//
// "$Id$"
//
// OpenGL visual selection code for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2016 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     http://www.fltk.org/COPYING.php
//
// Please report all bugs and problems on the following page:
//
//     http://www.fltk.org/str.php
//

#include "config_lib.h"
#if HAVE_GL

#  include <FL/Fl.H>
#  include <stdlib.h>
#  include "Fl_Gl_Choice.H"
#  include <FL/Fl_Gl_Window.H>
#  include <FL/Fl_Gl_Window_Driver.H>
#  include <FL/gl_draw.H>
#  include "flstring.h"
#  include <FL/fl_utf8.h>


static GLContext *context_list = 0;
static int nContext = 0, NContext = 0;

static void add_context(GLContext ctx) {
  if (!ctx) return;
  if (nContext==NContext) {
    if (!NContext) NContext = 8;
    NContext *= 2;
    context_list = (GLContext*)realloc(
      context_list, NContext*sizeof(GLContext));
  }
  context_list[nContext++] = ctx;
}

static void del_context(GLContext ctx) {
  int i; 
  for (i=0; i<nContext; i++) {
    if (context_list[i]==ctx) {
      memmove(context_list+i, context_list+i+1,
        (nContext-i-1) * sizeof(GLContext));
      context_list[--nContext] = 0;
      break;
    }
  }
  if (!nContext) gl_remove_displaylist_fonts();
}

static Fl_Gl_Choice *first;

// this assumes one of the two arguments is zero:
// We keep the list system in Win32 to stay compatible and interpret
// the list later...
Fl_Gl_Choice *Fl_Gl_Window_Driver::find_begin(int m, const int *alistp) {
  Fl_Gl_Choice *g;
  for (g = first; g; g = g->next)
    if (g->mode == m && g->alist == alistp)
      return g;
  return NULL;
}


static GLContext cached_context;
static Fl_Window* cached_window;


#ifdef FL_CFG_GFX_QUARTZ
extern void gl_texture_reset();

Fl_Gl_Choice *Fl_Cocoa_Gl_Window_Driver::find(int m, const int *alistp)
{
  Fl_Gl_Choice *g = Fl_Gl_Window_Driver::find_begin(m, alistp);
  if (g) return g;
  NSOpenGLPixelFormat* fmt = mode_to_NSOpenGLPixelFormat(m, alistp);
  if (!fmt) return 0;
  g = new Fl_Gl_Choice(m, alistp, first);
  first = g;
  g->pixelformat = fmt;
  return g;
}

GLContext Fl_Cocoa_Gl_Window_Driver::create_gl_context(Fl_Window* window, const Fl_Gl_Choice* g, int layer) {
  GLContext context, shared_ctx = 0;
  if (context_list && nContext) shared_ctx = context_list[0];
  // resets the pile of string textures used to draw strings
  // necessary before the first context is created
  if (!shared_ctx) gl_texture_reset();
  context = create_GLcontext_for_window((NSOpenGLPixelFormat*)g->pixelformat, shared_ctx, window);
  if (!context) return 0;
  add_context(context);
  return (context);
}

void Fl_Cocoa_Gl_Window_Driver::set_gl_context(Fl_Window* w, GLContext context) {
  if (context != cached_context || w != cached_window) {
    cached_context = context;
    cached_window = w;
    GLcontext_makecurrent(context);
  }
}

void Fl_Cocoa_Gl_Window_Driver::delete_gl_context(GLContext context) {
  if (cached_context == context) {
    cached_context = 0;
    cached_window = 0;
    GL_cleardrawable();
  }
  GLcontext_release(context);
  del_context(context);
}

#endif // FL_CFG_GFX_QUARTZ

#ifdef FL_CFG_GFX_GDI
#  include <FL/x.H>
#  include <FL/Fl_Graphics_Driver.H>
#include "drivers/WinAPI/Fl_WinAPI_Window_Driver.H"
extern void fl_save_dc(HWND, HDC);

Fl_Gl_Choice *Fl_WinAPI_Gl_Window_Driver::find(int m, const int *alistp)
{
  Fl_Gl_Choice *g = Fl_Gl_Window_Driver::find_begin(m, alistp);
  if (g) return g;
  
