Opengl transparent sphere. accessing glsl variable from java.
Opengl transparent sphere These things are like very specific. 3, but you probably want to use a uniform, or read it from a RGBA texture ( TGA I'm trying to render a spherical panorama in OpenGL by mapping it onto a sphere centered at the origin, and also placing the camera the origin. If i multiply the radiance of the object by the shadowRay output, it seems like only the "edge" of the sphere is lighten up. Improve this question. I need both sphere to be displayed on screen. That is something you can not do efficiently with OpenGL; all the internal reflections in anything more complex than a sphere or a cube are hard to deal with. Opaque fill (OK): Transparent fill (bad): Opaque texture (OK): Transparent texture (bad): I am relatively new to OpenGL and C++ in general and I've been working on a custom framework in which I am asked to render spheres. icare3d. Here is a good article explaining why you can't achieve the perfect transparency: Transparency Sorting. 5 }; glMaterialfv(GL_FRONT, GL_DIFFUSE, diffuse); picture (but it does get . GLU Remember to import OpenGL. Whenever I try to draw something it some why draws semi-transparent like this, but I want it opaque: The fragment shader is #ve ebnable depth test enable backface culling enable depth writes disable alpha testing disable blending draw the sphere if the stars are still before the sphere post a screenshot + small (5-10lines) piece of code. If you want to render transparent layers with OpenGL you dont typically depend on texture-files to hold the transparency but instead use the GLBlendFunc(). OpenGL draw transparent sphere over solid sphere. Any reasonable way of defining the coordinates is acceptable. A standard technique is to use a ray/sphere intersection test inside a pixel shader. Currently, in order to minimize I made the sphere semi-transparent so it's easy to say when the particle is on the front side and when it is on the back side of the sphere. I've rewritten it in JavaScript for canvas and I've got a demo rendering the earth as a sphere : create your own sphere mesh. When the texture is bound to the object it shows through to the solid color of the object itself. A sphere is drawn using a grey material characteristic. Blending blends resulting colour with framebuffer based on resulting alpha value; after that, your 'transparency' is gone, you can't add something behind what is already drawn (or at least not directly via You can do it by enabling culling, and using two draw calls - one with glFrontFace(GL_CW) and another with glFrontFace(GL_CCW). Always. OpenGL Set Transparent Color for textures. – isti_spl. I came up with the idea of using a sphere. OpenGL Sphere Creation (Version 2. Rather than calculate the many vertices you'll need to replicate a smooth sphere, you can take advantage of the fact that a sphere looks pretty much the same from any angle. I use it to draw some spheres flying around 3d space. 0, let me suggest an alternative approach for creating smooth spheres, and that's to draw them as raytraced impostors. 7f, 1f); and gl. If I can draw the cube and the sphere, I've no You can simply draw a transparent sphere with some glassy texture and be done with it. org/2010/06/fast-and-accurate-single-pass OpenGL program using GLM, GLEW and GLFW libraries featuring a transparent scene cube defining a scene, within which smaller moving geometric solids interact. Noticed that when I use a texture with 255 alpha, it appears brighter. Think of these as the uniforms. I think the problem is that I'm inside the sphere, so opengl will just ignore it(not draw it). It seems like gluSphere and related functions are all deprecated for some reason. Date: Sat, 06 Feb 2010 09:15:12 -0800 From: cessenat at free. How developers (really) used AI coding tools in 2024 I want to apply a texture from a . With modern OpenGL, it is possible to implement: Movie with invading spheres Can I add a Yeah, I had no idea that for some reason, geometry is made out of many matching vertices. I ve done research and managed to generate a somewhat-sphere made from points. 