/**************************************************************************/
/*  debug_effects.cpp                                                     */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#include "debug_effects.h"
#include "servers/rendering/renderer_rd/renderer_compositor_rd.h"
#include "servers/rendering/renderer_rd/storage_rd/light_storage.h"
#include "servers/rendering/renderer_rd/storage_rd/material_storage.h"
#include "servers/rendering/renderer_rd/uniform_set_cache_rd.h"

using namespace RendererRD;

DebugEffects::DebugEffects() {
	{
		// Shadow Frustum debug shader
		Vector<String> modes;
		modes.push_back("");

		shadow_frustum.shader.initialize(modes);
		shadow_frustum.shader_version = shadow_frustum.shader.version_create();

		RD::PipelineRasterizationState raster_state = RD::PipelineRasterizationState();
		shadow_frustum.pipelines[SFP_TRANSPARENT].setup(shadow_frustum.shader.version_get_shader(shadow_frustum.shader_version, 0), RD::RENDER_PRIMITIVE_TRIANGLES, raster_state, RD::PipelineMultisampleState(), RD::PipelineDepthStencilState(), RD::PipelineColorBlendState::create_blend(), 0);

		raster_state.wireframe = true;
		shadow_frustum.pipelines[SFP_WIREFRAME].setup(shadow_frustum.shader.version_get_shader(shadow_frustum.shader_version, 0), RD::RENDER_PRIMITIVE_LINES, raster_state, RD::PipelineMultisampleState(), RD::PipelineDepthStencilState(), RD::PipelineColorBlendState::create_disabled(), 0);
	}
}

void DebugEffects::_create_frustum_arrays() {
	if (frustum.vertex_buffer.is_null()) {
		// Create vertex buffer, but don't put data in it yet
		frustum.vertex_buffer = RD::get_singleton()->vertex_buffer_create(8 * sizeof(float) * 3, Vector<uint8_t>(), false);

		Vector<RD::VertexAttribute> attributes;
		Vector<RID> buffers;
		RD::VertexAttribute vd;

		vd.location = 0;
		vd.stride = sizeof(float) * 3;
		vd.format = RD::DATA_FORMAT_R32G32B32_SFLOAT;

		attributes.push_back(vd);
		buffers.push_back(frustum.vertex_buffer);

		frustum.vertex_format = RD::get_singleton()->vertex_format_create(attributes);
		frustum.vertex_array = RD::get_singleton()->vertex_array_create(8, frustum.vertex_format, buffers);
	}

	if (frustum.index_buffer.is_null()) {
		uint32_t indices[6 * 2 * 3] = {
			// Far
			0, 1, 2, // FLT, FLB, FRT
			1, 3, 2, // FLB, FRB, FRT
			// Near
			4, 6, 5, // NLT, NRT, NLB
			6, 7, 5, // NRT, NRB, NLB
			// Left
			0, 4, 1, // FLT, NLT, FLB
			4, 5, 1, // NLT, NLB, FLB
			// Right
			6, 2, 7, // NRT, FRT, NRB
			2, 3, 7, // FRT, FRB, NRB
			// Top
			0, 2, 4, // FLT, FRT, NLT
			2, 6, 4, // FRT, NRT, NLT
			// Bottom
			5, 7, 1, // NLB, NRB, FLB,
			7, 3, 1, // NRB, FRB, FLB
		};

		// Create our index_array
		PackedByteArray data;
		data.resize(6 * 2 * 3 * 4);
		{
			uint8_t *w = data.ptrw();
			int *p32 = (int *)w;
			for (int i = 0; i < 6 * 2 * 3; i++) {
				*p32 = indices[i];
				p32++;
			}
		}

		frustum.index_buffer = RD::get_singleton()->index_buffer_create(6 * 2 * 3, RenderingDevice::INDEX_BUFFER_FORMAT_UINT32, data);
		frustum.index_array = RD::get_singleton()->index_array_create(frustum.index_buffer, 0, 6 * 2 * 3);
	}

	if (frustum.lines_buffer.is_null()) {
		uint32_t indices[12 * 2] = {
			0, 1, // FLT - FLB
			1, 3, // FLB - FRB
			3, 2, // FRB - FRT
			2, 0, // FRT - FLT

			4, 6, // NLT - NRT
			6, 7, // NRT - NRB
			7, 5, // NRB - NLB
			5, 4, // NLB - NLT

			0, 4, // FLT - NLT
			1, 5, // FLB - NLB
			2, 6, // FRT - NRT
			3, 7, // FRB - NRB
		};

		// Create our lines_array
		PackedByteArray data;
		data.resize(12 * 2 * 4);
		{
			uint8_t *w = data.ptrw();
			int *p32 = (int *)w;
			for (int i = 0; i < 12 * 2; i++) {
				*p32 = indices[i];
				p32++;
			}
		}

		frustum.lines_buffer = RD::get_singleton()->index_buffer_create(12 * 2, RenderingDevice::INDEX_BUFFER_FORMAT_UINT32, data);
		frustum.lines_array = RD::get_singleton()->index_array_create(frustum.lines_buffer, 0, 12 * 2);
	}
}

