrokePreview::m_sampler_mipmap;
DynamicShape NodeStrokePreview::m_brush_shape;


void NodeStrokePreview::terminate_renderer()
{
    if (s_running && s_renderer.joinable())
    {
        s_running = false;
        s_queue.UnlockGetters();
        s_renderer.join();
    }
}

void NodeStrokePreview::empty_queue()
{
    s_queue.q.clear();
}

Node* NodeStrokePreview::clone_instantiate() const
{
    return new NodeStrokePreview();
}

void NodeStrokePreview::clone_copy(Node* dest) const
{
    NodeBorder::clone_copy(dest);
}

void NodeStrokePreview::clone_children(Node* dest) const
{
    // stop children cloning
}

void NodeStrokePreview::clone_finalize(Node* dest) const
{
    NodeStrokePreview* n = (NodeStrokePreview*)dest;
    n->init_controls();
}

void NodeStrokePreview::init_controls()
{
//     TextureManager::load("data/thumbs/Round-Hard.png");
//     Canvas::I->m_current_brush.m_tex_id = const_hash("data/thumbs/Round-Hard.png");
}

void NodeStrokePreview::restore_context()
{
    NodeBorder::restore_context();
    init_controls();
    if (m_size.x > 0 && m_size.y > 0)
        m_tex_preview.create(m_size.x, m_size.y);
    draw_stroke();
}

void NodeStrokePreview::clear_context()
{
    NodeBorder::clear_context();
    m_tex_preview.destroy();
}

void NodeStrokePreview::stroke_draw_mix(const glm::vec2& bb_min, const glm::vec2& bb_sz)
{
    gl_state gl;
    gl.save();

    m_rtt_mixer.bindFramebuffer();

    glViewport(0, 0, m_rtt_mixer.getWidth(), m_rtt_mixer.getHeight());
    glDisable(GL_DEPTH_TEST);
    glEnable(GL_SCISSOR_TEST);
    glDisable(GL_BLEND);

    glScissor(bb_min.x, bb_min.y, bb_sz.x, bb_sz.y);

    const auto& b = m_brush;
    glm::vec2 patt_scale = glm::vec2(b->m_pattern_scale);
    if (b->m_pattern_flipx) patt_scale.x *= -1.f;
    if (b->m_pattern_flipy) patt_scale.y *= -1.f;

    ShaderManager::use(kShader::CompDraw);
    ShaderManager::u_int(kShaderUniform::Tex, 0);
    ShaderManager::u_int(kShaderUniform::TexStroke, 1);
    ShaderManager::u_int(kShaderUniform::TexMask, 2);
    ShaderManager::u_int(kShaderUniform::TexDual, 3);
    ShaderManager::u_int(kShaderUniform::TexPattern, 4);
    ShaderManager::u_vec2(kShaderUniform::Resolution, m_size);
    ShaderManager::u_float(kShaderUniform::Alpha, 1);
    ShaderManager::u_int(kShaderUniform::Lock, false);
    ShaderManager::u_int(kShaderUniform::Mask, false);
    ShaderManager::u_int(kShaderUniform::UseFragcoord, false);
    ShaderManager::u_int(kShaderUniform::BlendMode, b->m_blend_mode);
    ShaderManager::u_mat4(kShaderUniform::MVP, glm::ortho(-.5f, .5f, -.5f, .5f, -1.f, 1.f));
    ShaderManager::u_int(kShaderUniform::UseDual, b->m_dual_enabled);
    ShaderManager::u_int(kShaderUniform::UsePattern, b->m_pattern_enabled && !b->m_pattern_eachsample);
    ShaderManager::u_int(kShaderUniform::DualBlendMode, b->m_dual_blend_mode);
    ShaderManager::u_vec2(kShaderUniform::PatternScale, patt_scale);
    ShaderManager::u_float(kShaderUniform::PatternInvert, b->m_pattern_invert);
    ShaderManager::u_float(kShaderUniform::PatternBright, b->m_pattern_brightness);
    ShaderManager::u_float(kShaderUniform::PatternContrast, b->m_pattern_contrast);
    ShaderManager::u_float(kShaderUniform::PatternDepth, b->m_pattern_depth);
    ShaderManager::u_int(kShaderUniform::PatternBlendMode, b->m_pattern_blend_mode);
    ShaderManager::u_vec2(kShaderUniform::PatternOffset, glm::vec2(b->m_pattern_rand_offset ? 0.5f : 0.0f));
    ShaderManager::u_float(kShaderUniform::DualAlpha, b->m_dual_opacity);