0, 1. x. 0 Androi. c++; draw two seme-transparent spheres on top of each other then move them apart or something like that. Assigned the same texture to each square, which shows correctly. I verified multiple times the code without finding where the problem comes from. Share. You’ll have to remove the index buffer, though. I then textured it, and did the blending, with the GL_ONE, GL_ONE blendfunc and got a semi- transparent texture with quad lines visible in the non-transparent part of the second texture am I making any sense? Hellos, I have a light and a transparent sphere. I want to use it to render a transparent background. GL_BLEND); This has however no effect and the object in front is still transparent. c. filled boundary plot of 'stars' with reduced opacity and 'sphere' point type. OpenGL: Transparent texture issue. h> #include "Cluster. However I have many of this objects but do not want to see through them to see the other Those transparent fragments that fall behind the non-transparent one — well, they don’t pass depth test and are discarded, naturally. Look here for a GIMP tutorial or here for a Photoshop tutorial. Of course, certain way to get desired result is to Here's an example. See the function xyz. This way you will always have an alpha channel, even if it was not specified in the PNG. Couldn't see any thing lit! OpenGL draw transparent sphere over solid sphere. I've checked, my texture files is a PNG with transparency. GLU I've asked a question at How create a camera on PyOpenGL that can do "perspective rotations" on mouse movements? and the example answer might help you. spheres3d(dat[4,],col=rgb(1,0,0), alpha=0. GLViewWidget() sphere = gl. Blending Advanced-OpenGL/Blending. Transparency for PNG textures in OpenGL 1. I draw two triangles by pressing a button (function on_drawMapPushButton_clicked()). Especially since the sphere is rendered so close to the edges/corner of the screen where you might not think to look. fr (Olivier Cessenat) This post was imported from the visit-developers@ornl. 5 Quick summary The game work fine, but have graphical issues on some effects, It exists in OpenGL and Vulkan, and trying any settings doesn't help. You need to make an image with alpha transparency. I've put the camera on the origin watching (0,0,-100). File formats like TGA aren't just a byte[] array full of the color values of each pixel, there are file headers, compression, etc. Here, we simply hardcode the alpha channel at 0. Simply we can’t change the color of object while running for this we have to create a timer thread by using . Sphere(); Then I create a material and set its colout with alpha value. This tutorial takes a basic stencil buffer, and uses it as a stencil to Numeric vector of point coordinates corresponding to the center of each sphere. I always see my red object against a black background. But now openGL will expect xh*4 texels, so allocate another buffer, just like (GLubyte *)malloc(tga. We want to do that in a way which is transparent to the other parts of the code and one solution is to Firstly, your coordinates maps incorrectly to the screen pixels (and mouse coordinates are given in screen pixels, starting from top/left). This is done with SDL_GL_SetAttribute, for example: When I try to render transparent shapes in Processing using OpenGL mode (fill(r, g, b, a)), it works fine. The Overflow Blog Breaking up is hard to do: Chunking in RAG applications . I expect that the sphere is always in the middle of my camera when I perform pan and tilt movements. A single light source illuminates the object. Quadrics. depthFunc to gl. If you are OK with only two alpha values (zero and one), then you can enable alpha test (glAlphaFunc) to discard the transparent fragments completely. system July 7, 2003, 2:31pm 1. I just want to change the background. Since the depth of the viewing frustum is significantly smaller than the diameter of the sphere (less than half), only a sliver of the sphere will be within the viewing frustum, rendering only that part. The problem is whenever I draw my image IMG on the screen it appears everywhere where the image has been drawn, whether the pixels are transparent or not. Android GL_BLEND no alpha and GREEN Background. Transparency is all about objects (or parts of them) not having a solid color, but having a combination of colors from the object itself and any other object behind it with varying intensity. A vivid shade of gray remains. Thread per window, seperate context per window. Hot Network Questions Finding additive span of a list, without repeating elements Destroying scales draw small spheres on cube vertices in 3D using tikz Multisampling to a seperate FBO; Resolve the multisample to a FBO. You can sort whatever you want with qsort (in C) or std::sort (in C++). gov email archive Hello, I use the galaxy. I want everything which is rendered to the framebuffer to kept their transparency. SharpGL. I can make the texture transparent by using glColor4f(1. 