use super::{Context, Euler, Matrix, MatrixEntry, Quaternion};
use std::fmt;
// @short_description: Functions for efficiently tracking many
// related transformations
//
// Matrices can be used (for example) to describe the model-view
// transforms of objects, texture transforms, and projective
// transforms.
//
// The #Matrix api provides a good way to manipulate individual
// matrices representing a single transformation but if you need to
// track many-many such transformations for many objects that are
// organized in a scenegraph for example then using a separate
// #Matrix for each object may not be the most efficient way.
//
// A #MatrixStack enables applications to track lots of
// transformations that are related to each other in some kind of
// hierarchy. In a scenegraph for example if you want to know how to
// transform a particular node then you usually have to walk up
// through the ancestors and accumulate their transforms before
// finally applying the transform of the node itself. In this model
// things are grouped together spatially according to their ancestry
// and all siblings with the same parent share the same initial
// transformation. The #MatrixStack API is suited to tracking lots
// of transformations that fit this kind of model.
//
// Compared to using the #Matrix api directly to track many
// related transforms, these can be some advantages to using a
// #MatrixStack:
// <itemizedlist>
// - Faster equality comparisons of transformations</listitem>
// - Efficient comparisons of the differences between arbitrary
// transformations</listitem>
// - Avoid redundant arithmetic related to common transforms
// </listitem>
// - Can be more space efficient (not always though)</listitem>
// </itemizedlist>
//
// For reference (to give an idea of when a #MatrixStack can
// provide a space saving) a #Matrix can be expected to take 72
// bytes whereas a single #MatrixEntry in a #MatrixStack is
// currently around 32 bytes on a 32bit CPU or 36 bytes on a 64bit
// CPU. An entry is needed for each individual operation applied to
// the stack (such as rotate, scale, translate) so if most of your
// leaf node transformations only need one or two simple operations
// relative to their parent then a matrix stack will likely take less
// space than having a #Matrix for each node.
//
// Even without any space saving though the ability to perform fast
// comparisons and avoid redundant arithmetic (especially sine and
// cosine calculations for rotations) can make using a matrix stack
// worthwhile.
// MatrixStack:
//
// Tracks your current position within a hierarchy and lets you build
// up a graph of transformations as you traverse through a hierarchy
// such as a scenegraph.
//
// A #MatrixStack always maintains a reference to a single
// transformation at any point in time, representing the
// transformation at the current position in the hierarchy. You can
// get a reference to the current transformation by calling
// matrix_stack_get_entry().
//
// When a #MatrixStack is first created with
// matrix_stack_new() then it is conceptually positioned at the
// root of your hierarchy and the current transformation simply
// represents an identity transformation.
//
// As you traverse your object hierarchy (your scenegraph) then you
// should call matrix_stack_push() whenever you move down one
// level and call matrix_stack_pop() whenever you move back up
// one level towards the root.
//
// At any time you can apply a set of operations, such as "rotate",
// "scale", "translate" on top of the current transformation of a
// #MatrixStack using functions such as
// matrix_stack_rotate(), matrix_stack_scale() and
// matrix_stack_translate(). These operations will derive a new
// current transformation and will never affect a transformation
// that you have referenced using matrix_stack_get_entry().
//
// Internally applying operations to a #MatrixStack builds up a
// graph of #MatrixEntry structures which each represent a single
// immutable transform.
pub struct MatrixStack {
// Context *context;
// MatrixEntry *last_entry;
}
impl MatrixStack {
/// Allocates a new `MatrixStack` that can be used to build up
/// transformations relating to objects in a scenegraph like hierarchy.
/// (See the description of `MatrixStack` and `MatrixEntry` for
/// more details of what a matrix stack is best suited for)
///
/// When a `MatrixStack` is first allocated it is conceptually
/// positioned at the root of your scenegraph hierarchy. As you
/// traverse your scenegraph then you should call
/// `MatrixStack::push` whenever you move down a level and
/// `MatrixStack::pop` whenever you move back up a level towards
/// the root.
///
/// Once you have allocated a `MatrixStack` you can get a reference
/// to the current transformation for the current position in the
/// hierarchy by calling `MatrixStack::get_entry`.