    m_sampler_linear.bind(0);
    glActiveTexture(GL_TEXTURE0);
    m_tex_background.bind();
    glActiveTexture(GL_TEXTURE1);
    m_tex.bind();
    glActiveTexture(GL_TEXTURE3);
    m_tex_dual.bind();
    glActiveTexture(GL_TEXTURE4);
    b->m_pattern_texture ?
        b->m_pattern_texture->bind() :
        glBindTexture(GL_TEXTURE_2D, 0);
    m_plane.draw_fill();

    m_rtt_mixer.unbindFramebuffer();
    gl.restore();
}

glm::vec4 NodeStrokePreview::stroke_draw_samples(std::array<vertex_t, 4>& P, Texture2D& blend_tex)
{
    if (!ShaderManager::ext_framebuffer_fetch)
    {
        glActiveTexture(GL_TEXTURE1);
        blend_tex.bind(); // bg, copy of framebuffer (copied before drawing)
    }

    glm::vec2 size = { m_rtt.getWidth(), m_rtt.getHeight() };

    glm::vec2 bb_min(size);
    glm::vec2 bb_max(0, 0);
    for (int j = 0; j < P.size(); j++)
    {
        bb_min = glm::max({ 0, 0 }, glm::min(bb_min, xy(P[j].pos)));
        bb_max = glm::min(size, glm::max(bb_max, xy(P[j].pos)));
    }
    auto bb_sz = bb_max - bb_min;

    glm::vec2 pad(1);
    glm::ivec2 tex_pos = glm::clamp(glm::floor(bb_min) - pad, { 0, 0 }, size);
    glm::ivec2 tex_sz = glm::clamp(glm::ceil(bb_sz) + pad * 2.f, { 0, 0 }, (glm::vec2)(glm::ivec2(size) - tex_pos));
    if (!ShaderManager::ext_framebuffer_fetch)
    {
        glCopyTexSubImage2D(GL_TEXTURE_2D, 0, tex_pos.x, tex_pos.y,
            tex_pos.x, tex_pos.y, tex_sz.x, tex_sz.y);
    }

    if (P.size() == 4)
    {
        static vertex_t rect[6];
        rect[0] = P[0];
        rect[1] = P[1];
        rect[2] = P[2];
        rect[3] = P[0];
        rect[4] = P[2];
        rect[5] = P[3];
        m_brush_shape.update_vertices(rect, 6);
    }
    m_brush_shape.draw_fill();

    if (!ShaderManager::ext_framebuffer_fetch)
    {
        glActiveTexture(GL_TEXTURE1);
        blend_tex.unbind();
    }

    return glm::vec4(tex_pos, tex_pos + tex_sz);
}

std::vector<NodeStrokePreview::StrokeFrame> NodeStrokePreview::stroke_draw_compute(Stroke& stroke, float zoom) const
{
    std::vector<StrokeFrame> ret;
    StrokeSample prev = stroke.m_prev_sample;
    auto samples = stroke.compute_samples();
    std::array<vertex_t, 4> B = {
        vertex_t{ {0, 0, 1, 1}, {0, 0}, {0, 0} },
        vertex_t{ {0, 0, 1, 1}, {0, 1}, {0, 1} },
        vertex_t{ {0, 0, 1, 1}, {1, 1}, {1, 1} },
        vertex_t{ {0, 0, 1, 1}, {1, 0}, {1, 0} },
    };
    for (const auto& s : samples)
    {
        if (!s.valid())
            continue;

