mirror of
https://github.com/RGBCube/serenity
synced 2025-07-25 20:57:35 +00:00
LibSoftGPU: Simplify Clipper
interpolation
By setting the clip plane normals' W coordinate to 1, we can skip two coordinate retrievals and three additions. This works because the Vector `.dot()` operation multiplies the W coordinates of both vectors.
This commit is contained in:
parent
f680d82086
commit
838cee37a2
1 changed files with 11 additions and 11 deletions
|
@ -1,6 +1,7 @@
|
|||
/*
|
||||
* Copyright (c) 2021, Jesse Buhagiar <jooster669@gmail.com>
|
||||
* Copyright (c) 2021, Stephan Unverwerth <s.unverwerth@serenityos.org>
|
||||
* Copyright (c) 2022, Jelle Raaijmakers <jelle@gmta.nl>
|
||||
* Copyright (c) 2022, the SerenityOS developers.
|
||||
*
|
||||
* SPDX-License-Identifier: BSD-2-Clause
|
||||
|
@ -35,23 +36,22 @@ template<Clipper::ClipPlane plane>
|
|||
static constexpr GPU::Vertex clip_intersection_point(GPU::Vertex const& p1, GPU::Vertex const& p2)
|
||||
{
|
||||
constexpr FloatVector4 clip_plane_normals[] = {
|
||||
{ 1, 0, 0, 0 }, // Left Plane
|
||||
{ -1, 0, 0, 0 }, // Right Plane
|
||||
{ 0, -1, 0, 0 }, // Top Plane
|
||||
{ 0, 1, 0, 0 }, // Bottom plane
|
||||
{ 0, 0, 1, 0 }, // Near Plane
|
||||
{ 0, 0, -1, 0 } // Far Plane
|
||||
{ 1, 0, 0, 1 }, // Left Plane
|
||||
{ -1, 0, 0, 1 }, // Right Plane
|
||||
{ 0, -1, 0, 1 }, // Top Plane
|
||||
{ 0, 1, 0, 1 }, // Bottom plane
|
||||
{ 0, 0, 1, 1 }, // Near Plane
|
||||
{ 0, 0, -1, 1 } // Far Plane
|
||||
};
|
||||
constexpr auto clip_plane_normal = clip_plane_normals[to_underlying(plane)];
|
||||
|
||||
// See https://www.microsoft.com/en-us/research/wp-content/uploads/1978/01/p245-blinn.pdf
|
||||
// "Clipping Using Homogeneous Coordinates" Blinn/Newell, 1978
|
||||
// Clip plane normals have W=1 so the vertices' W coordinates are included in x1 and x2.
|
||||
|
||||
float const w1 = p1.clip_coordinates.w();
|
||||
float const w2 = p2.clip_coordinates.w();
|
||||
float const x1 = clip_plane_normal.dot(p1.clip_coordinates);
|
||||
float const x2 = clip_plane_normal.dot(p2.clip_coordinates);
|
||||
float const a = (w1 + x1) / ((w1 + x1) - (w2 + x2));
|
||||
auto const x1 = clip_plane_normal.dot(p1.clip_coordinates);
|
||||
auto const x2 = clip_plane_normal.dot(p2.clip_coordinates);
|
||||
auto const a = x1 / (x1 - x2);
|
||||
|
||||
GPU::Vertex out;
|
||||
out.position = mix(p1.position, p2.position, a);
|
||||
|
|
Loading…
Add table
Add a link
Reference in a new issue