/*
 * ***** 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 2016, Blender Foundation.
 * Contributor(s): Blender Institute
 *
 * ***** END GPL LICENSE BLOCK *****
 *
 */

/** \file eevee_lookdev.c
 *  \ingroup draw_engine
 */
#include "DRW_render.h"

#include "BKE_camera.h"
#include "BKE_studiolight.h"

#include "DNA_screen_types.h"
#include "DNA_world_types.h"

#include "DEG_depsgraph_query.h"

#include "ED_screen.h"

#include "UI_resources.h"

#include "eevee_private.h"
#include "eevee_lightcache.h"

#include "draw_common.h"

static void eevee_lookdev_lightcache_delete(EEVEE_Data *vedata)
{
	EEVEE_StorageList *stl = vedata->stl;
	EEVEE_TextureList *txl = vedata->txl;

	MEM_SAFE_FREE(stl->lookdev_lightcache);
	MEM_SAFE_FREE(stl->lookdev_grid_data);
	MEM_SAFE_FREE(stl->lookdev_cube_data);
	DRW_TEXTURE_FREE_SAFE(txl->lookdev_grid_tx);
	DRW_TEXTURE_FREE_SAFE(txl->lookdev_cube_tx);
}

void EEVEE_lookdev_cache_init(
        EEVEE_Data *vedata, DRWShadingGroup **grp, DRWPass *pass,
        World *UNUSED(world), EEVEE_LightProbesInfo *pinfo)
{
	EEVEE_StorageList *stl = vedata->stl;
	EEVEE_TextureList *txl = vedata->txl;
	const DRWContextState *draw_ctx = DRW_context_state_get();
	View3D *v3d = draw_ctx->v3d;
	if (LOOK_DEV_STUDIO_LIGHT_ENABLED(v3d)) {
		StudioLight *sl = BKE_studiolight_find(v3d->shading.lookdev_light, STUDIOLIGHT_ORIENTATIONS_MATERIAL_MODE);
		if (sl && (sl->flag & STUDIOLIGHT_TYPE_WORLD)) {
			GPUShader *shader = EEVEE_shaders_default_studiolight_sh_get();
			struct GPUBatch *geom = DRW_cache_fullscreen_quad_get();
			GPUTexture *tex = NULL;

			/* If one of the component is missing we start from scratch. */
			if ((stl->lookdev_grid_data == NULL) ||
			    (stl->lookdev_cube_data == NULL) ||
			    (txl->lookdev_grid_tx == NULL) ||
			    (txl->lookdev_cube_tx == NULL))
			{
				eevee_lookdev_lightcache_delete(vedata);
			}

			if (stl->lookdev_lightcache == NULL) {
				const Scene *scene_eval = DEG_get_evaluated_scene(draw_ctx->depsgraph);
#if defined(IRRADIANCE_SH_L2)
				int grid_res = 4;
#elif defined(IRRADIANCE_CUBEMAP)
				int grid_res = 8;
#elif defined(IRRADIANCE_HL2)
				int grid_res = 4;
#endif
				int cube_res = OCTAHEDRAL_SIZE_FROM_CUBESIZE(scene_eval->eevee.gi_cubemap_resolution);
				int vis_res = scene_eval->eevee.gi_visibility_resolution;

				stl->lookdev_lightcache = EEVEE_lightcache_create(1, 1, cube_res, vis_res, (int[3]){grid_res, grid_res, 1});

				/* XXX: Fix memleak. TODO find out why. */
				MEM_SAFE_FREE(stl->lookdev_cube_mips);

				/* We do this to use a special light cache for lookdev.
				 * This lightcache needs to be per viewport. But we need to
				 * have correct freeing when the viewport is closed. So we
				 * need to reference all textures to the txl and the memblocks
				 * to the stl. */
				stl->lookdev_grid_data = stl->lookdev_lightcache->grid_data;
				stl->lookdev_cube_data = stl->lookdev_lightcache->cube_data;
				stl->lookdev_cube_mips = stl->lookdev_lightcache->cube_mips;
				txl->lookdev_grid_tx = stl->lookdev_lightcache->grid_tx.tex;
				txl->lookdev_cube_tx = stl->lookdev_lightcache->cube_tx.tex;
			}

			stl->g_data->light_cache = stl->lookdev_lightcache;

			static float background_color[4];
			UI_GetThemeColor4fv(TH_BACK, background_color);
			/* XXX: Really quick conversion to avoid washed out background.
			 * Needs to be addressed properly (color managed using ocio). */
			srgb_to_linearrgb_v4(background_color, background_color);

			*grp = DRW_shgroup_create(shader, pass);
			axis_angle_to_mat3_single(stl->g_data->studiolight_matrix, 'Z', v3d->shading.studiolight_rot_z);
			DRW_shgroup_uniform_mat3(*grp, "StudioLightMatrix", stl->g_data->studiolight_matrix);
			DRW_shgroup_uniform_float(*grp, "backgroundAlpha", &stl->g_data->background_alpha, 1);
			DRW_shgroup_uniform_vec3(*grp, "color", background_color, 1);
			DRW_shgroup_call_add(*grp, geom, NULL);
			if (!pinfo) {
				/* Do not fadeout when doing probe rendering, only when drawing the background */
				DRW_shgroup_uniform_float(*grp, "studioLightBackground", &v3d->shading.studiolight_background, 1);
				BKE_studiolight_ensure_flag(sl, STUDIOLIGHT_EQUIRECT_IRRADIANCE_GPUTEXTURE);
				tex = sl->equirect_irradiance_gputexture;
			}
			else {
				DRW_shgroup_uniform_float_copy(*grp, "studioLightBackground", 1.0f);
				BKE_studiolight_ensure_flag(sl, STUDIOLIGHT_EQUIRECT_RADIANCE_GPUTEXTURE);
				tex = sl->equirect_radiance_gputexture;
			}
			DRW_shgroup_uniform_texture(*grp, "image", tex);

