libigl_Martin/include/igl/viewer/TextRenderer.cpp

// This file is part of libigl, a simple c++ geometry processing library.
//
// Copyright (C) 2014 Wenzel Jacob <wenzel@inf.ethz.ch>
//
// This Source Code Form is subject to the terms of the Mozilla Public License
// v. 2.0. If a copy of the MPL was not distributed with this file, You can
// obtain one at http://mozilla.org/MPL/2.0/.
#include "TextRenderer.h"
#include "TextRenderer_fonts.h"
#include <igl/project.h>

#include <nanogui/opengl.h>
#include <nanovg.h>

#include <Eigen/Dense>

#define NANOVG_GL3
#include <nanovg_gl.h>

using namespace std;

  IGL_INLINE igl::viewer::TextRenderer::TextRenderer(): ctx(nullptr) {}

  IGL_INLINE int igl::viewer::TextRenderer::Init()
  {
    #ifdef NDEBUG
      ctx = nvgCreateGL3(NVG_STENCIL_STROKES | NVG_ANTIALIAS);
    #else
      ctx = nvgCreateGL3(NVG_STENCIL_STROKES | NVG_ANTIALIAS | NVG_DEBUG);
    #endif

    nvgCreateFontMem(ctx, "sans", igl_roboto_regular_ttf,
                               igl_roboto_regular_ttf_size, 0);

    return 0;
  }

  IGL_INLINE int igl::viewer::TextRenderer::Shut()
  {
    if(ctx)
      nvgDeleteGL3(ctx);
    return 0;
  }

  IGL_INLINE void igl::viewer::TextRenderer::BeginDraw(const Eigen::Matrix4f &view, const Eigen::Matrix4f &proj,
    const Eigen::Vector4f &_viewport, float _object_scale)
  {
    viewport = _viewport;
    proj_matrix = proj;
    view_matrix = view;
    object_scale = _object_scale;

    Eigen::Vector2i mFBSize;
    Eigen::Vector2i mSize;

    GLFWwindow* mGLFWWindow = glfwGetCurrentContext();
    glfwGetFramebufferSize(mGLFWWindow,&mFBSize[0],&mFBSize[1]);
    glfwGetWindowSize(mGLFWWindow,&mSize[0],&mSize[1]);
    glViewport(0,0,mFBSize[0],mFBSize[1]);

    glClear(GL_STENCIL_BUFFER_BIT);

    /* Calculate pixel ratio for hi-dpi devices. */
    mPixelRatio = (float)mFBSize[0] / (float)mSize[0];
    nvgBeginFrame(ctx,mSize[0],mSize[1],mPixelRatio);
  }

  IGL_INLINE void igl::viewer::TextRenderer::EndDraw()
  {
    nvgEndFrame(ctx);
  }

  IGL_INLINE void igl::viewer::TextRenderer::DrawText(Eigen::Vector3d pos, Eigen::Vector3d normal, const std::string &text)
  {
    pos += normal * 0.005f * object_scale;
    Eigen::Vector3f coord = igl::project(Eigen::Vector3f(pos(0), pos(1), pos(2)),
        view_matrix, proj_matrix, viewport);

    nvgFontSize(ctx, 16/mPixelRatio);
    nvgFontFace(ctx, "sans");
    nvgTextAlign(ctx, NVG_ALIGN_LEFT | NVG_ALIGN_MIDDLE);
    nvgFillColor(ctx, nvgRGBA(10,10,250,255));
    nvgText(ctx, coord[0]/mPixelRatio, (viewport[3] - coord[1])/mPixelRatio, text.c_str(), NULL);
  }