/*
 * Copyright 2016, Blender Foundation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Contributor(s): Blender Institute
 *
 */

/** \file blender/draw/modes/edit_mesh_mode.c
 *  \ingroup draw
 */

#include "DRW_engine.h"
#include "DRW_render.h"

#include "GPU_shader.h"
#include "GPU_viewport.h"
#include "DNA_view3d_types.h"

#include "draw_mode_pass.h"

#include "edit_mesh_mode.h"

/* keep it under MAX_PASSES */
typedef struct EDIT_MESH_PassList {
	struct DRWPass *non_meshes_pass;
	struct DRWPass *ob_center_pass;
	struct DRWPass *wire_outline_pass;
	struct DRWPass *depth_pass_hidden_wire;
	struct DRWPass *edit_face_overlay_pass;
	struct DRWPass *edit_face_occluded_pass;
	struct DRWPass *mix_occlude_pass;
	struct DRWPass *facefill_occlude_pass;
} EDIT_MESH_PassList;

/* keep it under MAX_BUFFERS */
typedef struct EDIT_MESH_FramebufferList {
	struct GPUFrameBuffer *occlude_wire_fb;
} EDIT_MESH_FramebufferList;

/* keep it under MAX_TEXTURES */
typedef struct EDIT_MESH_TextureList {
	struct GPUTexture *occlude_wire_depth_tx;
	struct GPUTexture *occlude_wire_color_tx;
} EDIT_MESH_TextureList;

static DRWShadingGroup *depth_shgrp_hidden_wire;

static DRWShadingGroup *face_overlay_shgrp;
static DRWShadingGroup *ledges_overlay_shgrp;
static DRWShadingGroup *lverts_overlay_shgrp;
static DRWShadingGroup *facedot_overlay_shgrp;

static DRWShadingGroup *face_occluded_shgrp;
static DRWShadingGroup *ledges_occluded_shgrp;
static DRWShadingGroup *lverts_occluded_shgrp;
static DRWShadingGroup *facedot_occluded_shgrp;
static DRWShadingGroup *facefill_occluded_shgrp;

extern struct GPUUniformBuffer *globals_ubo; /* draw_mode_pass.c */

static struct GPUShader *overlay_tri_sh = NULL;
static struct GPUShader *overlay_tri_fast_sh = NULL;
static struct GPUShader *overlay_tri_vcol_sh = NULL;
static struct GPUShader *overlay_tri_vcol_fast_sh = NULL;
static struct GPUShader *overlay_edge_sh = NULL;
static struct GPUShader *overlay_edge_vcol_sh = NULL;
static struct GPUShader *overlay_vert_sh = NULL;
static struct GPUShader *overlay_facedot_sh = NULL;
static struct GPUShader *overlay_mix_sh = NULL;
static struct GPUShader *overlay_facefill_sh = NULL;

extern char datatoc_edit_overlay_frag_glsl[];
extern char datatoc_edit_overlay_vert_glsl[];
extern char datatoc_edit_overlay_geom_tri_glsl[];
extern char datatoc_edit_overlay_geom_edge_glsl[];
extern char datatoc_edit_overlay_loosevert_vert_glsl[];
extern char datatoc_edit_overlay_facedot_frag_glsl[];
extern char datatoc_edit_overlay_facedot_vert_glsl[];
extern char datatoc_edit_overlay_mix_vert_glsl[];
extern char datatoc_edit_overlay_mix_frag_glsl[];
extern char datatoc_edit_overlay_facefill_vert_glsl[];
extern char datatoc_edit_overlay_facefill_frag_glsl[];

void EDIT_MESH_init(void)
{
	EDIT_MESH_TextureList *txl = DRW_mode_texture_list_get();
	EDIT_MESH_FramebufferList *fbl = DRW_mode_framebuffer_list_get();

	float *viewport_size = DRW_viewport_size_get();

