panopainter/engine/util.h

#pragma once

uint16_t constexpr const_hash(const char* input)
{
    return *input ?
        static_cast<uint16_t>(*input) + 33 * const_hash(input + 1) :
        5381;
}

bool point_in_rect(const glm::vec2& point, const glm::vec4& rect);
glm::vec4 rect_intersection(glm::vec4 a, glm::vec4 b);
glm::vec4 rect_union(glm::vec4 a, glm::vec4 b);
bool segments_intersect(const glm::vec2& p0a, const glm::vec2& p0b,
    const glm::vec2& p1a, const glm::vec2& p1b, glm::vec2& out_pt);
glm::vec4 rand_color();
glm::vec3 convert_hsv2rgb(const glm::vec3 c);
glm::vec3 convert_rgb2hsv(const glm::vec3 c);

void check_OpenGLError(const char* stmt, const char* fname, int line);

template<typename T, int N> struct cbuffer
{
    T m_vec[N];
    int m_capacity;
    int m_count;
    int m_index;
    cbuffer()
    {
        m_capacity = N;
        m_index = 0;
        m_count = 0;
    }
    void clear()
    {
        m_index = 0;
        m_count = 0;
    }
    T& head()
    {
        return m_index == 0 ? m_vec[m_count - 1] : m_vec[m_index - 1];
    }
    void add(const T& v)
    {
        m_vec[m_index] = v;
        m_index = (m_index + 1) % m_capacity;
        m_count = m_count < m_capacity ? m_count + 1 : m_count;
    }
    int count() const
    {
        return m_count;
    }
    template<typename T2 = T> T2 average() const
    {
        T2 tot{};
        if (m_count == 0)
            return tot;
        for (int i = 0; i < m_count; i++)
            tot += m_vec[i];
        return tot / (float)m_count;
    }
};

NS_START
template<typename T, int Max = 0>
class BlockingQueue
{
    std::deque<T> q;
    std::condition_variable post_cv;
    std::condition_variable get_cv;
    mutable std::mutex mutex;
public:
    volatile bool unlocked = false;
    BlockingQueue() = default;
    BlockingQueue(const BlockingQueue& other) = delete;
    BlockingQueue& operator=(const BlockingQueue& other) = delete;
    BlockingQueue(BlockingQueue&& other) : q(std::move(q)) { }
    BlockingQueue& operator=(BlockingQueue&& other) { q = std::move(q); return *this; }
    void Post(T&& pkt)
    {
        std::unique_lock<std::mutex> lock(mutex);
        if (Max > 0)
        {
            post_cv.wait(lock, [&]() { return unlocked | (q.size() < Max); });
            if (q.size() >= Max) return;
        }
        q.push_back(std::forward<T>(pkt));
        get_cv.notify_one();
    }
    T Get()
    {
        static T emptyT{};
        std::unique_lock<std::mutex> lock(mutex);
        get_cv.wait(lock, [&]() { return unlocked | (q.size() > 0); });
        if (q.empty())
            return std::move(emptyT);
        T tmp = std::move(q.front());
        q.pop_front();
        if (Max > 0) post_cv.notify_all();
        return std::move(tmp);
    }
    void UnlockGetters()
    {
        unlocked = true;
        get_cv.notify_all();
        if (Max > 0) post_cv.notify_all();
    }
    int Size() const
    {
        std::lock_guard<std::mutex> lock(mutex);
        return (int)q.size();
    }
};

struct gl_state
{
    GLboolean blend;
    GLboolean depth_test;
    GLboolean scissor_test;
    GLint vp[4];
    GLfloat cc[4];
    GLint tex[10];
    GLint cube;
    GLint sampler[10];
    GLint program;
    GLint fb;
    GLint active_tex;
    void save()
    {
        blend = glIsEnabled(GL_BLEND);
        depth_test = glIsEnabled(GL_DEPTH_TEST);
        scissor_test = glIsEnabled(GL_SCISSOR_TEST);
        glGetIntegerv(GL_VIEWPORT, vp);
        glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);
        glGetIntegerv(GL_CURRENT_PROGRAM, &program);
        glGetIntegerv(GL_FRAMEBUFFER_BINDING, &fb);
        glGetIntegerv(GL_ACTIVE_TEXTURE, &active_tex);
        glGetIntegerv(GL_TEXTURE_BINDING_CUBE_MAP, &cube);
        for (int i = 0; i < 10; ++i)
        {
            glActiveTexture(GL_TEXTURE0 + i);
            glGetIntegerv(GL_TEXTURE_BINDING_2D, tex + i);
            glGetIntegerv(GL_SAMPLER_BINDING, sampler + i);
        }
    }
    void restore()
    {
        blend ? glEnable(GL_BLEND) : glDisable(GL_BLEND);
        depth_test ? glEnable(GL_DEPTH_TEST) : glDisable(GL_DEPTH_TEST);
        scissor_test ? glEnable(GL_SCISSOR_TEST) : glDisable(GL_SCISSOR_TEST);
        glViewport(vp[0], vp[1], vp[2], vp[3]);
        glClearColor(cc[0], cc[1], cc[2], cc[3]);
        glBindFramebuffer(GL_FRAMEBUFFER, fb);
        glUseProgram(program);
        for (int i = 0; i < 10; ++i)
        {
            glActiveTexture(GL_TEXTURE0 + i);
            glBindTexture(GL_TEXTURE_2D, tex[i]);
            glBindSampler(i, sampler[i]);
        }
        glActiveTexture(active_tex);
        glBindTexture(GL_TEXTURE_BINDING_CUBE_MAP, cube);
    }
};

NS_END