Shadow mapping render pass (#11244)

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

src/client/shadows/dynamicshadows.cpp

@@ -0,0 +1,145 @@
+/*
+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.
+*/
+
+#include <cmath>
+
+#include "client/shadows/dynamicshadows.h"
+#include "client/client.h"
+#include "client/clientenvironment.h"
+#include "client/clientmap.h"
+#include "client/camera.h"
+
+using m4f = core::matrix4;
+
+void DirectionalLight::createSplitMatrices(const Camera *cam)
+{
+	float radius;
+	v3f newCenter;
+	v3f look = cam->getDirection();
+
+	v3f camPos2 = cam->getPosition();
+	v3f camPos = v3f(camPos2.X - cam->getOffset().X * BS,
+			camPos2.Y - cam->getOffset().Y * BS,
+			camPos2.Z - cam->getOffset().Z * BS);
+	camPos += look * shadow_frustum.zNear;
+	camPos2 += look * shadow_frustum.zNear;
+	float end = shadow_frustum.zNear + shadow_frustum.zFar;
+	newCenter = camPos + look * (shadow_frustum.zNear + 0.05f * end);
+	v3f world_center = camPos2 + look * (shadow_frustum.zNear + 0.05f * end);
+	// Create a vector to the frustum far corner
+	// @Liso: move all vars we can outside the loop.
+	float tanFovY = tanf(cam->getFovY() * 0.5f);
+	float tanFovX = tanf(cam->getFovX() * 0.5f);
+
+	const v3f &viewUp = cam->getCameraNode()->getUpVector();
+	// viewUp.normalize();
+
+	v3f viewRight = look.crossProduct(viewUp);
+	// viewRight.normalize();
+
+	v3f farCorner = look + viewRight * tanFovX + viewUp * tanFovY;
+	// Compute the frustumBoundingSphere radius
+	v3f boundVec = (camPos + farCorner * shadow_frustum.zFar) - newCenter;
+	radius = boundVec.getLength() * 2.0f;
+	// boundVec.getLength();
+	float vvolume = radius * 2.0f;
+
+	float texelsPerUnit = getMapResolution() / vvolume;
+	m4f mTexelScaling;
+	mTexelScaling.setScale(texelsPerUnit);
+
+	m4f mLookAt, mLookAtInv;
+
+	mLookAt.buildCameraLookAtMatrixLH(v3f(0.0f, 0.0f, 0.0f), -direction, v3f(0.0f, 1.0f, 0.0f));
+
+	mLookAt *= mTexelScaling;
+	mLookAtInv = mLookAt;
+	mLookAtInv.makeInverse();
+
+	v3f frustumCenter = newCenter;
+	mLookAt.transformVect(frustumCenter);
+	frustumCenter.X = floorf(frustumCenter.X); // clamp to texel increment
+	frustumCenter.Y = floorf(frustumCenter.Y); // clamp to texel increment
+	frustumCenter.Z = floorf(frustumCenter.Z);
+	mLookAtInv.transformVect(frustumCenter);
+	// probar radius multipliacdor en funcion del I, a menor I mas multiplicador
+	v3f eye_displacement = direction * vvolume;
+
+	// we must compute the viewmat with the position - the camera offset
+	// but the shadow_frustum position must be the actual world position
+	v3f eye = frustumCenter - eye_displacement;
+	shadow_frustum.position = world_center - eye_displacement;
+	shadow_frustum.length = vvolume;
+	shadow_frustum.ViewMat.buildCameraLookAtMatrixLH(eye, frustumCenter, v3f(0.0f, 1.0f, 0.0f));
+	shadow_frustum.ProjOrthMat.buildProjectionMatrixOrthoLH(shadow_frustum.length,
+			shadow_frustum.length, -shadow_frustum.length,
+			shadow_frustum.length,false);
+}
+
+DirectionalLight::DirectionalLight(const u32 shadowMapResolution,
+		const v3f &position, video::SColorf lightColor,
+		f32 farValue) :
+		diffuseColor(lightColor),
+		farPlane(farValue), mapRes(shadowMapResolution), pos(position)
+{}
+
+void DirectionalLight::update_frustum(const Camera *cam, Client *client)
+{
+	should_update_map_shadow = true;
+	float zNear = cam->getCameraNode()->getNearValue();
+	float zFar = getMaxFarValue();
+
+	///////////////////////////////////
+	// update splits near and fars
+	shadow_frustum.zNear = zNear;
+	shadow_frustum.zFar = zFar;
+
+	// update shadow frustum
+	createSplitMatrices(cam);
+	// get the draw list for shadows
+	client->getEnv().getClientMap().updateDrawListShadow(
+			getPosition(), getDirection(), shadow_frustum.length);
+	should_update_map_shadow = true;
+}
+
+void DirectionalLight::setDirection(v3f dir)
+{
+	direction = -dir;
+	direction.normalize();
+}
+
+v3f DirectionalLight::getPosition() const
+{
+	return shadow_frustum.position;
+}
+
+const m4f &DirectionalLight::getViewMatrix() const
+{
+	return shadow_frustum.ViewMat;
+}
+
+const m4f &DirectionalLight::getProjectionMatrix() const
+{
+	return shadow_frustum.ProjOrthMat;
+}
+
+m4f DirectionalLight::getViewProjMatrix()
+{
+	return shadow_frustum.ProjOrthMat * shadow_frustum.ViewMat;
+}

