transfer_function.cxx

#include "transfer_function.h"
 
#include <cgv/media/ticks.h>
#include <cgv/utils/algorithm.h>
 
namespace cgv {
namespace media {
 
transfer_function::transfer_function(std::initializer_list<color_point_type> colors) {
    set_color_points(colors);
}
 
transfer_function::transfer_function(std::initializer_list<color_point_type> colors, std::initializer_list<opacity_point_type> opacities) {
    set_color_points(colors);
    set_opacity_points(opacities);
}
 
void transfer_function::set_color_points(const std::vector<color_point_type>& colors) {
    color_points_ = colors;
    sort_points_and_update_domain(color_points_);
    ensure_control_points_cover_domain(color_points_);
    ensure_control_points_cover_domain(opacity_points_);
}
 
void transfer_function::set_color_points_from_scheme(const cgv::media::continuous_color_scheme& scheme, size_t n) {
    std::vector<float> positions;
    cgv::utils::subdivision_sequence(std::back_inserter(positions), 0.0f, 1.0f, n);
    std::vector<cgv::rgb> colors = scheme.quantize(n);
    set_color_points(cgv::utils::zip(positions.begin(), positions.end(), colors.begin()));
}
 
void transfer_function::set_opacity_points(const std::vector<opacity_point_type>& opacities) {
    opacity_points_ = opacities;
    std::for_each(opacity_points_.begin(), opacity_points_.end(), [](const opacity_point_type& point) { cgv::math::saturate(point.second); });
    sort_points_and_update_domain(opacity_points_);
    ensure_control_points_cover_domain(opacity_points_);
    ensure_control_points_cover_domain(color_points_);
}
 
void transfer_function::add_color_point(float x, const color_type& color) {
    remove_color_point(x);
    color_points_.push_back({ x, color });
    sort_points_and_update_domain(color_points_);
    ensure_control_points_cover_domain(opacity_points_);
}
 
void transfer_function::add_opacity_point(float x, float opacity) {
    remove_opacity_point(x);
    opacity_points_.push_back({ x, cgv::math::saturate(opacity) });
    sort_points_and_update_domain(opacity_points_);
    ensure_control_points_cover_domain(color_points_);
}
 
bool transfer_function::remove_color_point(float x) {
    if(remove_point(color_points_, x)) {
        modified();
        return true;
    }
    return false;
}
 
bool transfer_function::remove_opacity_point(float x) {
    if(remove_point(opacity_points_, x)) {
        modified();
        return true;
    }
    return false;
}
 
void transfer_function::set_domain(cgv::vec2 domain) {
    const vec2 current_domain = get_domain();
 
    // Make sure we have points at either end of the new domain.
    float lower_bound = current_domain[0] < domain[0] ? domain[0] : current_domain[0];
    float upper_bound = current_domain[1] > domain[1] ? domain[1] : current_domain[1];
 
    if(!color_points_.empty() && color_points_.front().first != lower_bound)
        add_color_point(domain[0], get_mapped_color(lower_bound));
    if(!opacity_points_.empty() && opacity_points_.front().first != lower_bound)
        add_opacity_point(domain[0], get_mapped_opacity(lower_bound));
    
    if(!color_points_.empty() && color_points_.back().first != upper_bound)
        add_color_point(domain[1], get_mapped_color(upper_bound));
    if(!opacity_points_.empty() && opacity_points_.back().first != upper_bound)
        add_opacity_point(domain[1], get_mapped_opacity(upper_bound));
 
    // Remove all points that are outside the new domain.
    const auto is_point_out_of_range = [domain](const auto& point) {
        return point.first < domain[0] || point.first > domain[1];
    };
 
    const auto remove_points_out_of_range = [domain, &is_point_out_of_range](auto& points) {
        bool done = false;
        bool removed = false;
        while(!done) {
            done = true;
 
            auto it = std::find_if(points.begin(), points.end(), is_point_out_of_range);
            if(it != points.end()) {
                points.erase(it);
                done = false;
                removed = true;
            }
        }
        return removed;
    };
 
    // Use temporary variables to ensure both functions are called which they otherwise may not due to short-circuit evaluation.
    bool removed_color_points = remove_points_out_of_range(color_points_);
    bool removed_opacity_points = remove_points_out_of_range(opacity_points_);
    if(removed_color_points || removed_opacity_points)
        modified();
 
    sort_points_and_update_domain(color_points_);
}
 
void transfer_function::rescale(cgv::vec2 domain) {
    const cgv::vec2 current_domain = get_domain();
 
    if(current_domain == domain)
        return;
 
    const auto map_point = [this, current_domain, domain](auto& point) {
        point.first = map_range_safe(point.first, current_domain[0], current_domain[1], domain[0], domain[1]);
    };
 
