/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file graphicsStateGuardian.I
 * @author drose
 * @date 1999-09-24
 * @author fperazzi, PandaSE
 * @date 2010-04-29
 * get_max_2d_texture_array_layers and related)
 */

/**
 * Releases all prepared objects.
 */
INLINE void GraphicsStateGuardian::
release_all() {
  _prepared_objects->release_all();
}

/**
 * Frees the resources for all textures associated with this GSG.
 */
INLINE int GraphicsStateGuardian::
release_all_textures() {
  return _prepared_objects->release_all_textures();
}

/**
 * Frees the resources for all samplers associated with this GSG.
 */
INLINE int GraphicsStateGuardian::
release_all_samplers() {
  return _prepared_objects->release_all_samplers();
}

/**
 * Frees the resources for all geoms associated with this GSG.
 */
INLINE int GraphicsStateGuardian::
release_all_geoms() {
  return _prepared_objects->release_all_geoms();
}

/**
 * Frees the resources for all vertex buffers associated with this GSG.
 */
INLINE int GraphicsStateGuardian::
release_all_vertex_buffers() {
  return _prepared_objects->release_all_vertex_buffers();
}

/**
 * Frees the resources for all index buffers associated with this GSG.
 */
INLINE int GraphicsStateGuardian::
release_all_index_buffers() {
  return _prepared_objects->release_all_index_buffers();
}

/**
 * Frees the resources for all index buffers associated with this GSG.
 */
INLINE int GraphicsStateGuardian::
release_all_shader_buffers() {
  return _prepared_objects->release_all_shader_buffers();
}

/**
 * Sets the active flag associated with the GraphicsStateGuardian.  If the
 * GraphicsStateGuardian is marked inactive, nothing is rendered.  This is not
 * normally turned off unless there is a problem with the rendering detected
 * at a low level.
 */
INLINE void GraphicsStateGuardian::
set_active(bool active) {
  _active = active;
}

/**
 * Returns the active flag associated with the GraphicsStateGuardian.
 */
INLINE bool GraphicsStateGuardian::
is_active() const {
  return _active && _is_valid;
}

/**
 * Returns true if the GSG has been correctly initialized within a graphics
 * context, false if there has been some problem or it hasn't been initialized
 * yet.
 */
INLINE bool GraphicsStateGuardian::
is_valid() const {
  return _is_valid;
}

/**
 * Returns true if the gsg is marked as needing a reset.
 */
INLINE bool GraphicsStateGuardian::
needs_reset() const {
  return _needs_reset;
}

/**
 * Sets the incomplete_render flag.  When this is true, the frame will be
 * rendered even if some of the geometry or textures in the scene are not
 * available (e.g.  they have been temporarily paged out).  When this is
 * false, the frame will be held up while this data is reloaded.
 *
 * Setting this true allows for a smoother frame rate, but occasionally parts
 * of the frame will be invisible or missing (they will generally come in
 * within a second or two).  Setting this false guarantees that every frame
 * will be complete, but may cause more chugs as things are loaded up at
 * runtime.
 *
 * You may want to set this false during loading screens, to guarantee that
 * all of your assets are available by the time you take the loading screen
 * down.
 *
 * This flag may also be set individually on each DisplayRegion.  It will be
 * considered true for a given DisplayRegion only if it is true on both the
 * GSG and on the DisplayRegion.
 */
INLINE void GraphicsStateGuardian::
set_incomplete_render(bool incomplete_render) {
  _incomplete_render = incomplete_render;
}

/**
 * Returns the incomplete_render flag.  See set_incomplete_render().
 */
INLINE bool GraphicsStateGuardian::
get_incomplete_render() const {
  return _incomplete_render;
}

/**
 * Returns true if the GSG is effectively in incomplete_render state,
 * considering both the GSG's incomplete_render and its current
 * DisplayRegion's incomplete_render flags.  It only makes sense to call this
 * during the draw traversal; at other times this return value will be
 * meaningless.
 *
 * See CullTraverser::get_effective_incomplete_render() for this same
 * information during the cull traversal.
 */
INLINE bool GraphicsStateGuardian::
get_effective_incomplete_render() const {
  return _effective_incomplete_render;
}

