/* cairo - a vector graphics library with display and print output
 *
 * Copyright © 2009 Eric Anholt
 * Copyright © 2009 Chris Wilson
 * Copyright © 2005 Red Hat, Inc
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is Red Hat, Inc.
 *
 * Contributor(s):
 *	Carl Worth <cworth@cworth.org>
 *	Chris Wilson <chris@chris-wilson.co.uk>
 *      T. Zachary Laine <whatwasthataddress@gmail.com>
 */

#ifndef CAIRO_GL_PRIVATE_H
#define CAIRO_GL_PRIVATE_H

#include "cairoint.h"
#include "cairo-device-private.h"
#include "cairo-rtree-private.h"

#include <GL/glew.h>

#include "cairo-gl.h"

#include <GL/gl.h>
#define GL_GLEXT_PROTOTYPES
#include <GL/glext.h>

#define DEBUG_GL 0

#if DEBUG_GL && __GNUC__
#define UNSUPPORTED(reason) ({ \
    fprintf (stderr, \
	     "cairo-gl: hit unsupported operation in %s(), line %d: %s\n", \
	     __FUNCTION__, __LINE__, reason); \
    CAIRO_INT_STATUS_UNSUPPORTED; \
})
#else
#define UNSUPPORTED(reason) CAIRO_INT_STATUS_UNSUPPORTED
#endif

typedef struct _cairo_gl_surface {
    cairo_surface_t base;

    int width, height;

    GLuint tex; /* GL texture object containing our data. */
    GLuint fb; /* GL framebuffer object wrapping our data. */
} cairo_gl_surface_t;

typedef struct cairo_gl_glyph_cache {
    cairo_rtree_t rtree;
    GLuint tex;
    unsigned int width, height;
} cairo_gl_glyph_cache_t;

typedef struct cairo_gl_shader_program {
    GLuint vertex_shader;
    GLuint fragment_shader;
    GLuint program;
    cairo_bool_t build_failure;
} cairo_gl_shader_program_t;

typedef enum cairo_gl_shader_source {
    CAIRO_GL_SHADER_SOURCE_CONSTANT,
    CAIRO_GL_SHADER_SOURCE_TEXTURE,
    CAIRO_GL_SHADER_SOURCE_TEXTURE_ALPHA,
    CAIRO_GL_SHADER_SOURCE_LINEAR_GRADIENT,
    CAIRO_GL_SHADER_SOURCE_RADIAL_GRADIENT,
    CAIRO_GL_SHADER_SOURCE_COUNT,
} cairo_gl_shader_source_t;

typedef enum cairo_gl_shader_mask {
    CAIRO_GL_SHADER_MASK_CONSTANT,
    CAIRO_GL_SHADER_MASK_TEXTURE,
    CAIRO_GL_SHADER_MASK_TEXTURE_ALPHA,
    CAIRO_GL_SHADER_MASK_LINEAR_GRADIENT,
    CAIRO_GL_SHADER_MASK_RADIAL_GRADIENT,
    CAIRO_GL_SHADER_MASK_NONE,
    CAIRO_GL_SHADER_MASK_SPANS,
    CAIRO_GL_SHADER_MASK_COUNT,
} cairo_gl_shader_mask_t;

typedef enum cairo_gl_shader_in {
    CAIRO_GL_SHADER_IN_NORMAL,
    CAIRO_GL_SHADER_IN_CA_SOURCE,
    CAIRO_GL_SHADER_IN_CA_SOURCE_ALPHA,
    CAIRO_GL_SHADER_IN_COUNT,
} cairo_gl_shader_in_t;

typedef struct _cairo_gl_context {
    cairo_device_t base;

    GLuint dummy_tex;
    GLuint texture_load_pbo;
    GLuint vbo;
    GLint max_framebuffer_size;
    GLint max_texture_size;
    cairo_bool_t using_glsl;

    cairo_bool_t using_shaders;
    cairo_gl_shader_program_t fill_rectangles_shader;
    cairo_gl_shader_program_t shaders[CAIRO_GL_SHADER_SOURCE_COUNT]
					[CAIRO_GL_SHADER_MASK_COUNT]
					[CAIRO_GL_SHADER_IN_COUNT];

    cairo_gl_surface_t *current_target;
    cairo_gl_surface_t *glyphs_temporary_mask;
    cairo_gl_glyph_cache_t glyph_cache[2];

    void (*make_current)(void *ctx, cairo_gl_surface_t *surface);
    void (*swap_buffers)(void *ctx, cairo_gl_surface_t *surface);
    void (*destroy) (void *ctx);
} cairo_gl_context_t;

enum cairo_gl_composite_operand_type {
    OPERAND_CONSTANT,
    OPERAND_TEXTURE,
    OPERAND_LINEAR_GRADIENT,
    OPERAND_RADIAL_GRADIENT,
};

/* This union structure describes a potential source or mask operand to the
 * compositing equation.
 */
typedef struct cairo_gl_composite_operand {
    enum cairo_gl_composite_operand_type type;
    cairo_gl_shader_source_t source;
    cairo_gl_shader_mask_t mask;
    union {
	struct {
	    GLuint tex;
	    cairo_gl_surface_t *surface;
	    cairo_surface_attributes_t attributes;
	} texture;
	struct {
	    GLfloat color[4];
	} constant;
	struct {
	    GLuint tex;
	    cairo_matrix_t m;
	    float segment_x;
	    float segment_y;
	    float first_stop_offset;
	    float last_stop_offset;
	} linear;
	struct {
	    GLuint tex;
	    cairo_matrix_t m;
	    float circle_1_x;
	    float circle_1_y;
	    float radius_0;
	    float radius_1;
	    float first_stop_offset;
	    float last_stop_offset;
	} radial;
    } operand;

