Opengl thicker lines example. here i am giving only my draw() function.
Opengl thicker lines example 6 (Core Profile) Mesa 20. Mar 24, 2023 · The 1 pixel thick lines are very thin on 4K and retina displays so we would like thicker lines so meshes are more visible. This easy by using a flat interpolation qualifier. 37) and the granularity returned is 0. I did something similar with this in SFML a while back and the hardest part was ending any line segment and starting a new one. Although they look like core functionality my experience is that lots of hardware doesn't implement these - the ones that do don't implement it consistently, and if they do implement it the performance hit can be considerable. Since lines are just 2 points, we can feasibly store the vertex data in a list. For that reason, when I'm drawing thick lines, I use odd values for the thickness. For computer graphics, we usually specify this width in screen pixels. Here's the result using a glLineWidth of 1 for comparison. FreeType TrueType Font Text. Text. render the front faces as regular filled-in polygons, covering up everything other than the extended silhouettes. GL. It involves drawing the object in wireframe with the GL line style set to use very thick lines, then over-drawing the image using the background color. NET 5. Aug 14, 2010 · vertex[line_t+1] and vertex[line_t+2] are the start respectively end coordinate of the line segment. Check what your OpenGL implementation actually supports via glGet() and GL_LINE_WIDTH_RANGE. But you see, the horizontal line is a 2px grey line. • In OpenGL, the programmer is provided the following primitives for use in constructing geometric objects. Nov 21, 2012 · The unit-square is very simply created from a two-triangle strip GL_TRIANGLE_STRIP, that turns into your solid line after the above transformations. I just want to draw a think line!! OpenTK examples. e. Hello Triangle. f, depending on the machine). But on Windows and Feb 12, 2018 · It provides several links to resources about using geometry shaders to draw smooth, thick lines in OpenGL, including forums discussing techniques for drawing antialiased lines and curves using geometry shaders. I know how you can draw triangles using buf Aug 26, 2016 · The red color line is drawn by using OpenGL default GL_LINE_STRIP, while the greenish line is drawn by using the shader program. Dec 29, 2009 · The nodes need to behave like dimensionless points, and the edges, like one-dimensional lines. However notice that due to computation of the line data points, the performance of the thick lines is nearly 6 times slower than the normal lines. Now, I understand that if I use a rectangle to achieve this effect, it will look a bit pixelated once the polygon is far enough. 0f) works perfectly, and enabling GL_LINE_SMOOTH doesn’t seem to make any difference other than slightly thicker lines. Jul 7, 2017 · Now the lines need to be . In my code, I tried hard to give a 1px #000000 line when you request a 1px #000000 line on the exact pixel coordinate, especially at horizontal/vertical condition. 5px outlines. 5 means half of the line is visible, 0 means the whole line is invisible) (default: 1) Mar 9, 2015 · If you just want simple thick lines in WebGL, it can be a bit overkill. 0f, 0. Everything is ok. Using a line width other than 1 has different effects, depending on whether line antialiasing is enabled. I'll be honest this approach really only makes sense vertical and horizontal lines, however, for diagonal lines, following this post, you could save the rectangle to a texture and rotate the texture. The vertex shader has to pass the normalized device coordinate to the fragment shader. seeing "jaggies"). I had tried to code by my own, but not get desired result, so i come here, help me to find out where i was wrong. This tutorial is perfect for The result with a line width of 1 is good enough: However, when I set a thicker line width (> 3), this happens: OpenGL render lines as quads, resulting in blank spaces between edges and a popping effect whenever the model is rotated. So, a line in our case is defined by two end points plus a width parameter. . Apr 18, 2017 1 min read. The benefit this gives you is that you do not have to know the original value of the line width in order to restore it. Mathematically, a line has no thickness per se and the thick lines we've been drawing so far were actually ribbon. Nevertheless, I would like to have thicker lines and I tried to do it by glLineWidth but it does