/**
 * Sets the Loader object that will be used by this GSG to load textures when
 * necessary, if get_incomplete_render() is true.
 */
INLINE void GraphicsStateGuardian::
set_loader(Loader *loader) {
  _loader = loader;
}

/**
 * Returns the Loader object that will be used by this GSG to load textures
 * when necessary, if get_incomplete_render() is true.
 */
INLINE Loader *GraphicsStateGuardian::
get_loader() const {
  return _loader;
}

/**
 * Sets the ShaderGenerator object that will be used by this GSG to generate
 * shaders when necessary.
 */
INLINE void GraphicsStateGuardian::
set_shader_generator(ShaderGenerator *shader_generator) {
  _shader_generator = shader_generator;
}

/**
 * Returns the ShaderGenerator object that will be used by this GSG to
 * generate shaders when necessary.
 */
INLINE ShaderGenerator *GraphicsStateGuardian::
get_shader_generator() const {
  return _shader_generator;
}

/**
 * Returns the graphics pipe on which this GSG was created.
 */
INLINE GraphicsPipe *GraphicsStateGuardian::
get_pipe() const {
  return _pipe;
}

/**
 * Returns the threading model that was used to create this GSG.
 */
INLINE const GraphicsThreadingModel &GraphicsStateGuardian::
get_threading_model() const {
  return _threading_model;
}

/**
 * Returns true if this GSG appears to be hardware-accelerated, or false if it
 * is known to be software only.
 */
INLINE bool GraphicsStateGuardian::
is_hardware() const {
  return _is_hardware;
}

/**
 * Returns true if this GSG strongly prefers triangle strips to individual
 * triangles (such as SGI), or false if it prefers to minimize the number of
 * primitive batches, even at the expense of triangle strips (such as most PC
 * hardware).
 */
INLINE bool GraphicsStateGuardian::
prefers_triangle_strips() const {
  return _prefers_triangle_strips;
}

/**
 * Returns the maximum number of vertices that should be put into any one
 * GeomVertexData object for use with this GSG.
 */
INLINE int GraphicsStateGuardian::
get_max_vertices_per_array() const {
  return _max_vertices_per_array;
}

/**
 * Returns the maximum number of vertex indices that should be put into any
 * one GeomPrimitive object for use with this GSG.
 */
INLINE int GraphicsStateGuardian::
get_max_vertices_per_primitive() const {
  return _max_vertices_per_primitive;
}

/**
 * Returns the maximum number of simultaneous textures that may be applied to
 * geometry with multitexturing, as supported by this particular GSG.  If you
 * exceed this number, the lowest-priority texture stages will not be applied.
 * Use TextureStage::set_priority() to adjust the relative importance of the
 * different texture stages.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_texture_stages() const {
  if (max_texture_stages > 0) {
    return std::min(_max_texture_stages, (int)max_texture_stages);
  }
  return _max_texture_stages;
}

/**
 * Returns the largest possible texture size in any one dimension supported by
 * the GSG, or -1 if there is no particular limit.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_texture_dimension() const {
  return _max_texture_dimension;
}

/**
 * Returns the largest possible texture size in any one dimension for a 3-d
 * texture, or -1 if there is no particular limit.  Returns 0 if 3-d textures
 * are not supported.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_3d_texture_dimension() const {
  return _max_3d_texture_dimension;
}

/**
 * Returns the largest possible number of pages, or -1 if there is no
 * particular limit.  Returns 0 if 2-d texture arrays not supported.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_2d_texture_array_layers() const {
  return _max_2d_texture_array_layers;
}

/**
 * Returns the largest possible texture size in any one dimension for a cube
 * map texture, or -1 if there is no particular limit.  Returns 0 if cube map
 * textures are not supported.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_cube_map_dimension() const {
  return _max_cube_map_dimension;
}

/**
 * Returns the largest possible buffer texture size, or -1 if there is no
 * particular limit.  Returns 0 if cube map textures are not supported.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_buffer_texture_size() const {
  return _max_buffer_texture_size;
}

/**
 * Returns true if this particular GSG can use the TextureStage::M_combine
 * mode, which includes all of the texture blend modes specified by
 * set_combine_rgb() and/or set_combine_alpha().  If this is false, you must
 * limit yourself to using the simpler blend modes.
 */
INLINE bool GraphicsStateGuardian::
get_supports_texture_combine() const {
  return _supports_texture_combine;
}

