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3d X11 projection example

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This commit is contained in:
Jiri Pittner 2023-04-08 20:05:45 +02:00
parent c24efe43a1
commit 072888e2d5
3 changed files with 65 additions and 36 deletions
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93
tX.cc
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@ -143,13 +143,13 @@ public:
void plotobject(Display* display, Pixmap pixmap, GC gc, int width,int height, const NRVec<LINE> &lines, const Mat3<double> &camera_angle, const Vec3<double> &camera, const Vec3<double> &plane_to_camera, double xod,double xdo,double yod,double ydo) void plotobject(Display* display, Pixmap pixmap, GC gc, int width,int height, const NRVec<LINE> &lines, const Mat3<double> &rot_angle, const Vec3<double> &camera, const Vec3<double> &plane_to_camera, double xod,double xdo,double yod,double ydo)
{ {
for(int i=0; i<lines.size(); ++i) for(int i=0; i<lines.size(); ++i)
{ {
double xy0[2],xy1[2]; double xy0[2],xy1[2];
perspective(&xy0[0], lines[i].point0, camera_angle, camera, plane_to_camera); perspective(&xy0[0], lines[i].point0, rot_angle, camera, plane_to_camera);
perspective(&xy1[0], lines[i].point1, camera_angle, camera, plane_to_camera); perspective(&xy1[0], lines[i].point1, rot_angle, camera, plane_to_camera);
int x0,x1,y0,y1; int x0,x1,y0,y1;
x0=width*(xy0[0]-xod)/(xdo-xod); x0=width*(xy0[0]-xod)/(xdo-xod);
x1=width*(xy1[0]-xod)/(xdo-xod); x1=width*(xy1[0]-xod)/(xdo-xod);
@ -251,30 +251,32 @@ xod = -100; xdo=100;
yod = -100; xdo=100; yod = -100; xdo=100;
LINE lines0[]= { LINE lines0[]= {
{{0,0,0},{0,0,5}}, {{-5,-5,-5},{-5,-5,5}},
{{0,5,5},{0,0,5}}, {{-5,5,5},{-5,-5,5}},
{{0,5,5},{0,5,0}}, {{-5,5,5},{-5,5,-5}},
{{0,5,0},{0,0,0}}, {{-5,5,-5},{-5,-5,-5}},
{{5,0,0},{5,0,5}}, {{5,-5,-5},{5,-5,5}},
{{5,5,5},{5,0,5}}, {{5,5,5},{5,-5,5}},
{{5,5,5},{5,5,0}}, {{5,5,5},{5,5,-5}},
{{5,5,0},{5,0,0}}, {{5,5,-5},{5,-5,-5}},
{{0,0,0},{5,0,0}}, {{-5,-5,-5},{5,-5,-5}},
{{0,0,5},{5,0,5}}, {{-5,-5,5},{5,-5,5}},
{{0,5,0},{5,5,0}}, {{-5,5,-5},{5,5,-5}},
{{0,5,5},{5,5,5}}, {{-5,5,5},{5,5,5}},
}; };
NRVec<LINE> lines(lines0); NRVec<LINE> lines(lines0);
Mat3<double> camera_angle; Mat3<double> rot_angle;
double eul[3]={40.*M_PI/180.,40.*M_PI/180.,10.*M_PI/180.}; double eul[3]={40.*M_PI/180.,40.*M_PI/180.,10.*M_PI/180.};
euler2rotmat(eul,camera_angle,"xyz"); euler2rotmat(eul,rot_angle,"zyz");
Vec3<double> camera={50,30,40}; double zoom=1;
rot_angle *= zoom;
Vec3<double> camera={50,60,40};
Vec3<double> plane_to_camera={-20,-20,-20}; Vec3<double> plane_to_camera={-20,-20,-20};
XSetForeground(display,gc,mycolor.pixel); XSetForeground(display,gc,mycolor.pixel);
plotobject(display, pixmap, gc, width,height, lines,camera_angle,camera,plane_to_camera,xod,xdo,yod,ydo); plotobject(display, pixmap, gc, width,height, lines,rot_angle,camera,plane_to_camera,xod,xdo,yod,ydo);
XClearWindow(display,win); //expose the pixmap XClearWindow(display,win); //expose the pixmap
XSetForeground(display, gc, BlackPixel(display, DefaultScreen(display)));//vratit cernou XSetForeground(display, gc, BlackPixel(display, DefaultScreen(display)));//vratit cernou
@ -289,6 +291,7 @@ int ispressed3=0;
int x,y,x0,y0; int x,y,x0,y0;
while(1) //LOOP .... process events while(1) //LOOP .... process events
{ {
bool redraw=0;
XNextEvent(display, &event); XNextEvent(display, &event);
switch (event.type) switch (event.type)
{ {
@ -304,31 +307,47 @@ while(1) //LOOP .... process events
if(event.xbutton.button==Button1) ispressed1=1; if(event.xbutton.button==Button1) ispressed1=1;
if(event.xbutton.button==Button2) ispressed2=1; if(event.xbutton.button==Button2) ispressed2=1;
if(event.xbutton.button==Button3) ispressed3=1; if(event.xbutton.button==Button3) ispressed3=1;
if(event.xbutton.button==Button4)
{
if(ispressed1) {eul[2]+=0.02; redraw=1;}
else if(ispressed2) {camera[2]+=0.2; redraw=1;}
else if (ispressed3) {plane_to_camera[2]+=0.5; redraw=1;}
else {zoom*=1.01; redraw=1;}
}
if(event.xbutton.button==Button5)
{
if(ispressed1) {eul[2]-=0.02; redraw=1;}
else if(ispressed2) {camera[2]-=0.2; redraw=1;}
else if (ispressed3) {plane_to_camera[2]-=0.5; redraw=1;}
else {zoom*=.99; redraw=1;}
}
break; break;
case MotionNotify: case MotionNotify:
x = event.xbutton.x; x = event.xbutton.x;
y = event.xbutton.y; y = event.xbutton.y;
if(ispressed1) if(ispressed1)
{ {
if(x0>x) eul[0]+=0.01; if(x0>x) eul[0]+=0.02;
if(x0<x) eul[0]-=0.01; if(x0<x) eul[0]-=0.02;
if(y0>y) eul[1]+=0.01; if(y0>y) eul[1]+=0.02;
if(y0<y) eul[1]-=0.01; if(y0<y) eul[1]-=0.02;
} }
if(ispressed2) if(ispressed2)
{ {
if(x0>x) camera[0]+=0.2;
if(x0<x) camera[0]-=0.2;
if(y0>y) camera[1]-=0.2;
if(y0<y) camera[1]+=0.2;
} }
if(ispressed3) if(ispressed3)
{ {
if(x0>x) plane_to_camera[0]-=0.5;
if(x0<x) plane_to_camera[0]+=0.5;
if(y0>y) plane_to_camera[1]+=0.5;
if(y0<y) plane_to_camera[1]-=0.5;
} }
if(ispressed1||ispressed2||ispressed3) if(ispressed1||ispressed2||ispressed3) redraw=1;
{ {
XSetForeground(display, gc, WhitePixel(display, DefaultScreen(display)));
XFillRectangle(display, pixmap, gc, 0, 0, width, height);
XSetForeground(display, gc, BlackPixel(display, DefaultScreen(display)));
euler2rotmat(eul,camera_angle,"xyz");
plotobject(display, pixmap, gc, width,height, lines,camera_angle,camera,plane_to_camera,xod,xdo,yod,ydo);
} }
x0=x; x0=x;
y0=y; y0=y;
@ -342,8 +361,18 @@ while(1) //LOOP .... process events
default: default:
break; break;
} }
XClearWindow(display,win); //expose the pixmap if(redraw)
XFlush(display); XSync(display, False); {
XSetForeground(display, gc, WhitePixel(display, DefaultScreen(display)));
XFillRectangle(display, pixmap, gc, 0, 0, width, height);
XSetForeground(display, gc, BlackPixel(display, DefaultScreen(display)));
euler2rotmat(eul,rot_angle,"zyz");
rot_angle*= zoom;
plotobject(display, pixmap, gc, width,height, lines,rot_angle,camera,plane_to_camera,xod,xdo,yod,ydo);
XClearWindow(display,win); //expose the pixmap
XFlush(display); XSync(display, False);
}
} }
done: done:

