gpu_py_offscreen.cc

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/* SPDX-FileCopyrightText: 2015 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include <Python.h>
 
#include "BLI_string.h"
#include "BLI_utildefines.h"
 
#include "BKE_global.hh"
#include "BKE_lib_id.hh" /* For #BKE_id_is_in_global_main. */
#include "BKE_scene.hh"
 
#include "DNA_view3d_types.h"
 
#include "GPU_context.hh"
#include "GPU_framebuffer.hh"
#include "GPU_texture.hh"
#include "GPU_viewport.hh"
 
#include "ED_view3d_offscreen.hh"
 
#include "../mathutils/mathutils.hh"
 
#include "../generic/py_capi_utils.hh"
#include "../generic/python_compat.hh"
 
#include "gpu_py.hh"
#include "gpu_py_texture.hh"
 
#include "gpu_py_offscreen.hh" /* own include */
 
/* Define the free method to avoid breakage. */
#define BPYGPU_USE_GPUOBJ_FREE_METHOD
 
/* -------------------------------------------------------------------- */
static const PyC_StringEnumItems pygpu_framebuffer_color_texture_formats[] = {
    {GPU_RGBA8, "RGBA8"},
    {GPU_RGBA16, "RGBA16"},
    {GPU_RGBA16F, "RGBA16F"},
    {GPU_RGBA32F, "RGBA32F"},
    {0, nullptr},
};
 
static int pygpu_offscreen_valid_check(BPyGPUOffScreen *py_ofs)
{
  if (UNLIKELY(py_ofs->ofs == nullptr)) {
    PyErr_SetString(PyExc_ReferenceError,
#ifdef BPYGPU_USE_GPUOBJ_FREE_METHOD
                    "GPU offscreen was freed, no further access is valid"
#else
                    "GPU offscreen: internal error"
#endif
    );
    return -1;
  }
  return 0;
}
 
#define BPY_GPU_OFFSCREEN_CHECK_OBJ(bpygpu) \
  { \
    if (UNLIKELY(pygpu_offscreen_valid_check(bpygpu) == -1)) { \
      return nullptr; \
    } \
  } \
  ((void)0)
 
/* -------------------------------------------------------------------- */
struct OffScreenStackContext {
  PyObject_HEAD /* Required Python macro. */
  BPyGPUOffScreen *py_offscreen;
  int level;
  bool is_explicitly_bound; /* Bound by "bind" method. */
};
 
static void pygpu_offscreen_stack_context__tp_dealloc(OffScreenStackContext *self)
{
  Py_DECREF(self->py_offscreen);
  PyObject_DEL(self);
}
 
static PyObject *pygpu_offscreen_stack_context_enter(OffScreenStackContext *self)
{
  BPYGPU_IS_INIT_OR_ERROR_OBJ;
 
  BPY_GPU_OFFSCREEN_CHECK_OBJ(self->py_offscreen);
 
  if (!self->is_explicitly_bound) {
    if (self->level != -1) {
      PyErr_SetString(PyExc_RuntimeError, "Already in use");
      return nullptr;
    }
 
    GPU_offscreen_bind(self->py_offscreen->ofs, true);
    self->level = GPU_framebuffer_stack_level_get();
  }
 
  Py_RETURN_NONE;
}
 
static PyObject *pygpu_offscreen_stack_context_exit(OffScreenStackContext *self,
                                                    PyObject * /*args*/)
{
  BPYGPU_IS_INIT_OR_ERROR_OBJ;
 
  BPY_GPU_OFFSCREEN_CHECK_OBJ(self->py_offscreen);
 
  if (self->level == -1) {
    PyErr_SetString(PyExc_RuntimeError, "Not yet in use\n");
    return nullptr;
  }
 
  const int level = GPU_framebuffer_stack_level_get();
  if (level != self->level) {
    PyErr_Format(
        PyExc_RuntimeError, "Level of bind mismatch, expected %d, got %d\n", self->level, level);
  }
 