src/client/shadows/dynamicshadows.h

@@ -0,0 +1,102 @@
+/*
+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 "irrlichttypes_bloated.h"
+#include <matrix4.h>
+#include "util/basic_macros.h"
+
+class Camera;
+class Client;
+
+struct shadowFrustum
+{
+	float zNear{0.0f};
+	float zFar{0.0f};
+	float length{0.0f};
+	core::matrix4 ProjOrthMat;
+	core::matrix4 ViewMat;
+	v3f position;
+};
+
+class DirectionalLight
+{
+public:
+	DirectionalLight(const u32 shadowMapResolution,
+			const v3f &position,
+			video::SColorf lightColor = video::SColor(0xffffffff),
+			f32 farValue = 100.0f);
+	~DirectionalLight() = default;
+
+	//DISABLE_CLASS_COPY(DirectionalLight)
+
+	void update_frustum(const Camera *cam, Client *client);
+
+	// when set direction is updated to negative normalized(direction)
+	void setDirection(v3f dir);
+	v3f getDirection() const{
+		return direction;
+	};
+	v3f getPosition() const;
+
+	/// Gets the light's matrices.
+	const core::matrix4 &getViewMatrix() const;
+	const core::matrix4 &getProjectionMatrix() const;
+	core::matrix4 getViewProjMatrix();
+
+	/// Gets the light's far value.
+	f32 getMaxFarValue() const
+	{
+		return farPlane;
+	}
+
+
+	/// Gets the light's color.
+	const video::SColorf &getLightColor() const
+	{
+		return diffuseColor;
+	}
+
+	/// Sets the light's color.
+	void setLightColor(const video::SColorf &lightColor)
+	{
+		diffuseColor = lightColor;
+	}
+
+	/// Gets the shadow map resolution for this light.
+	u32 getMapResolution() const
+	{
+		return mapRes;
+	}
+
+	bool should_update_map_shadow{true};
+
+private:
+	void createSplitMatrices(const Camera *cam);
+
+	video::SColorf diffuseColor;
+
+	f32 farPlane;
+	u32 mapRes;
+
+	v3f pos;
+	v3f direction{0};
+	shadowFrustum shadow_frustum;
+};