/**
 * Returns true if this GSG can use the TextureStage::CS_last_saved_result
 * source, which allows you to save the result of a TextureStage and re-use it
 * for multiple inputs.
 */
INLINE bool GraphicsStateGuardian::
get_supports_texture_saved_result() const {
  return _supports_texture_saved_result;
}

/**
 * Returns true if this GSG can use the TextureStage::CM_dot3_rgb or
 * CM_dot3_rgba combine modes.
 */
INLINE bool GraphicsStateGuardian::
get_supports_texture_dot3() const {
  return _supports_texture_dot3;
}

/**
 * Returns true if this GSG can render 3-d (volumetric) textures.
 */
INLINE bool GraphicsStateGuardian::
get_supports_3d_texture() const {
  return _supports_3d_texture;
}

/**
 * Returns true if this GSG can render 2-d textures array.
 */
INLINE bool GraphicsStateGuardian::
get_supports_2d_texture_array() const {
  return _supports_2d_texture_array;
}

/**
 * Returns true if this GSG can render cube map textures.
 */
INLINE bool GraphicsStateGuardian::
get_supports_cube_map() const {
  return _supports_cube_map;
}

/**
 * Returns true if this GSG can render buffer textures.
 */
INLINE bool GraphicsStateGuardian::
get_supports_buffer_texture() const {
  return _supports_buffer_texture;
}

/**
 * Returns true if this GSG can render cube map arrays.
 */
INLINE bool GraphicsStateGuardian::
get_supports_cube_map_array() const {
  return _supports_cube_map_array;
}

/**
 * Returns true if this GSG can handle non power of two sized textures.
 */
INLINE bool GraphicsStateGuardian::
get_supports_tex_non_pow2() const {
  return _supports_tex_non_pow2;
}

/**
 * Returns true if this GSG can handle sRGB textures.
 */
INLINE bool GraphicsStateGuardian::
get_supports_texture_srgb() const {
  return _supports_texture_srgb;
}

/**
 * Returns true if this GSG can compress textures as it loads them into
 * texture memory, and/or accept pre-compressed textures for storing.
 */
INLINE bool GraphicsStateGuardian::
get_supports_compressed_texture() const {
  return _supports_compressed_texture;
}

/**
 * Returns true if this GSG can accept textures pre-compressed in the
 * indicated format.  compression_mode may be any of the
 * Texture::CompressionMode enums.
 */
INLINE bool GraphicsStateGuardian::
get_supports_compressed_texture_format(int compression_mode) const {
  return _compressed_texture_formats.get_bit(compression_mode);
}

/**
 * Returns the maximum number of simultaneous lights that may be rendered on
 * geometry, or -1 if there is no particular limit.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_lights() const {
  return _max_lights;
}

/**
 * Returns the maximum number of simultaneous clip planes that may be applied
 * to geometry, or -1 if there is no particular limit.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_clip_planes() const {
  return _max_clip_planes;
}

/**
 * Returns the maximum number of transform matrices that may be simultaneously
 * used to transform any one vertex by the graphics hardware.  If this number
 * is 0, then the hardware (or the graphics backend) doesn't support soft-
 * skinned vertices (in which case Panda will animate the vertices in
 * software).
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_vertex_transforms() const {
  return _max_vertex_transforms;
}

/**
 * Returns the maximum number of transforms there may be in a single
 * TransformTable for this graphics hardware.  If this number is 0 (but
 * get_max_transforms() is nonzero), then the graphics hardware (or API)
 * doesn't support indexed transforms, but can support direct transform
 * references.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_vertex_transform_indices() const {
  return _max_vertex_transform_indices;
}

/**
 * Returns true if this particular GSG has the property that any framebuffer-
 * to-texture copy results in a texture that is upside-down and backwards from
 * Panda's usual convention; that is, it copies into a texture from the bottom
 * up instead of from the top down.
 *
 * If this is true, then on offscreen GraphicsBuffer created for the purposes
 * of rendering into a texture should be created with the invert flag set
 * true, to compensate.  Panda will do this automatically if you create an
 * offscreen buffer using GraphicsOutput::make_texture_buffer().
 */
INLINE bool GraphicsStateGuardian::
get_copy_texture_inverted() const {
  // If this is set from a Config variable, that overrides.
  if (copy_texture_inverted.has_value()) {
    return copy_texture_inverted;
  }