  GPU_offscreen_unbind(self->py_offscreen->ofs, true);
  Py_RETURN_NONE;
}
 
#if (defined(__GNUC__) && !defined(__clang__))
#  pragma GCC diagnostic push
#  pragma GCC diagnostic ignored "-Wcast-function-type"
#endif
 
static PyMethodDef pygpu_offscreen_stack_context__tp_methods[] = {
    {"__enter__", (PyCFunction)pygpu_offscreen_stack_context_enter, METH_NOARGS},
    {"__exit__", (PyCFunction)pygpu_offscreen_stack_context_exit, METH_VARARGS},
    {nullptr},
};
 
#if (defined(__GNUC__) && !defined(__clang__))
#  pragma GCC diagnostic pop
#endif
 
static PyTypeObject PyGPUOffscreenStackContext_Type = {
    /*ob_base*/ PyVarObject_HEAD_INIT(nullptr, 0)
    /*tp_name*/ "GPUFrameBufferStackContext",
    /*tp_basicsize*/ sizeof(OffScreenStackContext),
    /*tp_itemsize*/ 0,
    /*tp_dealloc*/ (destructor)pygpu_offscreen_stack_context__tp_dealloc,
    /*tp_vectorcall_offset*/ 0,
    /*tp_getattr*/ nullptr,
    /*tp_setattr*/ nullptr,
    /*tp_as_async*/ nullptr,
    /*tp_repr*/ nullptr,
    /*tp_as_number*/ nullptr,
    /*tp_as_sequence*/ nullptr,
    /*tp_as_mapping*/ nullptr,
    /*tp_hash*/ nullptr,
    /*tp_call*/ nullptr,
    /*tp_str*/ nullptr,
    /*tp_getattro*/ nullptr,
    /*tp_setattro*/ nullptr,
    /*tp_as_buffer*/ nullptr,
    /*tp_flags*/ Py_TPFLAGS_DEFAULT,
    /*tp_doc*/ nullptr,
    /*tp_traverse*/ nullptr,
    /*tp_clear*/ nullptr,
    /*tp_richcompare*/ nullptr,
    /*tp_weaklistoffset*/ 0,
    /*tp_iter*/ nullptr,
    /*tp_iternext*/ nullptr,
    /*tp_methods*/ pygpu_offscreen_stack_context__tp_methods,
    /*tp_members*/ nullptr,
    /*tp_getset*/ nullptr,
    /*tp_base*/ nullptr,
    /*tp_dict*/ nullptr,
    /*tp_descr_get*/ nullptr,
    /*tp_descr_set*/ nullptr,
    /*tp_dictoffset*/ 0,
    /*tp_init*/ nullptr,
    /*tp_alloc*/ nullptr,
    /*tp_new*/ nullptr,
    /*tp_free*/ nullptr,
    /*tp_is_gc*/ nullptr,
    /*tp_bases*/ nullptr,
    /*tp_mro*/ nullptr,
    /*tp_cache*/ nullptr,
    /*tp_subclasses*/ nullptr,
    /*tp_weaklist*/ nullptr,
    /*tp_del*/ nullptr,
    /*tp_version_tag*/ 0,
    /*tp_finalize*/ nullptr,
    /*tp_vectorcall*/ nullptr,
};
 
PyDoc_STRVAR(
    /* Wrap. */
    pygpu_offscreen_bind_doc,
    ".. function:: bind()\n"
    "\n"
    "   Context manager to ensure balanced bind calls, even in the case of an error.\n");
static PyObject *pygpu_offscreen_bind(BPyGPUOffScreen *self)
{
  OffScreenStackContext *ret = PyObject_New(OffScreenStackContext,
                                            &PyGPUOffscreenStackContext_Type);
  ret->py_offscreen = self;
  ret->level = -1;
  ret->is_explicitly_bound = false;
  Py_INCREF(self);
 
  pygpu_offscreen_stack_context_enter(ret);
  ret->is_explicitly_bound = true;
 
  return (PyObject *)ret;
}
 
PyDoc_STRVAR(
    /* Wrap. */
    pygpu_offscreen_unbind_doc,
    ".. method:: unbind(restore=True)\n"
    "\n"
    "   Unbind the offscreen object.\n"
    "\n"
    "   :arg restore: Restore the OpenGL state, can only be used when the state has been "
    "saved before.\n"
    "   :type restore: bool\n");
static PyObject *pygpu_offscreen_unbind(BPyGPUOffScreen *self, PyObject *args, PyObject *kwds)
{
  bool restore = true;
 