src/client/shadows/dynamicshadowsrender.cpp

@@ -0,0 +1,539 @@
+/*
+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.
+*/
+
+#include <cstring>
+#include "client/shadows/dynamicshadowsrender.h"
+#include "client/shadows/shadowsScreenQuad.h"
+#include "client/shadows/shadowsshadercallbacks.h"
+#include "settings.h"
+#include "filesys.h"
+#include "util/string.h"
+#include "client/shader.h"
+#include "client/client.h"
+#include "client/clientmap.h"
+
+ShadowRenderer::ShadowRenderer(IrrlichtDevice *device, Client *client) :
+		m_device(device), m_smgr(device->getSceneManager()),
+		m_driver(device->getVideoDriver()), m_client(client)
+{
+	m_shadows_enabled = true;
+
+	m_shadow_strength = g_settings->getFloat("shadow_strength");
+
+	m_shadow_map_max_distance = g_settings->getFloat("shadow_map_max_distance");
+
+	m_shadow_map_texture_size = g_settings->getFloat("shadow_map_texture_size");
+
+	m_shadow_map_texture_32bit = g_settings->getBool("shadow_map_texture_32bit");
+	m_shadow_map_colored = g_settings->getBool("shadow_map_color");
+	m_shadow_samples = g_settings->getS32("shadow_filters");
+	m_update_delta = g_settings->getFloat("shadow_update_time");
+}
+
+ShadowRenderer::~ShadowRenderer()
+{
+	if (m_shadow_depth_cb)
+		delete m_shadow_depth_cb;
+	if (m_shadow_mix_cb)
+		delete m_shadow_mix_cb;
+	m_shadow_node_array.clear();
+	m_light_list.clear();
+
+	if (shadowMapTextureDynamicObjects)
+		m_driver->removeTexture(shadowMapTextureDynamicObjects);
+
+	if (shadowMapTextureFinal)
+		m_driver->removeTexture(shadowMapTextureFinal);
+
+	if (shadowMapTextureColors)
+		m_driver->removeTexture(shadowMapTextureColors);
+
+	if (shadowMapClientMap)
+		m_driver->removeTexture(shadowMapClientMap);
+}
+
+void ShadowRenderer::initialize()
+{
+	auto *gpu = m_driver->getGPUProgrammingServices();
+
+	// we need glsl
+	if (m_shadows_enabled && gpu && m_driver->queryFeature(video::EVDF_ARB_GLSL)) {
+		createShaders();
+	} else {
+		m_shadows_enabled = false;
+
+		warningstream << "Shadows: GLSL Shader not supported on this system."
+			<< std::endl;
+		return;
+	}
+
+	m_texture_format = m_shadow_map_texture_32bit
+					   ? video::ECOLOR_FORMAT::ECF_R32F
+					   : video::ECOLOR_FORMAT::ECF_R16F;
+
+	m_texture_format_color = m_shadow_map_texture_32bit
+						 ? video::ECOLOR_FORMAT::ECF_G32R32F
+						 : video::ECOLOR_FORMAT::ECF_G16R16F;
+}
+
+
+float ShadowRenderer::getUpdateDelta() const
+{
+	return m_update_delta;
+}
+
+size_t ShadowRenderer::addDirectionalLight()
+{
+	m_light_list.emplace_back(m_shadow_map_texture_size,
+			v3f(0.f, 0.f, 0.f),
+			video::SColor(255, 255, 255, 255), m_shadow_map_max_distance);
+	return m_light_list.size() - 1;
+}
+
+DirectionalLight &ShadowRenderer::getDirectionalLight(u32 index)
+{
+	return m_light_list[index];
+}
+
+size_t ShadowRenderer::getDirectionalLightCount() const
+{
+	return m_light_list.size();
+}
+
+f32 ShadowRenderer::getMaxShadowFar() const
+{
+	if (!m_light_list.empty()) {
+		float wanted_range = m_client->getEnv().getClientMap().getWantedRange();
+
+		float zMax = m_light_list[0].getMaxFarValue() > wanted_range
+					     ? wanted_range
+					     : m_light_list[0].getMaxFarValue();
+		return zMax * MAP_BLOCKSIZE;
+	}
+	return 0.0f;
+}
+
+void ShadowRenderer::addNodeToShadowList(
+		scene::ISceneNode *node, E_SHADOW_MODE shadowMode)
+{
+	m_shadow_node_array.emplace_back(NodeToApply(node, shadowMode));
+}
+
