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7571ef0343
We now have one set of texture coordinates per texture unit. Texture coordinate generation and texture coordinate assignment is currently only stubbed. This will be rectified in another commit.
87 lines
3.1 KiB
C++
87 lines
3.1 KiB
C++
/*
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* Copyright (c) 2021, Jesse Buhagiar <jooster669@gmail.com>
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* Copyright (c) 2021, Stephan Unverwerth <s.unverwerth@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Format.h>
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#include <AK/ScopeGuard.h>
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#include <LibSoftGPU/Clipper.h>
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namespace SoftGPU {
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bool Clipper::point_within_clip_plane(const FloatVector4& vertex, ClipPlane plane)
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{
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switch (plane) {
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case ClipPlane::LEFT:
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return vertex.x() >= -vertex.w();
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case ClipPlane::RIGHT:
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return vertex.x() <= vertex.w();
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case ClipPlane::TOP:
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return vertex.y() <= vertex.w();
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case ClipPlane::BOTTOM:
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return vertex.y() >= -vertex.w();
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case ClipPlane::NEAR:
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return vertex.z() >= -vertex.w();
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case ClipPlane::FAR:
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return vertex.z() <= vertex.w();
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}
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return false;
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}
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Vertex Clipper::clip_intersection_point(const Vertex& p1, const Vertex& p2, ClipPlane plane_index)
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{
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// See https://www.microsoft.com/en-us/research/wp-content/uploads/1978/01/p245-blinn.pdf
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// "Clipping Using Homogeneous Coordinates" Blinn/Newell, 1978
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float w1 = p1.clip_coordinates.w();
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float w2 = p2.clip_coordinates.w();
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float x1 = clip_plane_normals[plane_index].dot(p1.clip_coordinates);
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float x2 = clip_plane_normals[plane_index].dot(p2.clip_coordinates);
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float a = (w1 + x1) / ((w1 + x1) - (w2 + x2));
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Vertex out;
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out.position = mix(p1.position, p2.position, a);
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out.eye_coordinates = mix(p1.eye_coordinates, p2.eye_coordinates, a);
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out.clip_coordinates = mix(p1.clip_coordinates, p2.clip_coordinates, a);
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out.color = mix(p1.color, p2.color, a);
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for (size_t i = 0; i < NUM_SAMPLERS; ++i)
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out.tex_coords[i] = mix(p1.tex_coords[i], p2.tex_coords[i], a);
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out.normal = mix(p1.normal, p2.normal, a);
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return out;
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}
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void Clipper::clip_triangle_against_frustum(Vector<Vertex>& input_verts)
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{
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list_a = input_verts;
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list_b.clear_with_capacity();
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auto read_from = &list_a;
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auto write_to = &list_b;
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for (size_t plane = 0; plane < NUMBER_OF_CLIPPING_PLANES; plane++) {
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write_to->clear_with_capacity();
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// Save me, C++23
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for (size_t i = 0; i < read_from->size(); i++) {
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const auto& curr_vec = read_from->at((i + 1) % read_from->size());
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const auto& prev_vec = read_from->at(i);
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if (point_within_clip_plane(curr_vec.clip_coordinates, static_cast<ClipPlane>(plane))) {
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if (!point_within_clip_plane(prev_vec.clip_coordinates, static_cast<ClipPlane>(plane))) {
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auto intersect = clip_intersection_point(prev_vec, curr_vec, static_cast<ClipPlane>(plane));
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write_to->append(intersect);
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}
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write_to->append(curr_vec);
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} else if (point_within_clip_plane(prev_vec.clip_coordinates, static_cast<ClipPlane>(plane))) {
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auto intersect = clip_intersection_point(prev_vec, curr_vec, static_cast<ClipPlane>(plane));
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write_to->append(intersect);
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}
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}
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swap(write_to, read_from);
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}
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input_verts = *read_from;
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}
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}
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