earth-reverse-engineering/client/main.cpp

#include <math.h>
#include <fstream>
#include <sys/stat.h>
#ifdef _WIN32
	#include <direct.h>
#endif
#include <SDL.h>
#if defined(_WIN32) || defined(__linux__)
	#include <glad/glad.h>
	#include "gl2/src/glad.c"
#else
	#define GL_GLEXT_PROTOTYPES
#endif
#include <SDL_opengl.h>

#define HTTP_IMPLEMENTATION
#include "http.h"
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

#include "proto/rocktree.pb.h"
#include "proto/rocktree.pb.cc"
using namespace geo_globetrotter_proto_rocktree;

#include "imgui.h"
#include "examples/imgui_impl_sdl.h"
#include "examples/imgui_impl_opengl2.h"
#include "imgui.cpp"
#include "imgui_widgets.cpp"
#include "imgui_draw.cpp"
#include "examples/imgui_impl_sdl.cpp"
#include "examples/imgui_impl_opengl2.cpp"

#include "vector_math.h"
#include "util.cpp"

SDL_Window* sdl_window;

const int MAX_LEVEL = 20;

typedef struct {
	double n, s, w, e;
} llbounds_t;

void latLonToOctant(double lat, double lon, char octant[MAX_LEVEL]) {
	octant[0] = 0;
	octant[1] = 0;
	llbounds_t box;

	if (lat < 0.0) { octant[1] |= 2; box.n = 0.0; box.s = -90.0;}
	else { octant[0] |= 2; box.n = 90.0; box.s = 0.0; }

	if (lon < -90.0) { box.w = -180.0; box.e = -90.0; }
	else if (lon < 0.0) { octant[1] |= 1; box.w = -90.0; box.e = 0.0; }
	else if (lon < 90.0) { octant[0] |= 1; box.w = 0.0; box.e = 90.0; }
	else { octant[0] |= 1; octant[1] |= 1; box.w = 90.0; box.e = 180.0; }

	int level = MAX_LEVEL;
	for (int i = 2; i < level; i++) {
		octant[i] = 0;

		double mid_lat = (box.n + box.s) / 2.0;
		double mid_lon = (box.w + box.e) / 2.0;

		if (lat < mid_lat) {
			box.n = mid_lat;
		} else {
			box.s = mid_lat;
			octant[i] |= 2;
		}

		if (lon < mid_lon) {
			box.e = mid_lon;
		} else {
			box.w = mid_lon;
			octant[i] |= 1;
		}
	}

	// to ascii
	for (int i = 0; i < level; i++) octant[i] += '0';
}

void getPathAndFlags(int path_id, char path[], int* level, int* flags) {
	*level = 1 + (path_id & 3);
	path_id >>= 2;
	for (int i = 0; i < *level; i++) {
		path[i] = '0' + (path_id & 7);
		path_id >>= 3;
	}
	*flags = path_id;
}

PlanetoidMetadata* getPlanetoid() {
	unsigned char* data; size_t len;
	if (!fetchData("PlanetoidMetadata", &data, &len)) return NULL;

	PlanetoidMetadata* planetoid = new PlanetoidMetadata();
	if (planetoid->ParseFromArray(data, len)) {
		free(data);
		return planetoid;
	}
	free(data);
	delete planetoid;
	return NULL;
}

BulkMetadata* getBulk(const char* path, int epoch) {
	char path_buf[200];
	sprintf(path_buf, "cache/bulk_%s_%d.bin", path, epoch);
	unsigned char* data = NULL; size_t len;
	if (!readFile(path_buf, &data, &len)) {
		char url_buf[200];
		sprintf(url_buf, "BulkMetadata/pb=!1m2!1s%s!2u%d", path, epoch);
		if (!fetchData(url_buf, &data, &len)) return NULL;
		writeFile(path_buf, data, len);
	}

	BulkMetadata* bulk = new BulkMetadata();
	if (bulk->ParseFromArray(data, len)) {
		free(data);
		return bulk;
	}
	free(data);
	delete bulk;
	return NULL;
}

