mirror of https://github.com/fltk/fltk
92 lines
2.1 KiB
C++
92 lines
2.1 KiB
C++
/* Tiny GL-drawing demo from documentation */
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#include <config.h>
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#include <FL/Fl.H>
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#include <FL/Fl_Window.H>
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#include <FL/Fl_Hor_Slider.H>
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#include <FL/math.h>
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#if HAVE_GL
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#include <FL/gl.h>
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#include <FL/Fl_Gl_Window.H>
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class shape_window : public Fl_Gl_Window {
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void draw();
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public:
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int sides;
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shape_window(int x,int y,int w,int h,const char *l=0);
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};
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shape_window::shape_window(int x,int y,int w,int h,const char *l) :
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Fl_Gl_Window(x,y,w,h,l) {
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sides = 3;
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}
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void shape_window::draw() {
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// the valid() property may be used to avoid reinitializing your
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// GL transformation for each redraw:
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if (!valid()) {
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valid(1);
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glLoadIdentity();
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glViewport(0,0,w(),h());
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}
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// draw an amazing graphic:
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glClear(GL_COLOR_BUFFER_BIT);
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glColor3f(.5,.6,.7);
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glBegin(GL_POLYGON);
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for (int i=0; i<sides; i++) {
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double ang = i*2*M_PI/sides;
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glVertex3f(cos(ang),sin(ang),0);
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}
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glEnd();
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}
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#else
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#include <FL/Fl_Box.H>
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class shape_window : public Fl_Box {
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public:
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int sides;
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shape_window(int x,int y,int w,int h,const char *l=0)
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:Fl_Box(FL_DOWN_BOX,x,y,w,h,l){
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label("This demo does\nnot work without GL");
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}
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};
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#endif
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// when you change the data, as in this callback, you must call redraw():
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void sides_cb(Fl_Widget *o, void *p) {
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shape_window *sw = (shape_window *)p;
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sw->sides = int(((Fl_Slider *)o)->value());
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sw->redraw();
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}
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int main(int argc, char **argv) {
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Fl_Window window(300, 330);
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// the shape window could be it's own window, but here we make it
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// a child window:
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shape_window sw(10, 10, 280, 280);
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// make it resize:
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window.resizable(&sw);
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// window.size_range(300,330,0,0,1,1,1);
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// add a knob to control it:
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Fl_Hor_Slider slider(50, 295, window.w()-60, 30, "Sides:");
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slider.align(FL_ALIGN_LEFT);
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slider.callback(sides_cb,&sw);
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slider.value(sw.sides);
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slider.step(1);
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slider.bounds(3,40);
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window.end();
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window.show(argc,argv);
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// in the X version you must show() all Fl_Window's in top/down order
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// other systems may not require this, but it will be harmless:
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//sw.show();
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return Fl::run();
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}
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