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