        ret.emplace_back();
        auto& f = ret.back();

        glm::vec2 dx_mix(prev.size * 0.5f, 0), dy_mix(0, prev.size * 0.5f);
        glm::vec2 off_mix[4] = {
            -dx_mix - dy_mix, // A - bottom-left
            -dx_mix + dy_mix, // B - top-left
            +dx_mix + dy_mix, // C - top-right
            +dx_mix - dy_mix, // D - bottom-right
        };
        // P is the initial square centered at the cursor location 
        glm::vec2 dx(s.size * 0.5f, 0), dy(0, s.size * 0.5f);
        glm::vec2 off[4] = {
            -dx - dy, // A - bottom-left
            -dx + dy, // B - top-left
            +dx + dy, // C - top-right
            +dx - dy, // D - bottom-right
        };

        glm::vec2 mixer_sz(m_rtt.getWidth(), m_rtt.getHeight());
        glm::vec2 mixer_bb_min(mixer_sz);
        glm::vec2 mixer_bb_max(0, 0);
        for (int j = 0; j < 4; j++)
        {
            auto p = (xy(prev.pos) + zoom * s.scale * off_mix[j] * glm::orientate2(-s.angle));
            mixer_bb_min = glm::max({ 0, 0 }, glm::min(mixer_bb_min, p));
            mixer_bb_max = glm::min(mixer_sz, glm::max(mixer_bb_max, p));

            B[j].pos = glm::vec4(xy(s.pos) + zoom * s.scale * off[j] * glm::orientate2(-s.angle) - glm::vec2(0, 1), 1, 1);
            B[j].uvs2 = p / mixer_sz;
        }

        f.m_mixer_rect = { glm::floor(mixer_bb_min), glm::ceil(mixer_bb_max - mixer_bb_min) };
        f.col = glm::vec4(s.col, 1);
        f.flow = s.flow;
        f.opacity = s.opacity;
        f.shapes = B;

        prev = s;
    }
    return ret;
}

void NodeStrokePreview::draw_stroke_immediate()
{
    if (m_size.x == 0 || m_size.y == 0)
        return;

    GLint vp[4];
    GLfloat cc[4];
    glGetIntegerv(GL_VIEWPORT, vp);
    glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);
    
    float zoom = root()->m_zoom;

    glm::vec2 size = { m_rtt.getWidth(), m_rtt.getHeight() };
    glm::mat4 ortho_proj = glm::ortho<float>(0, size.x, 0, size.y, -1, 1);
    glViewport(0, 0, m_rtt.getWidth(), m_rtt.getHeight());
    m_rtt.bindFramebuffer();
    m_rtt.clear();
    m_sampler_mipmap.bind(0);
    m_sampler_linear.bind(1);
    m_sampler_linear_repeat.bind(2);
    m_sampler_linear.bind(3);
    m_sampler_linear.bind(4);

    const auto& b = m_brush;

    Stroke m_stroke;
    Stroke m_dual_stroke;

    m_stroke.m_filter_points = false;
    m_stroke.m_max_size = m_max_size > 0 ? m_max_size : m_size.y * .75f;
    m_stroke.m_camera.fov = Canvas::I->m_cam_fov;
    m_stroke.m_camera.rot = Canvas::I->m_cam_rot;
    m_stroke.reset(true);
    m_stroke.start(b);

