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Add support for zoom relative depth planes #49

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Add support for zoom relative depth planes #49

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111 changes: 85 additions & 26 deletions src/camera.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -240,6 +240,7 @@ pub struct Camera {
projection_type: ProjectionType,
z_near: f32,
z_far: f32,
zoom_relative_depth: bool,
position: Vec3,
target: Vec3,
up: Vec3,
Expand All @@ -259,10 +260,11 @@ impl Camera {
height: f32,
z_near: f32,
z_far: f32,
zoom_relative_depth: bool,
) -> Self {
let mut camera = Camera::new(viewport);
camera.set_view(position, target, up);
camera.set_orthographic_projection(height, z_near, z_far);
camera.set_orthographic_projection(height, z_near, z_far, zoom_relative_depth);
camera
}

Expand All @@ -277,15 +279,17 @@ impl Camera {
field_of_view_y: impl Into<Radians>,
z_near: f32,
z_far: f32,
zoom_relative_depth: bool,
) -> Self {
let mut camera = Camera::new(viewport);
camera.set_view(position, target, up);
camera.set_perspective_projection(field_of_view_y, z_near, z_far);
camera.set_perspective_projection(field_of_view_y, z_near, z_far, zoom_relative_depth);
camera
}

///
/// New camera which projects the world with a general planar projection.
/// This is best used with the relative depth unit if zooming is allowed.
///
pub fn new_planar(
viewport: Viewport,
Expand All @@ -295,10 +299,11 @@ impl Camera {
field_of_view_y: impl Into<Radians>,
z_near: f32,
z_far: f32,
zoom_relative_depth: bool,
) -> Self {
let mut camera = Camera::new(viewport);
camera.set_view(position, target, up);
camera.set_planar_projection(field_of_view_y, z_near, z_far);
camera.set_planar_projection(field_of_view_y, z_near, z_far, zoom_relative_depth);
camera
}

Expand All @@ -308,13 +313,20 @@ impl Camera {
pub fn set_perspective_projection(
&mut self,
field_of_view_y: impl Into<Radians>,
z_near: f32,
z_far: f32,
mut z_near: f32,
mut z_far: f32,
zoom_relative_depth: bool,
) {
self.z_near = z_near;
self.z_far = z_far;
self.zoom_relative_depth = zoom_relative_depth;
let field_of_view_y = field_of_view_y.into();
self.projection_type = ProjectionType::Perspective { field_of_view_y };
if zoom_relative_depth {
let zoom = self.position.distance(self.target);
z_near *= zoom;
z_far *= zoom;
}
self.projection =
cgmath::perspective(field_of_view_y, self.viewport.aspect(), z_near, z_far);
}
Expand All @@ -326,13 +338,24 @@ impl Camera {
/// The view frustum depth is `z_near` to `z_far`.
/// All of the above values are scaled by the zoom factor which is one over the distance between the camera position and target.
///
pub fn set_orthographic_projection(&mut self, height: f32, z_near: f32, z_far: f32) {
pub fn set_orthographic_projection(
&mut self,
height: f32,
mut z_near: f32,
mut z_far: f32,
zoom_relative_depth: bool,
) {
self.projection_type = ProjectionType::Orthographic { height };
self.z_near = z_near;
self.z_far = z_far;
self.zoom_relative_depth = zoom_relative_depth;
let zoom = self.position.distance(self.target);
let height = zoom * height;
let width = height * self.viewport.aspect();
if zoom_relative_depth {
z_near *= zoom;
z_far *= zoom;
}
self.projection = cgmath::ortho(
-0.5 * width,
0.5 * width,
Expand All @@ -345,35 +368,33 @@ impl Camera {

///
/// Specify the camera to use planar projection with the given field of view in the y-direction and near and far plane.
/// This can be either a planar or perspective projection depending on the field of view provided, which is permitted to be zero or negative.
/// This can be either an orthographic or perspective projection depending on the field of view provided, which is permitted to be zero or negative.
/// This is best used with the relative depth unit if zooming is allowed.
///
pub fn set_planar_projection(
&mut self,
field_of_view_y: impl Into<Radians>,
mut z_near: f32,
mut z_far: f32,
zoom_relative_depth: bool,
) {
self.z_near = z_near;
self.z_far = z_far;
self.zoom_relative_depth = zoom_relative_depth;
let field_of_view_y = field_of_view_y.into();
self.projection_type = ProjectionType::Planar { field_of_view_y };
let depth = self.position.distance(self.target);
let height = 2.0 * depth;
let focal = -Rad::cot(field_of_view_y / 2.0) * depth;
z_near -= depth;
z_far -= depth;
// Required to ensure near/far plane does not cross focal point when at close zoom levels
if focal < 0.0 && z_near < focal {
z_near = focal + 0.001;
} else if focal > 0.0 && z_far > focal {
z_far = focal - 0.001;
if zoom_relative_depth {
z_near *= depth;
z_far *= depth;
}
self.projection = planar(
field_of_view_y,
self.viewport.aspect(),
height,
z_near,
z_far,
z_near - depth,
z_far - depth,
) * Mat4::from_translation(vec3(0.0, 0.0, depth));
}

Expand All @@ -386,13 +407,28 @@ impl Camera {
self.viewport = viewport;
match self.projection_type {
ProjectionType::Orthographic { height } => {
self.set_orthographic_projection(height, self.z_near, self.z_far);
self.set_orthographic_projection(
height,
self.z_near,
self.z_far,
self.zoom_relative_depth,
);
}
ProjectionType::Perspective { field_of_view_y } => {
self.set_perspective_projection(field_of_view_y, self.z_near, self.z_far);
self.set_perspective_projection(
field_of_view_y,
self.z_near,
self.z_far,
self.zoom_relative_depth,
);
}
ProjectionType::Planar { field_of_view_y } => {
self.set_planar_projection(field_of_view_y, self.z_near, self.z_far);
self.set_planar_projection(
field_of_view_y,
self.z_near,
self.z_far,
self.zoom_relative_depth,
);
}
}
true
Expand All @@ -415,13 +451,28 @@ impl Camera {
self.up,
);
match self.projection_type {
ProjectionType::Orthographic { height } => {
self.set_orthographic_projection(height, self.z_near, self.z_far)
}
ProjectionType::Planar { field_of_view_y } => {
self.set_planar_projection(field_of_view_y, self.z_near, self.z_far)
ProjectionType::Perspective { field_of_view_y } => {
if self.zoom_relative_depth {
self.set_perspective_projection(
field_of_view_y,
self.z_near,
self.z_far,
self.zoom_relative_depth,
);
}
}
_ => {}
ProjectionType::Orthographic { height } => self.set_orthographic_projection(
height,
self.z_near,
self.z_far,
self.zoom_relative_depth,
),
ProjectionType::Planar { field_of_view_y } => self.set_planar_projection(
field_of_view_y,
self.z_near,
self.z_far,
self.zoom_relative_depth,
),
};
}

Expand Down Expand Up @@ -578,6 +629,13 @@ impl Camera {
self.z_far
}

///
/// Returns if the near and far planes are calculated relative to the current zoom level.
///
pub fn zoom_relative_depth(&self) -> bool {
self.zoom_relative_depth
}

///
/// Returns the position of this camera.
///
Expand Down Expand Up @@ -627,6 +685,7 @@ impl Camera {
projection_type: ProjectionType::Orthographic { height: 1.0 },
z_near: 0.0,
z_far: 0.0,
zoom_relative_depth: false,
position: vec3(0.0, 0.0, 5.0),
target: vec3(0.0, 0.0, 0.0),
up: vec3(0.0, 1.0, 0.0),
Expand Down
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