buffer_text.cpp

#include <iostream>
#include "glviewer.h"
#include "buffer_text.h"
using namespace std;
using namespace MaxLib;


namespace GLViewer {

// Global counter for buffer
static uint m_Counter_TextID = 0;


// Text at 3D (World) Position, text is aligned centre by default (0, 0 if top left)
RenderableText::RenderableText(Viewer* viewer, const std::string& text, const glm::vec3& pos3d, const glm::vec4& colour, const glm::vec2& textAlign)
    : m_Label(text), m_Colour(colour)
{
    // Get 2d screen position of 3d point (pair<bool, glm::vec2>)
    if(std::optional<glm::vec2> pos2d = viewer->WorldToScreenCoords(pos3d)) {
        ImVec2 textSize = ImGui::CalcTextSize(m_Label.c_str()); 
        // Align the text
        m_Position = *pos2d - textAlign * glm::vec2(textSize.x, textSize.y);
        m_Valid = true;  
    }
    
}

// Text at 2D (Window) Position, text is aligned centre by default
RenderableText::RenderableText(Viewer* viewer, const std::string& text, const glm::vec2& pos2d, const glm::vec4& colour, const glm::vec2& textAlign)
    : m_Label(text), m_Colour(colour), m_Valid(true)
{
    (void)viewer; 
    // Send text to imgui draw list (first align the text)
    ImVec2 textSize = ImGui::CalcTextSize(m_Label.c_str());
    m_Position = pos2d - textAlign * glm::vec2(textSize.x, textSize.y);  
}

// TODO: Viewer in render only
void RenderableText::Render() 
{  
    if(!m_Valid) { return; }
    // convert colour
    ImU32 colour = ImGui::GetColorU32(ImVec4(m_Colour.r, m_Colour.g, m_Colour.b, m_Colour.a));
    // Send text to imgui draw list
    ImGui::GetBackgroundDrawList()->AddText(ImVec2(m_Position.x, m_Position.y), colour, m_Label.c_str());
} 



TextBuffer::TextBuffer(Viewer* viewer) 
    : m_Parent(viewer), m_ID(++m_Counter_TextID)
{}

void TextBuffer::Add2DText(const std::string& label, const glm::vec2& position, const glm::vec4& colour, const glm::vec2& textAlign)
{
    m_Texts.emplace_back(m_Parent, label, position, colour, textAlign);
}

void TextBuffer::Add3DText(const std::string& label, const glm::vec3& position, const glm::vec4& colour, const glm::vec2& textAlign)
{
    m_Texts.emplace_back(m_Parent, label, position, colour, textAlign);
}

void TextBuffer::Add3DAxisLabels(const Transform& transform, const glm::vec4& colour, const glm::vec2& textAlign)
{
    Add3DText("X", transform.TransformVertex(glm::vec3(1.0f, 0.0f, 0.0f)), colour, textAlign);
    Add3DText("Y", transform.TransformVertex(glm::vec3(0.0f, 1.0f, 0.0f)), colour, textAlign);
    Add3DText("Z", transform.TransformVertex(glm::vec3(0.0f, 0.0f, 1.0f)), colour, textAlign);
}

void TextBuffer::ClearAll() 
{ 
    m_Texts.erase(m_Texts.begin(), m_Texts.end()); 
}
void TextBuffer::SetData(std::function<void(TextBuffer&)> cb_AddData)
{   // Clear old data
    ClearAll();
    // Add vertices via callback
    cb_AddData(*this);  
}

void TextBuffer::Render() 
{
    // add each text to imgui draw list
    for(RenderableText& text : m_Texts) {
        text.Render();
    } 
}
    
} // End namespace GLViewer