    auto dual_brush = std::make_shared<Brush>();
    dual_brush->m_tip_scale = b->m_dual_scale;
    dual_brush->m_tip_angle = b->m_dual_angle;
    dual_brush->m_tip_flow = b->m_dual_flow;
    dual_brush->m_tip_opacity = b->m_dual_opacity;
    dual_brush->m_tip_flipx = b->m_dual_flipx;
    dual_brush->m_tip_flipy = b->m_dual_flipy;
    dual_brush->m_tip_invert = b->m_dual_invert;
    dual_brush->m_blend_mode = b->m_dual_blend_mode;
    dual_brush->m_tip_randflipx = b->m_dual_randflip;
    dual_brush->m_tip_randflipy = b->m_dual_randflip;
    dual_brush->m_tip_size = b->m_dual_size * b->m_tip_size;
    dual_brush->m_tip_spacing = b->m_dual_spacing;
    dual_brush->m_jitter_scatter = b->m_dual_scatter;
    dual_brush->m_jitter_scatter_bothaxis = b->m_dual_scatter_bothaxis;
    dual_brush->m_jitter_angle = b->m_dual_rotate;
    dual_brush->m_tip_texture = b->m_dual_texture;
    dual_brush->m_tip_aspect = b->m_dual_aspect;

    if (b->m_dual_enabled)
    {
        m_dual_stroke.m_filter_points = false;
        m_dual_stroke.m_max_size = m_stroke.m_max_size * b->m_dual_size;
        m_dual_stroke.m_camera.fov = Canvas::I->m_cam_fov;
        m_dual_stroke.m_camera.rot = Canvas::I->m_cam_rot;
        m_dual_stroke.reset(true);
        m_dual_stroke.start(dual_brush);
    }

    {
        float min_pad = size.x * 0.05f;
        float pad = (5.f + glm::max(glm::min(m_stroke.m_max_size, m_brush->m_tip_size) / 2.f, min_pad)) * zoom;
        if (b->m_tip_size_pressure)
            pad = min_pad * zoom;
        if (!glm::isnan(m_pad_override))
            pad = m_pad_override;
        float w = m_size.x * zoom;
        float h = m_size.y * zoom;
        std::vector<glm::vec2> kp = {
            { pad, h / 2.f },
            { w / 2.f, 0 },
            { w / 2.f, h },
            { w - pad, h / 2.f },
        };
        for (int i = 0; i < 100; i++)
        {
            float t = (float)i / 100.f;
            float p = glm::clamp((1.f - glm::abs(t * 2.f - 1.f)) * 1.1f, 0.f, 1.f);
            m_stroke.add_point(glm::vec3(BezierCurve::Bezier2D(kp, t), 0), p);
            if (b->m_dual_enabled)
                m_dual_stroke.add_point(glm::vec3(BezierCurve::Bezier2D(kp, t), 0), p);
        }
    }

    glm::vec2 patt_scale = glm::vec2(b->m_pattern_scale);
    if (b->m_pattern_flipx) patt_scale.x *= -1.f;
    if (b->m_pattern_flipy) patt_scale.y *= -1.f;

    glDisable(GL_BLEND);
    ShaderManager::use(kShader::Stroke);
    ShaderManager::u_int(kShaderUniform::Tex, 0); // brush
    if (!ShaderManager::ext_framebuffer_fetch)
        ShaderManager::u_int(kShaderUniform::TexBG, 1); // bg
    ShaderManager::u_int(kShaderUniform::TexPattern, 2); // pattern
    ShaderManager::u_int(kShaderUniform::TexMix, 3); // mixer
    //ShaderManager::u_int(kShaderUniform::TexMixA, 4); // mixer
    ShaderManager::u_vec2(kShaderUniform::Resolution, size);
    ShaderManager::u_vec2(kShaderUniform::PatternScale, patt_scale);
    ShaderManager::u_float(kShaderUniform::PatternInvert, b->m_pattern_invert);
    ShaderManager::u_float(kShaderUniform::PatternBright, b->m_pattern_brightness);
    ShaderManager::u_float(kShaderUniform::PatternContrast, b->m_pattern_contrast);
    ShaderManager::u_float(kShaderUniform::PatternDepth, b->m_pattern_depth);
    ShaderManager::u_int(kShaderUniform::PatternBlendMode, b->m_pattern_blend_mode);
    ShaderManager::u_vec2(kShaderUniform::PatternOffset, glm::vec2(b->m_pattern_rand_offset ? 0.5f : 0.0f));
    ShaderManager::u_mat4(kShaderUniform::MVP, ortho_proj);