+void ShadowRenderer::removeNodeFromShadowList(scene::ISceneNode *node)
+{
+	for (auto it = m_shadow_node_array.begin(); it != m_shadow_node_array.end();) {
+		if (it->node == node) {
+			it = m_shadow_node_array.erase(it);
+			break;
+		} else {
+			++it;
+		}
+	}
+}
+
+void ShadowRenderer::setClearColor(video::SColor ClearColor)
+{
+	m_clear_color = ClearColor;
+}
+
+void ShadowRenderer::update(video::ITexture *outputTarget)
+{
+	if (!m_shadows_enabled || m_smgr->getActiveCamera() == nullptr) {
+		m_smgr->drawAll();
+		return;
+	}
+
+	if (!shadowMapTextureDynamicObjects) {
+
+		shadowMapTextureDynamicObjects = getSMTexture(
+			std::string("shadow_dynamic_") + itos(m_shadow_map_texture_size),
+			m_texture_format, true);
+	}
+
+	if (!shadowMapClientMap) {
+
+		shadowMapClientMap = getSMTexture(
+			std::string("shadow_clientmap_") + itos(m_shadow_map_texture_size),
+			m_shadow_map_colored ? m_texture_format_color : m_texture_format,
+			true);
+	}
+
+	if (m_shadow_map_colored && !shadowMapTextureColors) {
+		shadowMapTextureColors = getSMTexture(
+			std::string("shadow_colored_") + itos(m_shadow_map_texture_size),
+			m_shadow_map_colored ? m_texture_format_color : m_texture_format,
+			true);
+	}
+
+	// The merge all shadowmaps texture
+	if (!shadowMapTextureFinal) {
+		video::ECOLOR_FORMAT frt;
+		if (m_shadow_map_texture_32bit) {
+			if (m_shadow_map_colored)
+				frt = video::ECOLOR_FORMAT::ECF_A32B32G32R32F;
+			else
+				frt = video::ECOLOR_FORMAT::ECF_R32F;
+		} else {
+			if (m_shadow_map_colored)
+				frt = video::ECOLOR_FORMAT::ECF_A16B16G16R16F;
+			else
+				frt = video::ECOLOR_FORMAT::ECF_R16F;
+		}
+		shadowMapTextureFinal = getSMTexture(
+			std::string("shadowmap_final_") + itos(m_shadow_map_texture_size),
+			frt, true);
+	}
+
+	if (!m_shadow_node_array.empty() && !m_light_list.empty()) {
+		// for every directional light:
+		for (DirectionalLight &light : m_light_list) {
+			// Static shader values.
+			m_shadow_depth_cb->MapRes = (f32)m_shadow_map_texture_size;
+			m_shadow_depth_cb->MaxFar = (f32)m_shadow_map_max_distance * BS;
+
+			// set the Render Target
+			// right now we can only render in usual RTT, not
+			// Depth texture is available in irrlicth maybe we
+			// should put some gl* fn here
+
+			if (light.should_update_map_shadow) {
+				light.should_update_map_shadow = false;
+
+				m_driver->setRenderTarget(shadowMapClientMap, true, true,
+						video::SColor(255, 255, 255, 255));
+				renderShadowMap(shadowMapClientMap, light);
+
+				if (m_shadow_map_colored) {
+					m_driver->setRenderTarget(shadowMapTextureColors,
+							true, false, video::SColor(255, 255, 255, 255));
+				}
+				renderShadowMap(shadowMapTextureColors, light,
+						scene::ESNRP_TRANSPARENT);
+				m_driver->setRenderTarget(0, false, false);
+			}
+
+			// render shadows for the n0n-map objects.
+			m_driver->setRenderTarget(shadowMapTextureDynamicObjects, true,
+					true, video::SColor(255, 255, 255, 255));
+			renderShadowObjects(shadowMapTextureDynamicObjects, light);
+			// clear the Render Target
+			m_driver->setRenderTarget(0, false, false);
+
+			// in order to avoid too many map shadow renders,
+			// we should make a second pass to mix clientmap shadows and
+			// entities shadows :(
+			m_screen_quad->getMaterial().setTexture(0, shadowMapClientMap);
+			// dynamic objs shadow texture.
+			if (m_shadow_map_colored)
+				m_screen_quad->getMaterial().setTexture(1, shadowMapTextureColors);