	DRWFboTexture tex[2] = {{&txl->occlude_wire_depth_tx, DRW_BUF_DEPTH_24},
	                        {&txl->occlude_wire_color_tx, DRW_BUF_RGBA_8}};
	DRW_framebuffer_init(&fbl->occlude_wire_fb,
	                     (int)viewport_size[0], (int)viewport_size[1],
	                     tex, 2);

	if (!overlay_tri_sh) {
		overlay_tri_sh = DRW_shader_create(datatoc_edit_overlay_vert_glsl,
		                                   datatoc_edit_overlay_geom_tri_glsl,
		                                   datatoc_edit_overlay_frag_glsl, "#define EDGE_FIX\n");
	}
	if (!overlay_tri_fast_sh) {
		overlay_tri_fast_sh = DRW_shader_create(datatoc_edit_overlay_vert_glsl,
		                                       datatoc_edit_overlay_geom_tri_glsl,
		                                       datatoc_edit_overlay_frag_glsl, NULL);
	}
	if (!overlay_tri_vcol_sh) {
		overlay_tri_vcol_sh = DRW_shader_create(datatoc_edit_overlay_vert_glsl,
		                                        datatoc_edit_overlay_geom_tri_glsl,
		                                        datatoc_edit_overlay_frag_glsl, "#define EDGE_FIX\n"
		                                                                        "#define VERTEX_SELECTION\n");
	}
	if (!overlay_tri_vcol_fast_sh) {
		overlay_tri_vcol_fast_sh = DRW_shader_create(datatoc_edit_overlay_vert_glsl,
		                                             datatoc_edit_overlay_geom_tri_glsl,
		                                             datatoc_edit_overlay_frag_glsl, "#define VERTEX_SELECTION\n");
	}
	if (!overlay_edge_sh) {
		overlay_edge_sh = DRW_shader_create(datatoc_edit_overlay_vert_glsl,
		                                    datatoc_edit_overlay_geom_edge_glsl,
		                                    datatoc_edit_overlay_frag_glsl, NULL);
	}
	if (!overlay_edge_vcol_sh) {
		overlay_edge_vcol_sh = DRW_shader_create(datatoc_edit_overlay_vert_glsl,
		                                         datatoc_edit_overlay_geom_edge_glsl,
		                                         datatoc_edit_overlay_frag_glsl, "#define VERTEX_SELECTION\n");
	}
	if (!overlay_vert_sh) {
		overlay_vert_sh = DRW_shader_create(datatoc_edit_overlay_loosevert_vert_glsl, NULL,
		                                    datatoc_edit_overlay_frag_glsl, "#define VERTEX_SELECTION\n");
	}
	if (!overlay_facedot_sh) {
		overlay_facedot_sh = DRW_shader_create(datatoc_edit_overlay_facedot_vert_glsl, NULL,
		                                       datatoc_edit_overlay_facedot_frag_glsl, NULL);
	}
	if (!overlay_mix_sh) {
		overlay_mix_sh = DRW_shader_create(datatoc_edit_overlay_mix_vert_glsl, NULL,
		                                   datatoc_edit_overlay_mix_frag_glsl, NULL);
	}
	if (!overlay_facefill_sh) {
		overlay_facefill_sh = DRW_shader_create(datatoc_edit_overlay_facefill_vert_glsl, NULL,
		                                        datatoc_edit_overlay_facefill_frag_glsl, NULL);
	}
}

static DRWPass *edit_mesh_create_overlay_pass(DRWShadingGroup **face_shgrp, DRWShadingGroup **ledges_shgrp,
                                              DRWShadingGroup **lverts_shgrp, DRWShadingGroup **facedot_shgrp,
                                              float *faceAlpha, DRWState statemod)
{
	static struct GPUShader *tri_sh, *ledge_sh;
	const struct bContext *C = DRW_get_context();
	RegionView3D *rv3d = CTX_wm_region_view3d(C);
	Scene *scene = CTX_data_scene(C);
	ToolSettings *ts = scene->toolsettings;

	if ((ts->selectmode & SCE_SELECT_VERTEX) != 0) {
		ledge_sh = overlay_edge_vcol_sh;

		if ((rv3d->rflag & RV3D_NAVIGATING) != 0)
			tri_sh = overlay_tri_vcol_fast_sh;
		else
			tri_sh = overlay_tri_vcol_sh;
	}
	else {
		ledge_sh = overlay_edge_sh;

		if ((rv3d->rflag & RV3D_NAVIGATING) != 0)
			tri_sh = overlay_tri_fast_sh;
		else
			tri_sh = overlay_tri_sh;
	}