not work. Mar 27, 2009 · Write yourself a routine that checks if the joins can be constructed from simple geometry without problems. Mar 8, 2016 · I am making a simple 2d drawing program in which i have an array of vertices(say a1,a2,a3,. One way to draw lines in modern OpenGL is by batching. Mar 3, 2004 · can the thickness of a line be defined…so that, for example, a thick line could be draw instead of a rectangle? Jan 13, 2016 · Use textures and bilinear interpolation to your advantage by emulating OpenGL's primitives via textures. All vertices are in one common buffer. It is known that the native GL_LINE_STRIP_ADJACENCY creates gaps when drawing a polyline. Whenever there is a need to draw a line in computer graphics, we need to take the help of the Line function. Thus if the model has interior curves that just barely touch the 90-degree threshold, it’ll just make a thin black line. For example, if you request glPointSize(2. McKesson. Using a texture (to emulate OpenGL's stipple patterns, for example) is quite sure to get you into a world of pain, with nonlinear interpolation of texture coordinates (which NVidia Quadros handle suprisingly bad, even compared to the mostly identical Geforce part). So, using the odd thickness value of 5, your example would look like: Apr 15, 2013 · Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand Aug 2, 2021 · Hi I would like to achieve a display-style like that: or that In my case I import a simple geometry of a house. I'm not sure how efficient this would be in your environment, but you can draw the aliased version of the line with thickness - 2 and then use Xiaolin Wu's approach twice to anti-alias the edges. Nov 11, 2011 · Only triangle_strip is supported (or line_strip if you need lines instead of triangles). 5 specification, section 3. On retina or high-dots-per-inch 4K displays these lines are very thin and faint and two pixel width lines would be better. • By default,each bit corresponds to a Aug 4, 2018 · You can use the class QLineWidth to set the width of rendered lines or QPointSize to set the size of points. A thin line might be one pixel wide, and a thick line might be three pixels wide. 2 the corresponding shader language version is 1. , 10. Also, these weird pointy edges appear when multisample is enabled: May 10, 2013 · My first issue is that w = 10 or w = 3000 (or any larger number) shows the same line thickness, but something smaller like w=3 produces a thinner line. See full list on vicrucann. Line - See also Thick lines with OpenGL core profile and Drawing a line in modern OpenGL. I tryed to set glScissor(-width_of_line, -width_of_line, screen_width + width_of_line, screen_heigth + width_of_line) but lines are still cliped incorrecly. I wanted to draw a line that will appear bigger when it's close. a) thick lines and . , you can use a geometry shader to expand your line to a quad around the ideal line (or, actually two triangles) which can pose as a thick line. pyopengl implmentation is May 8, 2009 · So I have an application with a wireframe type draw and I was wondering if anyone has any useful tips/hints on doing really good line Anti-Aliasing with basic OpenGL? Currently I… Enable GL_MULTISAMPLE. A moon is really just an OpenGL display list. OpenTK is a set of bindings to OpenGL, OpenCL and OpenAL. For example, here’s an orange line with a black outline rendered with two draw calls: May 24, 2013 · Hello! I’ve benn googling for months but I finally surrender. The circular fan on the right is drawn as 1px black lines by cairo_set_line_width (cr, 1. 0f); does not have any effect on lines, and they remain just one pixel thick (even if I try a whole range of numbers). I am able to render a wireframed cube. Note how the connection between the anchor point does not look broken compared to the red line. The example has a mode using OpenGL stenciling to avoid drawing the reflection not on the top of the floor. Jan 16, 2015 · "antialiased lines" is a different topic ("antialiasing" or "multisampling" determines whether the edges of the line look smooth against whatever is behind it, vs. It depends on the country, company, etc, but very often it’s drawn as a #opengl #shaders #line In this video, I'll show you how to draw lines with adjustable thickness using shaders vao vbo in OpenGL. Then you can click anywhere on the point/line, and the clip volume will be large anough to always contain the center of the point/line. 5 Enable GL_BLEND (with standard blend function) Set glDepthMask to FALSE Set