NodeData* getNode(const char* path, int epoch, int texture_format, int imagery_epoch) {
	char path_buf[200];
	sprintf(path_buf, "cache/node_%s_%d_%d_%d.bin",
		path, epoch, texture_format, imagery_epoch);
	unsigned char* data; size_t len;
	if (!readFile(path_buf, &data, &len)) {
		char url_buf[200];
		if (imagery_epoch == -1) { // none
			sprintf(url_buf, "NodeData/pb=!1m2!1s%s!2u%d!2e%d!4b0",
				path, epoch, texture_format);
		} else {
			sprintf(url_buf, "NodeData/pb=!1m2!1s%s!2u%d!2e%d!3u%d!4b0",
				path, epoch, texture_format, imagery_epoch);
		}
		if (!fetchData(url_buf, &data, &len)) return NULL;
		writeFile(path_buf, data, len);
	}

	NodeData* node = new NodeData();
	if (node->ParseFromArray(data, len)) {
		free(data);
		return node;
	}
	free(data);
	delete node;
	return NULL;
}

struct OrientedBoundingBox {
	vec3_t center;
	vec3_t extents;
	mat3_t orientation;
};

struct PlanetMesh {
	mat4_t transform;
	GLuint vertices_buffer;
	GLuint indices_buffer;
	int element_count;
	GLuint texture;
	float uv_offset[2];
	float uv_scale[2];

	OrientedBoundingBox obb;
	double lla_min[3]; // longitude, latitude, altitude
	double lla_max[3];
	int level;
} planet_meshes[128];
int planet_mesh_count = 0;
float planet_radius;

int unpackVarInt(std::string packed, int* index) {
	int c = 0, d = 1;
	int e;
	do {
		e = (unsigned char)packed[(*index)++];
		c += (e & 0x7F) * d;
		d <<= 7;
	} while (e & 0x80);
	return c;
}

short unpackShort(std::string packed, int* index) {
	auto result = *(short*)(packed.data() + *index);
	*index += 2;
	return result;
}

unsigned short unpackUnsignedShort(std::string packed, int* index) {
	auto result = *(unsigned short*)(packed.data() + *index);
	*index += 2;
	return result;
}

// from decode-resource.js:407
void unpackObb(std::string data, vec3_t head_node_center, float meters_per_texel, OrientedBoundingBox* obb) {
	int i = 0;
	obb->center[0] = unpackShort(data, &i) * meters_per_texel + head_node_center[0];
	obb->center[1] = unpackShort(data, &i) * meters_per_texel + head_node_center[1];
	obb->center[2] = unpackShort(data, &i) * meters_per_texel + head_node_center[2];
	obb->extents[0] = (unsigned)data[i++] * meters_per_texel;
	obb->extents[1] = (unsigned)data[i++] * meters_per_texel;
	obb->extents[2] = (unsigned)data[i++] * meters_per_texel;
	vec3_t euler;
	euler[0] = unpackUnsignedShort(data, &i) * M_PI / 32768.0f;
	euler[1] = unpackUnsignedShort(data, &i) * M_PI / 65536.0f;
	euler[2] = unpackUnsignedShort(data, &i) * M_PI / 32768.0f;
	float c0 = cosf(euler[0]);
	float s0 = sinf(euler[0]);
	float c1 = cosf(euler[1]);
	float s1 = sinf(euler[1]);
	float c2 = cosf(euler[2]);
	float s2 = sinf(euler[2]);
	obb->orientation[0] = c0 * c2 - c1 * s0 * s2;
	obb->orientation[1] = c1 * c0 * s2 + c2 * s0;
	obb->orientation[2] = s2 * s1;
	obb->orientation[3] = -c0 * s2 - c2 * c1 * s0;
	obb->orientation[4] = c0 * c1 * c2 - s0 * s2;
	obb->orientation[5] = c2 * s1;
	obb->orientation[6] = s1 * s0;
	obb->orientation[7] = -c0 * s1;
	obb->orientation[8] = c1;
}

// from minified js (only positions)
int unpackVertices(std::string packed, uint8_t** vertices) {
	auto input = (uint8_t*)packed.data();
	auto count = packed.size() / 3;
	*vertices = new uint8_t[8 * count];
	for (auto axis = 0; axis < 3; axis++) {
		uint8_t cycle = 0;
		for (auto j = 0; j < count; j++) {
			(*vertices)[8 * j + axis] = cycle += *(input++);
		}
	}
	return 8 * count;
}