	DRWPass *pass = DRW_pass_create("Edit Mesh Face Overlay Pass", DRW_STATE_WRITE_COLOR | DRW_STATE_POINT | statemod);

	*face_shgrp = DRW_shgroup_create(tri_sh, pass);
	DRW_shgroup_uniform_block(*face_shgrp, "globalsBlock", globals_ubo, 0);
	DRW_shgroup_uniform_vec2(*face_shgrp, "viewportSize", DRW_viewport_size_get(), 1);
	DRW_shgroup_uniform_float(*face_shgrp, "faceAlphaMod", faceAlpha, 1);

	*ledges_shgrp = DRW_shgroup_create(ledge_sh, pass);
	DRW_shgroup_uniform_vec2(*ledges_shgrp, "viewportSize", DRW_viewport_size_get(), 1);

	if ((ts->selectmode & (SCE_SELECT_VERTEX)) != 0) {
		*lverts_shgrp = DRW_shgroup_create(overlay_vert_sh, pass);
		DRW_shgroup_uniform_vec2(*lverts_shgrp, "viewportSize", DRW_viewport_size_get(), 1);
	}

	if ((ts->selectmode & (SCE_SELECT_FACE)) != 0) {
		*facedot_shgrp = DRW_shgroup_create(overlay_facedot_sh, pass);
	}

	return pass;
}

static float backwire_opacity;
static float face_mod;

void EDIT_MESH_cache_init(void)
{
	EDIT_MESH_PassList *psl = DRW_mode_pass_list_get();
	const struct bContext *C = DRW_get_context();
	View3D *v3d = CTX_wm_view3d(C);

	bool do_zbufclip = ((v3d->flag & V3D_ZBUF_SELECT) == 0);

	static float zero = 0.0f;
	static struct GPUShader *depth_sh;

	if (!depth_sh)
		depth_sh = DRW_shader_create_3D_depth_only();

	psl->depth_pass_hidden_wire = DRW_pass_create("Depth Pass Hidden Wire", DRW_STATE_WRITE_DEPTH | DRW_STATE_DEPTH_LESS | DRW_STATE_CULL_BACK);
	depth_shgrp_hidden_wire = DRW_shgroup_create(depth_sh, psl->depth_pass_hidden_wire);

	if (!do_zbufclip) {
		psl->edit_face_overlay_pass = edit_mesh_create_overlay_pass(&face_overlay_shgrp, &ledges_overlay_shgrp, &lverts_overlay_shgrp,
		                                                            &facedot_overlay_shgrp, &face_mod, DRW_STATE_DEPTH_LESS | DRW_STATE_WRITE_DEPTH | DRW_STATE_BLEND);
	}
	else {
		/* We render all wires with depth and opaque to a new fbo and blend the result based on depth values */
		psl->edit_face_occluded_pass = edit_mesh_create_overlay_pass(&face_occluded_shgrp, &ledges_occluded_shgrp, &lverts_occluded_shgrp,
		                                                             &facedot_occluded_shgrp, &zero,  DRW_STATE_DEPTH_LESS | DRW_STATE_WRITE_DEPTH);

		/* however we loose the front faces value (because we need the depth of occluded wires and
		 * faces are alpha blended ) so we recover them in a new pass. */
		psl->facefill_occlude_pass = DRW_pass_create("Front Face Color", DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_LESS | DRW_STATE_BLEND);
		facefill_occluded_shgrp = DRW_shgroup_create(overlay_facefill_sh, psl->facefill_occlude_pass);
		DRW_shgroup_uniform_block(facefill_occluded_shgrp, "globalsBlock", globals_ubo, 0);