glHint to GL_NICEST That is the basic stuff you can find in the Mar 3, 2014 · Lines/borders are simple with one color and 1px thick, but they may not always closed (do not form a loop). Please do not contribute May 24, 2016 · I think it draws thicker lines by expanding the line symmetrically outwards from the center, as given by the co-ordinates in the draw command, if that makes sense. To enable and disable line antialiasing, call glEnable and glDisable with argument GL_LINE_SMOOTH. Is Jul 30, 2015 · How can I draw many lines with GL_LINE_STRIP, but not to draw a extra line between these lines, because it jumps to next value? See image. Is there any way to get a colour gradient (red to blue) while drawing these lines so that v0 would be coloured red and v3 would be coloured blue? Oct 7, 2004 · The first technique I found is quick and dirty. gl_Position; gl_in is a built-in array (the size of the array is related to the number of vertices of the input primitive, here 3) that contains several variables, including the vertex position gl_Position. In such a case, one usually draws thick lines with triangle strips. All points are connected (v0v1,v1v2,v2v3). I need to draw the first line with GL_LINES and then draw the second line with the same length and an angle of 135° between them, the third line has also an angle of 135° to the second line, etc. Then draw lines using glDrawArrays (or Elements if your data is indexed) with mode=GL_LINES or one of the other line drawing modes. They should come out with thicker lines where the model edge stays closer to tangent with the eye vector for longer. Currently there are 5 implementations available in this repo: OpenGL lines - using glLineWidth(width_value) functionality. Jan 15, 2022 · Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. LineBasicMaterial( { color: 0xff0000, linewidth: 100 } ) ); But the linewidth property is ignored in Jul 12, 2016 · Yes, there is a parameter for that: ALIASED_LINE_WIDTH_RANGE. ) which is to be drawn using GL_LINE_STRIP . Thus, if you pass n vertices, you will get n-1 lines. OpenGL’s lines do not look very good. The faces are therefore drawn using GL_TRIANGLES, the edges are drawn uing GL_LINES with a separate vertex buffer. For best results also disable zbuffer writes during this pass. Jan 19, 2016 · OpenGL implementations are not required to support rendering of wide lines. (from the OpenGL 1. Jan 23, 2010 · glHint as the name implies is a hint to the driver. This is not the main repository, just a temporary import to allow Mono developers to make changes to this module. Jul 9, 2013 · I want to draw a series of connected lines (GL_LINE_STRIP) in following way. Aug 20, 2018 · There is no guarantee the GL_LINE_SMOOTH or GL_POLYGON_SMOOTH will do anything. 4. Read less For separate line segments, this is not very complicated at all. • By default,each bit corresponds to a Apr 16, 2016 · For the application I am trying to come up with the best strategy on how to render thick and smooth lines in 3D. Provide details and share your research! But avoid …. May 7, 2009 · The most consistent and portable way to draw think lines using OpenGL is to use camera aligned (otherwise know as billboarded) polygons. Apr 10, 2011 · You should be able to use technique of Loop and Blinn in the paper you mentioned. I have an array of all edges (lines) which are specified by two vertices. I want to make a loop to render it but I don't know how. To do so you have to check the join-angle, the width of the line and the length of the joined line-segments (line-segments that are shorter than their width are a PITA). Rather than a library, it is meant to be a number of reference implementations to produce thick, anti-aliased lines in OpenGL. Zooming should be "continuous" and "infinite", if possible. It also includes example GLSL code for using a geometry shader to close gaps when drawing thick lines. Mar 2, 2016 · The following diagram comes from the D3D10 documentation, but I feel it conveys primitive topology better than the diagrams in the OpenGL specification. These are the top rated real world Python examples of OpenGL. This will result in half the thickness of these lines extending outwards of the silhouette of the mesh. E. Nov 26, 2022 · Today I tried about a half-dozen of methods from shadertoy, to draw lines using a vertex-geometry-fragment shader, but none worked. With OpenGL, you can specify lines with different widths and lines that are stippled in various ways—dotted, dashed, drawn with