// from minified js
void unpackTexCoords(std::string packed, uint8_t* vertices, int vertices_len) {	
	auto data = (uint8_t*)packed.data();
	auto count = vertices_len / 8;
	auto u_mod = 1 + *(uint16_t *)(data + 0);
	auto v_mod = 1 + *(uint16_t *)(data + 2);
	data += 4;
	auto u_cycle = 0, v_cycle = 0;
	for (auto j = 0; j < count; j++, vertices += 8, data++) {
		*(uint16_t*)(vertices + 4) = u_cycle = (u_cycle + data[0 * count] + (data[2 * count] << 8)) % u_mod;
		*(uint16_t*)(vertices + 6) = v_cycle = (v_cycle + data[1 * count] + (data[3 * count] << 8)) % v_mod;
	}
}

// from minified js
int unpackIndices(std::string packed, uint16_t** indices) {
	auto offset = 0;	

	// packed -> triangle strip
	auto triangle_strip_len = unpackVarInt(packed, &offset);	
	auto triangle_strip = new uint16_t[triangle_strip_len];
	auto num_non_degenerate_triangles = 0;
	for (int zeros = 0, a, b = 0, c = 0, i = 0; i < triangle_strip_len; i++) {
		int val = unpackVarInt(packed, &offset);
		triangle_strip[i] = a = b, b = c, c = zeros - val;
		if (a != b && a != c && b != c) num_non_degenerate_triangles++;
		if (0 == val) zeros++;
	}	
	
	// triangle strip -> triangles
	auto triangles_len = 3 * num_non_degenerate_triangles;
	auto triangles = new uint16_t[triangles_len];
	for (int i = 0, j = 0; i < triangle_strip_len - 2; i++) {
		int a = triangle_strip[i + 0];
		int b = triangle_strip[i + 1];
		int c = triangle_strip[i + 2];
		if (a == b || a == c || b == c) continue;
		if (i & 1) { // reverse winding
			triangles[j++] = a;
			triangles[j++] = c;
			triangles[j++] = b;
		} else {
			triangles[j++] = a;
			triangles[j++] = b;
			triangles[j++] = c;
		}
	}

	*indices = triangles;
	delete [] triangle_strip;
	return triangles_len;
}

void loadPlanet() {
	PlanetoidMetadata* planetoid = getPlanetoid();
	printf("earth radius: %f\n", planetoid->radius());
	planet_radius = planetoid->radius();

	int root_epoch = planetoid->root_node_metadata().epoch();
	BulkMetadata* root_bulk = getBulk("", root_epoch);

	vec3_t head_node_center;
	for (int i = 0; i < 3; i++) head_node_center[i] = root_bulk->head_node_center()[i];

	printf("%d metas\n", root_bulk->node_metadata().size());
	for (auto node_meta : root_bulk->node_metadata()) {
		char path[MAX_LEVEL+1];
		int level, flags;
		getPathAndFlags(node_meta.path_and_flags(), path, &level, &flags);
		path[level] = '\0';
		float meters_per_texel = root_bulk->meters_per_texel(level - 1);

		if (node_meta.meters_per_texel() != 0) meters_per_texel = node_meta.meters_per_texel();

		if (!(flags & NodeMetadata_Flags_NODATA)) {
			int available_texture_formats = node_meta.has_available_texture_formats() ?
				node_meta.available_texture_formats() :
				root_bulk->default_available_texture_formats();

			static int supported_texture_formats[] = { // ordered by preference
				Texture_Format_CRN_DXT1,
				Texture_Format_DXT1,
				Texture_Format_JPG,
			};

			int texture_format = supported_texture_formats[0];
			for (int supported_texture_format : supported_texture_formats) {
				if (available_texture_formats & (1 << (supported_texture_format - 1))) {
					texture_format = supported_texture_format;
					break;
				}
			}

			int imagery_epoch = -1; // do not use imagery epoch
			if (flags & NodeMetadata_Flags_USE_IMAGERY_EPOCH) {
				imagery_epoch = node_meta.has_imagery_epoch() ?
					node_meta.imagery_epoch() :
					root_bulk->default_imagery_epoch();
			}

			assert(node_meta.has_epoch());
			NodeData* node = getNode(path, node_meta.epoch(), texture_format, imagery_epoch);
			if (node) {
				PlanetMesh* planet_mesh = &planet_meshes[planet_mesh_count++];