		/* we need a full screen pass to combine the result */
		EDIT_MESH_TextureList *txl = DRW_mode_texture_list_get();
		DefaultTextureList *dtxl = DRW_engine_texture_list_get();
		struct Batch *quad = DRW_cache_fullscreen_quad_get();
		static float mat[4][4]; /* not even used but avoid crash */


		psl->mix_occlude_pass = DRW_pass_create("Mix Occluded Wires", DRW_STATE_WRITE_COLOR | DRW_STATE_BLEND);
		DRWShadingGroup *mix_shgrp = DRW_shgroup_create(overlay_mix_sh, psl->mix_occlude_pass);
		DRW_shgroup_call_add(mix_shgrp, quad, mat);
		DRW_shgroup_uniform_float(mix_shgrp, "alpha", &backwire_opacity, 1);
		DRW_shgroup_uniform_buffer(mix_shgrp, "wireColor", &txl->occlude_wire_color_tx, 0);
		DRW_shgroup_uniform_buffer(mix_shgrp, "wireDepth", &txl->occlude_wire_depth_tx, 2);
		DRW_shgroup_uniform_buffer(mix_shgrp, "sceneDepth", &dtxl->depth, 3);
	}

	DRW_mode_passes_setup(NULL,
	                      NULL,
	                      &psl->wire_outline_pass,
	                      &psl->non_meshes_pass,
	                      &psl->ob_center_pass,
	                      NULL,
	                      NULL);
}

static void edit_mesh_add_ob_to_pass(Scene *scene, Object *ob, DRWShadingGroup *face_shgrp, DRWShadingGroup *ledges_shgrp,
                              DRWShadingGroup *lverts_shgrp, DRWShadingGroup *facedot_shgrp, DRWShadingGroup *facefill_shgrp)
{
	struct Batch *geo_ovl_tris, *geo_ovl_ledges, *geo_ovl_lverts, *geo_ovl_fcenter;
	ToolSettings *ts = scene->toolsettings;

	DRW_cache_wire_overlay_get(ob, &geo_ovl_tris, &geo_ovl_ledges, &geo_ovl_lverts);
	DRW_shgroup_call_add(face_shgrp, geo_ovl_tris, ob->obmat);
	DRW_shgroup_call_add(ledges_shgrp, geo_ovl_ledges, ob->obmat);

	if (facefill_shgrp)
		DRW_shgroup_call_add(facefill_shgrp, geo_ovl_tris, ob->obmat);

	if ((ts->selectmode & SCE_SELECT_VERTEX) != 0)
		DRW_shgroup_call_add(lverts_shgrp, geo_ovl_lverts, ob->obmat);

	if ((ts->selectmode & SCE_SELECT_FACE) != 0) {
		geo_ovl_fcenter = DRW_cache_face_centers_get(ob);
		DRW_shgroup_call_add(facedot_shgrp, geo_ovl_fcenter, ob->obmat);
	}
}

void EDIT_MESH_cache_populate(Object *ob)
{
	const struct bContext *C = DRW_get_context();
	View3D *v3d = CTX_wm_view3d(C);
	Scene *scene = CTX_data_scene(C);
	Object *obedit = scene->obedit;
	struct Batch *geom;

	CollectionEngineSettings *ces_mode_ed = BKE_object_collection_engine_get(ob, COLLECTION_MODE_EDIT, "");
	bool do_occlude_wire = BKE_collection_engine_property_value_get_bool(ces_mode_ed, "show_occlude_wire");
	backwire_opacity = BKE_collection_engine_property_value_get_float(ces_mode_ed, "backwire_opacity"); /* should be done only once */

	face_mod = (do_occlude_wire) ? 0.0f : 1.0f;

	switch (ob->type) {
		case OB_MESH:
			if (ob == obedit) {	
				if (do_occlude_wire) {
					geom = DRW_cache_surface_get(ob);
					DRW_shgroup_call_add(depth_shgrp_hidden_wire, geom, ob->obmat);
				}