alternating dots and dashes, and so on. vertex[line_t+1] and vertex[line_t+2] are the start respectively end coordinate of the line segment. After reading up on thick lines in OpenGL, I figured that this is relatively complicated, especially given my additional cylindrical shape in 3d requirement. for each vertex v_i_j where i is the index of the strip and j the index of the vertex in the strip. Only use thick lines when you need to see the lines clearly for example when highlighting a specific line. 0). It does not necessary achieve anything. The technique is described here. 1) This means that a line parallel to the x or y axis with integer endpoints will not be drawn at all. Line drawing is often not accelerated well on consumer-grade graphics cards, so this may be relatively slow. Aug 3, 2019 · I want to draw multiple line strips of different length. Apr 18, 2002 · I’ve drawn a 3D hollow cylindrical tunnel type of shape using glBegin(GL_QUAD_STRIP); I want the walls to have some thickness, but I don’t want to just draw a slightly smaller tunnel inside the tunnel…I want it to be completely solid so that if I were to then clip off the ends with two clipping planes, I would still see a thickness and not the appearance of one cylinder inserted into . The burden here is placed primarily on OpenGL (and your graphics hardware) rather than your application code. • Each geometric object is described by a set of vertices and the type of primitive to be drawn. Line antialiasing is initially disabled. render the backfaces as wireframe with thick lines. 2D Geometry. I followed accepted answer and other given solutions of stackoverflow, but it is wrong according to the screenshot. 0 feature level hardware without using MSAA or supersampling. gl. Wide Lines This may not seem much but this is an example of moving line segments using OpenGL 4. How can I make OpenGL clip thick lines correctly? May 24, 2013 · I didn't check it per-pixel, but for untextured, antialiased lines the results should be sufficiently similar. Obviously the flaw is with my software. 3) Is there a way to achieve this with some sort of arrays and not glBegin and glEnd? Python GL. The problem is more obvious with thicker lines (screenshots above used glLineWidth of 10). Asking for help, clarification, or responding to other answers. 0. A quad. The elongated quads will then look line wide lines and each ‘line segment’ can have its own thinkness. I'm using OpenGl 4. GL_LINE_STRIP_ADJACENCY) you actually have to supply additional data in your index buffer. Next, we have a global variable of type vec4 that will receive the position of a vertex, a GLSL vector that can store 4 values, by default this is initialized with (0,0,0,1). The coordinates have to be transformed from model space to window space. 1 of Loop and Blinn - this breaks up sections of the curve to avoid triangle overlaps, and then triangulates the ma Feb 5, 2021 · glLineWidth specifies the rasterized width of both aliased and antialiased lines. May 27, 2005 · If you want to use selection on thicker points/lines, you should increase the pick region (in gluPickMatrix, for example, the width and height parameters) to the same size as the points/lines you want to pick. Imagine a highway which is being constructed. Further information can be found below. This THREE. In 2D, perpendicular is simple. The actual functioning of glHint depends on the graphics driver. Sep 26, 2020 · Here, I can repeat the glBegin(GL_LINES) - glEnd() blocks multiple times to draw a fixed number of lines with fixed parameters. My problem is when I connect two thick lines together (thickness > 1) sometimes there are gaps at the connecting points of the line and I do not have a smooth edge. Set glLineWidth() to 0. For example drawing the GL_LINES primitives. For this case we turned on the multi-sampling. That's it. The GL_POINTS, GL_LINES, GL_LINE_STRIP, and GL_LINE_LOOP primitives can't be offset with glPolygonOffset(). Have you any idea what I am doing wrong? thx May 13, 2013 · The first line of the above shader specifies the shader language used, for OpenGL 3. Nov 24, 2011 · Since not all triangle edges should be visible, the edges are stored separately (simple example: in a cube, the diagonal edges should not be visible, although they are there since a quad is rendered as two triangles). glLineWidth(desired_line_size) If you require lines of varying thickness you'll have to call the function again with the new thickness before drawing each line. It doesn't appear to be complete, but if you get far enough for that to annoy you It can be used to draw thick lines with rendering APIs like OpenGL, which do not support line drawing out of the box. The // display list is created with create(), and the draw() method calls it. We submit two vertices for each point in our path, and pass the line normals and miter lengths as vertex attributes. LineSegments( edges, new THREE. 