6
vecmat3.cc
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@ -844,9 +844,9 @@ return sqrt(sum);
//cf. https://en.wikipedia.org/wiki/3D_projection //cf. https://en.wikipedia.org/wiki/3D_projection
template<typename T> template<typename T>
void perspective(T *proj_xy, const Vec3<T> &point, const Mat3<T> &camera_angle, const Vec3<T> &camera, const Vec3<T> &plane_to_camera) void perspective(T *proj_xy, const Vec3<T> &point, const Mat3<T> &rot_angle, const Vec3<T> &camera, const Vec3<T> &plane_to_camera)
{ {
Vec3<T> d=camera_angle*(point-camera); Vec3<T> d=rot_angle*point-camera;
T scale = plane_to_camera[2]/d[2]; T scale = plane_to_camera[2]/d[2];
for(int i=0; i<2; ++i) proj_xy[i]= scale*d[i] + plane_to_camera[i]; for(int i=0; i<2; ++i) proj_xy[i]= scale*d[i] + plane_to_camera[i];
} }
@ -858,7 +858,7 @@ template class Vec3<T>; \
template class Mat3<T>; \ template class Mat3<T>; \
template void euler2rotmat(const T *eul, Mat3<T> &a, const char *type, bool transpose=0, bool direction=0, bool reverse=0); \ template void euler2rotmat(const T *eul, Mat3<T> &a, const char *type, bool transpose=0, bool direction=0, bool reverse=0); \
template void rotmat2euler(T *eul, const Mat3<T> &a, const char *type, bool transpose=0, bool direction=0, bool reverse=0); \ template void rotmat2euler(T *eul, const Mat3<T> &a, const char *type, bool transpose=0, bool direction=0, bool reverse=0); \
template void perspective(T *proj_xy, const Vec3<T> &point, const Mat3<T> &camera_angle, const Vec3<T> &camera, const Vec3<T> &plane_to_camera); \ template void perspective(T *proj_xy, const Vec3<T> &point, const Mat3<T> &rot_angle, const Vec3<T> &camera, const Vec3<T> &plane_to_camera); \
#ifndef AVOID_STDSTREAM #ifndef AVOID_STDSTREAM

2
vecmat3.h
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@ -191,7 +191,7 @@ template<typename T>
void rotmat2euler(T *eul, const Mat3<T> &a, const char *type, bool transpose=0, bool direction=0, bool reverse=0); void rotmat2euler(T *eul, const Mat3<T> &a, const char *type, bool transpose=0, bool direction=0, bool reverse=0);
template<typename T> template<typename T>
void perspective(T *proj_xy, const Vec3<T> &point, const Mat3<T> &camera_angle, const Vec3<T> &camera, const Vec3<T> &plane_to_camera); void perspective(T *proj_xy, const Vec3<T> &point, const Mat3<T> &rot_angle, const Vec3<T> &camera, const Vec3<T> &plane_to_camera);
}//namespace }//namespace