/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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.
 *
 * Copyright 2018, Blender Foundation.
 * Contributor(s): Blender Institute
 *
 * ***** END GPL LICENSE BLOCK *****
 *
 */

#include "workbench_private.h"

#include "DNA_userdef_types.h"

#include "UI_resources.h"

#include "GPU_batch.h"


void workbench_effect_info_init(WORKBENCH_EffectInfo *effect_info)
{
	effect_info->jitter_index = 0;
	effect_info->view_updated = true;
}

void workbench_private_data_init(WORKBENCH_PrivateData *wpd)
{
	const DRWContextState *draw_ctx = DRW_context_state_get();
	const Scene *scene = draw_ctx->scene;
	wpd->material_hash = BLI_ghash_ptr_new(__func__);
	wpd->material_transp_hash = BLI_ghash_ptr_new(__func__);
	wpd->preferences = &U;

	View3D *v3d = draw_ctx->v3d;
	if (!v3d) {
		wpd->shading = scene->display.shading;
		wpd->use_color_view_settings = true;
	}
	else if (v3d->shading.type == OB_RENDER &&
	         BKE_scene_uses_blender_workbench(scene))
	{
		wpd->shading = scene->display.shading;
		wpd->use_color_view_settings = true;
	}
	else {
		wpd->shading = v3d->shading;
		wpd->use_color_view_settings = false;
	}

	if (wpd->shading.light == V3D_LIGHTING_MATCAP) {
		wpd->studio_light = BKE_studiolight_find(
		        wpd->shading.matcap, STUDIOLIGHT_TYPE_MATCAP);
	}
	else {
		wpd->studio_light = BKE_studiolight_find(
		        wpd->shading.studio_light, STUDIOLIGHT_TYPE_STUDIO);
	}

	/* If matcaps are missing, use this as fallback. */
	if (UNLIKELY(wpd->studio_light == NULL)) {
		wpd->studio_light = BKE_studiolight_find(
		        wpd->shading.studio_light, STUDIOLIGHT_TYPE_STUDIO);
	}


	float shadow_focus = scene->display.shadow_focus;
	/* Clamp to avoid overshadowing and shading errors. */
	CLAMP(shadow_focus, 0.0001f, 0.99999f);
	wpd->shadow_shift = scene->display.shadow_shift;
	wpd->shadow_focus = 1.0f - shadow_focus * (1.0f - wpd->shadow_shift);
	wpd->shadow_multiplier = 1.0 - wpd->shading.shadow_intensity;

	WORKBENCH_UBO_World *wd = &wpd->world_data;
	wd->matcap_orientation = (wpd->shading.flag & V3D_SHADING_MATCAP_FLIP_X) != 0;
	wd->background_alpha = (DRW_state_is_image_render() && scene->r.alphamode == R_ALPHAPREMUL) ? 0.0f : 1.0f;

	if ((scene->world != NULL) &&
	    (!v3d || (v3d && ((v3d->shading.background_type == V3D_SHADING_BACKGROUND_WORLD) ||
	                      (v3d->shading.type == OB_RENDER)))))
	{
		copy_v3_v3(wd->background_color_low, &scene->world->horr);
		copy_v3_v3(wd->background_color_high, &scene->world->horr);
	}
	else if (v3d && (v3d->shading.background_type == V3D_SHADING_BACKGROUND_VIEWPORT)) {
		copy_v3_v3(wd->background_color_low, v3d->shading.background_color);
		copy_v3_v3(wd->background_color_high, v3d->shading.background_color);
	}
	else if (v3d) {
		UI_GetThemeColor3fv(UI_GetThemeValue(TH_SHOW_BACK_GRAD) ? TH_BACK_GRAD : TH_BACK, wd->background_color_low);
		UI_GetThemeColor3fv(TH_BACK, wd->background_color_high);

		/* XXX: Really quick conversion to avoid washed out background.
		 * Needs to be addressed properly (color managed using ocio). */
		srgb_to_linearrgb_v3_v3(wd->background_color_high, wd->background_color_high);
		srgb_to_linearrgb_v3_v3(wd->background_color_low, wd->background_color_low);
	}
	else {
		zero_v3(wd->background_color_low);
		zero_v3(wd->background_color_high);
	}

	studiolight_update_world(wpd, wpd->studio_light, wd);

	copy_v3_v3(wd->object_outline_color, wpd->shading.object_outline_color);
	wd->object_outline_color[3] = 1.0f;

	wd->curvature_ridge = 0.5f / max_ff(SQUARE(wpd->shading.curvature_ridge_factor), 1e-4f);
	wd->curvature_valley = 0.7f / max_ff(SQUARE(wpd->shading.curvature_valley_factor), 1e-4f);

