ImGuiText.h

#pragma once
 
#include <imgui/imgui.h>
#include <glm/glm.hpp>
 
#include "./pch.h"
 
namespace TazGraphEngine {
 
 
    inline void drawTextAtWorldPositionPerspective(const glm::vec3& worldPos, const char* text,
        const glm::vec4& color, ICamera* camera) {
        glm::mat4 view = camera->getViewMatrix();
        glm::mat4 proj = camera->getProjMatrix();
 
        ImVec2 pos = ImGui::GetWindowPos();
        ImVec2 viewportSize = ImGui::GetWindowSize();
 
 
        // Convert world to clip space
        glm::vec4 clipPos = camera->getCameraMatrix() * glm::vec4(worldPos, 1.0f);
 
        // Perspective division
        if (clipPos.w > 0.0f) {
            clipPos.x /= clipPos.w;
            clipPos.y /= clipPos.w;
 
            if (clipPos.x < -1.0f || clipPos.x > 1.0f ||
                clipPos.y < -1.0f || clipPos.y > 1.0f) {
                return; // Point is outside view frustum
            }
 
            // Convert to screen coordinates
            glm::vec2 screenPos;
            screenPos.x = pos.x + (clipPos.x * 0.5f + 0.5f) * viewportSize.x;
            screenPos.y = pos.y + (-clipPos.y * 0.5f + 0.5f) * viewportSize.y;
            glm::vec4 viewPos = view * glm::vec4(worldPos, 1.0f);
            // Use clipPos.w (distance in clip space) for scaling
            float distance = -viewPos.z; // view space forward is -Z
            float baseFontSize = 16.0f;
            float scale = 1000.0f / distance;   // Adjust multiplier as needed
            float fontSize = glm::clamp(baseFontSize * scale, 6.0f, baseFontSize);
 
            ImDrawList* drawList = ImGui::GetForegroundDrawList();
 
            // Push scaled font
            ImGui::PushFont(ImGui::GetIO().Fonts->Fonts[0]);
            ImGui::SetWindowFontScale(fontSize / baseFontSize);
 
            ImFont* font = ImGui::GetIO().Fonts->Fonts[0];
            ImVec2 textSize = ImGui::CalcTextSize(text);
            drawList->AddText(
                font, fontSize,
                ImVec2(screenPos.x - textSize.x * 0.5f, screenPos.y - textSize.y * 0.5f),
                ImColor(color.r, color.g, color.b, color.a),
                text);
 
            ImGui::SetWindowFontScale(1.0f);
            ImGui::PopFont();
        }
    }
}