BGE: new bge.logic.Render() to perform render w/o logic step.

This function works only if python has control:
1. add scene custom property, call it __main__
2. give it string value as the name of a text block
3. code game loop in python in text block. Example:

import bge

bge.logic.setUseExternalClock(True)
t = 0.0;
scene = bge.logic.getCurrentScene()
cam = scene.cameras["Camera"]
cam.setViewport(120,120,370,370)
while not bge.logic.NextFrame():
    cam.useViewport = True
    # second render with viewport enable, clock time unchanged
    bge.logic.Render()
    # advance animation for next frame
    t += 0.02
    bge.logic.setClockTime(t)
    cam.useViewport = False

2 files changed, 13 insertions, 0 deletions

diff --git a/source/gameengine/Ketsji/KX_PythonInit.cpp b/source/gameengine/Ketsji/KX_PythonInit.cpp
index a93294e93ee..8b9dd2df9b1 100644
--- a/source/gameengine/Ketsji/KX_PythonInit.cpp
+++ b/source/gameengine/Ketsji/KX_PythonInit.cpp
@@ -905,6 +905,15 @@ static PyObject *gPyNextFrame(PyObject *)
 	}
 }
 
+static PyObject *gPyRender(PyObject *)
+{
+	if (pynextframestate.render == NULL) Py_RETURN_NONE;
+	if (pynextframestate.state == NULL) Py_RETURN_NONE; //should never happen; raise exception instead?
+
+	pynextframestate.render(pynextframestate.state);
+	Py_RETURN_NONE;
+}
+
 
 static struct PyMethodDef game_methods[] = {
 	{"expandPath", (PyCFunction)gPyExpandPath, METH_VARARGS, (const char *)gPyExpandPath_doc},
@@ -953,6 +962,7 @@ static struct PyMethodDef game_methods[] = {
 	{"PrintGLInfo", (PyCFunction)pyPrintExt, METH_NOARGS, (const char *)"Prints GL Extension Info"},
 	{"PrintMemInfo", (PyCFunction)pyPrintStats, METH_NOARGS, (const char *)"Print engine statistics"},
 	{"NextFrame", (PyCFunction)gPyNextFrame, METH_NOARGS, (const char *)"Render next frame (if Python has control)"},
+    {"Render", (PyCFunction)gPyRender, METH_NOARGS, (const char *)"Do only render (skip logic), if Python has control"},
 	{"getProfileInfo", (PyCFunction)gPyGetProfileInfo, METH_NOARGS, gPyGetProfileInfo_doc},
 	/* library functions */
 	{"LibLoad", (PyCFunction)gLibLoad, METH_VARARGS|METH_KEYWORDS, (const char *)""},
diff --git a/source/gameengine/Ketsji/KX_PythonInit.h b/source/gameengine/Ketsji/KX_PythonInit.h
index 6550934a916..3b754ea1e25 100644
--- a/source/gameengine/Ketsji/KX_PythonInit.h
+++ b/source/gameengine/Ketsji/KX_PythonInit.h
@@ -78,12 +78,15 @@ KX_Scene *KX_GetActiveScene();
 KX_KetsjiEngine *KX_GetActiveEngine();
 
 typedef int (*PyNextFrameFunc)(void *);
+typedef void (*PyRenderFunc)(void *);
 
 struct PyNextFrameState {
 	/** can be either a GPG_NextFrameState or a BL_KetsjiNextFrameState */
 	void *state;
 	/** can be either GPG_PyNextFrame or BL_KetsjiPyNextFrame */
 	PyNextFrameFunc func;
+	/** can be either GPG_PyRender or BL_KetsjiPyRender */
+	PyRenderFunc render;
 };
 extern struct PyNextFrameState pynextframestate;