DebugEffects::~DebugEffects() {
	shadow_frustum.shader.version_free(shadow_frustum.shader_version);

	// Destroy vertex buffer and array.
	if (frustum.vertex_buffer.is_valid()) {
		RD::get_singleton()->free(frustum.vertex_buffer); // Array gets freed as dependency.
	}

	// Destroy index buffer and array,
	if (frustum.index_buffer.is_valid()) {
		RD::get_singleton()->free(frustum.index_buffer); // Array gets freed as dependency.
	}

	// Destroy lines buffer and array.
	if (frustum.lines_buffer.is_valid()) {
		RD::get_singleton()->free(frustum.lines_buffer); // Array gets freed as dependency.
	}
}

void DebugEffects::draw_shadow_frustum(RID p_light, const Projection &p_cam_projection, const Transform3D &p_cam_transform, RID p_dest_fb, const Rect2 p_rect) {
	RendererRD::LightStorage *light_storage = RendererRD::LightStorage::get_singleton();

	RID base = light_storage->light_instance_get_base_light(p_light);
	ERR_FAIL_COND(light_storage->light_get_type(base) != RS::LIGHT_DIRECTIONAL);

	// Make sure our buffers and arrays exist.
	_create_frustum_arrays();

	// Setup a points buffer for our view frustum.
	PackedByteArray points;
	points.resize(8 * sizeof(float) * 3);

	// Get info about our splits.
	RS::LightDirectionalShadowMode shadow_mode = light_storage->light_directional_get_shadow_mode(base);
	bool overlap = light_storage->light_directional_get_blend_splits(base);
	int splits = 1;
	if (shadow_mode == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_4_SPLITS) {
		splits = 4;
	} else if (shadow_mode == RS::LIGHT_DIRECTIONAL_SHADOW_PARALLEL_2_SPLITS) {
		splits = 2;
	}

	// Setup our camera info (this is mostly a duplicate of the logic found in RendererSceneCull::_light_instance_setup_directional_shadow).
	bool is_orthogonal = p_cam_projection.is_orthogonal();
	real_t aspect = p_cam_projection.get_aspect();
	real_t fov = 0.0;
	Vector2 vp_he;
	if (is_orthogonal) {
		vp_he = p_cam_projection.get_viewport_half_extents();
	} else {
		fov = p_cam_projection.get_fov(); //this is actually yfov, because set aspect tries to keep it
	}
	real_t min_distance = p_cam_projection.get_z_near();
	real_t max_distance = p_cam_projection.get_z_far();
	real_t shadow_max = RSG::light_storage->light_get_param(base, RS::LIGHT_PARAM_SHADOW_MAX_DISTANCE);
	if (shadow_max > 0 && !is_orthogonal) {
		max_distance = MIN(shadow_max, max_distance);
	}

	// Make sure we've not got bad info coming in.
	max_distance = MAX(max_distance, min_distance + 0.001);
	min_distance = MIN(min_distance, max_distance);
	real_t range = max_distance - min_distance;

	real_t distances[5];
	distances[0] = min_distance;
	for (int i = 0; i < splits; i++) {
		distances[i + 1] = min_distance + RSG::light_storage->light_get_param(base, RS::LightParam(RS::LIGHT_PARAM_SHADOW_SPLIT_1_OFFSET + i)) * range;
	};
	distances[splits] = max_distance;

	Color colors[4] = {
		Color(1.0, 0.0, 0.0, 0.1),
		Color(0.0, 1.0, 0.0, 0.1),
		Color(0.0, 0.0, 1.0, 0.1),
		Color(1.0, 1.0, 0.0, 0.1),
	};

	for (int split = 0; split < splits; split++) {
		// Load frustum points into vertex buffer.
		uint8_t *w = points.ptrw();
		Vector3 *vw = (Vector3 *)w;

		Projection projection;

		if (is_orthogonal) {
			projection.set_orthogonal(vp_he.y * 2.0, aspect, distances[(split == 0 || !overlap) ? split : split - 1], distances[split + 1], false);
		} else {
			projection.set_perspective(fov, aspect, distances[(split == 0 || !overlap) ? split : split - 1], distances[split + 1], true);
		}

		bool res = projection.get_endpoints(p_cam_transform, vw);
		ERR_CONTINUE(!res);

		RD::get_singleton()->buffer_update(frustum.vertex_buffer, 0, 8 * sizeof(float) * 3, w);