  BPY_GPU_OFFSCREEN_CHECK_OBJ(self);
 
  static const char *_keywords[] = {"restore", nullptr};
  static _PyArg_Parser _parser = {
      PY_ARG_PARSER_HEAD_COMPAT()
      "|$" /* Optional keyword only arguments. */
      "O&" /* `restore` */
      ":unbind",
      _keywords,
      nullptr,
  };
  if (!_PyArg_ParseTupleAndKeywordsFast(args, kwds, &_parser, PyC_ParseBool, &restore)) {
    return nullptr;
  }
 
  GPU_offscreen_unbind(self->ofs, restore);
  GPU_apply_state();
  Py_RETURN_NONE;
}
 
/* -------------------------------------------------------------------- */
static PyObject *pygpu_offscreen__tp_new(PyTypeObject * /*self*/, PyObject *args, PyObject *kwds)
{
  BPYGPU_IS_INIT_OR_ERROR_OBJ;
 
  GPUOffScreen *ofs = nullptr;
  int width, height;
  PyC_StringEnum pygpu_textureformat = {pygpu_framebuffer_color_texture_formats, GPU_RGBA8};
  char err_out[256];
 
  static const char *_keywords[] = {"width", "height", "format", nullptr};
  static _PyArg_Parser _parser = {
      PY_ARG_PARSER_HEAD_COMPAT()
      "i"  /* `width` */
      "i"  /* `height` */
      "|$" /* Optional keyword only arguments. */
      "O&" /* `format` */
      ":GPUOffScreen.__new__",
      _keywords,
      nullptr,
  };
  if (!_PyArg_ParseTupleAndKeywordsFast(
          args, kwds, &_parser, &width, &height, PyC_ParseStringEnum, &pygpu_textureformat))
  {
    return nullptr;
  }
 
  if (GPU_context_active_get()) {
    ofs = GPU_offscreen_create(width,
                               height,
                               true,
                               eGPUTextureFormat(pygpu_textureformat.value_found),
                               GPU_TEXTURE_USAGE_SHADER_READ | GPU_TEXTURE_USAGE_HOST_READ,
                               err_out);
  }
  else {
    STRNCPY(err_out, "No active GPU context found");
  }
 
  if (ofs == nullptr) {
    PyErr_Format(PyExc_RuntimeError,
                 "gpu.offscreen.new(...) failed with '%s'",
                 err_out[0] ? err_out : "unknown error");
    return nullptr;
  }
 
  return BPyGPUOffScreen_CreatePyObject(ofs);
}
 
PyDoc_STRVAR(
    /* Wrap. */
    pygpu_offscreen_width_doc,
    "Width of the texture.\n"
    "\n"
    ":type: int");
static PyObject *pygpu_offscreen_width_get(BPyGPUOffScreen *self, void * /*type*/)
{
  BPY_GPU_OFFSCREEN_CHECK_OBJ(self);
  return PyLong_FromLong(GPU_offscreen_width(self->ofs));
}
 
PyDoc_STRVAR(
    /* Wrap. */
    pygpu_offscreen_height_doc,
    "Height of the texture.\n"
    "\n"
    ":type: int");
static PyObject *pygpu_offscreen_height_get(BPyGPUOffScreen *self, void * /*type*/)
{
  BPY_GPU_OFFSCREEN_CHECK_OBJ(self);
  return PyLong_FromLong(GPU_offscreen_height(self->ofs));
}
 
PyDoc_STRVAR(
    /* Wrap. */
    pygpu_offscreen_color_texture_doc,
    "OpenGL bindcode for the color texture.\n"
    "\n"
    ":type: int");
static PyObject *pygpu_offscreen_color_texture_get(BPyGPUOffScreen *self, void * /*type*/)
{
  BPY_GPU_OFFSCREEN_CHECK_OBJ(self);
  GPUTexture *texture = GPU_offscreen_color_texture(self->ofs);
  return PyLong_FromLong(GPU_texture_opengl_bindcode(texture));
}
 