  // Replacement for ChoosePixelFormat() that finds one with an overlay if possible:
  HDC gc = (HDC)(fl_graphics_driver ? fl_graphics_driver->gc() : 0);
  if (!gc) gc = fl_GetDC(0);
  int pixelformat = 0;
  PIXELFORMATDESCRIPTOR chosen_pfd;
  for (int i = 1; ; i++) {
    PIXELFORMATDESCRIPTOR pfd;
    if (!DescribePixelFormat(gc, i, sizeof(pfd), &pfd)) break;
    // continue if it does not satisfy our requirements:
    if (~pfd.dwFlags & (PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL)) continue;
    if (pfd.iPixelType != ((m&FL_INDEX)?PFD_TYPE_COLORINDEX:PFD_TYPE_RGBA)) continue;
    if ((m & FL_ALPHA) && !pfd.cAlphaBits) continue;
    if ((m & FL_ACCUM) && !pfd.cAccumBits) continue;
    if ((!(m & FL_DOUBLE)) != (!(pfd.dwFlags & PFD_DOUBLEBUFFER))) continue;
    if ((!(m & FL_STEREO)) != (!(pfd.dwFlags & PFD_STEREO))) continue;
    if ((m & FL_DEPTH) && !pfd.cDepthBits) continue;
    if ((m & FL_STENCIL) && !pfd.cStencilBits) continue;
    // see if better than the one we have already:
    if (pixelformat) {
      // offering non-generic rendering is better (read: hardware accelleration)
      if (!(chosen_pfd.dwFlags & PFD_GENERIC_FORMAT) &&
          (pfd.dwFlags & PFD_GENERIC_FORMAT)) continue;
      // offering overlay is better:
      else if (!(chosen_pfd.bReserved & 15) && (pfd.bReserved & 15)) {}
      // otherwise more bit planes is better:
      else if (chosen_pfd.cColorBits > pfd.cColorBits) continue;
      else if (chosen_pfd.cDepthBits > pfd.cDepthBits) continue;
    }
    pixelformat = i;
    chosen_pfd = pfd;
  }
  //printf("Chosen pixel format is %d\n", pixelformat);
  if (!pixelformat) return 0;
  
  g = new Fl_Gl_Choice(m, alistp, first);
  first = g;
  
  g->pixelformat = pixelformat;
  g->pfd = chosen_pfd;
  
  return g;
}


GLContext Fl_WinAPI_Gl_Window_Driver::create_gl_context(Fl_Window* window, const Fl_Gl_Choice* g, int layer)
{
  Fl_X* i = Fl_X::i(window);
  HDC hdc = Fl_WinAPI_Window_Driver::driver(window)->private_dc;
  if (!hdc) {
    hdc = Fl_WinAPI_Window_Driver::driver(window)->private_dc = GetDCEx(i->xid, 0, DCX_CACHE);
    fl_save_dc(i->xid, hdc);
    SetPixelFormat(hdc, g->pixelformat, (PIXELFORMATDESCRIPTOR*)(&g->pfd));
#    if USE_COLORMAP
    if (fl_palette) SelectPalette(hdc, fl_palette, FALSE);
#    endif
  }
  GLContext context = layer ? wglCreateLayerContext(hdc, layer) : wglCreateContext(hdc);
  if (context) {
    if (context_list && nContext)
      wglShareLists(context_list[0], context);
    add_context(context);
  }
  return context;
}


void Fl_WinAPI_Gl_Window_Driver::set_gl_context(Fl_Window* w, GLContext context) {
  if (context != cached_context || w != cached_window) {
    cached_context = context;
    cached_window = w;
    wglMakeCurrent(Fl_WinAPI_Window_Driver::driver(w)->private_dc, context);
  }
}

void Fl_WinAPI_Gl_Window_Driver::delete_gl_context(GLContext context) {
  if (cached_context == context) {
    cached_context = 0;
    cached_window = 0;
    wglMakeCurrent(0, 0);
  }
  wglDeleteContext(context);
  del_context(context);
}