    if(!color_points_.empty())
        std::for_each(color_points_.begin(), color_points_.end(), map_point);
 
    if(!opacity_points_.empty())
        std::for_each(opacity_points_.begin(), opacity_points_.end(), map_point);
 
    color_scale::set_domain(domain);
}
 
float transfer_function::normalize_value(float value) const {
    const vec2 domain = get_domain();
    value = cgv::math::clamp(value, domain[0], domain[1]);
    return map_range_safe(value, domain[0], domain[1], 0.0f, 1.0f);
}
 
cgv::rgba transfer_function::map_value(float value) const {
    cgv::rgb color = get_mapped_color(value);
    float opacity = get_mapped_opacity(value);
 
    return { color.R(), color.G(), color.B(), opacity };
}
 
cgv::rgb transfer_function::get_mapped_color(float value) const {
    if(is_unknown(value) || color_points_.empty())
        return get_unknown_color();
    //const vec2 domain = get_domain();
    //value = cgv::math::clamp(value, domain[0], domain[1]);
    return interpolate(color_points_, value, color_interpolation_);
}
 
float transfer_function::get_mapped_opacity(float value) const {
    if(opacity_points_.empty())
        return 1.0f;
    return interpolate(opacity_points_, value, opacity_interpolation_);
}
 
std::vector<cgv::rgba> transfer_function::quantize(size_t count) const {
    const std::vector<cgv::rgb> colors = quantize_color(count);
    const std::vector<float> opacities = quantize_opacity(count);
 
    std::vector<cgv::rgba> values;
    values.reserve(count);
    std::transform(colors.begin(), colors.end(), opacities.begin(), std::back_inserter(values), [](const cgv::rgba& color, float opacity) {
        return cgv::rgba(color, opacity);
    });
 
    return values;
}
 
std::vector<cgv::rgb> transfer_function::quantize_color(size_t count) const {
    if(color_points_.empty())
        return std::vector<cgv::rgb>(count, { 0.0f });
 
    std::vector<cgv::rgb> colors = quantize(color_points_, count, color_interpolation_);
    if(is_reversed())
        std::reverse(colors.begin(), colors.end());
    return colors;
}
 
std::vector<float> transfer_function::quantize_opacity(size_t count) const {
    if(opacity_points_.empty())
        return std::vector<float>(count, 1.0f);
    std::vector<float> opacities = quantize(opacity_points_, count, opacity_interpolation_);
    if(is_reversed())
        std::reverse(opacities.begin(), opacities.end());
    return opacities;
}
 
std::vector<float> transfer_function::get_ticks(size_t request_count) const {
    /* This would return one tick for every color or opacity point.
    std::vector<float> ticks;
    if(!color_points_.empty())
        std::transform(color_points_.begin(), color_points_.end(), std::back_inserter(ticks), cgv::utils::get_first<>{});// [] (const color_point_type& point))
    else
        std::transform(opacity_points_.begin(), opacity_points_.end(), std::back_inserter(ticks), cgv::utils::get_first<>{});
    return ticks;
    */
    const vec2 domain = get_domain();
    return compute_ticks(domain[0], domain[1], request_count);
}
 
void transfer_function::clear() {
    color_points_.clear();
    opacity_points_.clear();
    update_domain();
}
 
void transfer_function::clear_color_points() {
    color_points_.clear();
    update_domain();
}
 
void transfer_function::clear_opacity_points() {
    opacity_points_.clear();
    update_domain();
}
 
void transfer_function::set_interpolation(InterpolationMode interpolation) {
    if(color_interpolation_ != interpolation || opacity_interpolation_ != interpolation) {
        color_interpolation_ = interpolation;
        opacity_interpolation_ = interpolation;
        modified();
    }
}
 
void transfer_function::set_color_interpolation(InterpolationMode interpolation) {
    if(color_interpolation_ != interpolation) {
        color_interpolation_ = interpolation;
        modified();
    }
}
 
void transfer_function::set_opacity_interpolation(InterpolationMode interpolation) {
    if(opacity_interpolation_ != interpolation) {
        opacity_interpolation_ = interpolation;
        modified();
    }
}
 
bool transfer_function::update_domain() {
    cgv::vec2 old_domain = get_domain();
 
    cgv::vec2 domain = { 0.0f };
    if(!color_points_.empty()) {
        domain[0] = color_points_.front().first;
        domain[1] = color_points_.back().first;
    }
    if(!opacity_points_.empty()) {
        domain[0] = std::min(domain[0], opacity_points_.front().first);
        domain[1] = std::max(domain[1], opacity_points_.back().first);
    }
 
    if(old_domain != domain) {
        color_scale::set_domain(domain);
        return true;
    }
    return false;
}
 
} // namespace media
} // namespace cgv