8 OpenGL core profile shading language version string: 4. Feb 27, 2014 · A good tutorial is one that explains the rendering pipeline and puts you in a much better position to assess what the tool of OpenGL is best used for. What you need to understand is that when you use a primitive type w/Adjacency (e. OpenGL Gems is the authorative guide on OpenGL programming published by Learning Curve / Education for software developers! This book in 3D C++ programming series clearly, and in easy to follow language, explains fundamental principles used behind programming 3D games using the OpenGL cross-platform framework. Texture. Render the thick line in the color you want the outline to be, and then the slimmer line with the interior color. Here’s an example of GL_LINES: Mar 7, 2019 · You can change the width of lines by calling glLineWidth. 0f}; glGetFloatv(GL_ALIASED_LINE_WIDTH_RANGE, lineWidthRange); // Maximum supported line width is in lineWidthRange[1]. Oct 31, 2012 · I need to draw a Polygon iteratively. I tried this example: const geometry = new THREE. Based on a lot of googling, I've come up with the following geometry shader: glLineWidth specifies the rasterized width of both aliased and antialiased lines. If shading mode is set to smooth, OpenGL will interpolate the colors along the line. I simply want to draw a line to the screen. 3. 1, then the point size is rounded to 2. Here I looked at a few ideas to provide mesh lines greater than 1 pixel wide. But there is also some need to customize the line. Hello Triangle - Windows Forms. Basically you'll need to offset each control point in the normal direction, both ways, to get the control points for two curves (inner and outer). Example usage Feb 14, 2019 · I want to draw lines with a customizable width (doing this with a uniform suffices for now). In order to see a line on the display, however, we need to give it some thickness. here i am giving only my draw() function. I’m writing a GIS (Geographic Information System). Besides not being needed often, if they are needed, you will normally want lines with a thickness greater than 1, which is not well supported (read as: fast) on all implementations. If the user only Mar 19, 2011 · If your lines will always be straight and you aren't looking to anti-alias curves, you can do a three-pass approach. For example, you might code the following: This OpenGL tutorial builds on the code from Lesson 1. Must be compatible with older OpenGL versions (down to version 1. For example you might think you want to draw 4 connected lines each made from 4 points. Oct 2, 2017 · I am trying to draw a skeleton of a cube (i. Here's an implementation to draw 2D and 3D lines in C++ using glm with shaders. Modern opengl (core profile), the line width is limited by system. Jul 29, 2016 · Example: I have two further points v2 and v3. I found there are many different resources on how to Line Stippling • In addition to changing line widths, you can create lines with a dotted or dashed pattern, called stippling • The pattern parameter is a 16-bit value that specifies a pattern to use when drawing the lines. That is, zooming in, the circles representing the nodes move farther apart but each one stays the same size, and the lines connecting them get longer but not thicker. With some heuristics you should be able to sort out all the trivial Line Stippling • In addition to changing line widths, you can create lines with a dotted or dashed pattern, called stippling • The pattern parameter is a 16-bit value that specifies a pattern to use when drawing the lines. You can rate examples to help us improve the quality of examples. Dec 4, 2024 · Learn about the WebGLRenderingContext. WPF 3D mesh. Here is one such tutorial that I found recently: Learning Modern 3D Graphics Programming by Jason L. 13. The lines should always have the same thickness, regardless of the camera projection or distance to where the lines are. Shaders are written in a C-style language called GLSL (OpenGL Shading Language). Therefore, I have to render complicated maps. You can query the range of supported line widths with: GLfloat lineWidthRange[2] = {0. Do the lines on my texture just need to be thicker? This renders perfectly anti-aliased lines on OpenGL ES 2. MeshLine class. Or a line needs to be thick in someplace. Each extra point results in a new line between the new point and the previous point as you can see in the following image with 5 point vertices: How to Draw Thick Mesh Lines. Thus, you get n lines for n input vertices. Also, to enable LINE_SMOOTHing, you need to have blending enabled. 