0, 0. Sort the transparent triangles; Render the transparent triangles from back to front. Usage is simple after OpenGL context is created and extensions loaded call sphere_init() before closing app call sphere_exit() (while OpenGL context is still running) and when you want to render call sphere_draw(). If not then you can use single The second method would be to use an inscribed sphere, where the sphere is tangent to the faces of the cube (the sphere "touches" the centers of each cube face) and has a radius that is calculated as edgeLength*0. So i'm making a raytracer in OpenGL, fully shader based, and i'm struggling to know where the problem is with my Shadow rays. Snapshots: default (shown). scratchapixel. Here, the transparent sphere is inside the opaque sphere. 1 Rendering transparent geometry OpenGL. glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, i have to draw a sphere containing a cube using OpenGL, and I want my sphere to be transparent, to view the cube in the sphere. The skybox technique can actually be implemented using a sphere as well as a box. When you're rendering semi-transparent objects, you need to follow those rules. Suggested fragment shader: OpenGL draw transparent sphere over solid sphere. accessing glsl variable from java. Then for each texel, copy the R,G and B components from texture->imageData to the new buffer. Hot Network Questions Bidirectional rsync synchronization Does Ic reverse its current flow when BJT in common-emitter configuration goes from linear to saturated mode? Why are they putting insulating blankets around the new space coronagraph? OpenGL program using GLM, GLEW and GLFW libraries featuring a transparent scene cube defining a scene, within which smaller moving geometric solids interact. If you can't simulate the glowing effect with one sphere you could try to put a smaller brigther one into a colored transparent sphere. After half an orbit the yellow sphere is still drawn in front, even though it is further away. Disable blending after the cube is drawn or before the sphere is drawn and it will work. Improve this answer. EDIT: I'm updating my question to just have so example of the current state of my code. In my rendering loop, I calculated the coordinates of the sphere in the following way: So i have a transparent window with OpenGL 3. x through to 4. SceneGraph. Created a texture with a 200 bit alpha value (so, about 80% transparent). You can use a loop with sin and cos to generate the points. Remember to import OpenGL. I have created a shpere with texture and displayed correctly using opengl es on Android 2. However, the shield doesn't appear and the colors don't blend( as if it was not there ). for (int i=0; i< Skip to main Why might I see this OpenGL spherical mapping artifact in Please help with identify SF movie from the 1980s/1990s with a woman being put into a transparent iron maiden The non-opengl code can be pseudo (I don't care how you sort an array or create an GLFW window). I have seen this ticket, and it (There's also transparency: Alpha). More information here: I'm currently trying to learn OpenGL, and I'm having trouble with texture transparency. 0]). fastTransparency: logical value indicating whether fast sorting should be used for transparency Making 3d Models Transparent in OpenGl and OpenFrameworks. u should never Processing Forum Recent Topics. The code looks You render spheres after the cylinder, thenre is no way you'll see back spheres through cylinder - it's already rendered at that moment. h" // My own class. Maybe you could just show me how to make a sphere replicate. Yes, it is possible to do mouse-picking with OpenGL: you render all the geometry into a special buffer that stores a unique id of the object instead of its shaded color I am trying to add a transparent object in front of an image containing white. opengl as gl . e. You need to test against the depth values generated by the opaque objects for this to function correctly, otherwise you have to sort both your opaque and translucent objects (which is exactly what you did OpenGL draw transparent sphere over solid sphere. The most common blending function is glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); You can also check out the OpenGL Transparency FAQ. 5. Follow answered Mar 30, 2010 at 7:07. I use the width and height and divide the screen to get a Opengl point for every pixels. Next I set the new material to the sphere. where p is the point i am querying, s is the location of the sphere, and r is its radius. Again, there will be error, but this one will actually tend to have a bit MORE error, since it will be "underreactive" at 8 points You can plot transparent spheres using the alpha argument to spheres3d. I know that I should first render inside opaque objects and then transparent sphere but how ? I have something like this already but not working properly. Use something like this before drawing your sphere: // enable blending. It worked fine while i was calculating the distance to the spheres with: d = length(p - s) - r. imageSize); but with xh*4 bytes. 