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okonomiyaki

OpenGL OpenGL with Freetype font library has weird quirk

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All of my characters that comprise simply of a vertical line have dashes at the bottom (i.e. i, l, and |). This makes the character totally unreadable. Here is a screenshot: The "Name" box contains all "i''s" and the pass box contains all "l''s" (lowercase L) and the cursor is a blinking "|" which you can see suffers from the same torment.. I pretty much just encapsulated the Freetype font code from Nehe. However, I''ve totally gone through it and understand all of it (maybe not everything, obviously). It''s had this quirk for as long as I can remember. Here is the Freetype loading and printing code.. I know you might not want to go through it, but I''m hoping some people who have used this code before can help me out. A small bug like this make it look very bad, not to mention it bugs the crap out of me.. {code}
///Create a display list coresponding to the give character.

int font::MakeDispList(FT_Face face, char ch) {

	//The first thing we do is get FreeType to render our character

	//into a bitmap.  This actually requires a couple of FreeType commands:


	//Load the Glyph for our character.

	if(FT_Load_Glyph(face, FT_Get_Char_Index(face, ch), FT_LOAD_DEFAULT)) {
		printf("FT_Load_Glyph failed.");
    return 1;
  }
    

	//Move the face''s glyph into a Glyph object.

  FT_Glyph glyph;
  if(FT_Get_Glyph(face->glyph, &glyph)) {
		printf("FT_Get_Glyph failed.");
    return 2;
  }

	//Convert the glyph to a bitmap.

	FT_Glyph_To_Bitmap(&glyph, ft_render_mode_normal, 0, 1);
  FT_BitmapGlyph bitmap_glyph = (FT_BitmapGlyph)glyph;

	//This reference will make accessing the bitmap easier

	FT_Bitmap& bitmap=bitmap_glyph->bitmap;

	//Use our helper function to get the widths of

	//the bitmap data that we will need in order to create

	//our texture.

	int width = next_p2( bitmap.width );
	int height = next_p2( bitmap.rows );

	//Allocate memory for the texture data.

	GLubyte* expanded_data = new GLubyte[2 * width * height];

	//Here we fill in the data for the expanded bitmap.

	//Notice that we are using two channel bitmap (one for

	//luminocity and one for alpha), but we assign

	//both luminocity and alpha to the value that we

	//find in the FreeType bitmap. 

	//We use the ?: operator so that value which we use

	//will be 0 if we are in the padding zone, and whatever

	//is the the Freetype bitmap otherwise.

	for(int j=0; j <height;j++) {
		for(int i=0; i < width; i++){
			expanded_data[2*(i+j*width)]=
				0xFF;
			expanded_data[2*(i+j*width)+1] =
				(i>=bitmap.width || j>=bitmap.rows) ? 0 : bitmap.buffer[i + bitmap.width*j];
		}
	}


	//Now we just setup some texture paramaters.

	glBindTexture(GL_TEXTURE_2D, textures[ch]);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);

	//Here we actually create the texture itself, notice

	//that we are using GL_LUMINANCE_ALPHA to indicate that

	//we are using 2 channel data.

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height,
		  0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, expanded_data);

	//With the texture created, we don''t need to expanded data anymore

    delete [] expanded_data;

	//So now we can create the display list

	glNewList(list_base+ch,GL_COMPILE);

	glPushMatrix();

	glBindTexture(GL_TEXTURE_2D,textures[ch]);

	//first we need to move over a little so that

	//the character has the right amount of space

	//between it and the one before it.

	//Then we move down a little in the case that the

	//bitmap extends past the bottom of the line 

	//(this is only true for characters like ''g'' or ''y''.

	glTranslatef(bitmap_glyph->left, bitmap_glyph->top - bitmap.rows, 0);

	//Now we need to account for the fact that many of

	//our textures are filled with empty padding space.

	//We figure what portion of the texture is used by 

	//the actual character and store that information in 

	//the x and y variables, then when we draw the

	//quad, we will only reference the parts of the texture

	//that we contain the character itself.

	float	x = bitmap.width / (float)width,
			y = bitmap.rows  / (float)height;

	//Here we draw the texturemaped quads.