3D Geometry. In three dimensions however, the problem is different. For example, for your hour-arrow, don't use a flat black GL_POLYGON shaped like your arrow. Compute Jul 21, 2012 · First, set use the shaderprogram. Then follow the technique in Section 3. if you look at the OpenGL specification documents - these provide excellent reference Nov 15, 2001 · Help! I’ve been trying to sort out this problem for ages, and I am not getting anywhere! It seems that glLineWidth(5. Fourth option: Use a separate texture for every element of your clock. g. Dec 17, 2014 · Hello everybody, I would like to render thick lines strarting from a list of points. 6. Apr 29, 2011 · When you draw a line in OpenGL, glLineWidth creates a fixed-size line, regardless how close the line is to you. Use of textures/images is excluded. MeshLine class on GitHub is a nice workaround. It supports common joint and end cap styles. This is done by expanding the line into a quad slightly thicker than the wanted line width and calculating alpha coverage values on the line edges in the fragment shader. This demo above expands the stroke in the vertex shader, where the thickness is a uniform. This is the geometry shader that takes in input point and creates the thick lines: /////… Line Stippling • In addition to changing line widths, you can create lines with a dotted or dashed pattern, called stippling • The pattern parameter is a 16-bit value that specifies a pattern to use when drawing the lines. 50. The order looks for example as follow: v_1_1,v_1_2,v_1_3,v_2_1,v_2_2,v_3_1,. 0 with GL_LINE_STRIP. Jul 22, 2004 · A thick line can be easily implemented by creating a tri-strip along the path, where every pair of points (one “above” the line, one “below”) is displaced by +/- a displacement vector, defined as the line segment’s perpendicular vector, normalized, and scaled to 1/2 the desired thickness of your line. 0 polygon offset extension and OpenGL 1. BoxGeometry( 1, 1, 1 ); const edges = new THREE. In case you're wondering what a line strip is: a line strip binds together a set of points to form one continuous line between them with a minimum of 2 points. Jul 18, 2011 · The circular fan on the right is drawn as 1px black lines by cairo_set_line_width (cr, 1. May 12, 2012 · What i need is to have smoother lines (anti-aliased) and from what I read, in OpenGL ES 2 that can be done with multisampling. OpenGL ES does not require the implementation to support line widths other than 1, which basically makes this solution unusable on mobile and WebGL, unless you are okay with 0. 3D mesh. Initially, stenciling is not used so if you look (by holding down the left mouse button and moving) at the dinosaur from "below" the floor, you'll see a bogus dinosaur and appreciate how the basic technique works. f on my machine) when composing polylines I want to avoid the look of "broken lines" (see example image below) This is because GL restricts you to draw only on the geometry you submit to the rasterizer, so you need to use geometry that encompasses the jagged original line plus any smoothing vertices. I have also tried using a 128x128 texture version. getParameter(gl. If the user only specifies 1 vertex, the drawing command is ignored. The GL_LINES drawing mode is limited: it does not support line joins, line caps, non-integer line widths, widths greater than 10px, or varying widths in a single pass. EdgesGeometry( geometry , 15); const line = new THREE. edges) in OpenGL. Problem is that , say there are 3 consecutive vertices : p Dec 28, 2020 · glBegin(shape) and glEnd() - shape is an OpenGL primitive (in OpenGL-speak) such as GL_POINTS, GL_LINES, GL_TRIANGLES, GL_QUADS, or GL_POLYGON. This is an example project that demonstrates how to draw thick and smooth lines / curves in 3D. a line starting at (x,y) = (5, 5) and ending at (5,10) will never have a manhattan distance smaller than 1/2 to any fragment center. Do you have any tiny working examples in OpenGL 4 that draws thick lines? I can't seem to replicate anyone's