From 883dcbf16846d8820624f070c4062a061a20635c Mon Sep 17 00:00:00 2001
From: "@clasher113" <kizinvanya@gmail.com>
Date: Thu, 16 Nov 2023 16:42:57 +0200
Subject: [PATCH] Advancec Frustum Culling & fixes

---
 .gitignore                      |  14 ++--
 src/coders/png.cpp              |   2 +-
 src/frontend/hud.cpp            |   6 +-
 src/frontend/world_render.cpp   |  63 +++++++-----------
 src/frontend/world_render.h     |   3 +-
 src/maths/FrustumCulling.h      | 113 ++++++++++++++++++++++++++++++++
 src/objects/player_control.cpp  |   2 +-
 src/voxels/Chunk.cpp            |  18 +++++
 src/voxels/Chunk.h              |   3 +
 src/voxels/Chunks.cpp           |   4 ++
 src/voxels/Chunks.h             |   1 +
 src/voxels/ChunksController.cpp |   2 +
 12 files changed, 178 insertions(+), 53 deletions(-)
 create mode 100644 src/maths/FrustumCulling.h

diff --git a/.gitignore b/.gitignore
index a5c983ee..02ca8f1c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,18 +7,18 @@ Debug/voxel_engine
 
 /world
 /worlds/**/*
+/settings.toml
 
 .vscode
+/.vs
+*.sln
+*.vcxproj
+*.filters
+*.user
 
 .cache
 .settings
 .cproject
 .project
 .git
-/Default/
-/.vs
-/settings.toml
-/VoxelEngine-Cpp.sln
-/VoxelEngine-Cpp.vcxproj
-/VoxelEngine-Cpp.vcxproj.filters
-/VoxelEngine-Cpp.vcxproj.user
+/Default/
\ No newline at end of file
diff --git a/src/coders/png.cpp b/src/coders/png.cpp
index b3d0de00..e4d7090b 100644
--- a/src/coders/png.cpp
+++ b/src/coders/png.cpp
@@ -275,7 +275,7 @@ ImageData* _png_load(const char* file){
 		return 0;
 	}
 
-	char *clr_type_str;
+	const char *clr_type_str;
 	if(ihdr.color_type == SPNG_COLOR_TYPE_GRAYSCALE)
 		clr_type_str = "grayscale";
 	else if(ihdr.color_type == SPNG_COLOR_TYPE_TRUECOLOR)
diff --git a/src/frontend/hud.cpp b/src/frontend/hud.cpp
index 9d013398..5af2fadd 100644
--- a/src/frontend/hud.cpp
+++ b/src/frontend/hud.cpp
@@ -50,15 +50,15 @@ HudRenderer::HudRenderer(Engine* engine, Level* level) : level(level), assets(en
 	uicamera->perspective = false;
 	uicamera->flipped = true;
 
-	Panel* panel = new Panel(vec2(200, 200), vec4(5.0f), 1.0f);
+	Panel* panel = new Panel(vec2(250, 200), vec4(5.0f), 1.0f);
 	panel->listenInterval(1.0f, [this]() {
 		fpsString = std::to_wstring(fpsMax)+L" / "+std::to_wstring(fpsMin);
 		fpsMin = fps;
 		fpsMax = fps;
 	});
 	panel->setCoord(vec2(10, 10));
-	panel->add(shared_ptr<Label>(create_label([this](){
-		return L"chunks: "+std::to_wstring(this->level->chunks->chunksCount);
+	panel->add(shared_ptr<Label>(create_label([this, level]() {
+		return L"chunks: "+std::to_wstring(this->level->chunks->chunksCount)+L" visible: "+std::to_wstring(level->chunks->visible);
 	})));
 	panel->add(shared_ptr<Label>(create_label([this](){
 		return L"fps: "+this->fpsString;
diff --git a/src/frontend/world_render.cpp b/src/frontend/world_render.cpp
index 5810c705..3ab667f4 100644
--- a/src/frontend/world_render.cpp
+++ b/src/frontend/world_render.cpp
@@ -21,6 +21,7 @@
 #include "../objects/Player.h"
 #include "../assets/Assets.h"
 #include "../objects/player_control.h"
+#include "../maths/FrustumCulling.h"
 
 using std::shared_ptr;
 