				planet_mesh->level = level;

				for (int i = 0; i < 3; i++) {
					planet_mesh->lla_min[i] = node->kml_bounding_box()[i + 0];
					planet_mesh->lla_max[i] = node->kml_bounding_box()[i + 3];
				}

				printf("node %.*s %.2f to %.2f, %.2f to %.2f\n", level, path,
					planet_mesh->lla_min[0], planet_mesh->lla_max[0],
					planet_mesh->lla_min[1], planet_mesh->lla_max[1]);
				
				unpackObb(node_meta.oriented_bounding_box(), head_node_center,
					meters_per_texel, &planet_mesh->obb);

				for (int i = 0; i < 16; i++) planet_mesh->transform[i] = (float)node->matrix_globe_from_mesh(i);

				for (auto mesh : node->meshes()) {
					unsigned short* indices;
					unsigned char* vertices;
					int indices_len = unpackIndices(mesh.indices(), &indices);
					int vertices_len = unpackVertices(mesh.vertices(), &vertices);
					unpackTexCoords(mesh.texture_coordinates(), vertices, vertices_len);
					
					planet_mesh->uv_offset[0] = mesh.uv_offset_and_scale(0);
					planet_mesh->uv_offset[1] = mesh.uv_offset_and_scale(1);
					planet_mesh->uv_scale[0] = mesh.uv_offset_and_scale(2);
					planet_mesh->uv_scale[1] = mesh.uv_offset_and_scale(3);

					glGenBuffers(1, &planet_mesh->vertices_buffer);
					glBindBuffer(GL_ARRAY_BUFFER, planet_mesh->vertices_buffer);
					glBufferData(GL_ARRAY_BUFFER, vertices_len * sizeof(unsigned char), vertices, GL_STATIC_DRAW);
					glGenBuffers(1, &planet_mesh->indices_buffer);
					glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, planet_mesh->indices_buffer);
					glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices_len * sizeof(unsigned short), indices, GL_STATIC_DRAW);
					planet_mesh->element_count = indices_len;

					delete [] indices;
					delete [] vertices;

					glGenTextures(1, &planet_mesh->texture);
					glBindTexture(GL_TEXTURE_2D, planet_mesh->texture);
					glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
					glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
					glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
					glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
					assert(mesh.texture().size() == 1);
					auto tex = mesh.texture()[0];
					if (tex.format() == Texture_Format_JPG) {
						assert(tex.data().size() == 1); // else we have to concatenate
						std::string data = tex.data()[0];
						int width, height, comp;
						unsigned char* pixels = stbi_load_from_memory((unsigned char*)&data[0],
							data.size(), &width, &height, &comp, 0);
						if (pixels != NULL) {
							glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, pixels);
							unsigned char* pixels2 = new unsigned char[width * height];
							unsigned char* pixels_in = pixels;
							unsigned char* pixels_out = pixels2;
							for (int mipmap_level = 1; width > 1 && height > 1; mipmap_level++) {
								if (width > 1 && height > 1) {
									imageHalve(pixels_in, width, height, comp, pixels_out); width /= 2; height /= 2;
								} else if (width > 1) {
									imageHalveHorizontally(pixels_in, width, height, comp, pixels_out); width /= 2;
								} else if (height > 1) {
									imageHalveVertically(pixels_in, width, height, comp, pixels_out); height /= 2;
								}
								glTexImage2D(GL_TEXTURE_2D, mipmap_level, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, pixels_out);
								unsigned char* tmp = pixels_in; pixels_in = pixels_out; pixels_out = tmp; // swap
							}
							delete [] pixels2;
							stbi_image_free(pixels);
						}
					} else assert(false); // TODO: other formats
				}
				delete node;

				if (planet_mesh_count >= 128) return; // stop after a couple of nodes for now
			} else { // node == NULL
				assert(false);
			}
		}

#if 0
		// next level
		if (level == 4 && !(flags & NodeMetadata_Flags_LEAF)) { // bulk
			//return; // don't
			BulkMetadata* bulk = getBulk(path, root_epoch);
			if (bulk != NULL) {
				printf("metas %d\n", bulk->node_metadata().size());
				for (auto meta2 : bulk->node_metadata()) {
					getPathAndFlags(meta2.path_and_flags(), path, &level, &flags);
				}
				delete bulk;
			}
		}
#endif
	}
}