    // DRAW DUAL BRUSH

    if (b->m_dual_enabled)
    {
        m_rtt.clear();
        ShaderManager::use(kShader::Stroke);
        ShaderManager::u_int(kShaderUniform::UsePattern, false);
        ShaderManager::u_float(kShaderUniform::MixAlpha, 0);
        ShaderManager::u_float(kShaderUniform::Wet, 0);
        ShaderManager::u_float(kShaderUniform::Noise, 0);
        glActiveTexture(GL_TEXTURE0);
        dual_brush->m_tip_texture ?
            dual_brush->m_tip_texture->bind() :
            glBindTexture(GL_TEXTURE_2D, 0);
        auto frames_dual = stroke_draw_compute(m_dual_stroke, zoom);
        for (auto& f : frames_dual)
        {
            ShaderManager::u_vec4(kShaderUniform::Col, { 0, 0, 0, 1 });
            ShaderManager::u_float(kShaderUniform::Alpha, f.flow);
            ShaderManager::u_float(kShaderUniform::Opacity, f.opacity);
            /*auto rect =*/ stroke_draw_samples(f.shapes, m_tex_dual);
        }

        // copy raw stroke to tex
        glActiveTexture(GL_TEXTURE1);
        m_tex_dual.bind();
        glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, size.x, size.y);
    }

    // DRAW MAIN BRUSH

    ShaderManager::use(kShader::Stroke);
    ShaderManager::u_int(kShaderUniform::UsePattern, b->m_pattern_enabled && b->m_pattern_eachsample);
    ShaderManager::u_float(kShaderUniform::MixAlpha, b->m_tip_mix);
    ShaderManager::u_float(kShaderUniform::Wet, b->m_tip_wet);
    ShaderManager::u_float(kShaderUniform::Noise, b->m_tip_noise);

    glActiveTexture(GL_TEXTURE0);
    b->m_tip_texture->bind();
    glActiveTexture(GL_TEXTURE1);
    m_tex.bind(); // tmp swap for blending
    glActiveTexture(GL_TEXTURE2);
    b->m_pattern_texture ?
        b->m_pattern_texture->bind() :
        glBindTexture(GL_TEXTURE_2D, 0);
    glActiveTexture(GL_TEXTURE3);
    b->m_tip_mix > 0.f ? m_rtt_mixer.bindTexture() : glBindTexture(GL_TEXTURE_2D, 0);
    auto frames = stroke_draw_compute(m_stroke, zoom);
    m_rtt.clear();
    for (auto& f : frames)
    {
        if (b->m_tip_mix > 0.f)
        {
            stroke_draw_mix(xy(f.m_mixer_rect), zw(f.m_mixer_rect));
        }

        ShaderManager::use(kShader::Stroke);
        if (b->m_blend_mode != 0)
            ShaderManager::u_vec4(kShaderUniform::Col, { .7, .4, .1, 1 } /*f.col*/);
        else
            ShaderManager::u_vec4(kShaderUniform::Col, { 0, 0, 0, 1 } /*f.col*/);
        ShaderManager::u_float(kShaderUniform::Alpha, glm::max(f.flow, m_min_flow));
        ShaderManager::u_float(kShaderUniform::Opacity, f.opacity);
        /*auto rect =*/ stroke_draw_samples(f.shapes, m_tex);
    }
    glActiveTexture(GL_TEXTURE3);
    m_rtt_mixer.unbindTexture();

    // copy raw stroke to tex
    glActiveTexture(GL_TEXTURE1);
    m_tex.bind();
    glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, size.x, size.y);

