weston/libweston/vertex-clipping.h

/*
 * Copyright © 2012 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial
 * portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#ifndef _WESTON_VERTEX_CLIPPING_H
#define _WESTON_VERTEX_CLIPPING_H

#include <libweston/matrix.h>

struct polygon8 {
	struct weston_coord pos[8];
	int n;
};

struct clip_context {
	struct {
		float x;
		float y;
	} prev;

	struct {
		float x1, y1;
		float x2, y2;
	} clip;

	struct weston_coord *vertices;
};

float
float_difference(float a, float b);

int
clip_simple(struct clip_context *ctx,
	    struct polygon8 *surf,
	    struct weston_coord *e);

int
clip_transformed(struct clip_context *ctx,
		 struct polygon8 *surf,
		 struct weston_coord *e);

#endif