GLuint makeShader(const char* vert_src, const char* frag_src) {
	GLuint vert_shader = glCreateShader(GL_VERTEX_SHADER);
	glShaderSource(vert_shader, 1, &vert_src, NULL);
	glCompileShader(vert_shader);
	GLuint frag_shader = glCreateShader(GL_FRAGMENT_SHADER);
	glShaderSource(frag_shader, 1, &frag_src, NULL);
	glCompileShader(frag_shader);
	GLuint program = glCreateProgram();
	glAttachShader(program, vert_shader);
	glAttachShader(program, frag_shader);
	glLinkProgram(program);
	glDetachShader(program, vert_shader);
	glDetachShader(program, frag_shader);
	glDeleteShader(vert_shader);
	glDeleteShader(frag_shader);
	return program;
}

GLuint program;
GLint transform_loc;
GLint uv_offset_loc;
GLint uv_scale_loc;
GLint texture_loc;
GLint position_loc;
GLint texcoords_loc;
void initGL() {
	glEnable(GL_DEPTH_TEST);
	glEnable(GL_CULL_FACE);

	program = makeShader(
		"uniform mat4 transform;"
		"uniform vec2 uv_offset;"
		"uniform vec2 uv_scale;"
		"attribute vec3 position;"
		"attribute vec2 texcoords;"
		"varying vec2 v_texcoords;"
		"void main() {"
		"	v_texcoords = (texcoords + uv_offset) * uv_scale;"
		"	gl_Position = transform * vec4(position, 1.0);"
		"}",

		"#ifdef GL_ES\n"
		"precision mediump float;\n"
		"#endif\n"
		"uniform sampler2D texture;"
		"varying vec2 v_texcoords;"
		"void main() {"
		"	gl_FragColor = vec4(texture2D(texture, v_texcoords).rgb, 1.0);"
		"}"
	);
	glUseProgram(program);
	transform_loc = glGetUniformLocation(program, "transform");
	uv_offset_loc = glGetUniformLocation(program, "uv_offset");
	uv_scale_loc = glGetUniformLocation(program, "uv_scale");
	texture_loc = glGetUniformLocation(program, "texture");
	position_loc = glGetAttribLocation(program, "position");
	texcoords_loc = glGetAttribLocation(program, "texcoords");
}

mat4_t cam_rot = {
	0.0f, 0.0f, 1.0f, 0.0f,
	1.0f, 0.0f, 0.0f, 0.0f,
	0.0f, 1.0f, 0.0f, 0.0f,
	0.0f, 0.0f, 0.0f, 1.0f,
};
float cam_lat = 0.0f;
float cam_lon = 0.0f;
float cam_zoom = 0.0f;
int mouse_x = 0, mouse_y = 0;
int prev_mouse_x, prev_mouse_y;
void drawCube();
void drawPlanet() {
	mat4_t temp0, temp1, temp2, 
		translation, rotation, scale, 
		model, view, modelview, projection, transform;

	int width, height;
	SDL_GL_GetDrawableSize(sdl_window, &width, &height);
	glViewport(0, 0, width, height);
	glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	float aspect_ratio = (float)width / (float)height;
	float fov = 0.25f * (float)M_PI;
	float right_plane, top_plane, near_plane = 0.01f;
	if (aspect_ratio > 1.0f) {
		right_plane = tanf(0.5f * fov) * near_plane;
		top_plane = right_plane / aspect_ratio;
	} else {
		top_plane = tanf(0.5f * fov) * near_plane;
		right_plane = aspect_ratio * top_plane;
	}
	MatrixFrustum(-right_plane, right_plane, -top_plane, top_plane, near_plane, 10.0f, projection);

	vec3_t t = { 0.0f, 0.0f, 0.0f };
	t[2] = -(1.0f + near_plane + powf(1.337f, 5.0f - cam_zoom));

	prev_mouse_x = mouse_x; prev_mouse_y = mouse_y;
	unsigned mouse_buttons = SDL_GetMouseState(&mouse_x, &mouse_y);
	SDL_GetWindowSize(sdl_window, &width, &height);

