path: root/menu_demo/menu.c

#ifdef G_OS_WIN32
  #define WIN32_LEAN_AND_MEAN 1
  #include <windows.h>
#else
  #define FALSE 0
  #define TRUE !FALSE
#endif

#include <stdlib.h>
#include <GL/gl.h>
#include <GL/glut.h>
#include <string.h>

#include "menu.h"
#include "button.h"
#include "font.h"

#define MENU_MAX_BUTTONS 16

enum MenuState {
  MENU_MAIN,
  MENU_START,
  MENU_OPTIONS
};

struct MenuStruct {
  enum MenuState m_iMenuId;
  int m_iButtonCount;
  struct ButtonStruct m_sButtons[MENU_MAX_BUTTONS];
};

struct MenuStruct  g_sMenuMain;    // definition of the main menu
struct MenuStruct  g_sMenuStart;   // definition of the start menu
struct MenuStruct  g_sMenuOptions; // definition of the options menu
struct MenuStruct *g_pCurMenu;     // current menu

int g_iWinWidth;
int g_iWinHeight;


void MenuEnableGroup(int f_iGroup)
{
  struct ButtonStruct l_sButton;
  int l_iType, l_iGroup;
  int i = 0;

  // enable first radio button in this group
  while (i < g_pCurMenu->m_iButtonCount)
  {
    l_sButton = g_pCurMenu->m_sButtons[i];
    l_iType   = l_sButton.m_iType;
    l_iGroup  = l_sButton.m_iGroup;

    if (l_iType == BUTTON_RADIO && l_iGroup == f_iGroup)
    {
      ButtonEnable(&g_pCurMenu->m_sButtons[i]);
      return;
    }

    i++;
  }

} // MenuEnableGroup


void MenuAddButton(int f_dXPos, int f_dYPos, int f_dWidth, int f_dHeight, char *f_pcTitle, int f_iType, int f_iGroup)
{
  int i = g_pCurMenu->m_iButtonCount;;
  
  // create the button with the right parameters
  g_pCurMenu->m_sButtons[i] = ButtonCreate(f_dXPos, f_dYPos, f_dWidth, f_dHeight, f_pcTitle, f_iType, f_iGroup, i);
  g_pCurMenu->m_iButtonCount = i + 1;

} // MenuAddButton



void MenuClear(void)
{
  g_pCurMenu->m_iButtonCount = 0;
  memset(&g_pCurMenu->m_sButtons, 0, sizeof(g_pCurMenu->m_sButtons));

} // MenuClear



void MenuBuild (void)
{
  int l_iMenuId = g_pCurMenu->m_iMenuId;

  switch (l_iMenuId)
  {
    default:
    case MENU_MAIN:
      MenuAddButton(50,  50,  250, 64, "Button 1", BUTTON_CLICK, BUTTON_NO_GROUP);
      MenuAddButton(50,  150, 250, 64, "Button 2", BUTTON_CLICK, BUTTON_NO_GROUP);
      MenuAddButton(350, 50,   64, 64, "Radio 1",  BUTTON_RADIO, BUTTON_GROUP1);
      MenuAddButton(350, 150,  64, 64, "Radio 2",  BUTTON_RADIO, BUTTON_GROUP1);
      MenuEnableGroup(BUTTON_GROUP1);

      MenuAddButton(50,  250, 256, 64, "Button 3", BUTTON_CLICK, BUTTON_NO_GROUP);
      MenuAddButton(50,  350, 256, 64, "Button 4", BUTTON_CLICK, BUTTON_NO_GROUP);
      MenuAddButton(350, 250, 64,  64, "Radio A",  BUTTON_RADIO, BUTTON_GROUP2);
      MenuAddButton(350, 350, 64,  64, "Radio B",  BUTTON_RADIO, BUTTON_GROUP2);
      MenuEnableGroup(BUTTON_GROUP2);
      break;

    case MENU_START:
      MenuAddButton(50,  150, 250, 64, "Start",      BUTTON_CLICK, BUTTON_NO_GROUP);
      MenuAddButton(50,  250, 250, 64, "Back",       BUTTON_CLICK, BUTTON_NO_GROUP);
      MenuAddButton(350, 150, 64,  64, "Try first!", BUTTON_RADIO, BUTTON_GROUP1);
      MenuAddButton(350, 250, 64,  64, "10 games",   BUTTON_RADIO, BUTTON_GROUP1);
      MenuEnableGroup(BUTTON_GROUP1);
      break;

    case MENU_OPTIONS:
      MenuAddButton(50, 50,   64, 64, "Headtracking",  BUTTON_RADIO, BUTTON_GROUP1);
      MenuAddButton(50, 150,  64, 64, "Stereo vision", BUTTON_RADIO, BUTTON_GROUP1);
      MenuEnableGroup(BUTTON_GROUP1);
      break;
  }

} // MenuBuild



void MenuRebuild(void)
{
  MenuClear();
  MenuBuild();

} // MenuRebuild



void MenuNext(void)
{
  int l_iMenuId = g_pCurMenu->m_iMenuId;

  l_iMenuId = (l_iMenuId + 1) % 3;
  g_pCurMenu->m_iMenuId = l_iMenuId;
  MenuRebuild();

