/*
 * Copyright © 2004 David Reveman
 *
 * Permission to use, copy, modify, distribute, and sell this software
 * and its documentation for any purpose is hereby granted without
 * fee, provided that the above copyright notice appear in all copies
 * and that both that copyright notice and this permission notice
 * appear in supporting documentation, and that the name of
 * David Reveman not be used in advertising or publicity pertaining to
 * distribution of the software without specific, written prior permission.
 * David Reveman makes no representations about the suitability of this
 * software for any purpose. It is provided "as is" without express or
 * implied warranty.
 *
 * DAVID REVEMAN DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
 * NO EVENT SHALL DAVID REVEMAN BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Author: David Reveman <davidr@novell.com>
 */

#ifdef HAVE_CONFIG_H
#  include "../config.h"
#endif

#include "glitzint.h"

#include <stdlib.h>
#include <string.h>
#include <ctype.h>

static glitz_extension_map gl_extensions[] = {
    { 0.0, "GL_ARB_texture_rectangle", GLITZ_FEATURE_TEXTURE_RECTANGLE_MASK },
    { 0.0, "GL_EXT_texture_rectangle", GLITZ_FEATURE_TEXTURE_RECTANGLE_MASK },
    { 0.0, "GL_NV_texture_rectangle", GLITZ_FEATURE_TEXTURE_RECTANGLE_MASK },
    { 0.0, "GL_ARB_texture_non_power_of_two",
      GLITZ_FEATURE_TEXTURE_NON_POWER_OF_TWO_MASK },
    { 0.0, "GL_ARB_texture_mirrored_repeat",
      GLITZ_FEATURE_TEXTURE_MIRRORED_REPEAT_MASK },
    { 0.0, "GL_ARB_texture_border_clamp",
      GLITZ_FEATURE_TEXTURE_BORDER_CLAMP_MASK },
    { 0.0, "GL_ARB_texture_env_combine",
      GLITZ_FEATURE_TEXTURE_ENV_COMBINE_MASK },
    { 0.0, "GL_EXT_texture_env_combine",
      GLITZ_FEATURE_TEXTURE_ENV_COMBINE_MASK },
    { 0.0, "GL_ARB_texture_env_dot3", GLITZ_FEATURE_TEXTURE_ENV_DOT3_MASK },
    { 0.0, "GL_ARB_multisample", GLITZ_FEATURE_MULTISAMPLE_MASK },
    { 0.0, "GL_NV_multisample_filter_hint",
      GLITZ_FEATURE_MULTISAMPLE_FILTER_HINT_MASK },
    { 0.0, "GL_ARB_multitexture", GLITZ_FEATURE_MULTITEXTURE_MASK },
    { 0.0, "GL_EXT_multi_draw_arrays", GLITZ_FEATURE_MULTI_DRAW_ARRAYS_MASK },
    { 0.0, "GL_ARB_fragment_program", GLITZ_FEATURE_FRAGMENT_PROGRAM_MASK },
    { 0.0, "GL_ARB_vertex_buffer_object",
      GLITZ_FEATURE_VERTEX_BUFFER_OBJECT_MASK },
    { 0.0, "GL_ARB_pixel_buffer_object",
      GLITZ_FEATURE_PIXEL_BUFFER_OBJECT_MASK },
    { 0.0, "GL_EXT_pixel_buffer_object",
      GLITZ_FEATURE_PIXEL_BUFFER_OBJECT_MASK },
    { 0.0, "GL_EXT_blend_color", GLITZ_FEATURE_BLEND_COLOR_MASK },
    { 0.0, "GL_ARB_imaging", GLITZ_FEATURE_BLEND_COLOR_MASK },
    { 0.0, "GL_APPLE_packed_pixels", GLITZ_FEATURE_PACKED_PIXELS_MASK },
    { 0.0, "GL_EXT_framebuffer_object",
      GLITZ_FEATURE_FRAMEBUFFER_OBJECT_MASK },
    { 0.0, NULL, 0 }
};

static glitz_bool_t
_glitz_extension_check (const char *extensions,
			const char *ext_name)
{
    char *end;
    char *p = (char *) extensions;
    int ext_name_len = strlen (ext_name);