	//The bitmap that we got from FreeType was not 

	//oriented quite like we would like it to be,

	//so we need to link the texture to the quad

	//so that the result will be properly aligned.

	glBegin(GL_QUADS);
	glTexCoord2d(0,0); glVertex2f(0,bitmap.rows);
	glTexCoord2d(0,y); glVertex2f(0,0);
	glTexCoord2d(x,y); glVertex2f(bitmap.width,0);
	glTexCoord2d(x,0); glVertex2f(bitmap.width,bitmap.rows);
	glEnd();

	glPopMatrix();

	glTranslatef(face->glyph->advance.x >> 6 ,0,0);


	//increment the raster position as if we were a bitmap font.

	//(only needed if you want to calculate text length)

	//glBitmap(0,0,0,0,face->glyph->advance.x >> 6,0,NULL);


	//Finnish the display list

	glEndList();
  
  return 0;
}



int font::Init(const char * fname, unsigned int h) {
 
	//Allocate some memory to store the texture ids.

	textures = new GLuint[128];

	this->h=h;

	//Create and initilize a freetype font library.

	FT_Library library;
	if (FT_Init_FreeType( &library )) {
		printf("FreeType init failed");
    return 1;
  }

	//The object in which Freetype holds information on a given

	//font is called a "face".

	FT_Face face;

	//This is where we load in the font information from the file.

	//Of all the places where the code might die, this is the most likely,

	//as FT_New_Face will die if the font file does not exist or is somehow broken.

	if (FT_New_Face(library, fname, 0, &face)) {
		printf("Creating the font face failed.  Check the font name");
    return 2;
  }

	//For some twisted reason, Freetype measures font size

	//in terms of 1/64ths of pixels.  Thus, to make a font

	//h pixels high, we need to request a size of h*64.

	//(h << 6 is just a prettier way of writting h*64)

	FT_Set_Char_Size(face, h << 6, h << 6, 96, 96);

	//Here we ask opengl to allocate resources for

	//all the textures and displays lists which we

	//are about to create.  

	list_base=glGenLists(128);
	glGenTextures(128, textures);

	//This is where we actually create each of the fonts display lists.

	for(unsigned char i=0;i<128;i++)
		MakeDispList(face,i);

	//We don''t need the face information now that the display

	//lists have been created, so we free the assosiated resources.

	FT_Done_Face(face);

	//Ditto for the library.

	FT_Done_FreeType(library);
  
  return 0;
}

void font::Shutdown() {
	glDeleteLists(list_base,128);
	glDeleteTextures(128,textures);
	delete[] textures;
}

/// A fairly straight forward function that pushes

/// a projection matrix that will make object world 

/// coordinates identical to window coordinates.

inline void pushScreenCoordinateMatrix() {
	glMatrixMode(GL_PROJECTION);
	glPushMatrix();
	glLoadIdentity();

	glOrtho(0.0f,GameInfo::screenWidth,0.0f,GameInfo::screenHeight,-1.0f,1.0f);

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

/// Pops the projection matrix without changing the current

/// MatrixMode.

inline void pop_projection_matrix() {
	glMatrixMode(GL_PROJECTION);
	glPopMatrix();
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

void font::Print(float x, float y, char *text)  {

	y = GameInfo::screenHeight-y;  //flip it


	// We want a coordinate system where things coresponding to window pixels.

	pushScreenCoordinateMatrix();					
	
	GLuint font=list_base;
	float temph = h/.63f;						//We make the height about 1.5* that of


	glPushAttrib(GL_LIST_BIT | GL_CURRENT_BIT  | GL_ENABLE_BIT | GL_TRANSFORM_BIT);	
	glDisable(GL_LIGHTING);
	glEnable(GL_TEXTURE_2D);
	glDisable(GL_DEPTH_TEST);
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);	

	glListBase(font);
	glPushMatrix();
	glLoadIdentity();
	glTranslatef(x,y,0);

//  The commented out raster position stuff can be useful if you need to

//  know the length of the text that you are creating.