0. I'm creating a sphere like this. Hope this helps! This method enables or disables transparency. First draw call will draw back faces of sphere, and second one front faces, therefore you will get transparent sphere with correct polygons rendered from back to front. 2. It puts the data for 4 models (cube, sphere, cylinder, torus) into a texture (vertexDataTexture). Hi everyone, right now I’m depth sorting my models and rendering them from furthest to closest, so that I can use opengl’s built in transparency. (EDIT: win32 would be just fine if cross compatibility is a problem) In the official documentation , ofBackground seems to accept alpha blending, but when I write ofBackground(0, 255, 0, 10); and run the project, the window is not transparent. 1) first_layer, just one color. Some of the tasks include window setup, dynamic appearance of elementary objects on spacebar press, user-controlled sphere movement, camera The whole strategy is to effectively render spheres as sprites but trick it out to intersect the scene properly like a real sphere by calculating each point on the sphere's depth coordinate (I've done this with raymarching fragment shaders that must produce a result which intersects with existing 'scene' geometry in the depthbuffer, the Z Over ten years ago I wrote a Java applet to render a textured sphere by actually doing the math to work out where the surface of the sphere was in the scene (not using triangles). But I couldn't light it from inside. There is no problem at all but i have to select some region of the grabbed frame then i have to zoom it, first of all i can't draw a Rubber rectangle it must be transparent when i select the some region of grabbed frame i have to see textured frame transparently could you gimme im rendering png's on simple squares in opengl es 2. Now load the texture indicating the correct image formats. Or if using modern OpenGL (recommended) write an appropriate shader that takes the background color into account. The program automatically checks whether depth peeling is supported or not. Hello, I am trying to draw transparent sphere and something inside it (obj model) but I cannot render it properly. More virtual void setTransparencyLevel (const float a_level, const bool a_applyToVertices=false, const bool a_applyToTextures=false, const bool a_affectChildren=false) Android OpenGL Transparent Texture Draws Black. – As part of my 2D game engine, I would like to be able set the order (from back to front) in which my sprites are rendered on screen by manipulating their z-index. transparent object. radius: Vector or single value defining the sphere radius/radii. I want the color gone, or at least transparent. LWJGL tutorial series on how to create a 3D Java game with OpenGL!This week we add support for textures with transparency, allowing us to add loads of low po I'm using SharpGL library for Visual C#. SRC_ALPHA, BlendingFactorDest. Semi-transparent textures appear semi-transparent, but they're also getting white, color from the texture isn't considered while rendering That's what I've set: gl. We The eye position does not change. You may have to register or Login before you can post: click the register link above to proceed. MeshData. a "wireframe" sphere centered in 0 with a radius of 1; a point at coordinates [0, 0, 0] a vector that starts at this point and goes to [1, 1, 1] How to do that? python; matplotlib; geometry; matplotlib-3d; Share. I create the one texturized sphere, and then created the cloud sphere surrounding the first sphere, and slightly larger. You can rotate the plot to move the box line behind the sphere to prove it's transparent. Added WithAlphaComponent to initialDisplayMode. OpenGL calls such a texture a Cubemap. simple 2D loop through 2 angles (spherical coordinate system 2 Cartesian). You don't transform the geometry of the faces themselves, instead you make sure that you draw the faces in the right order: farthest from the camera first, nearest to the camera last, so that the colour is blended correctly in the frame buffer. The effect I'm trying to achieve is an object with a crack, and you should be able to see trough the crack. Ignore the fact that the model is somehow drawn on top of the background, that's because it is a bounding box for a light, but the concept is the same. So I thought about using the ALPHA_TEST but it's gone in the latest OpenGL versions, so I tried to discard fragment with v_color. Complete sourcecode here, the relevant bit (i think): GLfloat diffuse[] = { 1. 0. I want to do the same to the background. Hot Network Questions Sci-fi book where the protagonist has a revolver that gives him faster perception and reflexes How to use alpha transparency in OpenGL? 