    const cairo_pattern_t *pattern;
} cairo_gl_composite_operand_t;

typedef struct _cairo_gl_composite_setup {
    cairo_gl_composite_operand_t src;
    cairo_gl_composite_operand_t mask;
    cairo_gl_shader_program_t *shader;
} cairo_gl_composite_setup_t;

cairo_private extern const cairo_surface_backend_t _cairo_gl_surface_backend;

static inline cairo_device_t *
_cairo_gl_context_create_in_error (cairo_status_t status)
{
    return (cairo_device_t *) _cairo_device_create_in_error (status);
}

cairo_private cairo_status_t
_cairo_gl_context_init (cairo_gl_context_t *ctx);

cairo_private void
_cairo_gl_surface_init (cairo_device_t *device,
			cairo_gl_surface_t *surface,
			cairo_content_t content,
			int width, int height);

cairo_private cairo_status_t
_cairo_gl_surface_draw_image (cairo_gl_surface_t *dst,
			      cairo_image_surface_t *src,
			      int src_x, int src_y,
			      int width, int height,
			      int dst_x, int dst_y);

cairo_private cairo_int_status_t
_cairo_gl_operand_init (cairo_gl_composite_operand_t *operand,
			const cairo_pattern_t *pattern,
			cairo_gl_surface_t *dst,
			int src_x, int src_y,
			int dst_x, int dst_y,
			int width, int height);

static cairo_always_inline cairo_status_t cairo_warn
_cairo_gl_context_acquire (cairo_device_t *device,
			   cairo_gl_context_t **ctx)
{
    cairo_status_t status;

    status = cairo_device_acquire (device);
    if (unlikely (status))
	return status;

    *ctx = (cairo_gl_context_t *) device;
    return CAIRO_STATUS_SUCCESS;
}

static cairo_always_inline void
_cairo_gl_context_release (cairo_gl_context_t *ctx)
{
    cairo_device_release (&ctx->base);
}

cairo_private void
_cairo_gl_set_destination (cairo_gl_surface_t *surface);

cairo_private cairo_bool_t
_cairo_gl_operator_is_supported (cairo_operator_t op);

cairo_private cairo_status_t
_cairo_gl_surface_clear (cairo_gl_surface_t *surface);

cairo_private void
_cairo_gl_set_operator (cairo_gl_surface_t *dst, cairo_operator_t op,
			cairo_bool_t component_alpha);

cairo_private void
_cairo_gl_set_src_operand (cairo_gl_context_t *ctx,
			   cairo_gl_composite_setup_t *setup);

cairo_private void
_cairo_gl_set_src_alpha_operand (cairo_gl_context_t *ctx,
				 cairo_gl_composite_setup_t *setup);

cairo_private void
_cairo_gl_operand_destroy (cairo_gl_composite_operand_t *operand);

cairo_private cairo_bool_t
_cairo_gl_get_image_format_and_type (pixman_format_code_t pixman_format,
				     GLenum *internal_format, GLenum *format,
				     GLenum *type, cairo_bool_t *has_alpha);

cairo_private void
_cairo_gl_surface_scaled_glyph_fini (cairo_scaled_glyph_t *scaled_glyph,
				     cairo_scaled_font_t  *scaled_font);

cairo_private void
_cairo_gl_glyph_cache_init (cairo_gl_glyph_cache_t *cache);

cairo_private cairo_int_status_t
_cairo_gl_surface_show_glyphs (void			*abstract_dst,
			       cairo_operator_t		 op,
			       const cairo_pattern_t	*source,
			       cairo_glyph_t		*glyphs,
			       int			 num_glyphs,
			       cairo_scaled_font_t	*scaled_font,
			       cairo_clip_t		*clip,
			       int			*remaining_glyphs);

cairo_private void
_cairo_gl_glyph_cache_fini (cairo_gl_glyph_cache_t *cache);

static inline int
_cairo_gl_y_flip (cairo_gl_surface_t *surface, int y)
{
    if (surface->fb)
	return y;
    else
	return (surface->height - 1) - y;
}

void
init_shader_program (cairo_gl_shader_program_t *program);

void
destroy_shader_program (cairo_gl_shader_program_t *program);

cairo_status_t
create_shader_program (cairo_gl_shader_program_t *program,
                       const char *vertex_text,
                       const char *fragment_text);

cairo_status_t
create_linear_gradient_shader_program (cairo_gl_shader_program_t *program);

cairo_status_t
create_radial_gradient_shader_program (cairo_gl_shader_program_t *program);

cairo_status_t
bind_float_to_shader (GLuint program, const char *name,
                      float value);

cairo_status_t
bind_vec2_to_shader (GLuint program, const char *name,
                     float value0, float value1);

cairo_status_t
bind_vec3_to_shader (GLuint program, const char *name,
                     float value0, float value1,
                     float value2);

cairo_status_t
bind_vec4_to_shader (GLuint program, const char *name,
                     float value0, float value1,
                     float value2, float value3);

cairo_status_t
bind_matrix_to_shader (GLuint program, const char *name, cairo_matrix_t* m);

cairo_status_t
bind_texture_to_shader (GLuint program, const char *name, GLuint tex_unit);

void
_cairo_gl_use_program (cairo_gl_shader_program_t *shader);

cairo_status_t
_cairo_gl_get_program (cairo_gl_context_t *ctx,
		       cairo_gl_shader_source_t source,
		       cairo_gl_shader_mask_t mask,
		       cairo_gl_shader_in_t in,
		       cairo_gl_shader_program_t **out_program);

slim_hidden_proto (cairo_gl_surface_create);

#endif /* CAIRO_GL_PRIVATE_H */