    // CHEKCERBOARD

    // copy background color to tex2
    ShaderManager::use(kShader::Checkerboard);
    ShaderManager::u_int(kShaderUniform::Colorize, b->m_tip_mix > 0.f || b->m_blend_mode != 0);
    float aspect = size.x / size.y;
    ShaderManager::u_mat4(kShaderUniform::MVP, glm::ortho(-.5f, .5f, -.5f / aspect, .5f / aspect, -1.f, 1.f));
    m_plane.draw_fill();
    //m_rtt.clear({ .3f, .3f, .3f, 1.f });
    m_tex_background.bind();
    glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, size.x, size.y);

    // COMPOSITE

    ShaderManager::use(kShader::CompDraw);
    ShaderManager::u_int(kShaderUniform::Tex, 0);
    ShaderManager::u_int(kShaderUniform::TexStroke, 1);
    ShaderManager::u_int(kShaderUniform::TexMask, 2);
    ShaderManager::u_int(kShaderUniform::TexDual, 3);
    ShaderManager::u_int(kShaderUniform::TexPattern, 4);
    ShaderManager::u_vec2(kShaderUniform::Resolution, size);
    ShaderManager::u_float(kShaderUniform::Alpha, 1);
    ShaderManager::u_int(kShaderUniform::UseFragcoord, false);
    ShaderManager::u_int(kShaderUniform::Mask, false);
    ShaderManager::u_int(kShaderUniform::BlendMode, b->m_blend_mode);
    ShaderManager::u_mat4(kShaderUniform::MVP, glm::ortho(-.5f, .5f, -.5f, .5f, -1.f, 1.f));
    ShaderManager::u_int(kShaderUniform::UseDual, b->m_dual_enabled);
    ShaderManager::u_int(kShaderUniform::UsePattern, b->m_pattern_enabled && !b->m_pattern_eachsample);
    ShaderManager::u_int(kShaderUniform::DualBlendMode, b->m_dual_blend_mode);
    ShaderManager::u_vec2(kShaderUniform::PatternScale, patt_scale);
    ShaderManager::u_float(kShaderUniform::PatternInvert, b->m_pattern_invert);
    ShaderManager::u_float(kShaderUniform::PatternBright, b->m_pattern_brightness);
    ShaderManager::u_float(kShaderUniform::PatternContrast, b->m_pattern_contrast);
    ShaderManager::u_float(kShaderUniform::PatternDepth, b->m_pattern_depth);
    ShaderManager::u_int(kShaderUniform::PatternBlendMode, b->m_pattern_blend_mode);
    ShaderManager::u_vec2(kShaderUniform::PatternOffset, glm::vec2(b->m_pattern_rand_offset ? 0.5f : 0.0f));
    ShaderManager::u_float(kShaderUniform::DualAlpha, b->m_dual_opacity);

    m_sampler_linear.bind(0);
    m_sampler_linear.bind(1);
    m_sampler_linear.bind(2);
    m_sampler_linear.bind(3);
    m_sampler_linear_repeat.bind(4);

    glActiveTexture(GL_TEXTURE0);
    m_tex_background.bind();
    glActiveTexture(GL_TEXTURE1);
    m_tex.bind();
    glActiveTexture(GL_TEXTURE3);
    m_tex_dual.bind();
    glActiveTexture(GL_TEXTURE4);
    b->m_pattern_texture ?
        b->m_pattern_texture->bind() :
        glBindTexture(GL_TEXTURE_2D, 0);
    m_plane.draw_fill();

    // copy the result to the actual preview
    m_tex_preview.bind();
    glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, size.x, size.y);

    m_rtt.unbindFramebuffer();

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

Image NodeStrokePreview::render_to_image()
{
    std::lock_guard<std::mutex> _lock(s_render_mutex);

