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//
// implementation of class Fl_OpenGL_Display_Device for the Fast Light Tool Kit (FLTK).
//
// Copyright 2010-2017 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:
//
// https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
// https://www.fltk.org/bugs.php
//
#include <config.h>
#include <FL/Fl_Gl_Window.H>
#include "../../Fl_Gl_Window_Driver.H"
#include <FL/Fl_Image.H>
#include "../../Fl_Screen_Driver.H"
#include "../../Fl_Window_Driver.H"
#include <FL/gl.h>
#include <string.h>
#include "Fl_OpenGL_Graphics_Driver.H"
#include "Fl_OpenGL_Display_Device.H"
// TODO: much of Fl_Gl_Choice should probably go here
Fl_OpenGL_Display_Device *Fl_OpenGL_Display_Device::display_device() {
static Fl_OpenGL_Display_Device *display = new Fl_OpenGL_Display_Device(new Fl_OpenGL_Graphics_Driver());
return display;
};
Fl_OpenGL_Display_Device::Fl_OpenGL_Display_Device(Fl_OpenGL_Graphics_Driver *graphics_driver)
: Fl_Surface_Device(graphics_driver)
{
}
Fl_RGB_Image* Fl_OpenGL_Display_Device::capture_gl_rectangle(Fl_Gl_Window* glw, int x, int y, int w, int h)
{
return Fl_Gl_Window_Driver::driver(glw)->capture_gl_rectangle(x, y, w, h);
}
/* Captures a rectangle of a Fl_Gl_Window and returns it as a RGB image.
This is the platform-independent version. Some platforms may re-implement it.
*/
Fl_RGB_Image* Fl_Gl_Window_Driver::capture_gl_rectangle(int x, int y, int w, int h)
{
Fl_Gl_Window *glw = pWindow;
glw->flush(); // forces a GL redraw, necessary for the glpuzzle demo
// Read OpenGL context pixels directly.
// For extra safety, save & restore OpenGL states that are changed
glPushClientAttrib(GL_CLIENT_PIXEL_STORE_BIT);
glPixelStorei(GL_PACK_ALIGNMENT, 4); /* Force 4-byte alignment */
glPixelStorei(GL_PACK_ROW_LENGTH, 0);
glPixelStorei(GL_PACK_SKIP_ROWS, 0);
glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
//
float s = glw->pixels_per_unit();
if (s != 1) {
x = int(x * s); y = int(y * s); w = int(w * s); h = int(h * s);
}
// Read a block of pixels from the frame buffer
int mByteWidth = w * 3;
mByteWidth = (mByteWidth + 3) & ~3; // Align to 4 bytes
uchar *baseAddress = new uchar[mByteWidth * h];
glReadPixels(x, glw->pixel_h() - (y+h), w, h,
GL_RGB, GL_UNSIGNED_BYTE,
baseAddress);
glPopClientAttrib();
// GL gives a bottom-to-top image, convert it to top-to-bottom
uchar *tmp = new uchar[mByteWidth];
uchar *p = baseAddress ;
uchar *q = baseAddress + (h-1)*mByteWidth;
for (int i = 0; i < h/2; i++, p += mByteWidth, q -= mByteWidth) {
memcpy(tmp, p, mByteWidth);
memcpy(p, q, mByteWidth);
memcpy(q, tmp, mByteWidth);
}
delete[] tmp;
Fl_RGB_Image *img = new Fl_RGB_Image(baseAddress, w, h, 3, mByteWidth);
img->alloc_array = 1;
return img;
}
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