	if (mouse_buttons & SDL_BUTTON(SDL_BUTTON_LEFT) && 
		(mouse_x != prev_mouse_x || mouse_y != prev_mouse_y)) {
		vec3_t w0, w1;
		w0[0] = (2.0f * prev_mouse_x / width - 1.0f) * right_plane / near_plane;
		w0[1] = (1.0f - 2.0f * prev_mouse_y / height) * top_plane / near_plane;
		w0[2] = -1.0f;
		VectorNormalize(w0);
		w1[0] = (2.0f * mouse_x / width - 1.0f) * right_plane / near_plane;
		w1[1] = (1.0f - 2.0f * mouse_y / height) * top_plane / near_plane;
		w1[2] = -1.0f;
		VectorNormalize(w1);
		vec3_t origin = { 0.0f, 0.0f, 0.0f };
		float t0, t1;
		if (intersectRaySphere(origin, w0, t, 1.0f, &t0) && 
			intersectRaySphere(origin, w1, t, 1.0f, &t1)) {
			VectorScale(w0, t0, w0);
			VectorSubtract(w0, t, w0);
			VectorScale(w1, t1, w1);
			VectorSubtract(w1, t, w1);

			vec3_t axis;
			CrossProduct(w0, w1, axis);
			VectorNormalize(axis);
			float dot = DotProduct(w0, w1);
			if (dot > 1.0f) dot = 1.0f;
			float angle = acosf(dot);
			MatrixRotation(axis, angle, temp0);
			MatrixCopy(cam_rot, temp1);
			MatrixMultiply(temp0, temp1, cam_rot);
		}
	}

	ImGui::Text("%.2f %.2f %.2f", cam_rot[0], cam_rot[4], cam_rot[8]);
	ImGui::Text("%.2f %.2f %.2f", cam_rot[1], cam_rot[5], cam_rot[9]);
	ImGui::Text("%.2f %.2f %.2f", cam_rot[2], cam_rot[6], cam_rot[10]);
	vec3_t pos = { 0.0f, 0.0f, 1.0f }, out;
	mat4_t inv_cam_rot;
	MatrixCopy(cam_rot, inv_cam_rot);
	MatrixTranspose(inv_cam_rot);
	MatrixMultiplyPosition(inv_cam_rot, pos, out);
	cam_lat = asinf(out[2]);
	cam_lon = atan2f(out[1], out[0]);
	ImGui::Text("%.2f %.2f", cam_lat * 180.0f / M_PI, cam_lon * 180.0f / M_PI);

	float s = 1.0f / planet_radius;
	vec3_t s3 = { s, s, s };
	MatrixScale(s3, scale);
	MatrixTranslation(t, translation);
	MatrixCopy(cam_rot, rotation);
	MatrixMultiply(translation, rotation, temp1);

	glUseProgram(program);
	glEnableVertexAttribArray(position_loc);
	glEnableVertexAttribArray(texcoords_loc);
	int cam_level = (int)cam_zoom + 2;
	float cam_lon_deg = 180.0f * cam_lon / M_PI;
	float cam_lat_deg = 180.0f * cam_lat / M_PI;
	PlanetMesh* planet_mesh_drawn = NULL;
	for (int mesh_index = 0; mesh_index < planet_mesh_count; mesh_index++) {
		PlanetMesh* planet_mesh = &planet_meshes[mesh_index];

		if (cam_level != planet_mesh->level) continue;
		//if (cam_lon_deg < planet_mesh->lla_min[0] || 
		//	cam_lon_deg > planet_mesh->lla_max[0] ||
		//	cam_lat_deg < planet_mesh->lla_min[1] ||
		//	cam_lat_deg > planet_mesh->lla_max[1]) continue;