    App::I->render_task([this] {
        auto new_size = m_preview_size;
        if (!m_tex_preview.ready() || m_tex_preview.size() != new_size)
            m_tex_preview.create((int)new_size.x, (int)new_size.y);
        if (m_tex.size() != new_size)
        {
            m_rtt.create((int)new_size.x, (int)new_size.y);
            m_rtt_mixer.create((int)new_size.x, (int)new_size.y);
            m_tex.create((int)new_size.x, (int)new_size.y);
            m_tex_dual.create((int)new_size.x, (int)new_size.y);
            m_tex_background.create((int)new_size.x, (int)new_size.y);
        }
        draw_stroke_immediate();
    });
    return m_tex_preview.get_image();
}

void NodeStrokePreview::draw_stroke()
{
    if (m_size.x == 0 || m_size.y == 0)
        return;
    s_queue.mutex.lock();
    if (!s_running)
    {
        s_running = true;
        s_renderer = std::thread([] {
            BT_SetTerminate();

            m_sampler_linear.create();
            m_sampler_linear_repeat.create(GL_LINEAR, GL_REPEAT);
            m_sampler_mipmap.create();
            m_sampler_mipmap.set_filter(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR);
            m_brush_shape.create();
            while (s_running)
            {
                auto node = s_queue.Get();
                if (node)
                {
                    std::lock_guard<std::mutex> _lock(s_render_mutex);

                    // if the brush is not already loaded, load it and then destroy it
                    bool to_unload = (node->m_brush->m_tip_texture == nullptr);
                    node->m_brush->preload();

                    App::I->render_task([node, to_unload]
                    {
                        gl_state gl;
                        gl.save();

                        auto new_size = node->m_preview_size;
                        if (!node->m_tex_preview.ready() || node->m_tex_preview.size() != new_size)
                            node->m_tex_preview.create((int)new_size.x, (int)new_size.y);
                        if (m_tex.size() != new_size)
                        {
                            m_rtt.create((int)new_size.x, (int)new_size.y);
                            m_rtt_mixer.create((int)new_size.x, (int)new_size.y);
                            m_tex.create((int)new_size.x, (int)new_size.y);
                            m_tex_dual.create((int)new_size.x, (int)new_size.y);
                            m_tex_background.create((int)new_size.x, (int)new_size.y);
                        }

                        node->m_brush->load();
                        node->draw_stroke_immediate();
                        if (to_unload)
                            node->m_brush->unload();

                        gl.restore();
                    });
                    
                    node->app_redraw();

                    //std::this_thread::sleep_for(std::chrono::milliseconds(30));
                    std::this_thread::yield();
                }
            }
            m_rtt.destroy();
            m_rtt_mixer.destroy();
            m_tex.destroy();
            m_tex_dual.destroy();
            m_tex_background.destroy();
            m_brush_shape.destroy();
        });
    }
    s_queue.mutex.unlock();
    s_queue.PostUnique(std::static_pointer_cast<NodeStrokePreview>(shared_from_this()), m_draw_first);
}

void NodeStrokePreview::draw()
{
    ShaderManager::use(kShader::Texture);
    ShaderManager::u_mat4(kShaderUniform::MVP, m_mvp);
    ShaderManager::u_int(kShaderUniform::Tex, 0);
    m_tex_preview.bind();
    m_sampler_linear.bind(0);
    m_plane.draw_fill();
    m_sampler_linear.unbind();
    m_tex_preview.unbind();
}

void NodeStrokePreview::handle_resize(glm::vec2 old_size, glm::vec2 new_size, float zoom)
{
    if (m_preview_size == (new_size * root()->m_zoom) || !m_brush)
        return;

    m_preview_size = new_size * root()->m_zoom;

    if (m_on_screen)
        draw_stroke();
}

void NodeStrokePreview::destroy()
{
    m_tex_preview.destroy();
    Node::destroy();
}

void NodeStrokePreview::handle_on_screen(bool old_visibility, bool new_visibility)
{
    parent::handle_on_screen(old_visibility, new_visibility);
    if (new_visibility)
    {
        draw_stroke();
    }
    else
    {
        s_queue.Remove(std::static_pointer_cast<NodeStrokePreview>(shared_from_this()));
        m_tex_preview.destroy();
    }
}