///
/// Once you have allocated a `MatrixStack` you can apply operations
/// such as rotate, scale and translate to modify the current transform
/// for the current position in the hierarchy by calling
/// `MatrixStack::rotate`, `MatrixStack::scale` and
/// `MatrixStack::translate`.
/// ## `ctx`
/// A `Context`
///
/// # Returns
///
/// A newly allocated `MatrixStack`
pub fn new(ctx: &Context) -> MatrixStack {
// MatrixStack *stack = g_slice_new (MatrixStack);
// if (G_UNLIKELY (matrix_stack_magazine == NULL))
// {
// matrix_stack_magazine =
// _magazine_new (sizeof (MatrixEntryFull), 20);
// matrix_stack_matrices_magazine =
// _magazine_new (sizeof (Matrix), 20);
// }
// stack->context = ctx;
// stack->last_entry = NULL;
// matrix_entry_ref (&ctx->identity_entry);
// _matrix_stack_push_entry (stack, &ctx->identity_entry);
// return _matrix_stack_object_new (stack);
unimplemented!()
}
/// Replaces the current matrix with a perspective matrix for a given
/// viewing frustum defined by 4 side clip planes that all cross
/// through the origin and 2 near and far clip planes.
/// ## `left`
/// X position of the left clipping plane where it
/// intersects the near clipping plane
/// ## `right`
/// X position of the right clipping plane where it
/// intersects the near clipping plane
/// ## `bottom`
/// Y position of the bottom clipping plane where it
/// intersects the near clipping plane
/// ## `top`
/// Y position of the top clipping plane where it intersects
/// the near clipping plane
/// ## `z_near`
/// The distance to the near clipping plane (Must be positive)
/// ## `z_far`
/// The distance to the far clipping plane (Must be positive)
pub fn frustum(&self, left: f32, right: f32, bottom: f32, top: f32, z_near: f32, z_far: f32) {
// MatrixEntryLoad *entry;
// entry =
// _matrix_stack_push_replacement_entry (stack,
// MATRIX_OP_LOAD);
// entry->matrix =
// _magazine_chunk_alloc (matrix_stack_matrices_magazine);
// matrix_init_identity (entry->matrix);
// matrix_frustum (entry->matrix,
// left, right, bottom, top,
// z_near, z_far);
}
/// Resolves the current `self` transform into a `Matrix` by
/// combining the operations that have been applied to build up the
/// current transform.
///
/// There are two possible ways that this fn may return its
/// result depending on whether the stack is able to directly point
/// to an internal `Matrix` or whether the result needs to be
/// composed of multiple operations.
///
/// If an internal matrix contains the required result then this
/// fn will directly return a pointer to that matrix, otherwise
/// if the fn returns `None` then `matrix` will be initialized
/// to match the current transform of `self`.
///
/// `matrix` will be left untouched if a direct pointer is
/// returned.
/// ## `matrix`
/// The potential destination for the current matrix
///
/// # Returns
///
/// A direct pointer to the current transform or `None`
/// and in that case `matrix` will be initialized with
/// the value of the current transform.
pub fn get(&self) -> (Matrix, Matrix) {
// return matrix_entry_get (stack->last_entry, matrix);
unimplemented!()
}
/// Gets a reference to the current transform represented by a
/// `MatrixEntry` pointer.
///
/// The transform represented by a `MatrixEntry` is
/// immutable.
///
/// `MatrixEntry`s are reference counted using
/// `MatrixEntry::ref` and `MatrixEntry::unref` and you
/// should call `MatrixEntry::unref` when you are finished with
/// and entry you get via `MatrixStack::get_entry`.
///
/// # Returns
///
/// A pointer to the `MatrixEntry`
/// representing the current matrix stack transform.
pub fn entry(&self) -> Option<MatrixEntry> {
// return stack->last_entry;
unimplemented!()
}
/// Gets the inverse transform of the current matrix and uses it to
/// initialize a new `Matrix`.
/// ## `inverse`
/// The destination for a 4x4 inverse transformation matrix
///
/// # Returns
///
/// `true` if the inverse was successfully calculated or `false`
/// for degenerate transformations that can't be inverted (in this case the
/// `inverse` matrix will simply be initialized with the identity matrix)
pub fn inverse(&self) -> (bool, Matrix) {
// Matrix matrix;
// Matrix *internal = matrix_stack_get (stack, &matrix);
// if (internal)
// return matrix_get_inverse (internal, inverse);
// else
// return matrix_get_inverse (&matrix, inverse);
unimplemented!()
}
/// Resets the current matrix to the identity matrix.
pub fn load_identity(&self) {
// _matrix_stack_push_replacement_entry (stack,
// MATRIX_OP_LOAD_IDENTITY);
unimplemented!()
}
/// Multiplies the current matrix by the given matrix.