				if ((v3d->flag & V3D_ZBUF_SELECT) == 0) {
					edit_mesh_add_ob_to_pass(scene, ob, face_occluded_shgrp, ledges_occluded_shgrp,
					                         lverts_occluded_shgrp, facedot_occluded_shgrp, facefill_occluded_shgrp);
				}
				else {
					edit_mesh_add_ob_to_pass(scene, ob, face_overlay_shgrp, ledges_overlay_shgrp,
					                         lverts_overlay_shgrp, facedot_overlay_shgrp, NULL);
				}
			}
			break;
		case OB_LAMP:
			DRW_shgroup_lamp(ob);
			break;
		case OB_CAMERA:
			DRW_shgroup_camera(ob);
			break;
		case OB_EMPTY:
			DRW_shgroup_empty(ob);
			break;
		case OB_SPEAKER:
			DRW_shgroup_speaker(ob);
			break;
		case OB_ARMATURE:
			DRW_shgroup_armature_object(ob);
			break;
		default:
			break;
	}

	DRW_shgroup_object_center(ob);
	DRW_shgroup_relationship_lines(ob);
}

void EDIT_MESH_cache_finish(void)
{
	/* Do nothing */
}

void EDIT_MESH_draw(void)
{
	EDIT_MESH_PassList *psl = DRW_mode_pass_list_get();
	EDIT_MESH_FramebufferList *fbl = DRW_mode_framebuffer_list_get();
	DefaultFramebufferList *dfbl = DRW_engine_framebuffer_list_get();
	DefaultTextureList *dtxl = DRW_engine_texture_list_get();

	DRW_draw_pass(psl->depth_pass_hidden_wire);

	if (psl->edit_face_occluded_pass) {
		float clearcol[4] = {0.0f, 0.0f, 0.0f, 0.0f};
		/* render facefill */
		DRW_draw_pass(psl->facefill_occlude_pass);
		
		/* Render wires on a separate framebuffer */
		DRW_framebuffer_bind(fbl->occlude_wire_fb);
		DRW_framebuffer_clear(true, true, clearcol, 1.0f);
		DRW_draw_pass(psl->edit_face_occluded_pass);

		/* detach textures */
		DRW_framebuffer_texture_detach(dtxl->depth);

		/* Combine with scene buffer */
		DRW_framebuffer_bind(dfbl->default_fb);
		DRW_draw_pass(psl->mix_occlude_pass);

		/* reattach */
		DRW_framebuffer_texture_attach(dfbl->default_fb, dtxl->depth, 0);
	}
	else {
		DRW_draw_pass(psl->edit_face_overlay_pass);
	}

	DRW_draw_pass(psl->wire_outline_pass);
	DRW_draw_pass(psl->non_meshes_pass);
	DRW_draw_pass(psl->ob_center_pass);
}

void EDIT_MESH_collection_settings_create(CollectionEngineSettings *ces)
{
	BLI_assert(ces);
	BKE_collection_engine_property_add_int(ces, "show_occlude_wire", false);
	BKE_collection_engine_property_add_float(ces, "backwire_opacity", 0.5);
}

void EDIT_MESH_engine_free(void)
{
	if (overlay_tri_sh)
		DRW_shader_free(overlay_tri_sh);
	if (overlay_tri_fast_sh)
		DRW_shader_free(overlay_tri_fast_sh);
	if (overlay_tri_vcol_sh)
		DRW_shader_free(overlay_tri_vcol_sh);
	if (overlay_tri_vcol_fast_sh)
		DRW_shader_free(overlay_tri_vcol_fast_sh);
	if (overlay_edge_sh)
		DRW_shader_free(overlay_edge_sh);
	if (overlay_edge_vcol_sh)
		DRW_shader_free(overlay_edge_vcol_sh);
	if (overlay_vert_sh)
		DRW_shader_free(overlay_vert_sh);
	if (overlay_facedot_sh)
		DRW_shader_free(overlay_facedot_sh);
	if (overlay_mix_sh)
		DRW_shader_free(overlay_mix_sh);
	if (overlay_facefill_sh)
		DRW_shader_free(overlay_facefill_sh);
}