SoCoordinateSystemUtils.h

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/*************************************************************************************
**
** Copyright 2021, MeVis Medical Solutions AG
**
** The user may use this file in accordance with the license agreement provided with
** the Software or, alternatively, in accordance with the terms contained in a
** written agreement between the user and MeVis Medical Solutions AG.
**
** For further information use the contact form at https://www.mevislab.de/contact
**
**************************************************************************************/
 
#pragma once
 
#include <mlOpenGL.h>
#include <Inventor/So.h>
#include <mlGL2DFont.h>
#include <mlGLHiDPI.h>
 
#include <SoCoordinateSystem.h>
 
namespace
{
  void renderText(const LabelText& labelText);
  void renderLabel(const Label& label);
  void glDrawString(const SbVec2f& screenPosition, const LabelText& labelText);
  void applyLabelOffset(GLfloat& screenX, GLfloat& screenY, const GLfloat& textWidth, const GLfloat& textAscender, const LabelText& labelText);
  void fillScreenBoundingBox(Label& label);
 
  void setupRenderState();
  void resetRenderState();
 
  void setupRasterPositionStateScreen();
  void resetRasterPositionState();
 
  GLfloat getScreenTextWidth(const LabelText& labelText);
  GLfloat getScreenTextAscender(const LabelText& labelText);
 
  SbVec3f getScreenCoordinate(const SbVec3f& worldCoordinate);
  SbVec4f getColorWithAlpha(const SbColor& color, float alpha) { return SbVec4f(color[0], color[1], color[2], alpha); }
 
  void setupRenderState()
  {
    glPushMatrix();
    glPushAttrib(GL_ALL_ATTRIB_BITS);
    glDisable(GL_LIGHTING);
 
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glDepthFunc(GL_LEQUAL);
 
    glPushAttrib(GL_LINE_BIT);
  }
 
  void resetRenderState()
  {
    glPopAttrib();
 
    glFlush();
 
    glDisable(GL_BLEND);
 
    glEnable(GL_LIGHTING);
    glPopAttrib();
    glPopMatrix();
  }
 
  void setupRasterPositionStateScreen()
  {
    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();
    glMatrixMode(GL_PROJECTION);
 
    glPushAttrib(GL_ALL_ATTRIB_BITS);
 
    glDisable(GL_LIGHTING);
    glDisable(GL_CULL_FACE);
 
    ml::OpenGL::disableAllClipPlanes();
 
    glPushMatrix();
    glLoadIdentity();
    GLint viewport[4];
    glGetIntegerv(GL_VIEWPORT, viewport);
 
    glOrtho(0, viewport[2], 0, viewport[3], 0.f, 1.f);
 
    glMatrixMode(GL_MODELVIEW);
 
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  }
 
  void resetRasterPositionState()
  {
    glPopAttrib();
 
    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);
    glPopMatrix();
  }
 
  void applyLabelOffset(GLfloat& screenX, GLfloat& screenY, const GLfloat& textWidth, const GLfloat& textAscender, const LabelText& labelText)
  {
    screenX -= (textWidth * .5f);
    screenY -= (textAscender * .5f);
 
    // only use text height for distance from axis:
    screenX += (textAscender * labelText.textShiftFactorScreen[0]);
    screenY += (textAscender * labelText.textShiftFactorScreen[1]);
    // only left/right-justify if displacement along x-axis is greater than along y-axis
    if (abs(labelText.textShiftFactorScreen[0]) > abs(labelText.textShiftFactorScreen[1]))
    {
      screenX += (textWidth * .5f * sign(labelText.textShiftFactorScreen[0]));
    }
  }
 
  void renderText(const LabelText& labelText)
  {
    glRasterPos3f(labelText.textPosition[0], labelText.textPosition[1], labelText.textPosition[2]);
 
    GLboolean isValidPosition;
    glGetBooleanv(GL_CURRENT_RASTER_POSITION_VALID, &isValidPosition);
 
    if (isValidPosition)
    {
      GLfloat currentRasterPosition[4];
      glGetFloatv(GL_CURRENT_RASTER_POSITION, currentRasterPosition);
      auto screenX = currentRasterPosition[0];
      auto screenY = currentRasterPosition[1];
      const auto screenZ = currentRasterPosition[2];
 
      setupRasterPositionStateScreen();
 
      glTranslatef(0, 0, -screenZ);
 
      const auto textWidth = getScreenTextWidth(labelText);
      const auto textAscender = getScreenTextAscender(labelText);
 
      applyLabelOffset(screenX, screenY, textWidth, textAscender, labelText);
 