    if (! p)
	return 0;

    end = p + strlen (p);

    while (p < end) {
	int n = strcspn (p, " ");

	if ((ext_name_len == n) && (strncmp (ext_name, p, n) == 0)) {
	    return 1;
	}
	p += (n + 1);
    }
    return 0;
}

unsigned long
glitz_extensions_query (glitz_gl_float_t    version,
			const char          *extensions_string,
			glitz_extension_map *extensions_map)
{
    unsigned long mask = 0;
    int i;

    for (i = 0; extensions_map[i].name; i++)
	if (((extensions_map[i].version > 1.0) &&
	     (version >= extensions_map[i].version)) ||
	    _glitz_extension_check (extensions_string, extensions_map[i].name))
	    mask |= extensions_map[i].mask;

    return mask;
}

static glitz_gl_float_t
_glitz_gl_version_string_to_float (const char *gl_version_string)
{
    glitz_gl_float_t version = 0.0f;
    int		     i;

    for (i = 0; isdigit (gl_version_string[i]); i++)
	version = version * 10.0f + (gl_version_string[i] - 48);

    if (gl_version_string[i++] != '.')
	return 0.0f;

    version = version * 10.0f + (gl_version_string[i] - 48);

    return (version + 0.1f) / 10.0f;
}

static glitz_status_t
_glitz_query_gl_extensions (glitz_gl_proc_address_list_t *gl,
			    glitz_gl_float_t             *gl_version,
			    unsigned long                *feature_mask)
{
    const char *gl_extensions_string;
    const char *gl_version_string;

    gl_version_string = (const char *) gl->get_string (GLITZ_GL_VERSION);
    if (!gl_version_string)
	return GLITZ_STATUS_NOT_SUPPORTED;

    *gl_version = _glitz_gl_version_string_to_float (gl_version_string);
    if (*gl_version < 1.2f)
	return GLITZ_STATUS_NOT_SUPPORTED;

    gl_extensions_string = (const char *) gl->get_string (GLITZ_GL_EXTENSIONS);

    *feature_mask = glitz_extensions_query (*gl_version,
					    gl_extensions_string,
					    gl_extensions);

    if ((*feature_mask & GLITZ_FEATURE_TEXTURE_ENV_COMBINE_MASK) &&
	(*feature_mask & GLITZ_FEATURE_TEXTURE_ENV_DOT3_MASK)) {
	glitz_gl_int_t max_texture_units;

	gl->get_integer_v (GLITZ_GL_MAX_TEXTURE_UNITS, &max_texture_units);
	if (max_texture_units >= 3)
	    *feature_mask |= GLITZ_FEATURE_PER_COMPONENT_RENDERING_MASK;
    }

    return GLITZ_STATUS_SUCCESS;
}

static void
_glitz_gl_proc_address_lookup (glitz_backend_t               *backend,
			       glitz_get_proc_address_proc_t get_proc_address,
			       void                          *closure)
{
    if (backend->feature_mask & GLITZ_FEATURE_BLEND_COLOR_MASK) {
	if (backend->gl_version >= 1.4f) {
	    backend->gl->blend_color = (glitz_gl_blend_color_t)
		get_proc_address ("glBlendColor", closure);
	} else {
	    backend->gl->blend_color = (glitz_gl_blend_color_t)
		get_proc_address ("glBlendColorEXT", closure);
	}

	if (!backend->gl->blend_color)
	    backend->feature_mask &= ~GLITZ_FEATURE_BLEND_COLOR_MASK;
    }

    if (backend->feature_mask & GLITZ_FEATURE_MULTITEXTURE_MASK) {
	if (backend->gl_version >= 1.3f) {
	    backend->gl->active_texture = (glitz_gl_active_texture_t)
		get_proc_address ("glActiveTexture", closure);
	    backend->gl->client_active_texture =
		(glitz_gl_client_active_texture_t)
		get_proc_address ("glClientActiveTexture", closure);
	} else {
	    backend->gl->active_texture = (glitz_gl_active_texture_t)
		get_proc_address ("glActiveTextureARB", closure);
	    backend->gl->client_active_texture =
		(glitz_gl_client_active_texture_t)
		get_proc_address ("glClientActiveTextureARB", closure);
	}