2. This is true for all OpenGL state. "I know I can do it if I replace the black background with a transparent color instead using an image editing software, but I would like to get this working without that" Are you trying to say that the black background is Is there any example code of a transparent sphere or cylinder, cube, whatever that you can show me? – UndefinedReference. Creating 'laserlights' with Java3D/other 3D API. I then set glDepthFunc(GL_LESS) for drawing the cube and glDepthFunc(GL_ALWAYS) for drawing the sphere It wasn't that good looking. Copy pixel data out of FBO instead of BPO. GLSL - Set color of vertex. OpenGL Basic Shadows (Version 2. So it feel that is very hard to do mouse picking intersections on a global scale. I try with gl. a == 0 or v_color. I am playing around with marching spheres for rendering. C 0 in formula (2) is color of the non-transparent fragment rendered in that point (x, y). Demonstrates "screen door" transparency using OpenGL's polygon stipple feature. 1 Drawing a transparent object inside an opaque one. All Forums OpenGL transparency not working properly. I want to add transparency to objects that I'm drawing. I need to load it to my program that uses SDL and OpenGL on C++, but when I try it, instead of it displaying correctly, the space around the bag in the image is "fuzzy" (I can only put it that way). Blending in OpenGL is commonly known as the technique to implement transparency within objects. 5. 0) With lighting, comes shadowing. anim = gl. Opaque fill (OK): Transparent fill (bad): Opaque texture (OK): Transparent texture (bad): Basically you need to calculate the lighting in vertex shader and pass the vertex color to the fragment shader if you want a per-vertex lighting or pass the normal and light direction as the varying variables and calculate everything there for the per-pixel lighting. Also, gluOrtho2D defines a clipping region of depth from -1 to 1. Your sphere is similarly being rendered at the origin, so your viewpoint is at the center of the sphere. To start viewing messages, select the forum that you want to visit from the selection below. I draw my objects like this. T = triangles, Nv = vertex normals. This would give the illusion that the triangle is floating on The reason for this is that OpenGL doesn't really support transparency, it emulates it through alpha-blending, and so if a new object is drawn behind a "transparent" primitive after it has already been rendered, the new object will not be visible through it. However, when I use the same code in ProcessingJS, transparency is ignored and my shapes are opaque. Ray Tracer not rendering sphere properly. 2) semi-transparent sphere, that blends with first_laye OpenGL draw transparent sphere over solid sphere. Trying to draw sphere in OpenGL, Only part of the sphere is showing, seems clipped? Hot Network Questions Does the earliest known use of an "average" occur after the invention of calculus? I tried to paint a transparent texture over a sphere, but the transparent areas are not completely transparent. With Processing 4, I'm able to draw an opaque sphere OK, but a transparent sphere PShape looks wrong. That got me thinking, so I just used gl_FrontFacing to colour front vs back facing fragments differently, without any transparency. glColor4f(0. 1 How to clip this part of mesh in Opengl? Load 7 more related questions Show fewer related questions Sorted by: Reset to default Know someone who can answer? Share a link to this question Some things to consider: Do you really need to draw millions of points? Perhaps you could get away with only drawing the points on the surface, in which case you check to see if point center > radius of the sphere - some threshold, and only Ie I want it to act like the spheres are solid but want to I want to be able to draw an arrow inside a sphere. OpenGL - How Transparency works? 0. 4. Ambient and specular light source also at the origin. . OpenGL. I tried to construct my own textured sphere, but ran into a ton of issues, such as incorrect texturing at the boundaries (the same issue is described in this post). I want to use Python PyOpenGL for generating a scene of three spheres. able to provide a customized shader in libgdx? If so, create a shader that samples from the mask texture and also the sphere tex so that the mask is applied in the fragment OpenGL draw transparent sphere over solid sphere. ; Changed color to a Color4 with 0. DrawOBJ(head->m_iMeshID); renderSphere_convenient(0, 0, 0, 15, 10); any ideas how to do One object should be displayed in front of 2 objects with transparent textures. C output from data I chose a sphere too, but with a larger radius and set the alpha factor 0. In WebGL, we can draw transparent sphere by setting gl. More bool getUseTransparency const This method