+			m_screen_quad->getMaterial().setTexture(2, shadowMapTextureDynamicObjects);
+
+			m_driver->setRenderTarget(shadowMapTextureFinal, false, false,
+					video::SColor(255, 255, 255, 255));
+			m_screen_quad->render(m_driver);
+			m_driver->setRenderTarget(0, false, false);
+
+		} // end for lights
+
+		// now render the actual MT render pass
+		m_driver->setRenderTarget(outputTarget, true, true, m_clear_color);
+		m_smgr->drawAll();
+
+		/* this code just shows shadows textures in screen and in ONLY for debugging*/
+		#if 0
+		// this is debug, ignore for now.
+		m_driver->draw2DImage(shadowMapTextureFinal,
+				core::rect<s32>(0, 50, 128, 128 + 50),
+				core::rect<s32>({0, 0}, shadowMapTextureFinal->getSize()));
+
+		m_driver->draw2DImage(shadowMapClientMap,
+				core::rect<s32>(0, 50 + 128, 128, 128 + 50 + 128),
+				core::rect<s32>({0, 0}, shadowMapTextureFinal->getSize()));
+		m_driver->draw2DImage(shadowMapTextureDynamicObjects,
+				core::rect<s32>(0, 128 + 50 + 128, 128,
+						128 + 50 + 128 + 128),
+				core::rect<s32>({0, 0}, shadowMapTextureDynamicObjects->getSize()));
+
+		if (m_shadow_map_colored) {
+
+			m_driver->draw2DImage(shadowMapTextureColors,
+					core::rect<s32>(128,128 + 50 + 128 + 128,
+							128 + 128, 128 + 50 + 128 + 128 + 128),
+					core::rect<s32>({0, 0}, shadowMapTextureColors->getSize()));
+		}
+		#endif
+		m_driver->setRenderTarget(0, false, false);
+	}
+}
+
+
+video::ITexture *ShadowRenderer::getSMTexture(const std::string &shadow_map_name,
+		video::ECOLOR_FORMAT texture_format, bool force_creation)
+{
+	if (force_creation) {
+		return m_driver->addRenderTargetTexture(
+				core::dimension2du(m_shadow_map_texture_size,
+						m_shadow_map_texture_size),
+				shadow_map_name.c_str(), texture_format);
+	}
+
+	return m_driver->getTexture(shadow_map_name.c_str());
+}
+
+void ShadowRenderer::renderShadowMap(video::ITexture *target,
+		DirectionalLight &light, scene::E_SCENE_NODE_RENDER_PASS pass)
+{
+	m_driver->setTransform(video::ETS_VIEW, light.getViewMatrix());
+	m_driver->setTransform(video::ETS_PROJECTION, light.getProjectionMatrix());
+
+	// Operate on the client map
+	for (const auto &shadow_node : m_shadow_node_array) {
+		if (strcmp(shadow_node.node->getName(), "ClientMap") != 0)
+			continue;
+
+		ClientMap *map_node = static_cast<ClientMap *>(shadow_node.node);
+
+		video::SMaterial material;
+		if (map_node->getMaterialCount() > 0) {
+			// we only want the first material, which is the one with the albedo info
+			material = map_node->getMaterial(0);
+		}
+
+		material.BackfaceCulling = false;
+		material.FrontfaceCulling = true;
+		material.PolygonOffsetFactor = 4.0f;
+		material.PolygonOffsetDirection = video::EPO_BACK;
+		//material.PolygonOffsetDepthBias = 1.0f/4.0f;
+		//material.PolygonOffsetSlopeScale = -1.f;
+
+		if (m_shadow_map_colored && pass != scene::ESNRP_SOLID)
+			material.MaterialType = (video::E_MATERIAL_TYPE) depth_shader_trans;
+		else
+			material.MaterialType = (video::E_MATERIAL_TYPE) depth_shader;
+
+		// FIXME: I don't think this is needed here
+		map_node->OnAnimate(m_device->getTimer()->getTime());
+
+		m_driver->setTransform(video::ETS_WORLD,
+				map_node->getAbsoluteTransformation());
+
+		map_node->renderMapShadows(m_driver, material, pass);
+		break;
+	}
+}
+
+void ShadowRenderer::renderShadowObjects(
+		video::ITexture *target, DirectionalLight &light)
+{