} // MenuNext



void MenuInit(int f_iWinWidth, int f_iWinHeight)
{
  // init menu props
  g_iWinWidth  = f_iWinWidth;
  g_iWinHeight = f_iWinHeight;

  // set pointer to the current menu
  g_pCurMenu = &g_sMenuStart;

  // init main menu
  g_sMenuMain.m_iMenuId = MENU_MAIN;

  // init start menu
  g_sMenuStart.m_iMenuId = MENU_START;

  // init options menu
  g_sMenuOptions.m_iMenuId = MENU_OPTIONS;

  // init font
  FontInit(f_iWinWidth, f_iWinHeight);

  // build the current menu (main)
  MenuBuild();

} // MenuInit



void MenuRender(void)
{
  int i = 0;

  glClearColor(0.9, 0.9, 0.9, 1);

  glDisable(GL_DEPTH_TEST);
  glEnable(GL_TEXTURE_2D);

  glColor4d(1, 1, 1, 1);

  glMatrixMode(GL_PROJECTION);
  glPushMatrix();

    glLoadIdentity();
    glOrtho(0, g_iWinWidth, g_iWinHeight, 0, 0, 1);
    glMatrixMode(GL_MODELVIEW);

    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    // render the buttons of the current menu
    for (i; i < g_pCurMenu->m_iButtonCount; i++)
    {
      ButtonRender(&g_pCurMenu->m_sButtons[i]);
    }

    glDisable(GL_BLEND);

    //restore the previous projection matrix
    glMatrixMode(GL_PROJECTION);

  glPopMatrix();

} // MenuRender



int MenuCollision(struct ButtonStruct *f_sButton, int f_iXPos, int f_iYPos)
{
  int l_iCollision;
  int l_iButtonX, l_iButtonY;
  int l_iButtonWidth, l_iButtonHeight;

  l_iButtonX      = f_sButton->m_dXPos;
  l_iButtonY      = f_sButton->m_dYPos;
  l_iButtonWidth  = f_sButton->m_dWidth;
  l_iButtonHeight = f_sButton->m_dHeight;

  l_iCollision  = f_iXPos >= l_iButtonX;
  l_iCollision &= f_iYPos >= l_iButtonY;
  l_iCollision &= f_iXPos <= l_iButtonX + l_iButtonWidth;
  l_iCollision &= f_iYPos <= l_iButtonY + l_iButtonHeight;


  if (l_iCollision) return TRUE;
  return FALSE;

} // MenuCollision



void MenuMouseClick(int f_iGlutButton, int f_iGlutState, int f_iXPos, int f_iYPos)
{
  int i = 0;
  int l_iXPos, l_iYPos;
  int l_iWidth, l_iHeight;
  int l_iType, l_iId, l_iGroup;
  struct ButtonStruct l_sButton;
  
  // button released
  if (f_iGlutButton == GLUT_LEFT_BUTTON  && f_iGlutState == GLUT_UP)
  {
    // post a button released event to all buttons
    for (i; i < g_pCurMenu->m_iButtonCount; i++)
    {
      l_iType = g_pCurMenu->m_sButtons[i].m_iType;
      ButtonRelease(&g_pCurMenu->m_sButtons[i]);
    }
  }

  // check if any button needs attention from the mouse
  i = g_pCurMenu->m_iButtonCount;
  for (i; i >= 0; i--)
  {
    l_sButton = g_pCurMenu->m_sButtons[i];
    l_iXPos   = l_sButton.m_dXPos;
    l_iYPos   = l_sButton.m_dYPos;
    l_iWidth  = l_sButton.m_dWidth;
    l_iHeight = l_sButton.m_dHeight;
    l_iType   = l_sButton.m_iType;
    l_iId     = l_sButton.m_iId;
    l_iGroup  = l_sButton.m_iGroup;

    if (MenuCollision(&l_sButton, f_iXPos, f_iYPos))
    {
      // button pressed?
      if (f_iGlutButton == GLUT_LEFT_BUTTON && f_iGlutState == GLUT_DOWN)
      {
        ButtonPress(&g_pCurMenu->m_sButtons[i]);

        if (l_iType == BUTTON_RADIO)
        {
          i = 0;
          while (i < g_pCurMenu->m_iButtonCount)
          {

            if (l_iId    != g_pCurMenu->m_sButtons[i].m_iId   &&
                l_iType  == g_pCurMenu->m_sButtons[i].m_iType &&
                l_iGroup == g_pCurMenu->m_sButtons[i].m_iGroup)
            {
              ButtonDisable(&g_pCurMenu->m_sButtons[i]);
            }
            i++;
          }
        }

        return;
      }
    }
  }

} // MenuMouseClick


void MenuMouseMove(int f_iXPos, int f_iYPos)
{
  int i = 0;
  struct ButtonStruct l_sButton;

  // check if any button needs attention from the mouse
  for (i; i < g_pCurMenu->m_iButtonCount; i++)
  {
    l_sButton = g_pCurMenu->m_sButtons[i];

    if (MenuCollision(&l_sButton, f_iXPos, f_iYPos))
    {
      ButtonEnter(&g_pCurMenu->m_sButtons[i]);
    }
    else // mouse leaves button
    {
      ButtonExit(&g_pCurMenu->m_sButtons[i]);
    }
  }

} // MenuMouseMove