@@ -28,6 +29,7 @@ WorldRenderer::WorldRenderer(Level* level, Assets* assets) : assets(assets), lev
 	lineBatch = new LineBatch(4096);
 	batch3d = new Batch3D(1024);
 	renderer = new ChunksRenderer(level);
+	frustumCulling = new Frustum();
 	level->events->listen(EVT_CHUNK_HIDDEN, [this](lvl_event_type type, Chunk* chunk) {
 		renderer->unload(chunk);
 	});
@@ -37,6 +39,7 @@ WorldRenderer::~WorldRenderer() {
 	delete batch3d;
 	delete lineBatch;
 	delete renderer;
+	delete frustumCulling;
 }
 
 bool WorldRenderer::drawChunk(size_t index, Camera* camera, Shader* shader, bool occlusion){
@@ -49,22 +52,15 @@ bool WorldRenderer::drawChunk(size_t index, Camera* camera, Shader* shader, bool
 
 	// Simple frustum culling
 	if (occlusion){
-		float y = camera->position.y+camera->front.y * CHUNK_H * 0.5f;
-		if (y < 0.0f)
-			y = 0.0f;
-		if (y > CHUNK_H)
-			y = CHUNK_H;
-		vec3 v = vec3(chunk->x*CHUNK_W, y, chunk->z*CHUNK_D)-camera->position;
-		if (v.x*v.x+v.z*v.z > (CHUNK_W*3)*(CHUNK_W*3)) {
-			if (dot(camera->front, v) < 0.0f){
-				return true;
-			}
-		}
+		glm::vec3 min = glm::vec3(chunk->x * CHUNK_W, chunk->bottom, chunk->z * CHUNK_D);
+		glm::vec3 max = glm::vec3(chunk->x * CHUNK_W + CHUNK_W, chunk->top, chunk->z * CHUNK_D + CHUNK_D);
+
+		if (!frustumCulling->IsBoxVisible(min, max)) return false;
 	}
 	mat4 model = glm::translate(mat4(1.0f), vec3(chunk->x*CHUNK_W, 0.0f, chunk->z*CHUNK_D+1));
 	shader->uniformMatrix("u_model", model);
 	mesh->draw(GL_TRIANGLES);
-	return false;
+	return true;
 }
 
 
@@ -120,10 +116,10 @@ void WorldRenderer::draw(Camera* camera, bool occlusion, float fogFactor, float
 				(b->x + 0.5f - px)*(b->x + 0.5f - px) + (b->z + 0.5f - pz)*(b->z + 0.5f - pz));
 	});
 
-
-	int occludedChunks = 0;
+	frustumCulling->update(camera->getProjection() * camera->getView());
+	chunks->visible = 0;
 	for (size_t i = 0; i < indices.size(); i++){
-		occludedChunks += drawChunk(indices[i], camera, shader, occlusion);
+		chunks->visible += drawChunk(indices[i], camera, shader, occlusion);
 	}
 
 	shader->uniformMatrix("u_model", mat4(1.0f));
@@ -146,39 +142,26 @@ void WorldRenderer::draw(Camera* camera, bool occlusion, float fogFactor, float
 	}
 
 	if (level->player->debug) {
-		linesShader->use();
-		linesShader->uniformMatrix("u_projview", camera->getProjection()*camera->getView());
+		float lenght = 40.f;
 
-		vec3 point = vec3(camera->position.x+camera->front.x,
-						  camera->position.y+camera->front.y,
-						  camera->position.z+camera->front.z);
+		linesShader->use();
+		glm::mat4 model(1.0f);
+		model = glm::translate(model, glm::vec3(Window::width >> 1, -static_cast<int>(Window::height) >> 1, 0.f));
+		linesShader->uniformMatrix("u_projview", glm::ortho(0.f, static_cast<float>(Window::width), -static_cast<float>(Window::height), 0.f, -lenght, lenght) * model * glm::inverse(camera->rotation));
 
 		glDisable(GL_DEPTH_TEST);
 
 		glLineWidth(4.0f);
-		lineBatch->line(point.x, point.y, point.z,
-						point.x+0.1f, point.y, point.z,
-						0, 0, 0, 1);
-		lineBatch->line(point.x, point.y, point.z,
-						point.x, point.y, point.z+0.1f,
-						0, 0, 0, 1);
-		lineBatch->line(point.x, point.y, point.z,
-						point.x, point.y+0.1f, point.z,
-						0, 0, 0, 1);
+		lineBatch->line(0.f, 0.f, 0.f, lenght, 0.f, 0.f, 0.f, 0.f, 0.f, 1.f);
+		lineBatch->line(0.f, 0.f, 0.f, 0.f, lenght, 0.f, 0.f, 0.f, 0.f, 1.f);
+		lineBatch->line(0.f, 0.f, 0.f, 0.f, 0.f, lenght, 0.f, 0.f, 0.f, 1.f);
 		lineBatch->render();
+		glEnable(GL_DEPTH_TEST);
 