+	m_driver->setTransform(video::ETS_VIEW, light.getViewMatrix());
+	m_driver->setTransform(video::ETS_PROJECTION, light.getProjectionMatrix());
+
+	for (const auto &shadow_node : m_shadow_node_array) {
+		// we only take care of the shadow casters
+		if (shadow_node.shadowMode == ESM_RECEIVE ||
+				strcmp(shadow_node.node->getName(), "ClientMap") == 0)
+			continue;
+
+		// render other objects
+		u32 n_node_materials = shadow_node.node->getMaterialCount();
+		std::vector<s32> BufferMaterialList;
+		std::vector<std::pair<bool, bool>> BufferMaterialCullingList;
+		BufferMaterialList.reserve(n_node_materials);
+		BufferMaterialCullingList.reserve(n_node_materials);
+
+		// backup materialtype for each material
+		// (aka shader)
+		// and replace it by our "depth" shader
+		for (u32 m = 0; m < n_node_materials; m++) {
+			auto &current_mat = shadow_node.node->getMaterial(m);
+
+			BufferMaterialList.push_back(current_mat.MaterialType);
+			current_mat.MaterialType =
+					(video::E_MATERIAL_TYPE)depth_shader;
+
+			current_mat.setTexture(3, shadowMapTextureFinal);
+
+			BufferMaterialCullingList.emplace_back(
+				(bool)current_mat.BackfaceCulling, (bool)current_mat.FrontfaceCulling);
+
+			current_mat.BackfaceCulling = true;
+			current_mat.FrontfaceCulling = false;
+			current_mat.PolygonOffsetFactor = 1.0f/2048.0f;
+			current_mat.PolygonOffsetDirection = video::EPO_BACK;
+			//current_mat.PolygonOffsetDepthBias = 1.0 * 2.8e-6;
+			//current_mat.PolygonOffsetSlopeScale = -1.f;
+		}
+
+		m_driver->setTransform(video::ETS_WORLD,
+				shadow_node.node->getAbsoluteTransformation());
+		shadow_node.node->render();
+
+		// restore the material.
+
+		for (u32 m = 0; m < n_node_materials; m++) {
+			auto &current_mat = shadow_node.node->getMaterial(m);
+
+			current_mat.MaterialType = (video::E_MATERIAL_TYPE) BufferMaterialList[m];
+
+			current_mat.BackfaceCulling = BufferMaterialCullingList[m].first;
+			current_mat.FrontfaceCulling = BufferMaterialCullingList[m].second;
+		}
+
+	} // end for caster shadow nodes
+}
+
+void ShadowRenderer::mixShadowsQuad()
+{
+}
+
+/*
+ * @Liso's disclaimer ;) This function loads the Shadow Mapping Shaders.
+ * I used a custom loader because I couldn't figure out how to use the base
+ * Shaders system with custom IShaderConstantSetCallBack without messing up the
+ * code too much. If anyone knows how to integrate this with the standard MT
+ * shaders, please feel free to change it.
+ */
+
+void ShadowRenderer::createShaders()
+{
+	video::IGPUProgrammingServices *gpu = m_driver->getGPUProgrammingServices();
+
+	if (depth_shader == -1) {
+		std::string depth_shader_vs = getShaderPath("shadow_shaders", "pass1_vertex.glsl");
+		if (depth_shader_vs.empty()) {
+			m_shadows_enabled = false;
+			errorstream << "Error shadow mapping vs shader not found." << std::endl;
+			return;
+		}
+		std::string depth_shader_fs = getShaderPath("shadow_shaders", "pass1_fragment.glsl");
+		if (depth_shader_fs.empty()) {
+			m_shadows_enabled = false;
+			errorstream << "Error shadow mapping fs shader not found." << std::endl;
+			return;
+		}
+		m_shadow_depth_cb = new ShadowDepthShaderCB();
+
+		depth_shader = gpu->addHighLevelShaderMaterial(
+				readShaderFile(depth_shader_vs).c_str(), "vertexMain",
+				video::EVST_VS_1_1,
+				readShaderFile(depth_shader_fs).c_str(), "pixelMain",
+				video::EPST_PS_1_2, m_shadow_depth_cb);
+
+		if (depth_shader == -1) {