results. Suppose, if the user wants to draw a Red car, then the lines will definitely be in Red color. This code demonstrates how a The circular fan on the right is drawn as 1px black lines by cairo_set_line_width (cr, 1. When queried, it returns a range on possible values for a line width: gl. glBegin() instructs OpenGL to use the vertices that are drawn subsequently until the next glEnd() call to create the shape. b) as it is a 3d application, they basically must have an cylindrical shape (It would look very weird otherwise). If I understood your question wrong then maybe you can concertize it a bit more. All tutorials I found used a glVertexPointer, which is deprecated as far as I can tell. Maybe someone here can help me. Jun 9, 2014 · Unfortunately, drawing lines is a weak point of OpenGL. The OpenGL standard "deprecated" lines greater than 1 pixel wide, but I tested to see if current graphics drivers still support thicker lines. 1 (and later) polygon offset interfaces? Polygon Offset and Point and Lines Why doesn't polygon offset work when I draw line primitives over filled primitives? Drawing Coplanar Primitives Widthout Polygon Offset Apr 26, 2001 · The border lines won’t actually have a fixed width. glRotate - 58 examples found. 60 OpenGL core profile context flags: (none) OpenGL core profile profile mask: core profile OpenGL core profile extensions: OpenGL For horizontal and vertical lines just use SDL_DrawFillRect and make the height/width of the SDL_Rect to be the thickness. Given these limitations, it’s unsuitable for the line work necessary for high-quality maps. In 3D, we have the choice to consider a thick line to be a ribbon or a tube. 0 (windows) Hello Triangle. Enable GL_LINE_SMOOTH. 5. This leaves the edges of the thick wireframe lines that were protruding the object visible, and gives you your required outline. OpenGL will compile your program from source at runtime and copy it to the graphics card. Tom Goddard August 13, 2020 Modern OpenGL core profiles don't offer line widths except for 1 pixel. But how to do the variable line task? In other words, I want to create a function, which upon being called with x and y coordinates, adds a line to the bunch of lines already being displayed on the screen. Apr 30, 2006 · What's the difference between the OpenGL 1. Check gman's answer for more information. glPointSize(5. The trick is to know the start of the line segment in the fragment shader. This means that, if you want to use line thickness, the option below is the way to go: Use the THREE. Here is the full source, including the line shaders: Apr 16, 2016 · By thick and smooth I mean: line thickness can be more than OpenGL maximum linewidth value (it seems to be 10. The demonstration of ability to produce much thicker lines. One method is to alternate between vector containers of vertices and draw the currently selected vector. 050 What other options do I have for drawing coplanar primitives when I don't want to use polygon offset? You can simulate the effects of polygon offset by tinkering with glDepthRange(). Line Details. Aug 21, 2022 · I am trying to implement geometry shader for line thickness using OpenGL 4. You can use glPushAttrib (GL_LINE_BIT) before you set the line width for one line and glPopAttrib when you are done drawing that line. x, . Hello Triangle - WPF. • Each bit represents a section of the line segment that is either on or off. glRotate extracted from open source projects. Apr 6, 2014 · @Shuvo0o: Since you are using deprecated OpenGL, you still have access to the attrib stack. ALIASED_LINE_WIDTH_RANGE) // returns [1, 1] on my machine, for example Mar 29, 2021 · OpenGL vendor string: Intel OpenGL renderer string: Mesa Intel(R) UHD Graphics 620 (KBL GT2) OpenGL core profile version string: 4. Only geometry data. github. Now the red lines are the actual values for the lines in the graph but the yellow ones are because it finished the values for line1 and goes on to next but still draw a line between these values. Jun 16, 2020 · Hello I'm trying to achieve the following: My current code for achieving this in OpenGL is the following: void draw_thick_line(vec2 start, vec2 end, GLfloat thickness) { GLfloat slope_angle = Oct 11, 2003 · I have a problem with thick lines - they are cliped incorrectly, as if they were 1 pixel width. The thickness of the line should be set in pixel unit (uniform float u_thickness). Line. g). If you have not downloaded and set up GLUT on your machine, you will need to do that. f on my machine) when