/// ## `matrix`
/// the matrix to multiply with the current model-view
pub fn multiply(&self, matrix: &Matrix) {
// MatrixEntryMultiply *entry;
// entry = _matrix_stack_push_operation (stack, MATRIX_OP_MULTIPLY);
// entry->matrix =
// _magazine_chunk_alloc (matrix_stack_matrices_magazine);
// matrix_init_from_array (entry->matrix, (float *)matrix);
unimplemented!()
}
/// Replaces the current matrix with an orthographic projection matrix.
/// ## `x_1`
/// The x coordinate for the first vertical clipping plane
/// ## `y_1`
/// The y coordinate for the first horizontal clipping plane
/// ## `x_2`
/// The x coordinate for the second vertical clipping plane
/// ## `y_2`
/// The y coordinate for the second horizontal clipping plane
/// ## `near`
/// The distance to the near clipping
/// plane (will be negative if the plane is
/// behind the viewer)
/// ## `far`
/// The distance to the far clipping
/// plane (will be negative if the plane is
/// behind the viewer)
pub fn orthographic(&self, x_1: f32, y_1: f32, x_2: f32, y_2: f32, near: f32, far: f32) {
// MatrixEntryLoad *entry;
// entry =
// _matrix_stack_push_replacement_entry (stack,
// MATRIX_OP_LOAD);
// entry->matrix =
// _magazine_chunk_alloc (matrix_stack_matrices_magazine);
// matrix_init_identity (entry->matrix);
// matrix_orthographic (entry->matrix,
// x_1, y_1, x_2, y_2, near, far);
unimplemented!()
}
/// Replaces the current matrix with a perspective matrix based on the
/// provided values.
///
/// You should be careful not to have too great a `z_far` / `z_near`
/// ratio since that will reduce the effectiveness of depth testing
/// since there wont be enough precision to identify the depth of
/// objects near to each other.
/// ## `fov_y`
/// Vertical field of view angle in degrees.
/// ## `aspect`
/// The (width over height) aspect ratio for display
/// ## `z_near`
/// The distance to the near clipping plane (Must be positive,
/// and must not be 0)
/// ## `z_far`
/// The distance to the far clipping plane (Must be positive)
pub fn perspective(&self, fov_y: f32, aspect: f32, z_near: f32, z_far: f32) {
// MatrixEntryLoad *entry;
// entry =
// _matrix_stack_push_replacement_entry (stack,
// MATRIX_OP_LOAD);
// entry->matrix =
// _magazine_chunk_alloc (matrix_stack_matrices_magazine);
// matrix_init_identity (entry->matrix);
// matrix_perspective (entry->matrix,
// fov_y, aspect, z_near, z_far);
unimplemented!()
}
/// Restores the previous transform that was last saved by calling
/// `MatrixStack::push`.
///
/// This is usually called while traversing a scenegraph whenever you
/// return up one level in the graph towards the root node.
pub fn pop(&self) {
// MatrixEntry *old_top;
// MatrixEntry *new_top;
// _RETURN_IF_FAIL (stack != NULL);
// old_top = stack->last_entry;
// _RETURN_IF_FAIL (old_top != NULL);
// To pop we are moving the top of the stack to the old top's parent
// node. The stack always needs to have a reference to the top entry
// so we must take a reference to the new top. The stack would have
// previously had a reference to the old top so we need to decrease
// the ref count on that. We need to ref the new head first in case
// this stack was the only thing referencing the old top. In that
// case the call to matrix_entry_unref will unref the parent.
// Find the last save operation and remove it
// XXX: it would be an error to pop to the very beginning of the
// stack so we don't need to check for NULL pointer dereferencing.
// for (new_top = old_top;
// new_top->op != MATRIX_OP_SAVE;
// new_top = new_top->parent)
// ;
// new_top = new_top->parent;
// matrix_entry_ref (new_top);
// matrix_entry_unref (old_top);
// stack->last_entry = new_top;
}
/// Saves the current transform and starts a new transform that derives
/// from the current transform.
