mirror of
https://github.com/bevyengine/bevy
synced 2025-02-16 22:18:33 +00:00
Fix gizmo lines deforming or disappearing when partially behind the camera (#9470)
If a line has one point behind the camera(near plane) then it would deform or, if the `depth_bias` setting was set to a negative value, disappear. ## Solution The issue is that performing a perspective divide does not work correctly for points behind the near plane and a perspective divide is used inside the shader to define the line width in screen space. The solution is to perform near plane clipping manually inside the shader before the perspective divide is done.
This commit is contained in:
parent
5fac1fe0a9
commit
e2ed42fd75
1 changed files with 19 additions and 2 deletions
|
@ -43,8 +43,13 @@ fn vertex(vertex: VertexInput) -> VertexOutput {
|
|||
let position = positions[vertex.index];
|
||||
|
||||
// algorithm based on https://wwwtyro.net/2019/11/18/instanced-lines.html
|
||||
let clip_a = view.view_proj * vec4(vertex.position_a, 1.);
|
||||
let clip_b = view.view_proj * vec4(vertex.position_b, 1.);
|
||||
var clip_a = view.view_proj * vec4(vertex.position_a, 1.);
|
||||
var clip_b = view.view_proj * vec4(vertex.position_b, 1.);
|
||||
|
||||
// Manual near plane clipping to avoid errors when doing the perspective divide inside this shader.
|
||||
clip_a = clip_near_plane(clip_a, clip_b);
|
||||
clip_b = clip_near_plane(clip_b, clip_a);
|
||||
|
||||
let clip = mix(clip_a, clip_b, position.z);
|
||||
|
||||
let resolution = view.viewport.zw;
|
||||
|
@ -92,6 +97,18 @@ fn vertex(vertex: VertexInput) -> VertexOutput {
|
|||
return VertexOutput(clip_position, color);
|
||||
}
|
||||
|
||||
fn clip_near_plane(a: vec4<f32>, b: vec4<f32>) -> vec4<f32> {
|
||||
// Move a if a is behind the near plane and b is in front.
|
||||
if a.z > a.w && b.z <= b.w {
|
||||
// Interpolate a towards b until it's at the near plane.
|
||||
let distance_a = a.z - a.w;
|
||||
let distance_b = b.z - b.w;
|
||||
let t = distance_a / (distance_a - distance_b);
|
||||
return a + (b - a) * t;
|
||||
}
|
||||
return a;
|
||||
}
|
||||
|
||||
struct FragmentInput {
|
||||
@location(0) color: vec4<f32>,
|
||||
};
|
||||
|
|
Loading…
Add table
Reference in a new issue