composing polylines I want to avoid the look of "broken lines" (see example image below) At the moment I render my polylines by using GL_LINE_STRIP_ADJACENCY. Nov 18, 2019 · Outlines can be accomplished by rendering a thick line with a slimmer line on top, using the same data set for each. io This repository explores different ways of rendering wide lines using OpenGL. vertex[line_t] and vertex[line_t+3] are required to compute the miter. glVertex2f(x, y) - Sends a vertex to OpenGL. Sep 24, 2005 · Hi, I’m making a program that draws lines by coloring in each pixel one at a time to form the line (using Bresenhan’s algorithm) and the line can have thickness from 1 to 15. When all else fails Additionally, when viewing the lines from the side (so the line is nearly perpendicular to the camera) I get these bumps (marked in yellow). For benchmarking, see the benchmark section. If you are looking to draw thicker lines on a wireframe model you can use the wireframe example as a basis. I wouldn't be surprised if it topped out at 10. Must be used between glBegin Apr 18, 2017 · OpenGL; Programming; Computer; Life; Tags; X; OpenGL; Programming; Computer; Life; Tags; Draw thick lines in opengl core profile. • By default,each bit corresponds to a The thickness of such lines is rather intuitive because they live in the screen space. This tutorial covers the 10 geometric primitives in OpenGL: Points, Lines, Triangles, Triangle Strip, Quad Strip, Line Strip, Line Loop, Quads, Polygon, and Triangle Fan. lineWidth - width of the line (if sizeAttenuation is true, the value is in world units; othwerwise it is in screen pixels) (default: 1) visibility - A number from 0 to 1 denoting the portion of the line that is visible, starting from the end (0. // The reason we don't create the display list in the constructor is that // clients may want to declare moon objects before the call to initializing // OpenGL. In order to draw a free width line smooth, we draw multiple triangles to construct a thick line. for example, I want to draw a Polygon with 8 corners. One of the main challenges consists in drawing thick dashed lines (roads, e. Another restriction of the above mode is that thickness cannot surpass certain threshold (e. Some implementations consider Nov 21, 2012 · The only way to achieve varying line thinkness among the various line segments in a single draw call would be to use a geometry shader: turn the line primitives into screen-aligned quads (along the original line) inside the geometry shader. GL_LINE_LOOP: As line strips, except that the first and last vertices are also used as a line. Ignore the first line of this answer - the rest of the answer is correct. Like TRIANGLE_FAN and TRIANGLE_STRIP the situations to use them are rare. Here's a code example for 2D lines with different color in each end. The thinest part of the white lines are only a couple of pixels thick. Feb 15, 2023 · The Line function can only be able to draw lines. gl_Position = gl_in[i]. – Note: Native OpenGL is no longer a valid solution since the latest OpenGL versions no longer support line thickness either. OpenTK 4. You can see from the code that I have tried using some methods specific to this technique but I was unable to fully understand their usage and got bad results: Jul 18, 2020 · GL_LINE_STRIP: The adjacent vertices are considered lines. Each version of OpenGL has its own version of the shader language with availability of a certain feature set and we will be using GLSL 1. Different implementations of the OpenGL API handle the end points of the lines differently and GL_LINE_SMOOTH produces drastically different results depending on the platform. lineWidth() method, including its syntax, code examples, specifications, and browser compatibility. By thick and smooth I mean: line thickness can be more than OpenGL maximum linewidth value (it seems to be 10. This is accomplished through pyglet like so: pyglet. These primitives are simple shapes May 17, 2013 · I was doing tests where I composite a motion tracking scene with an opengl render, but the lines were barely visible so I was wondering what possible ways there are to make them thicker? See the example: Feb 27, 2014 · GL_LINES have little use in games (mostly useful for CAD or modelling apps). I found that Mac OpenGL only supports 1 pixel wide lines. Can anyone help? Similarly LINE_LOOP and LINE_STRIP are not so useful and have similar issues. uzjulxaqgzfenneforzetzlhuvlnzshpwompghahxigscakzumohzmzhenbnjkwqfedfrhyojjjrtwcdt