//  If you decide to use it make sure to also uncomment the glBitmap command

//  in make_dlist().

//	glRasterPos2f(0,0);


	glCallLists(strlen(text), GL_UNSIGNED_BYTE, text);
	glBindTexture(GL_TEXTURE_2D, 0);
//	float rpos[4];

//	glGetFloatv(GL_CURRENT_RASTER_POSITION ,rpos);

//	float len=x-rpos[0];


	glPopMatrix();
	glPopAttrib();

	pop_projection_matrix();

}
To narrow it down, here is the part where it actually makes the display list and the texture.. it might be in here somewhere?
//This reference will make accessing the bitmap easier

	FT_Bitmap& bitmap=bitmap_glyph->bitmap;

	//Use our helper function to get the widths of

	//the bitmap data that we will need in order to create

	//our texture.

	int width = next_p2( bitmap.width );
	int height = next_p2( bitmap.rows );

	//Allocate memory for the texture data.

	GLubyte* expanded_data = new GLubyte[2 * width * height];

	//Here we fill in the data for the expanded bitmap.

	//Notice that we are using two channel bitmap (one for

	//luminocity and one for alpha), but we assign

	//both luminocity and alpha to the value that we

	//find in the FreeType bitmap. 

	//We use the ?: operator so that value which we use

	//will be 0 if we are in the padding zone, and whatever

	//is the the Freetype bitmap otherwise.

	for(int j=0; j <height;j++) {
		for(int i=0; i < width; i++){
			expanded_data[2*(i+j*width)]=
				0xFF;
			expanded_data[2*(i+j*width)+1] =
				(i>=bitmap.width || j>=bitmap.rows) ? 0 : bitmap.buffer[i + bitmap.width*j];
		}
	}


	//Now we just setup some texture paramaters.

	glBindTexture(GL_TEXTURE_2D, textures[ch]);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);

	//Here we actually create the texture itself, notice

	//that we are using GL_LUMINANCE_ALPHA to indicate that

	//we are using 2 channel data.

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height,
		  0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, expanded_data);

	//With the texture created, we don''t need to expanded data anymore

    delete [] expanded_data;

	//So now we can create the display list

	glNewList(list_base+ch,GL_COMPILE);

	glPushMatrix();

	glBindTexture(GL_TEXTURE_2D,textures[ch]);

	//first we need to move over a little so that

	//the character has the right amount of space

	//between it and the one before it.

	//Then we move down a little in the case that the

	//bitmap extends past the bottom of the line 

	//(this is only true for characters like ''g'' or ''y''.

	glTranslatef(bitmap_glyph->left, bitmap_glyph->top - bitmap.rows, 0);

	//Now we need to account for the fact that many of

	//our textures are filled with empty padding space.

	//We figure what portion of the texture is used by 

	//the actual character and store that information in 

	//the x and y variables, then when we draw the

	//quad, we will only reference the parts of the texture

	//that we contain the character itself.

	float	x = bitmap.width / (float)width,
			y = bitmap.rows  / (float)height;

	//Here we draw the texturemaped quads.

	//The bitmap that we got from FreeType was not 

	//oriented quite like we would like it to be,

	//so we need to link the texture to the quad

	//so that the result will be properly aligned.

	glBegin(GL_QUADS);
	glTexCoord2d(0,0); glVertex2f(0,bitmap.rows);
	glTexCoord2d(0,y); glVertex2f(0,0);
	glTexCoord2d(x,y); glVertex2f(bitmap.width,0);
	glTexCoord2d(x,0); glVertex2f(bitmap.width,bitmap.rows);
	glEnd();

	glPopMatrix();

	glTranslatef(face->glyph->advance.x >> 6 ,0,0);


	//increment the raster position as if we were a bitmap font.