PyDoc_STRVAR(
    /* Wrap. */
    pygpu_offscreen_texture_color_doc,
    "The color texture attached.\n"
    "\n"
    ":type: :class:`gpu.types.GPUTexture`");
static PyObject *pygpu_offscreen_texture_color_get(BPyGPUOffScreen *self, void * /*type*/)
{
  BPY_GPU_OFFSCREEN_CHECK_OBJ(self);
  GPUTexture *texture = GPU_offscreen_color_texture(self->ofs);
  return BPyGPUTexture_CreatePyObject(texture, true);
}
 
PyDoc_STRVAR(
    /* Wrap. */
    pygpu_offscreen_draw_view3d_doc,
    ".. method:: draw_view3d(scene, view_layer, view3d, region, view_matrix, projection_matrix, "
    "do_color_management=False, draw_background=True)\n"
    "\n"
    "   Draw the 3d viewport in the offscreen object.\n"
    "\n"
    "   :arg scene: Scene to draw.\n"
    "   :type scene: :class:`bpy.types.Scene`\n"
    "   :arg view_layer: View layer to draw.\n"
    "   :type view_layer: :class:`bpy.types.ViewLayer`\n"
    "   :arg view3d: 3D View to get the drawing settings from.\n"
    "   :type view3d: :class:`bpy.types.SpaceView3D`\n"
    "   :arg region: Region of the 3D View (required as temporary draw target).\n"
    "   :type region: :class:`bpy.types.Region`\n"
    "   :arg view_matrix: View Matrix (e.g. ``camera.matrix_world.inverted()``).\n"
    "   :type view_matrix: :class:`mathutils.Matrix`\n"
    "   :arg projection_matrix: Projection Matrix (e.g. ``camera.calc_matrix_camera(...)``).\n"
    "   :type projection_matrix: :class:`mathutils.Matrix`\n"
    "   :arg do_color_management: Color manage the output.\n"
    "   :type do_color_management: bool\n"
    "   :arg draw_background: Draw background.\n"
    "   :type draw_background: bool\n");
static PyObject *pygpu_offscreen_draw_view3d(BPyGPUOffScreen *self, PyObject *args, PyObject *kwds)
{
  MatrixObject *py_mat_view, *py_mat_projection;
  PyObject *py_scene, *py_view_layer, *py_region, *py_view3d;
 
  Depsgraph *depsgraph;
  Scene *scene;
  ViewLayer *view_layer;
  View3D *v3d;
  ARegion *region;
 
  bool do_color_management = false;
  bool draw_background = true;
 
  BPY_GPU_OFFSCREEN_CHECK_OBJ(self);
 
  static const char *_keywords[] = {
      "scene",
      "view_layer",
      "view3d",
      "region",
      "view_matrix",
      "projection_matrix",
      "do_color_management",
      "draw_background",
      nullptr,
  };
  static _PyArg_Parser _parser = {
      PY_ARG_PARSER_HEAD_COMPAT()
      "O"  /* `scene` */
      "O"  /* `view_layer` */
      "O"  /* `view3d` */
      "O"  /* `region` */
      "O&" /* `view_matrix` */
      "O&" /* `projection_matrix` */
      "|$" /* Optional keyword only arguments. */
      "O&" /* `do_color_management` */
      "O&" /* `draw_background` */
      ":draw_view3d",
      _keywords,
      nullptr,
  };
  if (!_PyArg_ParseTupleAndKeywordsFast(args,
                                        kwds,
                                        &_parser,
                                        &py_scene,
                                        &py_view_layer,
                                        &py_view3d,
                                        &py_region,
                                        Matrix_Parse4x4,
                                        &py_mat_view,
                                        Matrix_Parse4x4,
                                        &py_mat_projection,
                                        PyC_ParseBool,
                                        &do_color_management,
                                        PyC_ParseBool,
                                        &draw_background) ||
      (!(scene = static_cast<Scene *>(PyC_RNA_AsPointer(py_scene, "Scene"))) ||
       !(view_layer = static_cast<ViewLayer *>(PyC_RNA_AsPointer(py_view_layer, "ViewLayer"))) ||
       !(v3d = static_cast<View3D *>(PyC_RNA_AsPointer(py_view3d, "SpaceView3D"))) ||
       !(region = static_cast<ARegion *>(PyC_RNA_AsPointer(py_region, "Region")))))
  {
    return nullptr;
  }
 
  if (ED_view3d_draw_offscreen_check_nested()) {
    /* NOTE(@ideasman42): Nested draw calls could be supported.
     * Adding support for this looks to be possible but non-trivial. */
    PyErr_SetString(PyExc_RuntimeError, "Nested off-screen drawing not supported");
    return nullptr;
  }
 