		MatrixMultiply(scale, planet_mesh->transform, temp0);
		MatrixMultiply(temp1, temp0, modelview);
		MatrixMultiply(projection, modelview, transform);
		glUniformMatrix4fv(transform_loc, 1, GL_FALSE, transform);
		glUniform2fv(uv_offset_loc, 1, planet_mesh->uv_offset);
		glUniform2fv(uv_scale_loc, 1, planet_mesh->uv_scale);

		glUniform1i(texture_loc, 0);
		glBindTexture(GL_TEXTURE_2D, planet_mesh->texture);

		glBindBuffer(GL_ARRAY_BUFFER, planet_mesh->vertices_buffer);
		glVertexAttribPointer(position_loc, 3, GL_UNSIGNED_BYTE, GL_FALSE, 8, (void*)0);
		glVertexAttribPointer(texcoords_loc, 2, GL_UNSIGNED_SHORT, GL_FALSE, 8, (void*)4);
		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, planet_mesh->indices_buffer);
		glDrawElements(GL_TRIANGLES, planet_mesh->element_count, GL_UNSIGNED_SHORT, NULL);

		planet_mesh_drawn = planet_mesh;
	}
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glDisableVertexAttribArray(position_loc);
	glDisableVertexAttribArray(texcoords_loc);
	glUseProgram(0);

	glMatrixMode(GL_PROJECTION);
	glLoadMatrixf(projection);
	glMatrixMode(GL_MODELVIEW);
	glLoadMatrixf(temp1);
	glDisable(GL_DEPTH_TEST);
	glBegin(GL_LINES);
	glColor3f(1.0f, 0.0f, 0.0f);
	glVertex3f(0.0f, 0.0f, 0.0f);
	glVertex3f(1.0f, 0.0f, 0.0f);
	glColor3f(0.0f, 1.0f, 0.0f);
	glVertex3f(0.0f, 0.0f, 0.0f);
	glVertex3f(0.0f, 1.0f, 0.0f);
	glColor3f(0.0f, 0.0f, 1.0f);
	glVertex3f(0.0f, 0.0f, 0.0f);
	glVertex3f(0.0f, 0.0f, 1.0f);
	glEnd();
	glPointSize(5.0f);
	glBegin(GL_POINTS);
	glColor3f(1.0f, 0.0f, 1.0f);
	glVertex3f(out[0], out[1], out[2]);
	glEnd();
	glColor3f(0.0f, 0.0f, 0.0f);
	if (planet_mesh_drawn) { // visualize obb
		MatrixCopy(temp1, view);
		
		MatrixCopy(scale, temp0); // save
		MatrixTranslation(planet_mesh_drawn->obb.center, translation);
		MatrixCopy34(planet_mesh_drawn->obb.orientation, rotation);
		MatrixScale(planet_mesh_drawn->obb.extents, scale);

		MatrixMultiply(rotation, scale, temp2);
		MatrixMultiply(translation, temp2, temp1);
		MatrixMultiply(temp0, temp1, model);
		MatrixMultiply(view, model, modelview);

		glPushMatrix();
		glLoadMatrixf(modelview);
		drawCube();
		glPopMatrix();
	}
	glEnable(GL_DEPTH_TEST);
}

void drawCube() {
	glBegin(GL_LINES);
	glVertex3f(-1.0f, -1.0f, -1.0f);
	glVertex3f(1.0f, -1.0f, -1.0f);
	glVertex3f(1.0f, -1.0f, -1.0f);
	glVertex3f(1.0f, 1.0f, -1.0f);
	glVertex3f(1.0f, 1.0f, -1.0f);
	glVertex3f(-1.0f, 1.0f, -1.0f);
	glVertex3f(-1.0f, 1.0f, -1.0f);
	glVertex3f(-1.0f, -1.0f, -1.0f);

	glVertex3f(-1.0f, -1.0f, 1.0f);
	glVertex3f(1.0f, -1.0f, 1.0f);
	glVertex3f(1.0f, -1.0f, 1.0f);
	glVertex3f(1.0f, 1.0f, 1.0f);
	glVertex3f(1.0f, 1.0f, 1.0f);
	glVertex3f(-1.0f, 1.0f, 1.0f);
	glVertex3f(-1.0f, 1.0f, 1.0f);
	glVertex3f(-1.0f, -1.0f, 1.0f);

	glVertex3f(-1.0f, -1.0f, -1.0f);
	glVertex3f(-1.0f, -1.0f, 1.0f);
	glVertex3f(1.0f, -1.0f, -1.0f);
	glVertex3f(1.0f, -1.0f, 1.0f);
	glVertex3f(1.0f, 1.0f, -1.0f);
	glVertex3f(1.0f, 1.0f, 1.0f);
	glVertex3f(-1.0f, 1.0f, -1.0f);
	glVertex3f(-1.0f, 1.0f, 1.0f);
	glEnd();
}