  // Otherwise, use whatever behavior the GSG figured for itself.
  return _copy_texture_inverted;
}

/**
 * Returns true if this particular GSG can generate mipmaps for a texture
 * automatically, or if they must be generated in software.  If this is true,
 * then mipmaps can safely be enabled for rendered textures (e.g.  using the
 * MultitexReducer).
 */
INLINE bool GraphicsStateGuardian::
get_supports_generate_mipmap() const {
  return _supports_generate_mipmap;
}

/**
 * Returns true if this particular GSG supports textures whose format is
 * F_depth_stencil.  This returns true if the GSG supports GL_DEPTH_COMPONENT
 * textures, which are considered a limited but still valid case of
 * F_depth_stencil.
 */
INLINE bool GraphicsStateGuardian::
get_supports_depth_texture() const {
  return _supports_depth_texture;
}

/**
 * Returns true if this particular GSG supports textures whose format is
 * F_depth_stencil.  This only returns true if the GSG supports the full
 * packed depth-stencil functionality.
 */
INLINE bool GraphicsStateGuardian::
get_supports_depth_stencil() const {
  return _supports_depth_stencil;
}

/**
 * Returns true if this particular GSG supports luminance textures.
 */
INLINE bool GraphicsStateGuardian::
get_supports_luminance_texture() const {
  return _supports_luminance_texture;
}

/**
 * Returns true if this particular GSG supports the filter mode FT_shadow for
 * depth textures.
 */
INLINE bool GraphicsStateGuardian::
get_supports_shadow_filter() const {
  return _supports_shadow_filter;
}

/**
 * Returns true if this particular GSG supports the use of sampler objects to
 * record texture sampling parameters separately from the texture objects.
 * This doesn't really affect functionality, but if this is false, it may mean
 * that using the same texture with different SamplerState objects will result
 * in reduced performance.
 */
INLINE bool GraphicsStateGuardian::
get_supports_sampler_objects() const {
  return _supports_sampler_objects;
}

/**
 * Returns true if this particular GSG supports arbfp1+arbvp1 or above.
 */
INLINE bool GraphicsStateGuardian::
get_supports_basic_shaders() const {
  return _supports_basic_shaders;
}

/**
 * Returns true if this particular GSG supports geometry shaders.
 */
INLINE bool GraphicsStateGuardian::
get_supports_geometry_shaders() const {
  return _supports_geometry_shaders;
}

/**
 * Returns true if this particular GSG supports tesselation shaders.
 */
INLINE bool GraphicsStateGuardian::
get_supports_tessellation_shaders() const {
  return _supports_tessellation_shaders;
}

/**
 * Returns true if this particular GSG supports compute shaders.
 */
INLINE bool GraphicsStateGuardian::
get_supports_compute_shaders() const {
  return _supports_compute_shaders;
}

/**
 * Returns true if this particular GSG supports GLSL shaders.
 */
INLINE bool GraphicsStateGuardian::
get_supports_glsl() const {
  return _supports_glsl;
}

/**
 * Returns true if this particular GSG supports HLSL shaders.
 */
INLINE bool GraphicsStateGuardian::
get_supports_hlsl() const {
  return _supports_hlsl;
}

/**
 * Returns true if this particular GSG supports stencil buffers at all.
 */
INLINE bool GraphicsStateGuardian::
get_supports_stencil() const {
  return _supports_stencil;
}

/**
 * Returns true if this particular GSG supports two sided stencil: different
 * stencil settings for the front and back side of the same polygon.
 */
INLINE bool GraphicsStateGuardian::
get_supports_two_sided_stencil() const {
  return _supports_two_sided_stencil;
}

/**
 * Returns true if this particular GSG supports hardware geometry instancing:
 * the ability to render multiple copies of a model.  In OpenGL, this is done
 * using the EXT_draw_instanced extension.
 */
INLINE bool GraphicsStateGuardian::
get_supports_geometry_instancing() const {
  return _supports_geometry_instancing;
}