 		glLineWidth(2.0f);
-		lineBatch->line(point.x, point.y, point.z,
-						point.x+0.1f, point.y, point.z,
-						1, 0, 0, 1);
-		lineBatch->line(point.x, point.y, point.z,
-						point.x, point.y, point.z+0.1f,
-						0, 0, 1, 1);
-		lineBatch->line(point.x, point.y, point.z,
-						point.x, point.y+0.1f, point.z,
-						0, 1, 0, 1);
+		lineBatch->line(0.f, 0.f, 0.f, lenght, 0.f, 0.f, 1.f, 0.f, 0.f, 1.f);
+		lineBatch->line(0.f, 0.f, 0.f, 0.f, lenght, 0.f, 0.f, 1.f, 0.f, 1.f);
+		lineBatch->line(0.f, 0.f, 0.f, 0.f, 0.f, lenght, 0.f, 0.f, 1.f, 1.f);
 		lineBatch->render();
-
-		glEnable(GL_DEPTH_TEST);
 	}
 }
diff --git a/src/frontend/world_render.h b/src/frontend/world_render.h
index 0e034660..7e263e68 100644
--- a/src/frontend/world_render.h
+++ b/src/frontend/world_render.h
@@ -20,12 +20,13 @@ class ChunksRenderer;
 class Shader;
 class Texture;
 class Framebuffer;
-
+class Frustum;
 