  BLI_assert(BKE_id_is_in_global_main(&scene->id));
 
  depsgraph = BKE_scene_ensure_depsgraph(G_MAIN, scene, view_layer);
 
  /* Disable 'bgl' state since it interfere with off-screen drawing, see: #84402. */
  const bool is_bgl = GPU_bgl_get();
  if (is_bgl) {
    GPU_bgl_end();
  }
 
  GPU_offscreen_bind(self->ofs, true);
 
  /* Cache the #GPUViewport so the frame-buffers and associated textures are
   * not reallocated each time, see: #89204 */
  if (!self->viewport) {
    self->viewport = GPU_viewport_create();
  }
  else {
    GPU_viewport_tag_update(self->viewport);
  }
 
  ED_view3d_draw_offscreen(depsgraph,
                           scene,
                           eDrawType(v3d->shading.type),
                           v3d,
                           region,
                           GPU_offscreen_width(self->ofs),
                           GPU_offscreen_height(self->ofs),
                           (const float(*)[4])py_mat_view->matrix,
                           (const float(*)[4])py_mat_projection->matrix,
                           true,
                           draw_background,
                           "",
                           do_color_management,
                           true,
                           self->ofs,
                           self->viewport);
 
  GPU_offscreen_unbind(self->ofs, true);
 
  if (is_bgl) {
    GPU_bgl_start();
  }
 
  Py_RETURN_NONE;
}
 
#ifdef BPYGPU_USE_GPUOBJ_FREE_METHOD
PyDoc_STRVAR(
    /* Wrap. */
    pygpu_offscreen_free_doc,
    ".. method:: free()\n"
    "\n"
    "   Free the offscreen object.\n"
    "   The framebuffer, texture and render objects will no longer be accessible.\n");
static PyObject *pygpu_offscreen_free(BPyGPUOffScreen *self)
{
  BPY_GPU_OFFSCREEN_CHECK_OBJ(self);
 
  if (self->viewport) {
    GPU_viewport_free(self->viewport);
    self->viewport = nullptr;
  }
 
  GPU_offscreen_free(self->ofs);
  self->ofs = nullptr;
  Py_RETURN_NONE;
}
#endif
 
static void BPyGPUOffScreen__tp_dealloc(BPyGPUOffScreen *self)
{
  if (self->viewport) {
    GPU_viewport_free(self->viewport);
  }
  if (self->ofs) {
    GPU_offscreen_free(self->ofs);
  }
  Py_TYPE(self)->tp_free((PyObject *)self);
}
 
static PyGetSetDef pygpu_offscreen__tp_getseters[] = {
    {"color_texture",
     (getter)pygpu_offscreen_color_texture_get,
     (setter) nullptr,
     pygpu_offscreen_color_texture_doc,
     nullptr},
    {"texture_color",
     (getter)pygpu_offscreen_texture_color_get,
     (setter) nullptr,
     pygpu_offscreen_texture_color_doc,
     nullptr},
    {"width",
     (getter)pygpu_offscreen_width_get,
     (setter) nullptr,
     pygpu_offscreen_width_doc,
     nullptr},
    {"height",
     (getter)pygpu_offscreen_height_get,
     (setter) nullptr,
     pygpu_offscreen_height_doc,
     nullptr},
    {nullptr, nullptr, nullptr, nullptr, nullptr} /* Sentinel */
};
 
#if (defined(__GNUC__) && !defined(__clang__))
#  pragma GCC diagnostic push
#  pragma GCC diagnostic ignored "-Wcast-function-type"
#endif
 
static PyMethodDef pygpu_offscreen__tp_methods[] = {
    {"bind", (PyCFunction)pygpu_offscreen_bind, METH_NOARGS, pygpu_offscreen_bind_doc},
    {"unbind",
     (PyCFunction)pygpu_offscreen_unbind,
     METH_VARARGS | METH_KEYWORDS,
     pygpu_offscreen_unbind_doc},
    {"draw_view3d",
     (PyCFunction)pygpu_offscreen_draw_view3d,
     METH_VARARGS | METH_KEYWORDS,
     pygpu_offscreen_draw_view3d_doc},
#ifdef BPYGPU_USE_GPUOBJ_FREE_METHOD
    {"free", (PyCFunction)pygpu_offscreen_free, METH_NOARGS, pygpu_offscreen_free_doc},
#endif
    {nullptr, nullptr, 0, nullptr},
};
 