	if ((!backend->gl->active_texture) ||
	    (!backend->gl->client_active_texture)) {
	    backend->feature_mask &= ~GLITZ_FEATURE_MULTITEXTURE_MASK;
	    backend->feature_mask &=
		~GLITZ_FEATURE_PER_COMPONENT_RENDERING_MASK;
	}
    }

    if (backend->feature_mask & GLITZ_FEATURE_MULTI_DRAW_ARRAYS_MASK) {
	backend->gl->multi_draw_arrays = (glitz_gl_multi_draw_arrays_t)
	    get_proc_address ("glMultiDrawArraysEXT", closure);

	if (!backend->gl->multi_draw_arrays)
	    backend->feature_mask &= ~GLITZ_FEATURE_MULTI_DRAW_ARRAYS_MASK;
    }

    if (backend->feature_mask & GLITZ_FEATURE_FRAGMENT_PROGRAM_MASK) {
	backend->gl->gen_programs = (glitz_gl_gen_programs_t)
	    get_proc_address ("glGenProgramsARB", closure);
	backend->gl->delete_programs = (glitz_gl_delete_programs_t)
	    get_proc_address ("glDeleteProgramsARB", closure);
	backend->gl->program_string = (glitz_gl_program_string_t)
	    get_proc_address ("glProgramStringARB", closure);
	backend->gl->bind_program = (glitz_gl_bind_program_t)
	    get_proc_address ("glBindProgramARB", closure);
	backend->gl->program_local_param_4fv =
	    (glitz_gl_program_local_param_4fv_t)
	    get_proc_address ("glProgramLocalParameter4fvARB", closure);
	backend->gl->get_program_iv = (glitz_gl_get_program_iv_t)
	    get_proc_address ("glGetProgramivARB", closure);

	if ((!backend->gl->gen_programs) ||
	    (!backend->gl->delete_programs) ||
	    (!backend->gl->program_string) ||
	    (!backend->gl->bind_program) ||
	    (!backend->gl->program_local_param_4fv))
	    backend->feature_mask &= ~GLITZ_FEATURE_FRAGMENT_PROGRAM_MASK;
    }

    if ((backend->feature_mask & GLITZ_FEATURE_VERTEX_BUFFER_OBJECT_MASK) ||
	(backend->feature_mask & GLITZ_FEATURE_PIXEL_BUFFER_OBJECT_MASK)) {
	if (backend->gl_version >= 1.5f) {
	    backend->gl->gen_buffers = (glitz_gl_gen_buffers_t)
		get_proc_address ("glGenBuffers", closure);
	    backend->gl->delete_buffers = (glitz_gl_delete_buffers_t)
		get_proc_address ("glDeleteBuffers", closure);
	    backend->gl->bind_buffer = (glitz_gl_bind_buffer_t)
		get_proc_address ("glBindBuffer", closure);
	    backend->gl->buffer_data = (glitz_gl_buffer_data_t)
		get_proc_address ("glBufferData", closure);
	    backend->gl->buffer_sub_data = (glitz_gl_buffer_sub_data_t)
		get_proc_address ("glBufferSubData", closure);
	    backend->gl->get_buffer_sub_data = (glitz_gl_get_buffer_sub_data_t)
		get_proc_address ("glGetBufferSubData", closure);
	    backend->gl->map_buffer = (glitz_gl_map_buffer_t)
		get_proc_address ("glMapBuffer", closure);
	    backend->gl->unmap_buffer = (glitz_gl_unmap_buffer_t)
		get_proc_address ("glUnmapBuffer", closure);
	} else {
	    backend->gl->gen_buffers = (glitz_gl_gen_buffers_t)
		get_proc_address ("glGenBuffersARB", closure);
	    backend->gl->delete_buffers = (glitz_gl_delete_buffers_t)
		get_proc_address ("glDeleteBuffersARB", closure);
	    backend->gl->bind_buffer = (glitz_gl_bind_buffer_t)
		get_proc_address ("glBindBufferARB", closure);
	    backend->gl->buffer_data = (glitz_gl_buffer_data_t)
		get_proc_address ("glBufferDataARB", closure);
	    backend->gl->buffer_sub_data = (glitz_gl_buffer_sub_data_t)
		get_proc_address ("glBufferSubDataARB", closure);
	    backend->gl->get_buffer_sub_data = (glitz_gl_get_buffer_sub_data_t)
		get_proc_address ("glGetBufferSubDataARB", closure);
	    backend->gl->map_buffer = (glitz_gl_map_buffer_t)
		get_proc_address ("glMapBufferARB", closure);
	    backend->gl->unmap_buffer = (glitz_gl_unmap_buffer_t)
		get_proc_address ("glUnmapBufferARB", closure);
	}

