/*
 * Copyright © 2012 John Kåre Alsaker
 *
 * 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.
 */

#include "config.h"

#include <stdint.h>

#include <libweston/libweston.h>
#include "backend.h"
#include "libweston-internal.h"

#ifdef ENABLE_EGL

#include <EGL/egl.h>
#include <EGL/eglext.h>

#else

typedef int EGLint;
typedef int EGLenum;
typedef void *EGLDisplay;
typedef void *EGLSurface;
typedef void *EGLConfig;
typedef intptr_t EGLNativeDisplayType;
typedef intptr_t EGLNativeWindowType;
#define EGL_DEFAULT_DISPLAY ((EGLNativeDisplayType)0)
#define EGL_PBUFFER_BIT                   0x0001
#define EGL_WINDOW_BIT                    0x0004

#endif /* ENABLE_EGL */

enum gl_renderer_border_side {
	GL_RENDERER_BORDER_TOP = 0,
	GL_RENDERER_BORDER_LEFT = 1,
	GL_RENDERER_BORDER_RIGHT = 2,
	GL_RENDERER_BORDER_BOTTOM = 3,
};

/**
 * Options passed to the \c display_create method of the GL renderer interface.
 *
 * \see struct gl_renderer_interface
 */
struct gl_renderer_display_options {
	/** The EGL platform identifier */
	EGLenum egl_platform;
	/** The native display corresponding to the given EGL platform */
	void *egl_native_display;
	/** EGL_SURFACE_TYPE bits for the base EGLConfig */
	EGLint egl_surface_type;
	/** Array of DRM pixel formats acceptable for the base EGLConfig */
	const uint32_t *drm_formats;
	/** The \c drm_formats array length */
	unsigned drm_formats_count;
};

struct gl_renderer_output_options {
	/** Native window handle for \c eglCreateWindowSurface */
	EGLNativeWindowType window_for_legacy;
	/** Native window handle for \c eglCreatePlatformWindowSurface */
	void *window_for_platform;
	/** Array of DRM pixel formats acceptable for the window */
	const uint32_t *drm_formats;
	/** The \c drm_formats array length */
	unsigned drm_formats_count;
};

struct gl_renderer_pbuffer_options {
	/** Width of the rendering surface in pixels */
	int width;
	/** Height of the rendering surface in pixels */
	int height;
	/** Array of DRM pixel formats acceptable for the pbuffer */
	const uint32_t *drm_formats;
	/** The \c drm_formats array length */
	unsigned drm_formats_count;
};

struct gl_renderer_interface {
	/**
	 * Initialize GL-renderer with the given EGL platform and native display
	 *
	 * \param ec The weston_compositor where to initialize.
	 * \param options The options struct describing display configuration
	 * \return 0 on success, -1 on failure.
	 *
	 * This function creates an EGLDisplay and initializes it. It also
	 * creates the GL ES context and sets it up. It attempts GL ES 3.0
	 * and falls back to GL ES 2.0 if 3.0 is not supported.
	 *
	 * If \c platform is zero or EGL_EXT_platform_base is not supported,
	 * choosing the platform is left for the EGL implementation. Otherwise
	 * the given platform is used explicitly if the EGL implementation
	 * advertises it. Without the advertisement this function fails.
	 *
	 * If neither EGL_KHR_no_config_context or EGL_MESA_configless_context
	 * are supported, the arguments egl_surface_type, drm_formats, and
	 * drm_formats_count are used to find a so called base EGLConfig. The
	 * GL context is created with the base EGLConfig, and outputs will be
	 * required to use the same config as well. If one or both of the
	 * extensions are supported, these arguments are unused, and each
	 * output can use a different EGLConfig (pixel format).
	 *
	 * The first format in drm_formats that matches any EGLConfig
	 * determines which EGLConfig is chosen. On EGL GBM platform, the
	 * pixel format must match exactly. On other platforms, it is enough
	 * that each R, G, B, A channel has the same number of bits as in the
	 * DRM format.
	 */
	int (*display_create)(struct weston_compositor *ec,
			      const struct gl_renderer_display_options *options);

	/**
	 * Attach GL-renderer to the output with a native window
	 *
	 * \param output The output to create a rendering surface for.
	 * \param options The options struct describing output configuration
	 * \return 0 on success, -1 on failure.
	 *
	 * This function creates the renderer data structures needed to repaint
	 * the output. The repaint results will be directed to the given native
	 * window.
	 *
	 * If EGL_EXT_platform_base is supported then \c window_for_platform is
	 * used, otherwise \c window_for_legacy is used. This is because the
	 * handle on X11 platform is different between the two.
	 *
	 * The first format in drm_formats that matches any EGLConfig
	 * determines which EGLConfig is chosen. See \c display_create about
	 * how the matching works and the possible limitations.
	 *
	 * This function should be used only if \c display_create was called
	 * with \c EGL_WINDOW_BIT in \c egl_surface_type.
	 */
	int (*output_window_create)(struct weston_output *output,
				    const struct gl_renderer_output_options *options);

	/**
	 * Attach GL-renderer to the output with internal pixel storage
	 *
	 * \param output The output to create a rendering surface for.
	 * \param options The options struct describing the pbuffer
	 * \return 0 on success, -1 on failure.
	 *
	 * This function creates the renderer data structures needed to repaint
	 * the output. The repaint results will be kept internal and can only
	 * be accessed through e.g. screen capture.
	 *
	 * The first format in drm_formats that matches any EGLConfig
	 * determines which EGLConfig is chosen. See \c display_create about
	 * how the matching works and the possible limitations.
	 *
	 * This function should be used only if \c display_create was called
	 * with \c EGL_PBUFFER_BIT in \c egl_surface_type.
	 */
	int (*output_pbuffer_create)(struct weston_output *output,
				     const struct gl_renderer_pbuffer_options *options);

	void (*output_destroy)(struct weston_output *output);

	/* Sets the output border.
	 *
	 * The side specifies the side for which we are setting the border.
	 * The width and height are the width and height of the border.
	 * The tex_width patemeter specifies the width of the actual
	 * texture; this may be larger than width if the data is not
	 * tightly packed.
	 *
	 * The top and bottom textures will extend over the sides to the
	 * full width of the bordered window.  The right and left edges,
	 * however, will extend only to the top and bottom of the
	 * compositor surface.  This is demonstrated by the picture below:
	 *
	 * +-----------------------+
	 * |          TOP          |
	 * +-+-------------------+-+
	 * | |                   | |
	 * |L|                   |R|
	 * |E|                   |I|
	 * |F|                   |G|
	 * |T|                   |H|
	 * | |                   |T|
	 * | |                   | |
	 * +-+-------------------+-+
	 * |        BOTTOM         |
	 * +-----------------------+
	 */
	void (*output_set_border)(struct weston_output *output,
				  enum gl_renderer_border_side side,
				  int32_t width, int32_t height,
				  int32_t tex_width, unsigned char *data);

	/* Create fence sync FD to wait for GPU rendering.
	 *
	 * Return FD on success, -1 on failure or unsupported
	 * EGL_ANDROID_native_fence_sync extension.
	 */
	int (*create_fence_fd)(struct weston_output *output);
};