#if (defined(__GNUC__) && !defined(__clang__))
#  pragma GCC diagnostic pop
#endif
 
PyDoc_STRVAR(
    /* Wrap. */
    pygpu_offscreen__tp_doc,
    ".. class:: GPUOffScreen(width, height, *, format='RGBA8')\n"
    "\n"
    "   This object gives access to off screen buffers.\n"
    "\n"
    "   :arg width: Horizontal dimension of the buffer.\n"
    "   :type width: int\n"
    "   :arg height: Vertical dimension of the buffer.\n"
    "   :type height: int\n"
    "   :arg format: Internal data format inside GPU memory for color attachment "
    "texture. Possible values are:\n"
    "      `RGBA8`,\n"
    "      `RGBA16`,\n"
    "      `RGBA16F`,\n"
    "      `RGBA32F`,\n"
    "   :type format: str\n");
PyTypeObject BPyGPUOffScreen_Type = {
    /*ob_base*/ PyVarObject_HEAD_INIT(nullptr, 0)
    /*tp_name*/ "GPUOffScreen",
    /*tp_basicsize*/ sizeof(BPyGPUOffScreen),
    /*tp_itemsize*/ 0,
    /*tp_dealloc*/ (destructor)BPyGPUOffScreen__tp_dealloc,
    /*tp_vectorcall_offset*/ 0,
    /*tp_getattr*/ nullptr,
    /*tp_setattr*/ nullptr,
    /*tp_compare*/ nullptr,
    /*tp_repr*/ nullptr,
    /*tp_as_number*/ nullptr,
    /*tp_as_sequence*/ nullptr,
    /*tp_as_mapping*/ nullptr,
    /*tp_hash*/ nullptr,
    /*tp_call*/ nullptr,
    /*tp_str*/ nullptr,
    /*tp_getattro*/ nullptr,
    /*tp_setattro*/ nullptr,
    /*tp_as_buffer*/ nullptr,
    /*tp_flags*/ Py_TPFLAGS_DEFAULT,
    /*tp_doc*/ pygpu_offscreen__tp_doc,
    /*tp_traverse*/ nullptr,
    /*tp_clear*/ nullptr,
    /*tp_richcompare*/ nullptr,
    /*tp_weaklistoffset*/ 0,
    /*tp_iter*/ nullptr,
    /*tp_iternext*/ nullptr,
    /*tp_methods*/ pygpu_offscreen__tp_methods,
    /*tp_members*/ nullptr,
    /*tp_getset*/ pygpu_offscreen__tp_getseters,
    /*tp_base*/ nullptr,
    /*tp_dict*/ nullptr,
    /*tp_descr_get*/ nullptr,
    /*tp_descr_set*/ nullptr,
    /*tp_dictoffset*/ 0,
    /*tp_init*/ nullptr,
    /*tp_alloc*/ nullptr,
    /*tp_new*/ pygpu_offscreen__tp_new,
    /*tp_free*/ nullptr,
    /*tp_is_gc*/ nullptr,
    /*tp_bases*/ nullptr,
    /*tp_mro*/ nullptr,
    /*tp_cache*/ nullptr,
    /*tp_subclasses*/ nullptr,
    /*tp_weaklist*/ nullptr,
    /*tp_del*/ nullptr,
    /*tp_version_tag*/ 0,
    /*tp_finalize*/ nullptr,
    /*tp_vectorcall*/ nullptr,
};
 
/* -------------------------------------------------------------------- */
PyObject *BPyGPUOffScreen_CreatePyObject(GPUOffScreen *ofs)
{
  BPyGPUOffScreen *self;
 
  self = PyObject_New(BPyGPUOffScreen, &BPyGPUOffScreen_Type);
  self->ofs = ofs;
  self->viewport = nullptr;
 
  return (PyObject *)self;
}
 
#undef BPY_GPU_OFFSCREEN_CHECK_OBJ