			/* Do we need to recalc the lightprobes? */
			if (pinfo &&
			    ((pinfo->studiolight_index != sl->index) ||
			     (pinfo->studiolight_rot_z != v3d->shading.studiolight_rot_z)))
			{
				stl->lookdev_lightcache->flag |= LIGHTCACHE_UPDATE_WORLD;
				pinfo->studiolight_index = sl->index;
				pinfo->studiolight_rot_z = v3d->shading.studiolight_rot_z;
			}
		}
	}
}

void EEVEE_lookdev_draw_background(EEVEE_Data *vedata)
{
	EEVEE_PassList *psl = vedata->psl;
	EEVEE_StorageList *stl = ((EEVEE_Data *)vedata)->stl;
	EEVEE_EffectsInfo *effects = stl->effects;
	EEVEE_ViewLayerData *sldata = EEVEE_view_layer_data_ensure();
	DefaultFramebufferList *dfbl = DRW_viewport_framebuffer_list_get();

	const DRWContextState *draw_ctx = DRW_context_state_get();

	if (psl->lookdev_pass && LOOK_DEV_OVERLAY_ENABLED(draw_ctx->v3d)) {
		DRW_stats_group_start("Look Dev");
		CameraParams params;
		BKE_camera_params_init(&params);
		View3D *v3d = draw_ctx->v3d;
		RegionView3D *rv3d = draw_ctx->rv3d;
		ARegion *ar = draw_ctx->ar;

		const float *viewport_size = DRW_viewport_size_get();
		rcti rect;
		ED_region_visible_rect(draw_ctx->ar, &rect);

		const float viewport_size_target[2] = {
			viewport_size[0] / 4,
			viewport_size[1] / 4,
		};
		const int viewport_inset[2] = {
			max_ii(viewport_size_target[0], 300),
			max_ii(viewport_size_target[0], 300) / 2,  /* intentionally use 'x' here for 'y' value. */
		};

		/* minimum size for preview spheres viewport */
		const float aspect[2] = {
			viewport_inset[0] / viewport_size_target[0],
			viewport_inset[1] / viewport_size_target[1],
		};

		BKE_camera_params_from_view3d(&params, draw_ctx->depsgraph, v3d, rv3d);
		params.is_ortho = true;
		params.ortho_scale = 3.0f;
		params.zoom = CAMERA_PARAM_ZOOM_INIT_PERSP;
		params.offsetx = 0.0f;
		params.offsety = 0.0f;
		params.shiftx = 0.0f;
		params.shifty = 0.0f;
		params.clipsta = 0.001f;
		params.clipend = 20.0f;
		BKE_camera_params_compute_viewplane(&params, ar->winx, ar->winy, aspect[0], aspect[1]);
		BKE_camera_params_compute_matrix(&params);

		EEVEE_CommonUniformBuffer *common = &sldata->common_data;
		common->la_num_light = 0;
		common->prb_num_planar = 0;
		common->prb_num_render_cube = 1;
		common->prb_num_render_grid = 1;
		common->ao_dist = 0.0f;
		common->ao_factor = 0.0f;
		common->ao_settings = 0.0f;
		DRW_uniformbuffer_update(sldata->common_ubo, common);

		/* override matrices */
		float winmat[4][4];
		float winmat_inv[4][4];
		copy_m4_m4(winmat, params.winmat);
		invert_m4_m4(winmat_inv, winmat);
		DRW_viewport_matrix_override_set(winmat, DRW_MAT_WIN);
		DRW_viewport_matrix_override_set(winmat_inv, DRW_MAT_WININV);
		float viewmat[4][4];
		DRW_viewport_matrix_get(viewmat, DRW_MAT_VIEW);
		float persmat[4][4];
		float persmat_inv[4][4];
		mul_m4_m4m4(persmat, winmat, viewmat);
		invert_m4_m4(persmat_inv, persmat);
		DRW_viewport_matrix_override_set(persmat, DRW_MAT_PERS);
		DRW_viewport_matrix_override_set(persmat_inv, DRW_MAT_PERSINV);

		GPUFrameBuffer *fb = effects->final_fb;
		GPU_framebuffer_bind(fb);
		GPU_framebuffer_viewport_set(fb, rect.xmax - viewport_inset[0], rect.ymin, viewport_inset[0], viewport_inset[1]);
		DRW_draw_pass(psl->lookdev_pass);

		fb = dfbl->depth_only_fb;
		GPU_framebuffer_bind(fb);
		GPU_framebuffer_viewport_set(fb, rect.xmax - viewport_inset[0], rect.ymin, viewport_inset[0], viewport_inset[1]);
		DRW_draw_pass(psl->lookdev_pass);

		DRW_viewport_matrix_override_unset_all();
		DRW_stats_group_end();
	}
}