Shadow mapping render pass (#11244)

Co-authored-by: x2048 <codeforsmile@gmail.com>

src/client/shadows/dynamicshadowsrender.h

@@ -0,0 +1,146 @@
+/*
+Minetest
+Copyright (C) 2021 Liso <anlismon@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser 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.
+*/
+
+#pragma once
+
+#include <string>
+#include <vector>
+#include "irrlichttypes_extrabloated.h"
+#include "client/shadows/dynamicshadows.h"
+
+class ShadowDepthShaderCB;
+class shadowScreenQuad;
+class shadowScreenQuadCB;
+
+enum E_SHADOW_MODE : u8
+{
+	ESM_RECEIVE = 0,
+	ESM_BOTH,
+};
+
+struct NodeToApply
+{
+	NodeToApply(scene::ISceneNode *n,
+			E_SHADOW_MODE m = E_SHADOW_MODE::ESM_BOTH) :
+			node(n),
+			shadowMode(m){};
+	bool operator<(const NodeToApply &other) const { return node < other.node; };
+
+	scene::ISceneNode *node;
+
+	E_SHADOW_MODE shadowMode{E_SHADOW_MODE::ESM_BOTH};
+	bool dirty{false};
+};
+
+class ShadowRenderer
+{
+public:
+	ShadowRenderer(IrrlichtDevice *device, Client *client);
+
+	~ShadowRenderer();
+
+	void initialize();
+
+	/// Adds a directional light shadow map (Usually just one (the sun) except in
+	/// Tattoine ).
+	size_t addDirectionalLight();
+	DirectionalLight &getDirectionalLight(u32 index = 0);
+	size_t getDirectionalLightCount() const;
+	f32 getMaxShadowFar() const;
+
+	float getUpdateDelta() const;
+	/// Adds a shadow to the scene node.
+	/// The shadow mode can be ESM_BOTH, or ESM_RECEIVE.
+	/// ESM_BOTH casts and receives shadows
+	/// ESM_RECEIVE only receives but does not cast shadows.
+	///
+	void addNodeToShadowList(scene::ISceneNode *node,
+			E_SHADOW_MODE shadowMode = ESM_BOTH);
+	void removeNodeFromShadowList(scene::ISceneNode *node);
+
+	void setClearColor(video::SColor ClearColor);
+
+	void update(video::ITexture *outputTarget = nullptr);
+
+	video::ITexture *get_texture()
+	{
+		return shadowMapTextureFinal;
+	}
+
+
+	bool is_active() const { return m_shadows_enabled; }
+	void setTimeOfDay(float isDay) { m_time_day = isDay; };
+
+	s32 getShadowSamples() const { return m_shadow_samples; }
+	float getShadowStrength() const { return m_shadow_strength; }
+	float getTimeOfDay() const { return m_time_day; }
+
+private:
+	video::ITexture *getSMTexture(const std::string &shadow_map_name,
+			video::ECOLOR_FORMAT texture_format,
+			bool force_creation = false);
+
+	void renderShadowMap(video::ITexture *target, DirectionalLight &light,
+			scene::E_SCENE_NODE_RENDER_PASS pass =
+					scene::ESNRP_SOLID);
+	void renderShadowObjects(video::ITexture *target, DirectionalLight &light);
+	void mixShadowsQuad();
+
+	// a bunch of variables
+	IrrlichtDevice *m_device{nullptr};
+	scene::ISceneManager *m_smgr{nullptr};
+	video::IVideoDriver *m_driver{nullptr};
+	Client *m_client{nullptr};
+	video::ITexture *shadowMapClientMap{nullptr};
+	video::ITexture *shadowMapTextureFinal{nullptr};
+	video::ITexture *shadowMapTextureDynamicObjects{nullptr};
+	video::ITexture *shadowMapTextureColors{nullptr};
+	video::SColor m_clear_color{0x0};
+
+	std::vector<DirectionalLight> m_light_list;
+	std::vector<NodeToApply> m_shadow_node_array;
+
+	float m_shadow_strength;
+	float m_shadow_map_max_distance;
+	float m_shadow_map_texture_size;
+	float m_time_day{0.0f};
+	float m_update_delta;
+	int m_shadow_samples;
+	bool m_shadow_map_texture_32bit;
+	bool m_shadows_enabled;
+	bool m_shadow_map_colored;
+
+	video::ECOLOR_FORMAT m_texture_format{video::ECOLOR_FORMAT::ECF_R16F};
+	video::ECOLOR_FORMAT m_texture_format_color{video::ECOLOR_FORMAT::ECF_R16G16};
+
+	// Shadow Shader stuff
+
+	void createShaders();
+	std::string readShaderFile(const std::string &path);
+
+	s32 depth_shader{-1};
+	s32 depth_shader_trans{-1};
+	s32 mixcsm_shader{-1};
+
+	ShadowDepthShaderCB *m_shadow_depth_cb{nullptr};
+	ShadowDepthShaderCB *m_shadow_depth_trans_cb{nullptr};
+
+	shadowScreenQuad *m_screen_quad{nullptr};
+	shadowScreenQuadCB *m_shadow_mix_cb{nullptr};
+};