	//(only needed if you want to calculate text length)

	//glBitmap(0,0,0,0,face->glyph->advance.x >> 6,0,NULL);


	//Finnish the display list

	glEndList();
Thanks a lot for any help.

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Those glyphs look to be one pixel wide. Is the bitmap returned by FreeType actually one pixel wide? If so, then you might want to try one of a couple things:

Pad the width out to 2 pixels. glTexImage2D requires a width of the form 2n+2(border) where n is an integer. 1 doesn''t fit the bill.

Or, try setting glPixelStorei(GL_UNPACK_ALIGNMENT, 1) to take care of any alignment problems with your pixel buffer.

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      #include "Window.h" #include <GL/glew.h> #include <GLFW/glfw3.h> #include "Error.h" #include "Renderer.h" #include "Scene.h" #include "Input.h" //Global Variables. int screen_width, screen_height; //On Window Resize. void OnWindowResize(GLFWwindow *window, int width, int height); //Implementation Structure. struct Window::Implementation { //GLFW Window. GLFWwindow *GLFW_window; //Renderer. Renderer *renderer; //Delta Time. double delta_time; //Frames Per Second. int fps; //Scene. Scene *scnene; //Input. Input *input; //Deconstructor. ~Implementation(); }; //Window Constructor. Window::Window(std::string title, int width, int height) { //Initializing width and height. screen_width = width; screen_height = height; //Create Pointer To Implementation. m_Impl = new Implementation(); //Try initializing GLFW. if (!glfwInit()) { std::cout << "GLFW could not be initialized!" << std::endl; std::cout << "Press ENTER to exit..." << std::endl; std::cin.get(); exit(-1); } //Setting up OpenGL Version 3.3 Core Profile. glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); /* Create a windowed mode window and its OpenGL context */ m_Impl->GLFW_window = glfwCreateWindow(width, height, title.c_str(), NULL, NULL); if (!m_Impl->GLFW_window) { std::cout << "GLFW could not create a window!" << std::endl; std::cout << "Press ENTER to exit..." << std::endl; std::cin.get(); glfwTerminate(); exit(-1); } /* Make the window's context current */ glfwMakeContextCurrent(m_Impl->GLFW_window); //Initialize GLEW. if(glewInit() != GLEW_OK) { std::cout << "GLEW could not be initialized!" << std::endl; std::cout << "Press ENTER to exit..." << std::endl; std::cin.get(); glfwTerminate(); exit(-1); } //Enabling Blending. GLCall(glEnable(GL_BLEND)); GLCall(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)); //Setting the ViewPort. GLCall(glViewport(0, 0, width, height)); //**********Initializing Implementation**********// m_Impl->renderer = new Renderer(); m_Impl->delta_time = 0.0; m_Impl->fps = 0; m_Impl->input = new Input(this); //**********Initializing Implementation**********// //Set Frame Buffer Size Callback. glfwSetFramebufferSizeCallback(m_Impl->GLFW_window, OnWindowResize); } //Window Deconstructor. Window::~Window() { delete m_Impl; } //Window Main Loop. void Window::MainLoop() { //Time Variables. double start_time = 0, end_time = 0, old_time = 0, total_time = 0; //Frames Counter. int frames = 0; /* Loop until the user closes the window */ while (!glfwWindowShouldClose(m_Impl->GLFW_window)) { old_time = start_time; //Total time of previous frame. start_time = glfwGetTime(); //Current frame start time. //Calculate the Delta Time. m_Impl->delta_time = start_time - old_time; //Get Frames Per Second. if (total_time >= 1) { m_Impl->fps = frames; total_time = 0; frames = 0; } //Clearing The Screen. m_Impl->renderer->Clear(0, 0, 0); //Render The Scene. if (m_Impl->scnene != NULL) m_Impl->scnene->Render(this); //Updating the Screen. m_Impl->renderer->Update(m_Impl->GLFW_window); //Increasing frames counter. frames++; //End Time. end_time = glfwGetTime(); //Total time after the frame completed. total_time += end_time - start_time; } //Terminate GLFW. glfwTerminate(); } //Load Scene. void Window::LoadScene(Scene * scene) { //Set the scene. m_Impl->scnene = scene; } //Get Delta Time. double Window::GetDeltaTime() { return m_Impl->delta_time; } //Get FPS. int Window::GetFPS() { return m_Impl->fps; } //Get Width. int Window::GetWidth() { return screen_width; } //Get Height. int Window::GetHeight() { return screen_height; } //Get Input. Input * Window::GetInput() { return m_Impl->input; } Renderer * Window::GetRenderer() { return m_Impl->renderer; } GLFWwindow * Window::GetGLFWindow() { return m_Impl->GLFW_window; } //Implementation Deconstructor. Window::Implementation::~Implementation() { delete renderer; delete input; } //OnWindowResize void OnWindowResize(GLFWwindow *window, int width, int height) { screen_width = width; screen_height = height; //Updating the ViewPort. GLCall(glViewport(0, 0, width, height)); }  
      Brain Class
      #include "Brain.h" #include "Sprite.h" #include "Window.h" struct Brain::Implementation { //Just A Flag. bool started; //Window Pointer. Window *window; //Sprite Pointer. Sprite *sprite; }; Brain::Brain(Window *window, Sprite *sprite) { //Create Pointer To Implementation. m_Impl = new Implementation(); //Initialize Implementation. m_Impl->started = true; m_Impl->window = window; m_Impl->sprite = sprite; } Brain::~Brain() { //Delete Pointer To Implementation. delete m_Impl; } void Brain::Start() { } void Brain::Update() { } Window * Brain::GetWindow() { return m_Impl->window; } Sprite * Brain::GetSprite() { return m_Impl->sprite; } bool Brain::GetStart() { return m_Impl->started; } void Brain::SetStart(bool value) { m_Impl->started = value; } Script Class (Its a Brain Subclass!!!)
      #include "Script.h" Script::Script(Window *window, Sprite *sprite) : Brain(window, sprite) { } Script::~Script() { } void Script::Start() { std::cout << "Game Started!" << std::endl; } void Script::Update() { Input *input = this->GetWindow()->GetInput(); Sprite *sp = this->GetSprite(); //Move this sprite. this->GetSprite()->Move(200 * this->GetWindow()->GetDeltaTime(), input->GetKeyDown("left"), input->GetKeyDown("right"), input->GetKeyDown("up"), input->GetKeyDown("down")); std::cout << sp->GetTag().c_str() << ".x = " << sp->GetPos()->x << ", " << sp->GetTag().c_str() << ".y = " << sp->GetPos()->y << std::endl; }  
      Main:
      #include "SpaceShooterEngine.h" #include "Script.h" int main() { Window w("title", 600,600); Scene *scene = new Scene(); Sprite *player = new Sprite("Resources/Images/player.png", "Player", 100,100); Sprite *other = new Sprite("Resources/Images/cherno.png", "Other", 400, 100); Sprite *other2 = new Sprite("Resources/Images/cherno.png", "Other", 300, 400); Brain *brain = new Script(&w, player); player->AddBrain(brain); scene->AddSprite(player); scene->AddSprite(other); scene->AddSprite(other2); w.LoadScene(scene); w.MainLoop(); return 0; }  
       