///
/// This is usually called while traversing a scenegraph whenever you
/// traverse one level deeper. `MatrixStack::pop` can then be
/// called when going back up one layer to restore the previous
/// transform of an ancestor.
pub fn push(&self) {
// MatrixEntrySave *entry;
// entry = _matrix_stack_push_operation (stack, MATRIX_OP_SAVE);
// entry->cache_valid = false;
}
/// Multiplies the current matrix by one that rotates the around the
/// axis-vector specified by `x`, `y` and `z`. The rotation follows the
/// right-hand thumb rule so for example rotating by 10 degrees about
/// the axis-vector (0, 0, 1) causes a small counter-clockwise
/// rotation.
/// ## `angle`
/// Angle in degrees to rotate.
/// ## `x`
/// X-component of vertex to rotate around.
/// ## `y`
/// Y-component of vertex to rotate around.
/// ## `z`
/// Z-component of vertex to rotate around.
pub fn rotate(&self, angle: f32, x: f32, y: f32, z: f32) {
// MatrixEntryRotate *entry;
// entry = _matrix_stack_push_operation (stack, MATRIX_OP_ROTATE);
// entry->angle = angle;
// entry->x = x;
// entry->y = y;
// entry->z = z;
unimplemented!()
}
/// Multiplies the current matrix by one that rotates according to the
/// rotation described by `euler`.
///
/// ## `euler`
/// A `Euler`
pub fn rotate_euler(&self, euler: &Euler) {
// MatrixEntryRotateEuler *entry;
// entry = _matrix_stack_push_operation (stack,
// MATRIX_OP_ROTATE_EULER);
// entry->heading = euler->heading;
// entry->pitch = euler->pitch;
// entry->roll = euler->roll;
unimplemented!()
}
/// Multiplies the current matrix by one that rotates according to the
/// rotation described by `quaternion`.
/// ## `quaternion`
/// A `Quaternion`
pub fn rotate_quaternion(&self, quaternion: &Quaternion) {
// MatrixEntryRotateQuaternion *entry;
// entry = _matrix_stack_push_operation (stack,
// MATRIX_OP_ROTATE_QUATERNION);
// entry->values[0] = quaternion->w;
// entry->values[1] = quaternion->x;
// entry->values[2] = quaternion->y;
// entry->values[3] = quaternion->z;
unimplemented!()
}
/// Multiplies the current matrix by one that scales the x, y and z
/// axes by the given values.
/// ## `x`
/// Amount to scale along the x-axis
/// ## `y`
/// Amount to scale along the y-axis
/// ## `z`
/// Amount to scale along the z-axis
pub fn scale(&self, x: f32, y: f32, z: f32) {
// MatrixEntryScale *entry;
// entry = _matrix_stack_push_operation (stack, MATRIX_OP_SCALE);
// entry->x = x;
// entry->y = y;
// entry->z = z;
unimplemented!()
}
/// Replaces the current `self` matrix value with the value of `matrix`.
/// This effectively discards any other operations that were applied
/// since the last time `MatrixStack::push` was called or since
/// the stack was initialized.
/// ## `matrix`
/// A `Matrix` replace the current matrix value with
pub fn set(&self, matrix: &Matrix) {
// MatrixEntryLoad *entry;
// entry =
// _matrix_stack_push_replacement_entry (stack,
// MATRIX_OP_LOAD);
// entry->matrix =
// _magazine_chunk_alloc (matrix_stack_matrices_magazine);
// matrix_init_from_array (entry->matrix, (float *)matrix);
unimplemented!()
}
/// Multiplies the current matrix by one that translates along all
/// three axes according to the given values.
/// ## `x`
/// Distance to translate along the x-axis
/// ## `y`
/// Distance to translate along the y-axis
/// ## `z`
/// Distance to translate along the z-axis
pub fn translate(&self, x: f32, y: f32, z: f32) {
// MatrixEntryTranslate *entry;
// entry = _matrix_stack_push_operation (stack, MATRIX_OP_TRANSLATE);
// entry->x = x;
// entry->y = y;
// entry->z = z;
unimplemented!()
}
}
impl fmt::Display for MatrixStack {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "MatrixStack")
}
}