		// Get our light projection info.
		Projection light_projection = light_storage->light_instance_get_shadow_camera(p_light, split);
		Transform3D light_transform = light_storage->light_instance_get_shadow_transform(p_light, split);
		Rect2 atlas_rect_norm = light_storage->light_instance_get_directional_shadow_atlas_rect(p_light, split);

		if (!is_orthogonal) {
			light_transform.orthogonalize();
		}

		// Setup our push constant.
		ShadowFrustumPushConstant push_constant;
		MaterialStorage::store_camera(light_projection * Projection(light_transform.inverse()), push_constant.mvp);
		push_constant.color[0] = colors[split].r;
		push_constant.color[1] = colors[split].g;
		push_constant.color[2] = colors[split].b;
		push_constant.color[3] = colors[split].a;

		// Adjust our rect to our atlas position.
		Rect2 rect = p_rect;
		rect.position.x += atlas_rect_norm.position.x * rect.size.x;
		rect.position.y += atlas_rect_norm.position.y * rect.size.y;
		rect.size.x *= atlas_rect_norm.size.x;
		rect.size.y *= atlas_rect_norm.size.y;

		// And draw our frustum.
		RD::FramebufferFormatID fb_format_id = RD::get_singleton()->framebuffer_get_format(p_dest_fb);

		RD::DrawListID draw_list = RD::get_singleton()->draw_list_begin(p_dest_fb, RD::INITIAL_ACTION_KEEP, RD::FINAL_ACTION_READ, RD::INITIAL_ACTION_KEEP, RD::FINAL_ACTION_DISCARD, Vector<Color>(), 1.0, 0, rect);

		RID pipeline = shadow_frustum.pipelines[SFP_TRANSPARENT].get_render_pipeline(frustum.vertex_format, fb_format_id);
		RD::get_singleton()->draw_list_bind_render_pipeline(draw_list, pipeline);
		RD::get_singleton()->draw_list_bind_vertex_array(draw_list, frustum.vertex_array);
		RD::get_singleton()->draw_list_bind_index_array(draw_list, frustum.index_array);
		RD::get_singleton()->draw_list_set_push_constant(draw_list, &push_constant, sizeof(ShadowFrustumPushConstant));
		RD::get_singleton()->draw_list_draw(draw_list, true);

		pipeline = shadow_frustum.pipelines[SFP_WIREFRAME].get_render_pipeline(frustum.vertex_format, fb_format_id);
		RD::get_singleton()->draw_list_bind_render_pipeline(draw_list, pipeline);
		RD::get_singleton()->draw_list_bind_vertex_array(draw_list, frustum.vertex_array);
		RD::get_singleton()->draw_list_bind_index_array(draw_list, frustum.lines_array);
		RD::get_singleton()->draw_list_set_push_constant(draw_list, &push_constant, sizeof(ShadowFrustumPushConstant));
		RD::get_singleton()->draw_list_draw(draw_list, true);

		RD::get_singleton()->draw_list_end();

		if (split < (splits - 1) && splits > 1) {
			// Also draw it in the last split so we get a proper overview of the whole view frustum...

			// Get our light projection info.
			light_projection = light_storage->light_instance_get_shadow_camera(p_light, (splits - 1));
			light_transform = light_storage->light_instance_get_shadow_transform(p_light, (splits - 1));
			atlas_rect_norm = light_storage->light_instance_get_directional_shadow_atlas_rect(p_light, (splits - 1));

			if (!is_orthogonal) {
				light_transform.orthogonalize();
			}

			// Update our push constant.
			MaterialStorage::store_camera(light_projection * Projection(light_transform.inverse()), push_constant.mvp);
			push_constant.color[0] = colors[split].r;
			push_constant.color[1] = colors[split].g;
			push_constant.color[2] = colors[split].b;
			push_constant.color[3] = colors[split].a;

			// Adjust our rect to our atlas position.
			rect = p_rect;
			rect.position.x += atlas_rect_norm.position.x * rect.size.x;
			rect.position.y += atlas_rect_norm.position.y * rect.size.y;
			rect.size.x *= atlas_rect_norm.size.x;
			rect.size.y *= atlas_rect_norm.size.y;

			draw_list = RD::get_singleton()->draw_list_begin(p_dest_fb, RD::INITIAL_ACTION_KEEP, RD::FINAL_ACTION_READ, RD::INITIAL_ACTION_KEEP, RD::FINAL_ACTION_DISCARD, Vector<Color>(), 1.0, 0, rect);

			pipeline = shadow_frustum.pipelines[SFP_TRANSPARENT].get_render_pipeline(frustum.vertex_format, fb_format_id);
			RD::get_singleton()->draw_list_bind_render_pipeline(draw_list, pipeline);
			RD::get_singleton()->draw_list_bind_vertex_array(draw_list, frustum.vertex_array);
			RD::get_singleton()->draw_list_bind_index_array(draw_list, frustum.index_array);
			RD::get_singleton()->draw_list_set_push_constant(draw_list, &push_constant, sizeof(ShadowFrustumPushConstant));
			RD::get_singleton()->draw_list_draw(draw_list, true);

			RD::get_singleton()->draw_list_end();
		}
	}
}