void init() {
#if 0
	vec3_t x_axis = {1.0f, 0.0f, 0.0f};
	vec3_t y_axis = {0.0f, 1.0f, 0.0f};
	MatrixRotation(x_axis, (float)M_PI * cam_lat / 180.0f, x_rotation);
	MatrixRotation(y_axis, (float)M_PI * cam_lon / 180.0f, y_rotation);
	MatrixMultiply(x_rotation, y_rotation, temp0);
	mat4_t base = {
		0.0f, 0.0f, 1.0f, 0.0f,
		1.0f, 0.0f, 0.0f, 0.0f,
		0.0f, 1.0f, 0.0f, 0.0f,
		0.0f, 0.0f, 0.0f, 1.0f,
	};
	MatrixMultiply(temp0, base, rotation);
#endif
}

bool quit = false;
void mainloop() {
	SDL_Event sdl_event;
	while (SDL_PollEvent(&sdl_event)) {
		switch (sdl_event.type) {
			case SDL_QUIT:
				quit = true;
				break;
			case SDL_KEYDOWN:
				if (sdl_event.key.keysym.sym == SDLK_ESCAPE) quit = true;
				break;
			case SDL_MOUSEWHEEL:
				if (sdl_event.wheel.y > 0) {
					if (cam_zoom < 20.0f) cam_zoom += 1.0f;
				} else if (sdl_event.wheel.y < 0) {
					if (cam_zoom > 0.0f) cam_zoom -= 1.0f;
				}
				break;
#ifdef EMSCRIPTEN // Touch controls
			case SDL_FINGERDOWN: {
				float x = sdl_event.tfinger.x;
				float y = sdl_event.tfinger.y;
			} break;
#endif
		}
		ImGui_ImplSDL2_ProcessEvent(&sdl_event);
	}

	ImGui_ImplOpenGL2_NewFrame();
	ImGui_ImplSDL2_NewFrame(sdl_window);
	ImGui::NewFrame();

	drawPlanet();

	ImGuiIO& io = ImGui::GetIO();
	ImGui::Render();
	glUseProgram(0);
	ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());

	SDL_GL_SwapWindow(sdl_window);
}

int main(int argc, char* argv[]) {
	// create cache directory
	createDir("cache");

	int video_width = 768;
	int video_height = 768;

	if (SDL_Init(SDL_INIT_VIDEO) != 0) {
		fprintf(stderr, "Couldn't init SDL2: %s\n", SDL_GetError());
		exit(1);
	}
#ifdef EMSCRIPTEN
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
		SDL_GL_CONTEXT_PROFILE_ES);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
#else
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
		SDL_GL_CONTEXT_PROFILE_COMPATIBILITY);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
#endif
	//SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
	//SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 4);
	sdl_window = SDL_CreateWindow("Earth Client", 
		SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 
		video_width, video_height, 
		SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
	if (!sdl_window) {
		fprintf(stderr, "Couldn't create window: %s\n", SDL_GetError());
		exit(1);
	}
	SDL_GLContext gl_context = SDL_GL_CreateContext(sdl_window);
	if (!gl_context) {
		fprintf(stderr, "Couldn't create OpenGL context: %s\n", SDL_GetError());
		exit(1);
	}
	SDL_GL_SetSwapInterval(1);

#if defined(_WIN32) || defined(__linux__)
	// init glad
	if (!gladLoadGL()) {
		fprintf(stderr, "Failed to init glad\n");
		exit(1);
	}
#endif

	IMGUI_CHECKVERSION();
	ImGui::CreateContext();
	ImGuiIO& io = ImGui::GetIO(); (void)io;
	ImGui::StyleColorsLight();

	ImGui_ImplSDL2_InitForOpenGL(sdl_window, gl_context);
	ImGui_ImplOpenGL2_Init();

	initGL();
	loadPlanet();
	init();

#ifdef EMSCRIPTEN
	emscripten_set_main_loop(mainloop, 0, 1);
#else
	while (!quit) mainloop();
#endif

	ImGui_ImplOpenGL2_Shutdown();
	ImGui_ImplSDL2_Shutdown();
	ImGui::DestroyContext();

	SDL_GL_DeleteContext(gl_context);
	SDL_DestroyWindow(sdl_window);
	SDL_Quit();
	
	return 0;
}