Using Intervals to move the Panda¶
Intervals and Sequences¶
The Program¶
Update the Code¶
The next step is to cause the panda to actually move back and forth. Update the code to the following:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 | #include "pandaFramework.h"
#include "pandaSystem.h"
#include "genericAsyncTask.h"
#include "asyncTaskManager.h"
#include "cIntervalManager.h"
#include "cLerpNodePathInterval.h"
#include "cMetaInterval.h"
// Global stuff
PT(AsyncTaskManager) taskMgr = AsyncTaskManager::get_global_ptr();
PT(ClockObject) globalClock = ClockObject::get_global_clock();
NodePath camera;
// Task to move the camera
AsyncTask::DoneStatus SpinCameraTask(GenericAsyncTask *task, void *data) {
double time = globalClock->get_real_time();
double angledegrees = time * 6.0;
double angleradians = angledegrees * (3.14 / 180.0);
camera.set_pos(20 * sin(angleradians), -20.0 * cos(angleradians), 3);
camera.set_hpr(angledegrees, 0, 0);
return AsyncTask::DS_cont;
}
int main(int argc, char *argv[]) {
// Open a new window framework and set the title
PandaFramework framework;
framework.open_framework(argc, argv);
framework.set_window_title("My Panda3D Window");
// Open the window
WindowFramework *window = framework.open_window();
camera = window->get_camera_group(); // Get the camera and store it
// Load the environment model
NodePath scene = window->load_model(framework.get_models(),
"models/environment");
scene.reparent_to(window->get_render());
scene.set_scale(0.25, 0.25, 0.25);
scene.set_pos(-8, 42, 0);
// Load our panda
NodePath pandaActor = window->load_model(framework.get_models(),
"models/panda-model");
pandaActor.set_scale(0.005);
pandaActor.reparent_to(window->get_render());
// Load the walk animation
window->load_model(pandaActor, "models/panda-walk4");
window->loop_animations(0);
// Create the lerp intervals needed to walk back and forth
PT(CLerpNodePathInterval) pandaPosInterval1, pandaPosInterval2,
pandaHprInterval1, pandaHprInterval2;
pandaPosInterval1 = new CLerpNodePathInterval("pandaPosInterval1",
13.0, CLerpInterval::BT_no_blend,
true, false, pandaActor, NodePath());
pandaPosInterval1->set_start_pos(LPoint3(0, 10, 0));
pandaPosInterval1->set_end_pos(LPoint3(0, -10, 0));
pandaPosInterval2 = new CLerpNodePathInterval("pandaPosInterval2",
13.0, CLerpInterval::BT_no_blend,
true, false, pandaActor, NodePath());
pandaPosInterval2->set_start_pos(LPoint3(0, -10, 0));
pandaPosInterval2->set_end_pos(LPoint3(0, 10, 0));
pandaHprInterval1 = new CLerpNodePathInterval("pandaHprInterval1", 3.0,
CLerpInterval::BT_no_blend,
true, false, pandaActor, NodePath());
pandaHprInterval1->set_start_hpr(LPoint3(0, 0, 0));
pandaHprInterval1->set_end_hpr(LPoint3(180, 0, 0));
pandaHprInterval2 = new CLerpNodePathInterval("pandaHprInterval2", 3.0,
CLerpInterval::BT_no_blend,
true, false, pandaActor, NodePath());
pandaHprInterval2->set_start_hpr(LPoint3(180, 0, 0));
pandaHprInterval2->set_end_hpr(LPoint3(0, 0, 0));
// Create and play the sequence that coordinates the intervals
PT(CMetaInterval) pandaPace;
pandaPace = new CMetaInterval("pandaPace");
pandaPace->add_c_interval(pandaPosInterval1, 0,
CMetaInterval::RS_previous_end);
pandaPace->add_c_interval(pandaHprInterval1, 0,
CMetaInterval::RS_previous_end);
pandaPace->add_c_interval(pandaPosInterval2, 0,
CMetaInterval::RS_previous_end);
pandaPace->add_c_interval(pandaHprInterval2, 0,
CMetaInterval::RS_previous_end);
pandaPace->loop();
// Add our task.
taskMgr->add(new GenericAsyncTask("Spins the camera",
&SpinCameraTask, nullptr));
// This is a simpler way to do stuff every frame,
// if you're too lazy to create a task.
Thread *current_thread = Thread::get_current_thread();
while (framework.do_frame(current_thread)) {
// Step the interval manager
CIntervalManager::get_global_ptr()->step();
}
framework.close_framework();
return 0;
}
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When the pandaPosInterval1
interval is started, it will gradually adjust the
position of the panda from (0, 10, 0) to (0, -10, 0) over a period of 13
seconds. Similarly, when the pandaHprInterval1
interval is started, the
heading of the panda will rotate 180 degrees over a period of 3 seconds.
The pandaPace
sequence above causes the panda to move in a straight line,
turn, move in the opposite straight line, and finally turn again. The code
pandaPace.loop()
causes the Sequence to be started in looping mode.
Run the Program¶
The result of all this is to cause the panda to pace back and forth from one tree to the other.