      I literally can't find what is wrong. If you need more code, ask me to post it. I will also attach all the source files.
      Brain.cpp
      Error.cpp
      IndexBuffer.cpp
      Input.cpp
      Renderer.cpp
      Scene.cpp
      Shader.cpp
      Sprite.cpp
      Texture.cpp
      VertexArray.cpp
      VertexBuffer.cpp
      VertexBufferLayout.cpp
      Window.cpp
      Brain.h
      Error.h
      IndexBuffer.h
      Input.h
      Renderer.h
      Scene.h
      Shader.h
      SpaceShooterEngine.h
      Sprite.h
      Texture.h
      VertexArray.h
      VertexBuffer.h
      VertexBufferLayout.h
      Window.h
    • By Cristian Decu
      Hello fellow programmers,
      For a couple of days now i've decided to build my own planet renderer just to see how floating point precision issues
      can be tackled. As you probably imagine, i've quickly faced FPP issues when trying to render absurdly large planets.
       
      I have used the classical quadtree LOD approach;
      I've generated my grids with 33 vertices, (x: -1 to 1, y: -1 to 1, z = 0).
      Each grid is managed by a TerrainNode class that, depending on the side it represents (top, bottom, left right, front, back),
      creates a special rotation-translation matrix that moves and rotates the grid away from the origin so that when i finally
      normalize all the vertices on my vertex shader i can get a perfect sphere.
      T = glm::translate(glm::dmat4(1.0), glm::dvec3(0.0, 0.0, 1.0)); R = glm::rotate(glm::dmat4(1.0), glm::radians(180.0), glm::dvec3(1.0, 0.0, 0.0)); sides[0] = new TerrainNode(1.0, radius, T * R, glm::dvec2(0.0, 0.0), new TerrainTile(1.0, SIDE_FRONT)); T = glm::translate(glm::dmat4(1.0), glm::dvec3(0.0, 0.0, -1.0)); R = glm::rotate(glm::dmat4(1.0), glm::radians(0.0), glm::dvec3(1.0, 0.0, 0.0)); sides[1] = new TerrainNode(1.0, radius, R * T, glm::dvec2(0.0, 0.0), new TerrainTile(1.0, SIDE_BACK)); // So on and so forth for the rest of the sides As you can see, for the front side grid, i rotate it 180 degrees to make it face the camera and push it towards the eye;
      the back side is handled almost the same way only that i don't need to rotate it but simply push it away from the eye.
      The same technique is applied for the rest of the faces (obviously, with the proper rotations / translations).
      The matrix that result from the multiplication of R and T (in that particular order) is send to my vertex shader as `r_Grid'.
      // spherify vec3 V = normalize((r_Grid * vec4(r_Vertex, 1.0)).xyz); gl_Position = r_ModelViewProjection * vec4(V, 1.0); The `r_ModelViewProjection' matrix is generated on the CPU in this manner.
      // No the most efficient way, but it works. glm::dmat4 Camera::getMatrix() { // Create the view matrix // Roll, Yaw and Pitch are all quaternions. glm::dmat4 View = glm::toMat4(Roll) * glm::toMat4(Pitch) * glm::toMat4(Yaw); // The model matrix is generated by translating in the oposite direction of the camera. glm::dmat4 Model = glm::translate(glm::dmat4(1.0), -Position); // Projection = glm::perspective(fovY, aspect, zNear, zFar); // zNear = 0.1, zFar = 1.0995116e12 return Projection * View * Model; } I managed to get rid of z-fighting by using a technique called Logarithmic Depth Buffer described in this article; it works amazingly well, no z-fighting at all, at least not visible.
      Each frame i'm rendering each node by sending the generated matrices this way.
      // set the r_ModelViewProjection uniform // Sneak in the mRadiusMatrix which is a matrix that contains the radius of my planet. Shader::setUniform(0, Camera::getInstance()->getMatrix() * mRadiusMatrix); // set the r_Grid matrix uniform i created earlier. Shader::setUniform(1, r_Grid); grid->render(); My planet's radius is around 6400000.0 units, absurdly large, but that's what i really want to achieve;
      Everything works well, the node's split and merge as you'd expect, however whenever i get close to the surface
      of the planet the rounding errors start to kick in giving me that lovely stairs effect.
      I've read that if i could render each grid relative to the camera i could get better precision on the surface, effectively
      getting rid of those rounding errors.
       
      My question is how can i achieve this relative to camera rendering in my scenario here?
      I know that i have to do most of the work on the CPU with double, and that's exactly what i'm doing.
      I only use double on the CPU side where i also do most of the matrix multiplications.
      As you can see from my vertex shader i only do the usual r_ModelViewProjection * (some vertex coords).
       
      Thank you for your suggestions!
       
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