 class WorldRenderer {
 	Batch3D* batch3d;
 	Assets* assets;
 	Level* level;
+	Frustum* frustumCulling;
 	bool drawChunk(size_t index, Camera* camera, Shader* shader, bool occlusion);
 public:
 	ChunksRenderer* renderer;
diff --git a/src/maths/FrustumCulling.h b/src/maths/FrustumCulling.h
new file mode 100644
index 00000000..c48e69f2
--- /dev/null
+++ b/src/maths/FrustumCulling.h
@@ -0,0 +1,113 @@
+#include <glm/matrix.hpp>
+
+class Frustum
+{
+public:
+	Frustum() {};
+
+	void update(glm::mat4 projview);
+	bool IsBoxVisible(const glm::vec3& minp, const glm::vec3& maxp) const;
+
+private:
+	enum Planes
+	{
+		Left = 0,
+		Right,
+		Bottom,
+		Top,
+		Near,
+		Far,
+		Count,
+		Combinations = Count * (Count - 1) / 2
+	};
+
+	template<Planes i, Planes j>
+	struct ij2k
+	{
+		enum { k = i * (9 - i) / 2 + j - 1 };
+	};
+
+	template<Planes a, Planes b, Planes c>
+	glm::vec3 intersection(const glm::vec3* crosses) const;
+
+	glm::vec4   m_planes[Count];
+	glm::vec3   m_points[8];
+};
+
+inline void Frustum::update(glm::mat4 m)
+{
+	m = glm::transpose(m);
+	m_planes[Left] = m[3] + m[0];
+	m_planes[Right] = m[3] - m[0];
+	m_planes[Bottom] = m[3] + m[1];
+	m_planes[Top] = m[3] - m[1];
+	m_planes[Near] = m[3] + m[2];
+	m_planes[Far] = m[3] - m[2];
+
+	glm::vec3 crosses[Combinations] = {
+		glm::cross(glm::vec3(m_planes[Left]),   glm::vec3(m_planes[Right])),
+		glm::cross(glm::vec3(m_planes[Left]),   glm::vec3(m_planes[Bottom])),
+		glm::cross(glm::vec3(m_planes[Left]),   glm::vec3(m_planes[Top])),
+		glm::cross(glm::vec3(m_planes[Left]),   glm::vec3(m_planes[Near])),
+		glm::cross(glm::vec3(m_planes[Left]),   glm::vec3(m_planes[Far])),
+		glm::cross(glm::vec3(m_planes[Right]),  glm::vec3(m_planes[Bottom])),
+		glm::cross(glm::vec3(m_planes[Right]),  glm::vec3(m_planes[Top])),
+		glm::cross(glm::vec3(m_planes[Right]),  glm::vec3(m_planes[Near])),
+		glm::cross(glm::vec3(m_planes[Right]),  glm::vec3(m_planes[Far])),
+		glm::cross(glm::vec3(m_planes[Bottom]), glm::vec3(m_planes[Top])),
+		glm::cross(glm::vec3(m_planes[Bottom]), glm::vec3(m_planes[Near])),
+		glm::cross(glm::vec3(m_planes[Bottom]), glm::vec3(m_planes[Far])),
+		glm::cross(glm::vec3(m_planes[Top]),    glm::vec3(m_planes[Near])),
+		glm::cross(glm::vec3(m_planes[Top]),    glm::vec3(m_planes[Far])),
+		glm::cross(glm::vec3(m_planes[Near]),   glm::vec3(m_planes[Far]))
+	};
+
+	m_points[0] = intersection<Left, Bottom, Near>(crosses);
+	m_points[1] = intersection<Left, Top, Near>(crosses);
+	m_points[2] = intersection<Right, Bottom, Near>(crosses);
+	m_points[3] = intersection<Right, Top, Near>(crosses);
+	m_points[4] = intersection<Left, Bottom, Far>(crosses);
+	m_points[5] = intersection<Left, Top, Far>(crosses);
+	m_points[6] = intersection<Right, Bottom, Far>(crosses);
+	m_points[7] = intersection<Right, Top, Far>(crosses);
+
+}
+
+inline bool Frustum::IsBoxVisible(const glm::vec3& minp, const glm::vec3& maxp) const
+{
+	// check box outside/inside of frustum
+	for (int i = 0; i < Count; i++)
+	{
+		if ((glm::dot(m_planes[i], glm::vec4(minp.x, minp.y, minp.z, 1.0f)) < 0.0) &&
+			(glm::dot(m_planes[i], glm::vec4(maxp.x, minp.y, minp.z, 1.0f)) < 0.0) &&
+			(glm::dot(m_planes[i], glm::vec4(minp.x, maxp.y, minp.z, 1.0f)) < 0.0) &&
+			(glm::dot(m_planes[i], glm::vec4(maxp.x, maxp.y, minp.z, 1.0f)) < 0.0) &&
+			(glm::dot(m_planes[i], glm::vec4(minp.x, minp.y, maxp.z, 1.0f)) < 0.0) &&
+			(glm::dot(m_planes[i], glm::vec4(maxp.x, minp.y, maxp.z, 1.0f)) < 0.0) &&
+			(glm::dot(m_planes[i], glm::vec4(minp.x, maxp.y, maxp.z, 1.0f)) < 0.0) &&
+			(glm::dot(m_planes[i], glm::vec4(maxp.x, maxp.y, maxp.z, 1.0f)) < 0.0))
+		{
+			return false;
+		}
+	}
+
+	// check frustum outside/inside box
+	int out;
+	out = 0; for (int i = 0; i < 8; i++) out += ((m_points[i].x > maxp.x) ? 1 : 0); if (out == 8) return false;
+	out = 0; for (int i = 0; i < 8; i++) out += ((m_points[i].x < minp.x) ? 1 : 0); if (out == 8) return false;
+	out = 0; for (int i = 0; i < 8; i++) out += ((m_points[i].y > maxp.y) ? 1 : 0); if (out == 8) return false;
+	out = 0; for (int i = 0; i < 8; i++) out += ((m_points[i].y < minp.y) ? 1 : 0); if (out == 8) return false;
+	out = 0; for (int i = 0; i < 8; i++) out += ((m_points[i].z > maxp.z) ? 1 : 0); if (out == 8) return false;
+	out = 0; for (int i = 0; i < 8; i++) out += ((m_points[i].z < minp.z) ? 1 : 0); if (out == 8) return false;
+
+	return true;
+}
+
+template<Frustum::Planes a, Frustum::Planes b, Frustum::Planes c>
+inline glm::vec3 Frustum::intersection(const glm::vec3* crosses) const
+{
+	float D = glm::dot(glm::vec3(m_planes[a]), crosses[ij2k<b, c>::k]);
+	glm::vec3 res = glm::mat3(crosses[ij2k<b, c>::k], -crosses[ij2k<a, c>::k], crosses[ij2k<a, b>::k]) *
+		glm::vec3(m_planes[a].w, m_planes[b].w, m_planes[c].w);
+	return res * (-1.0f / D);
+}
\ No newline at end of file
diff --git a/src/objects/player_control.cpp b/src/objects/player_control.cpp
index de454374..6c3b4fdc 100644
--- a/src/objects/player_control.cpp
+++ b/src/objects/player_control.cpp
@@ -157,7 +157,7 @@ void PlayerController::updateControls(float delta){
 		float dt = min(1.0f, delta * ZOOM_SPEED);
 		float zoomValue = 1.0f;
 		if (crouch){
-			cameraOffset += CROUCH_SHIFT_Y;
+			cameraOffset += vec3(0.f, CROUCH_SHIFT_Y, 0.f);
 			zoomValue = CROUCH_ZOOM;
 		} else if (input.sprint){
 			zoomValue = RUN_ZOOM;
diff --git a/src/voxels/Chunk.cpp b/src/voxels/Chunk.cpp
index fc372437..f1d86cc6 100644
--- a/src/voxels/Chunk.cpp
+++ b/src/voxels/Chunk.cpp
@@ -3,6 +3,8 @@
 #include "../lighting/Lightmap.h"
 