	if ((!backend->gl->gen_buffers) ||
	    (!backend->gl->delete_buffers) ||
	    (!backend->gl->bind_buffer) ||
	    (!backend->gl->buffer_data) ||
	    (!backend->gl->buffer_sub_data) ||
	    (!backend->gl->get_buffer_sub_data) ||
	    (!backend->gl->map_buffer) ||
	    (!backend->gl->unmap_buffer)) {
	    backend->feature_mask &= ~GLITZ_FEATURE_VERTEX_BUFFER_OBJECT_MASK;
	    backend->feature_mask &= ~GLITZ_FEATURE_PIXEL_BUFFER_OBJECT_MASK;
	}
    }

    if (backend->feature_mask & GLITZ_FEATURE_FRAMEBUFFER_OBJECT_MASK) {
	backend->gl->gen_framebuffers = (glitz_gl_gen_framebuffers_t)
	    get_proc_address ("glGenFramebuffersEXT", closure);
	backend->gl->delete_framebuffers = (glitz_gl_delete_framebuffers_t)
	    get_proc_address ("glDeleteFramebuffersEXT", closure);
	backend->gl->bind_framebuffer = (glitz_gl_bind_framebuffer_t)
	    get_proc_address ("glBindFramebufferEXT", closure);
	backend->gl->framebuffer_renderbuffer =
	    (glitz_gl_framebuffer_renderbuffer_t)
	    get_proc_address ("glFramebufferRenderbufferEXT", closure);
	backend->gl->framebuffer_texture_2d =
	    (glitz_gl_framebuffer_texture_2d_t)
	    get_proc_address ("glFramebufferTexture2DEXT", closure);
	backend->gl->check_framebuffer_status =
	    (glitz_gl_check_framebuffer_status_t)
	    get_proc_address ("glCheckFramebufferStatusEXT", closure);
	backend->gl->gen_renderbuffers = (glitz_gl_gen_renderbuffers_t)
	    get_proc_address ("glGenRenderbuffersEXT", closure);
	backend->gl->delete_renderbuffers = (glitz_gl_delete_renderbuffers_t)
	    get_proc_address ("glDeleteRenderbuffersEXT", closure);
	backend->gl->bind_renderbuffer = (glitz_gl_bind_renderbuffer_t)
	    get_proc_address ("glBindRenderbufferEXT", closure);
	backend->gl->renderbuffer_storage = (glitz_gl_renderbuffer_storage_t)
	    get_proc_address ("glRenderbufferStorageEXT", closure);
	backend->gl->get_renderbuffer_parameter_iv =
	    (glitz_gl_get_renderbuffer_parameter_iv_t)
	    get_proc_address ("glGetRenderbufferParameterivEXT", closure);

	if ((!backend->gl->gen_framebuffers) ||
	    (!backend->gl->delete_framebuffers) ||
	    (!backend->gl->bind_framebuffer) ||
	    (!backend->gl->framebuffer_renderbuffer) ||
	    (!backend->gl->framebuffer_texture_2d) ||
	    (!backend->gl->check_framebuffer_status) ||
	    (!backend->gl->gen_renderbuffers) ||
	    (!backend->gl->delete_renderbuffers) ||
	    (!backend->gl->bind_renderbuffer) ||
	    (!backend->gl->renderbuffer_storage) ||
	    (!backend->gl->get_renderbuffer_parameter_iv))
	    backend->feature_mask &= ~GLITZ_FEATURE_FRAMEBUFFER_OBJECT_MASK;
    }
}