      const SbVec2f screenPosition(screenX, screenY);
 
      glDrawString(screenPosition, labelText);
 
      resetRasterPositionState();
    }
  }
 
  void renderLabel(const Label& label)
  {
    auto offset = .25f;
    if (label.isVisible)
    {
      offset = .5f;
    }
    const auto tickStart = label.tickPosition + label.tickDirection * offset;
    const auto tickEnd   = label.tickPosition - label.tickDirection * offset;
 
    const auto tickColor = getColorWithAlpha(label.tickColor, label.tickAlpha);
    glColor4fv(tickColor.getValue());
 
    glBegin(GL_LINE_STRIP);
    {
      glVertex3f(tickStart[0], tickStart[1], tickStart[2]);
      glVertex3f(tickEnd[0], tickEnd[1], tickEnd[2]);
    }
    glEnd();
 
    if (label.isVisible)
    {
      const auto labelText = label.labelText;
      glRasterPos3f(labelText.textPosition[0], labelText.textPosition[1], labelText.textPosition[2]);
 
      GLfloat currentRasterPosition[4];
      glGetFloatv(GL_CURRENT_RASTER_POSITION, currentRasterPosition);
      const auto screenZ = currentRasterPosition[2];
 
      setupRasterPositionStateScreen();
 
      glTranslatef(0, 0, -screenZ);
 
      glDrawString(label.screenBoundingBox[0], labelText);
 
      resetRasterPositionState();
    }
  }
 
  void fillScreenBoundingBox(Label& label)
  {
    label.initializeScreenBoundingBox();
 
    const auto labelText = label.labelText;
 
    glRasterPos3f(labelText.textPosition[0], labelText.textPosition[1], labelText.textPosition[2]);
 
    GLboolean isValidPosition;
    glGetBooleanv(GL_CURRENT_RASTER_POSITION_VALID, &isValidPosition);
 
    label.isOnScreen = isValidPosition;
 
    if (isValidPosition)
    {
      GLfloat currentRasterPosition[4];
      glGetFloatv(GL_CURRENT_RASTER_POSITION, currentRasterPosition);
      auto screenX = currentRasterPosition[0];
      auto screenY = currentRasterPosition[1];
      const auto screenZ = currentRasterPosition[2];
 
      setupRasterPositionStateScreen();
 
      glTranslatef(0, 0, -screenZ);
 
      const auto textWidth = getScreenTextWidth(labelText);
      const auto textAscender = getScreenTextAscender(labelText);
 
      applyLabelOffset(screenX, screenY, textWidth, textAscender, labelText);
 
      label.screenBoundingBox[0].setValue(screenX, screenY);
      label.screenBoundingBox[1].setValue(screenX + textWidth, screenY + textAscender);
 
      resetRasterPositionState();
    }
  }
 
  void glDrawString(const SbVec2f& screenPosition, const LabelText& labelText)
  {
    const auto font = ml::GL2DFont::getDefaultSystemFont();
    const auto textColor = getColorWithAlpha(labelText.textColor, labelText.textAlpha);
    font->drawString(screenPosition[0], screenPosition[1], labelText.fontSize, textColor.getValue(), labelText.text.c_str(), 0, false, labelText.useTextShadow, labelText.textShadowColor.getValue());
  }
 
  GLfloat getScreenTextWidth(const LabelText& labelText)
  {
    const auto font = ml::GL2DFont::getDefaultSystemFont();
    return static_cast<GLfloat>(font->getStringWidth(labelText.fontSize,labelText.text.c_str()));
  }
 
  GLfloat getScreenTextAscender(const LabelText& labelText)
  {
    const auto font = ml::GL2DFont::getDefaultSystemFont();
    return static_cast<GLfloat>(font->getFontAscender(labelText.fontSize));
  }
 
  SbVec3f getScreenCoordinate(const SbVec3f& worldCoordinate)
  {
    GLdouble modelViewMatrix[16];
    glGetDoublev(GL_MODELVIEW_MATRIX, modelViewMatrix);
 
    GLdouble projectionMatrix[16];
    glGetDoublev(GL_PROJECTION_MATRIX, projectionMatrix);
 
    GLint viewport[4];
    glGetIntegerv(GL_VIEWPORT, viewport);
 
    GLdouble screenX, screenY, screenZ;
    gluProject(worldCoordinate[0], worldCoordinate[1], worldCoordinate[2],
      modelViewMatrix, projectionMatrix, viewport,
      &screenX, &screenY, &screenZ);
 
    return SbVec3f(static_cast<float>(screenX), static_cast<float>(screenY), static_cast<float>(screenZ));
  }
}