fff8dbd9b8
clip_quad() is a dedicated clipping function for quads that doesn't depend on any GL renderer internal structures. It can be moved out to the clipper to be called by both the renderer and the clipping test client without having to duplicate code. Signed-off-by: Loïc Molinari <loic.molinari@gmail.com>
83 lines
2.3 KiB
C
83 lines
2.3 KiB
C
/*
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* Copyright © 2012 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial
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* portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#ifndef _WESTON_VERTEX_CLIPPING_H
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#define _WESTON_VERTEX_CLIPPING_H
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#include <stdbool.h>
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#include <pixman.h>
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struct clip_vertex {
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float x, y;
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};
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struct polygon8 {
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struct clip_vertex pos[8];
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int n;
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};
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struct gl_quad {
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struct polygon8 vertices;
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struct { float x1, y1, x2, y2; } bbox; /* Valid if !axis_aligned. */
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bool axis_aligned;
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};
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struct clip_context {
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struct clip_vertex prev;
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struct {
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float x1, y1;
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float x2, y2;
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} clip;
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struct clip_vertex *vertices;
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};
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float
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float_difference(float a, float b);
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int
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clip_simple(struct clip_context *ctx,
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struct polygon8 *surf,
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struct clip_vertex *restrict vertices);
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int
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clip_transformed(struct clip_context *ctx,
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struct polygon8 *surf,
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struct clip_vertex *restrict vertices);
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/*
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* Compute the boundary vertices of the intersection of an arbitrary
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* quadrilateral 'quad' and the axis-aligned rectangle 'surf_rect'. The vertices
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* are written to 'vertices', and the return value is the number of vertices.
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* Vertices are produced in clockwise winding order. Guarantees to produce
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* either zero vertices, or 3-8 vertices with non-zero polygon area.
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*/
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int
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clip_quad(struct gl_quad *quad,
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pixman_box32_t *surf_rect,
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struct clip_vertex *vertices);
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#endif
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