void
glitz_backend_init (glitz_backend_t               *backend,
		    glitz_get_proc_address_proc_t get_proc_address,
		    void                          *closure)
{
    if (!_glitz_query_gl_extensions (backend->gl,
				     &backend->gl_version,
				     &backend->feature_mask)) {
	_glitz_gl_proc_address_lookup (backend, get_proc_address, closure);
	glitz_create_surface_formats (backend->gl,
				      &backend->formats,
				      &backend->texture_formats,
				      &backend->n_formats,
				      backend->feature_mask);
	_glitz_add_drawable_formats (backend->gl,
				     backend->feature_mask,
				     &backend->drawable_formats,
				     &backend->n_drawable_formats);
    }

    backend->gl->get_integer_v (GLITZ_GL_MAX_VIEWPORT_DIMS,
				backend->max_viewport_dims);

    backend->gl->get_integer_v (GLITZ_GL_MAX_TEXTURE_SIZE,
				&backend->max_texture_2d_size);

    if (backend->feature_mask & GLITZ_FEATURE_TEXTURE_RECTANGLE_MASK)
	backend->gl->get_integer_v (GLITZ_GL_MAX_RECTANGLE_TEXTURE_SIZE,
				    &backend->max_texture_rect_size);
    else
	backend->max_texture_rect_size = 0;
}

unsigned int
glitz_uint_to_power_of_two (unsigned int x)
{
    x |= (x >> 1);
    x |= (x >> 2);
    x |= (x >> 4);
    x |= (x >> 8);
    x |= (x >> 16);

    return (x + 1);
}

void
glitz_set_raster_pos (glitz_gl_proc_address_list_t *gl,
		      glitz_float_t                x,
		      glitz_float_t                y)
{
    gl->push_attrib (GLITZ_GL_TRANSFORM_BIT | GLITZ_GL_VIEWPORT_BIT);
    gl->matrix_mode (GLITZ_GL_PROJECTION);
    gl->push_matrix ();
    gl->load_identity ();
    gl->matrix_mode (GLITZ_GL_MODELVIEW);
    gl->push_matrix ();
    gl->load_identity ();
    gl->depth_range (0, 1);
    gl->viewport (-1, -1, 2, 2);

    gl->raster_pos_2f (0, 0);
    gl->bitmap (0, 0, 1, 1, x, y, NULL);

    gl->pop_matrix ();
    gl->matrix_mode (GLITZ_GL_PROJECTION);
    gl->pop_matrix ();
    gl->pop_attrib ();
}

void
glitz_clamp_value (glitz_float_t *value,
		   glitz_float_t min, glitz_float_t max)
{
    if (*value < min)
	*value = min;
    else if (*value > max)
	*value = max;
}

void
glitz_initiate_state (glitz_gl_proc_address_list_t *gl)
{
    gl->hint (GLITZ_GL_PERSPECTIVE_CORRECTION_HINT, GLITZ_GL_FASTEST);
    gl->disable (GLITZ_GL_CULL_FACE);
    gl->depth_mask (GLITZ_GL_FALSE);
    gl->polygon_mode (GLITZ_GL_FRONT_AND_BACK, GLITZ_GL_FILL);
    gl->disable (GLITZ_GL_POLYGON_SMOOTH);
    gl->disable (GLITZ_GL_LINE_SMOOTH);
    gl->disable (GLITZ_GL_POINT_SMOOTH);
    gl->shade_model (GLITZ_GL_FLAT);
    gl->color_mask (GLITZ_GL_TRUE, GLITZ_GL_TRUE,
		    GLITZ_GL_TRUE, GLITZ_GL_TRUE);
    gl->enable (GLITZ_GL_SCISSOR_TEST);
    gl->disable (GLITZ_GL_STENCIL_TEST);
    gl->enable_client_state (GLITZ_GL_VERTEX_ARRAY);
    gl->disable (GLITZ_GL_DEPTH_TEST);
}