 Chunk::Chunk(int xpos, int zpos) : x(xpos), z(zpos){
+	bottom = 0;
+	top = CHUNK_H;
 	voxels = new voxel[CHUNK_VOL];
 	for (size_t i = 0; i < CHUNK_VOL; i++) {
 		voxels[i].id = 2;
@@ -30,6 +32,22 @@ bool Chunk::isEmpty(){
 	return true;
 }
 
+void Chunk::updateHeights() {
+	for (int i = 0; i < CHUNK_VOL; i++) {
+		if (voxels[i].id != 0) {
+			bottom = i / (CHUNK_D * CHUNK_W);
+			break;
+		}
+	}
+
+	for (int i = CHUNK_VOL - 1; i > -1; i--) {
+		if (voxels[i].id != 0) {
+			top = i / (CHUNK_D * CHUNK_W) + 1;
+			break;
+		}
+	}
+}
+
 Chunk* Chunk::clone() const {
 	Chunk* other = new Chunk(x,z);
 	for (int i = 0; i < CHUNK_VOL; i++)
diff --git a/src/voxels/Chunk.h b/src/voxels/Chunk.h
index b3b8e2b6..8e751386 100644
--- a/src/voxels/Chunk.h
+++ b/src/voxels/Chunk.h
@@ -26,6 +26,7 @@ struct RenderData {
 class Chunk {
 public:
 	int x, z;
+	int bottom, top;
 	voxel* voxels;
 	Lightmap* lightmap;
 	int flags = 0;
@@ -37,6 +38,8 @@ public:
 
 	bool isEmpty();
 
+	void updateHeights();
+
 	Chunk* clone() const;
 
 	// flags getters/setters below
diff --git a/src/voxels/Chunks.cpp b/src/voxels/Chunks.cpp
index f63dcd18..6d055d98 100644
--- a/src/voxels/Chunks.cpp
+++ b/src/voxels/Chunks.cpp
@@ -139,6 +139,10 @@ void Chunks::set(int x, int y, int z, int id, uint8_t states){
 	chunk->setUnsaved(true);
 	chunk->setModified(true);
 
+	if (y < chunk->bottom) chunk->bottom = y;
+	else if (y + 1 > chunk->top) chunk->top = y + 1;
+	else if (id == 0) chunk->updateHeights();
+
 	if (lx == 0 && (chunk = getChunk(cx+ox-1, cz+oz))) chunk->setModified(true);
 	if (lz == 0 && (chunk = getChunk(cx+ox, cz+oz-1))) chunk->setModified(true);
 
diff --git a/src/voxels/Chunks.h b/src/voxels/Chunks.h
index d1cf0771..e7ec5d13 100644
--- a/src/voxels/Chunks.h
+++ b/src/voxels/Chunks.h
@@ -19,6 +19,7 @@ public:
 	std::shared_ptr<Chunk>* chunksSecond;
 	size_t volume;
 	size_t chunksCount;
+	size_t visible;
 	int w,d;
 	int ox,oz;
 	WorldFiles* worldFiles;
diff --git a/src/voxels/ChunksController.cpp b/src/voxels/ChunksController.cpp
index f4bee47b..6785ca57 100644
--- a/src/voxels/ChunksController.cpp
+++ b/src/voxels/ChunksController.cpp
@@ -116,6 +116,8 @@ bool ChunksController::loadVisible(){
 		chunk->setUnsaved(true);
 	}
 
+	chunk->updateHeights();
+
 	for (size_t i = 0; i < CHUNK_VOL; i++) {
 		blockid_t id = chunk->voxels[i].id;
 		if (Block::blocks[id] == nullptr) {