#endif // FL_CFG_GFX_GDI

#ifdef FL_CFG_GFX_XLIB
#  include <FL/x.H>

Fl_Gl_Choice *Fl_X11_Gl_Window_Driver::find(int m, const int *alistp)
{
  Fl_Gl_Choice *g = Fl_Gl_Window_Driver::find_begin(m, alistp);
  if (g) return g;
  
  const int *blist;
  int list[32];
  
  if (alistp)
    blist = alistp;
  else {
    int n = 0;
    if (m & FL_INDEX) {
      list[n++] = GLX_BUFFER_SIZE;
      list[n++] = 8; // glut tries many sizes, but this should work...
    } else {
      list[n++] = GLX_RGBA;
      list[n++] = GLX_GREEN_SIZE;
      list[n++] = (m & FL_RGB8) ? 8 : 1;
      if (m & FL_ALPHA) {
        list[n++] = GLX_ALPHA_SIZE;
        list[n++] = (m & FL_RGB8) ? 8 : 1;
      }
      if (m & FL_ACCUM) {
        list[n++] = GLX_ACCUM_GREEN_SIZE;
        list[n++] = 1;
        if (m & FL_ALPHA) {
          list[n++] = GLX_ACCUM_ALPHA_SIZE;
          list[n++] = 1;
        }
      }
    }
    if (m & FL_DOUBLE) {
      list[n++] = GLX_DOUBLEBUFFER;
    }
    if (m & FL_DEPTH) {
      list[n++] = GLX_DEPTH_SIZE; list[n++] = 1;
    }
    if (m & FL_STENCIL) {
      list[n++] = GLX_STENCIL_SIZE; list[n++] = 1;
    }
    if (m & FL_STEREO) {
      list[n++] = GLX_STEREO;
    }
#    if defined(GLX_VERSION_1_1) && defined(GLX_SGIS_multisample)
    if (m & FL_MULTISAMPLE) {
      list[n++] = GLX_SAMPLES_SGIS;
      list[n++] = 4; // value Glut uses
    }
#    endif
    list[n] = 0;
    blist = list;
  }
  
  fl_open_display();
  XVisualInfo *visp = glXChooseVisual(fl_display, fl_screen, (int *)blist);
  if (!visp) {
#    if defined(GLX_VERSION_1_1) && defined(GLX_SGIS_multisample)
    if (m&FL_MULTISAMPLE) return find(m&~FL_MULTISAMPLE,0);
#    endif
    return 0;
  }
  
  g = new Fl_Gl_Choice(m, alistp, first);
  first = g;
  
  g->vis = visp;
  
  if (/*MaxCmapsOfScreen(ScreenOfDisplay(fl_display,fl_screen))==1 && */
      visp->visualid == fl_visual->visualid &&
      !fl_getenv("MESA_PRIVATE_CMAP"))
    g->colormap = fl_colormap;
  else
    g->colormap = XCreateColormap(fl_display, RootWindow(fl_display,fl_screen),
                                  visp->visual, AllocNone);
  
  return g;
}


GLContext Fl_X11_Gl_Window_Driver::create_gl_context(Fl_Window* window, const Fl_Gl_Choice* g, int layer) {
  return create_gl_context(g->vis);
}

GLContext Fl_X11_Gl_Window_Driver::create_gl_context(XVisualInfo *vis) {
  GLContext shared_ctx = 0;
  if (context_list && nContext) shared_ctx = context_list[0];
  GLContext context = glXCreateContext(fl_display, vis, shared_ctx, 1);
  if (context)
    add_context(context);
  return context;
}

void Fl_X11_Gl_Window_Driver::set_gl_context(Fl_Window* w, GLContext context) {
  if (context != cached_context || w != cached_window) {
    cached_context = context;
    cached_window = w;
    glXMakeCurrent(fl_display, fl_xid(w), context);
  }
}

void Fl_X11_Gl_Window_Driver::delete_gl_context(GLContext context) {
  if (cached_context == context) {
    cached_context = 0;
    cached_window = 0;
    glXMakeCurrent(fl_display, 0, 0);
  }
  glXDestroyContext(fl_display, context);
  del_context(context);
}

#endif // FL_CFG_GFX_XLIB

#endif // HAVE_GL

//
// End of "$Id$".
//