	/* Will be NULL when rendering. */
	if (draw_ctx->rv3d != NULL) {
		RegionView3D *rv3d = draw_ctx->rv3d;
		if (rv3d->rflag & RV3D_CLIPPING) {
			wpd->world_clip_planes = rv3d->clip;
			DRW_state_clip_planes_set_from_rv3d(rv3d);
			UI_GetThemeColor4fv(TH_V3D_CLIPPING_BORDER, wpd->world_clip_planes_color);
			srgb_to_linearrgb_v3_v3(wpd->world_clip_planes_color, wpd->world_clip_planes_color);
		}
		else {
			wpd->world_clip_planes = NULL;
		}
	}

	wpd->world_ubo = DRW_uniformbuffer_create(sizeof(WORKBENCH_UBO_World), &wpd->world_data);

	/* Cavity settings */
	{
		const int ssao_samples = scene->display.matcap_ssao_samples;

		float invproj[4][4];
		const bool is_persp = DRW_viewport_is_persp_get();
		/* view vectors for the corners of the view frustum.
		 * Can be used to recreate the world space position easily */
		float viewvecs[3][4] = {
		    {-1.0f, -1.0f, -1.0f, 1.0f},
		    {1.0f, -1.0f, -1.0f, 1.0f},
		    {-1.0f, 1.0f, -1.0f, 1.0f}
		};
		int i;
		const float *size = DRW_viewport_size_get();

		wpd->ssao_params[0] = ssao_samples;
		wpd->ssao_params[1] = size[0] / 64.0;
		wpd->ssao_params[2] = size[1] / 64.0;
		wpd->ssao_params[3] = 0;

		/* distance, factor, factor, attenuation */
		copy_v4_fl4(
		        wpd->ssao_settings,
		        scene->display.matcap_ssao_distance,
		        wpd->shading.cavity_valley_factor,
		        wpd->shading.cavity_ridge_factor,
		        scene->display.matcap_ssao_attenuation);

		/* invert the view matrix */
		DRW_viewport_matrix_get(wpd->winmat, DRW_MAT_WIN);
		invert_m4_m4(invproj, wpd->winmat);

		/* convert the view vectors to view space */
		for (i = 0; i < 3; i++) {
			mul_m4_v4(invproj, viewvecs[i]);
			/* normalized trick see:
			 * http://www.derschmale.com/2014/01/26/reconstructing-positions-from-the-depth-buffer */
			mul_v3_fl(viewvecs[i], 1.0f / viewvecs[i][3]);
			if (is_persp) {
				mul_v3_fl(viewvecs[i], 1.0f / viewvecs[i][2]);
			}
			viewvecs[i][3] = 1.0;

			copy_v4_v4(wpd->viewvecs[i], viewvecs[i]);
		}

		/* we need to store the differences */
		wpd->viewvecs[1][0] -= wpd->viewvecs[0][0];
		wpd->viewvecs[1][1] = wpd->viewvecs[2][1] - wpd->viewvecs[0][1];

		/* calculate a depth offset as well */
		if (!is_persp) {
			float vec_far[] = {-1.0f, -1.0f, 1.0f, 1.0f};
			mul_m4_v4(invproj, vec_far);
			mul_v3_fl(vec_far, 1.0f / vec_far[3]);
			wpd->viewvecs[1][2] = vec_far[2] - wpd->viewvecs[0][2];
		}
	}

	wpd->volumes_do = false;
	BLI_listbase_clear(&wpd->smoke_domains);
}

void workbench_private_data_get_light_direction(WORKBENCH_PrivateData *wpd, float r_light_direction[3])
{
	const DRWContextState *draw_ctx = DRW_context_state_get();
	Scene *scene = draw_ctx->scene;
	WORKBENCH_UBO_World *wd = &wpd->world_data;
	float view_matrix[4][4];
	DRW_viewport_matrix_get(view_matrix, DRW_MAT_VIEW);

	copy_v3_v3(r_light_direction, scene->display.light_direction);
	SWAP(float, r_light_direction[2], r_light_direction[1]);
	r_light_direction[2] = -r_light_direction[2];
	r_light_direction[0] = -r_light_direction[0];

	/* Shadow direction. */
	mul_v3_mat3_m4v3(wd->shadow_direction_vs, view_matrix, r_light_direction);

	DRW_uniformbuffer_update(wpd->world_ubo, wd);
}

void workbench_private_data_free(WORKBENCH_PrivateData *wpd)
{
	BLI_ghash_free(wpd->material_hash, NULL, MEM_freeN);
	BLI_ghash_free(wpd->material_transp_hash, NULL, MEM_freeN);
	DRW_UBO_FREE_SAFE(wpd->world_ubo);
	DRW_UBO_FREE_SAFE(wpd->dof_ubo);
	GPU_BATCH_DISCARD_SAFE(wpd->world_clip_planes_batch);
}