+			// upsi, something went wrong loading shader.
+			delete m_shadow_depth_cb;
+			m_shadows_enabled = false;
+			errorstream << "Error compiling shadow mapping shader." << std::endl;
+			return;
+		}
+
+		// HACK, TODO: investigate this better
+		// Grab the material renderer once more so minetest doesn't crash
+		// on exit
+		m_driver->getMaterialRenderer(depth_shader)->grab();
+	}
+
+	if (mixcsm_shader == -1) {
+		std::string depth_shader_vs = getShaderPath("shadow_shaders", "pass2_vertex.glsl");
+		if (depth_shader_vs.empty()) {
+			m_shadows_enabled = false;
+			errorstream << "Error cascade shadow mapping fs shader not found." << std::endl;
+			return;
+		}
+
+		std::string depth_shader_fs = getShaderPath("shadow_shaders", "pass2_fragment.glsl");
+		if (depth_shader_fs.empty()) {
+			m_shadows_enabled = false;
+			errorstream << "Error cascade shadow mapping fs shader not found." << std::endl;
+			return;
+		}
+		m_shadow_mix_cb = new shadowScreenQuadCB();
+		m_screen_quad = new shadowScreenQuad();
+		mixcsm_shader = gpu->addHighLevelShaderMaterial(
+				readShaderFile(depth_shader_vs).c_str(), "vertexMain",
+				video::EVST_VS_1_1,
+				readShaderFile(depth_shader_fs).c_str(), "pixelMain",
+				video::EPST_PS_1_2, m_shadow_mix_cb);
+
+		m_screen_quad->getMaterial().MaterialType =
+				(video::E_MATERIAL_TYPE)mixcsm_shader;
+
+		if (mixcsm_shader == -1) {
+			// upsi, something went wrong loading shader.
+			delete m_shadow_mix_cb;
+			delete m_screen_quad;
+			m_shadows_enabled = false;
+			errorstream << "Error compiling cascade shadow mapping shader." << std::endl;
+			return;
+		}
+
+		// HACK, TODO: investigate this better
+		// Grab the material renderer once more so minetest doesn't crash
+		// on exit
+		m_driver->getMaterialRenderer(mixcsm_shader)->grab();
+	}
+
+	if (m_shadow_map_colored && depth_shader_trans == -1) {
+		std::string depth_shader_vs = getShaderPath("shadow_shaders", "pass1_trans_vertex.glsl");
+		if (depth_shader_vs.empty()) {
+			m_shadows_enabled = false;
+			errorstream << "Error shadow mapping vs shader not found." << std::endl;
+			return;
+		}
+		std::string depth_shader_fs = getShaderPath("shadow_shaders", "pass1_trans_fragment.glsl");
+		if (depth_shader_fs.empty()) {
+			m_shadows_enabled = false;
+			errorstream << "Error shadow mapping fs shader not found." << std::endl;
+			return;
+		}
+		m_shadow_depth_trans_cb = new ShadowDepthShaderCB();
+
+		depth_shader_trans = gpu->addHighLevelShaderMaterial(
+				readShaderFile(depth_shader_vs).c_str(), "vertexMain",
+				video::EVST_VS_1_1,
+				readShaderFile(depth_shader_fs).c_str(), "pixelMain",
+				video::EPST_PS_1_2, m_shadow_depth_trans_cb);
+
+		if (depth_shader_trans == -1) {
+			// upsi, something went wrong loading shader.
+			delete m_shadow_depth_trans_cb;
+			m_shadow_map_colored = false;
+			m_shadows_enabled = false;
+			errorstream << "Error compiling colored shadow mapping shader." << std::endl;
+			return;
+		}
+
+		// HACK, TODO: investigate this better
+		// Grab the material renderer once more so minetest doesn't crash
+		// on exit
+		m_driver->getMaterialRenderer(depth_shader_trans)->grab();
+	}
+}
+
+std::string ShadowRenderer::readShaderFile(const std::string &path)
+{
+	std::string prefix;
+	if (m_shadow_map_colored)
+		prefix.append("#define COLORED_SHADOWS 1\n");
+
+	std::string content;
+	fs::ReadFile(path, content);
+
+	return prefix + content;
+}