/**
 * Returns true if this particular GSG supports draw calls for which the
 * information comes from a buffer.
 */
INLINE bool GraphicsStateGuardian::
get_supports_indirect_draw() const {
  return _supports_indirect_draw;
}

/**
 * Returns true if this GSG supports an occlusion query.  If this is true,
 * then begin_occlusion_query() and end_occlusion_query() may be called to
 * bracket a sequence of draw_triangles() (or whatever) calls to measure
 * pixels that pass the depth test.
 */
bool GraphicsStateGuardian::
get_supports_occlusion_query() const {
  return _supports_occlusion_query;
}

/**
 * Returns true if this GSG supports a timer query.
 */
bool GraphicsStateGuardian::
get_supports_timer_query() const {
  return _supports_timer_query;
}

/**
 * Returns true if timer queries are currently enabled on this GSG.
 */
bool GraphicsStateGuardian::
get_timer_queries_active() const {
#ifdef DO_PSTATS
  return _timer_queries_active;
#else
  return false;
#endif
}

/**
 * Returns the maximum number of simultaneous color textures that may be
 * attached for render-to-texture, as supported by this particular GSG.  If
 * you exceed this number, the lowest-priority render targets will not be
 * applied.  Use RenderTarget::set_priority() to adjust the relative
 * importance of the different render targets.
 *
 * The value returned may not be meaningful until after the graphics context
 * has been fully created (e.g.  the window has been opened).
 */
INLINE int GraphicsStateGuardian::
get_max_color_targets() const {
  if (max_color_targets > 0) {
    return std::min(_max_color_targets, (int)max_color_targets);
  }
  return _max_color_targets;
}

/**
 * Returns true if dual source (incoming1_color and incoming1_alpha) blend
 * operands are supported by this GSG.
 */
INLINE bool GraphicsStateGuardian::
get_supports_dual_source_blending() const {
  return _supports_dual_source_blending;
}

/**
 * Deprecated.  Use get_max_color_targets() instead, which returns the exact
 * same value.
 */
INLINE int GraphicsStateGuardian::
get_maximum_simultaneous_render_targets() const {
  return get_max_color_targets();
}

/**
 * Returns the ShaderModel
 */
INLINE GraphicsStateGuardian::ShaderModel GraphicsStateGuardian::
get_shader_model() const {
  return _shader_model;
}

/**
 * Sets the ShaderModel.  This will override the auto- detected shader model
 * during GSG reset.  Useful for testing lower-end shaders.
 */
INLINE void GraphicsStateGuardian::
set_shader_model(ShaderModel shader_model) {
  if (shader_model <= _auto_detect_shader_model) {
    _shader_model = shader_model;
  }
}

/**
 * Returns true if this particular GSG can implement (or would prefer to
 * implement) set color and/or color scale using materials and/or ambient
 * lights, or false if we need to actually munge the color.
 */
INLINE bool GraphicsStateGuardian::
get_color_scale_via_lighting() const {
  return _color_scale_via_lighting;
}

/**
 * Returns true if this particular GSG can implement (or would prefer to
 * implement) an alpha scale via an additional Texture layer, or false if we
 * need to actually munge the alpha.
 */
INLINE bool GraphicsStateGuardian::
get_alpha_scale_via_texture() const {
  return _alpha_scale_via_texture;
}

/**
 * This variant of get_alpha_scale_via_texture() answers the question of
 * whether the GSG can implement an alpha scale via an additional Texture
 * layer, considering the current TextureAttrib that will be in effect.  This
 * considers whether there is at least one additional texture slot available
 * on the GSG.
 */
INLINE bool GraphicsStateGuardian::
get_alpha_scale_via_texture(const TextureAttrib *tex_attrib) const {
  return _alpha_scale_via_texture &&
    (tex_attrib == nullptr ||
     tex_attrib->get_num_on_stages() < get_max_texture_stages());
}

/**
 * Returns the TextureStage that will be used to apply an alpha scale, if
 * get_alpha_scale_via_texture() returns true.
 */
INLINE TextureStage *GraphicsStateGuardian::
get_alpha_scale_texture_stage() {
  if (_alpha_scale_texture_stage == nullptr) {
    _alpha_scale_texture_stage = new TextureStage("alpha-scale");
    _alpha_scale_texture_stage->set_sort(1000000000);
  }
  return _alpha_scale_texture_stage;
}

/**
 * Returns true if this particular GSG can implement (or would prefer to
 * implement) set color and/or color scale directly, without requiring any
 * munging of vertices or tricks with lighting.
 */
INLINE bool GraphicsStateGuardian::
get_runtime_color_scale() const {
  return _runtime_color_scale;
}

/**
 * Returns the coordinate system in effect on this particular gsg.  Normally,
 * this will be the default coordinate system, but it might be set differently
 * at runtime.
 */
INLINE CoordinateSystem GraphicsStateGuardian::
get_coordinate_system() const {
  return _coordinate_system;
}

/**
 * Specifies the global quality_level to be imposed for all Textures rendered
 * by this GSG.  This overrides the value set on individual textures via
 * Texture::set_quality_level().  Set this to Texture::QL_default in order to
 * allow the individual texture quality levels to be respected.
 *
 * This is mainly useful for the tinydisplay software renderer.  See
 * Texture::set_quality_level().
 */
INLINE void GraphicsStateGuardian::
set_texture_quality_override(Texture::QualityLevel quality_level) {
  _texture_quality_override = quality_level;
}

/**
 * Returns the global quality_level override specified by
 * set_texture_quality_override.
 *
 * This is mainly useful for the tinydisplay software renderer.  See
 * Texture::set_quality_level().
 */
INLINE Texture::QualityLevel GraphicsStateGuardian::
get_texture_quality_override() const {
  return _texture_quality_override;
}

/**
 * Calls reset() to initialize the GSG, but only if it hasn't been called yet.
 * Returns true if the GSG was new, false otherwise.
 */
INLINE bool GraphicsStateGuardian::
reset_if_new() {
  if (_needs_reset) {
    reset();
    return true;
  }
  return false;
}

/**
 * Marks the GSG as "new", so that the next call to reset_if_new() will be
 * effective.
 */
INLINE void GraphicsStateGuardian::
mark_new() {
  _needs_reset = true;
}

/**
 * Fetches the external net transform.  This transform is generally only set
 * when geometry is about to be rendered.  Therefore, this "get" function is
 * typically only meaningful during the geometry rendering process.
 */
INLINE CPT(TransformState) GraphicsStateGuardian::
get_external_transform() const {
  return _inv_cs_transform->compose(_internal_transform);
}

/**
 * Fetches the external net transform.  This transform is generally only set
 * when geometry is about to be rendered.  Therefore, this "get" function is
 * typically only meaningful during the geometry rendering process.
 */
INLINE CPT(TransformState) GraphicsStateGuardian::
get_internal_transform() const {
  return _internal_transform;
}

/**
 * Returns the current display region being rendered to, as set by the last
 * call to prepare_display_region().
 */
INLINE const DisplayRegion *GraphicsStateGuardian::
get_current_display_region() const {
  return _current_display_region;
}

/**
 * Returns the current stereo channel being rendered to, as set by the last
 * call to prepare_display_region().
 */
INLINE Lens::StereoChannel GraphicsStateGuardian::
get_current_stereo_channel() const {
  return _current_stereo_channel;
}

/**
 * Returns the current tex view offset, as set by the last call to
 * prepare_display_region().  This is read from the current DisplayRegion.
 */
INLINE int GraphicsStateGuardian::
get_current_tex_view_offset() const {
  return _current_tex_view_offset;
}

/**
 * Returns the current lens being used to render, according to the scene
 * specified via the last call to set_scene().
 */
INLINE const Lens *GraphicsStateGuardian::
get_current_lens() const {
  return _current_lens;
}

/**
 * Returns the inverse of the transform returned by get_cs_transform().
 */
INLINE CPT(TransformState) GraphicsStateGuardian::
get_inv_cs_transform() const {
  return _inv_cs_transform;
}

/**
 * Notifies the gsg that it is about to render into a window/buffer with the
 * given FrameBufferProperties
 */
INLINE void GraphicsStateGuardian::
set_current_properties(const FrameBufferProperties *prop) {
  _current_properties = prop;
}