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};
+};

src/client/shadows/shadowsScreenQuad.cpp

@@ -0,0 +1,67 @@
+/*
+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.
+*/
+
+#include "shadowsScreenQuad.h"
+
+shadowScreenQuad::shadowScreenQuad()
+{
+	Material.Wireframe = false;
+	Material.Lighting = false;
+
+	video::SColor color(0x0);
+	Vertices[0] = video::S3DVertex(
+			-1.0f, -1.0f, 0.0f, 0, 0, 1, color, 0.0f, 1.0f);
+	Vertices[1] = video::S3DVertex(
+			-1.0f, 1.0f, 0.0f, 0, 0, 1, color, 0.0f, 0.0f);
+	Vertices[2] = video::S3DVertex(
+			1.0f, 1.0f, 0.0f, 0, 0, 1, color, 1.0f, 0.0f);
+	Vertices[3] = video::S3DVertex(
+			1.0f, -1.0f, 0.0f, 0, 0, 1, color, 1.0f, 1.0f);
+	Vertices[4] = video::S3DVertex(
+			-1.0f, -1.0f, 0.0f, 0, 0, 1, color, 0.0f, 1.0f);
+	Vertices[5] = video::S3DVertex(
+			1.0f, 1.0f, 0.0f, 0, 0, 1, color, 1.0f, 0.0f);
+}
+
+void shadowScreenQuad::render(video::IVideoDriver *driver)
+{
+	u16 indices[6] = {0, 1, 2, 3, 4, 5};
+	driver->setMaterial(Material);
+	driver->setTransform(video::ETS_WORLD, core::matrix4());
+	driver->drawIndexedTriangleList(&Vertices[0], 6, &indices[0], 2);
+}
+
+void shadowScreenQuadCB::OnSetConstants(
+		video::IMaterialRendererServices *services, s32 userData)
+{
+	s32 TextureId = 0;
+	services->setPixelShaderConstant(
+		services->getPixelShaderConstantID("ShadowMapClientMap"),
+		&TextureId, 1);
+
+	TextureId = 1;
+	services->setPixelShaderConstant(
+		services->getPixelShaderConstantID("ShadowMapClientMapTraslucent"),
+		&TextureId, 1);
+
+	TextureId = 2;
+	services->setPixelShaderConstant(
+		services->getPixelShaderConstantID("ShadowMapSamplerdynamic"),
+		&TextureId, 1);
+}

src/client/shadows/shadowsScreenQuad.h

@@ -0,0 +1,45 @@
+/*
+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 "irrlichttypes_extrabloated.h"
+#include <IMaterialRendererServices.h>
+#include <IShaderConstantSetCallBack.h>
+
+class shadowScreenQuad
+{
+public:
+	shadowScreenQuad();
+
+	void render(video::IVideoDriver *driver);
+	video::SMaterial &getMaterial() { return Material; }
+
+private:
+	video::S3DVertex Vertices[6];
+	video::SMaterial Material;
+};
+
+class shadowScreenQuadCB : public video::IShaderConstantSetCallBack
+{
+public:
+	shadowScreenQuadCB(){};
+
+	virtual void OnSetConstants(video::IMaterialRendererServices *services,
+			s32 userData);
+};

src/client/shadows/shadowsshadercallbacks.cpp

@@ -0,0 +1,44 @@
+/*
+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.
+*/
+
+#include "client/shadows/shadowsshadercallbacks.h"
+
+void ShadowDepthShaderCB::OnSetConstants(
+		video::IMaterialRendererServices *services, s32 userData)
+{
+	video::IVideoDriver *driver = services->getVideoDriver();
+
+	core::matrix4 lightMVP = driver->getTransform(video::ETS_PROJECTION);
+	lightMVP *= driver->getTransform(video::ETS_VIEW);
+	lightMVP *= driver->getTransform(video::ETS_WORLD);
+
+	services->setVertexShaderConstant(
+		services->getPixelShaderConstantID("LightMVP"),
+		lightMVP.pointer(), 16);
+
+	services->setVertexShaderConstant(
+		services->getPixelShaderConstantID("MapResolution"), &MapRes, 1);
+	services->setVertexShaderConstant(
+		services->getPixelShaderConstantID("MaxFar"), &MaxFar, 1);
+
+	s32 TextureId = 0;
+	services->setPixelShaderConstant(
+		services->getPixelShaderConstantID("ColorMapSampler"), &TextureId,
+		1);
+}

src/client/shadows/shadowsshadercallbacks.h

@@ -0,0 +1,34 @@
+/*
+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 "irrlichttypes_extrabloated.h"
+#include <IMaterialRendererServices.h>
+#include <IShaderConstantSetCallBack.h>
+
+class ShadowDepthShaderCB : public video::IShaderConstantSetCallBack
+{
+public:
+	void OnSetMaterial(const video::SMaterial &material) override {}
+
+	void OnSetConstants(video::IMaterialRendererServices *services,
+			s32 userData) override;
+
+	f32 MaxFar{2048.0f}, MapRes{1024.0f};
+};