returns true if transparency is enabled, false otherwise. I would like if possible to reform it so I can have an actual sphere made from triangles having properties such as radius. Source code: screendoor. If you fix the internal format & it still doesn't work, edit your post to include an MCVE so we can see the rest of the code. As you can see from the picture, for each blue triangle, there is a transparent triangle to its left. Unfortunately, transparency is not a "flip a bit and it works" feature in OpenGL. It’s working okay, but it breaks down when one model intersects with another or is inside another (imagine a semitransparent sphere bouncing around inside another semitransparent sphere–which one is further back?). OpenGL: Basic Coding. Sphere sphere = new SharpGL. Correctly rendering translucent geometry with OpenGL-functionality in the background (as in the case of VTK) This example program generates a set of intersecting (overlapping) spheres that have transparency properties. The z-buffer will prevent transparent objects from being displayed behind other transparent objects. I was expecting the object to be drawn with some level of transparency, depending on alpha value. The object in front should not be transparent, but I can not disable transparent textures for that object. ; I would expect it to display a semi-transparent white square with the background red showing through. don't forget that OpenGL isn't a raytracer, you will need to submit your graphic primitives in depth order (ie draw background first then foreground objects) to achieve blending. You can easily add ellipsoid properties (earth is not a sphere) if you want more precision. I make an gl_draw() example with some settings and here the preview of it: With Processing 4, I'm able to draw an opaque sphere OK, but a transparent sphere PShape looks wrong. I want to add a 2-D PNG with alpha such that, transparent section of my PNG shows the sphere. You can use the mergeVertices function in BufferGeometryUtils to dedupe verts, as well, and get a position buffer of unique vertices. However after I plot the trajectory, even the parts that are supposed to be behind the sphere are the OpenGL transparency not working properly. You can do this by sorting your scene, which is what you have to do anyway to get transparency working correctly. com) that I use to write a image to memory that I then display at once using Opengl (glut). Thread: [PyMOL] shade on transparent spherical surface PyMOL is an OpenGL based molecular visualization system Brought to you by: In the current PyMOL version, you may see two artefacts for semi-transparent spheres in real-time rendering: 1) The "shading" that you describe comes from unsorted triangles. Instead it shows a solid white square, as if the opacity is being ignored. Since we are using pixels here, your sphere would appear as a longitudinal slice of 2 pixel wide (just a ring). about texturing im not sure if either sphere drawing method does texturing u say the glusphere method does so use that. glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // set color and alpha // draw your sphere // disable blending glDisable(GL_BLEND); You typically disable depth writes (e. Including newly revamped tutorials. One draws a billboard large enough cover the area the sphere could appear on the screen (or drawing a bounding cube) to reduce the The problem is that in the transparent part it's showing solid white. OpenGL Texture Transparency. Having trouble rendering a sphere in WebGL. There are MANY tutorials for "opengl alpha blending" on the internet - here is a C++ and SDL video tutorial. I have a ray tracer (from www. I Hi I am trying to draw a cube (each side with a different color) with one of its sides (i. Also give a look at Order Independent Transparency with Dual Depth Peeling article which covers two methods (one is quite straightforward and single pass) used to have exact (or approximate) order independant transparency. 1 How to clip this part of mesh in Opengl? Load 7 more related questions Show fewer related questions Sorted by: Reset to default Know someone who can answer? Share a link to this question You can use sphere = gluNewQuadric() and gluSphere(sphere, x, y, z) when you apply it. What should I do to disable transparent Here the yellow sphere is drawn in front of the purple one, as it should be. The camera is located in the center of the 1st sphere. ONE_MINUS_SRC_ALPHA); What are the possible solutions? When I'm drawing, the transparent part of the binded texture is white. Then i draw a sphere that placed above these triangles. Since you've tagged this with OpenGL ES 2. For transparency see OpenGL - How to create Order Independent transparency? but as you want the exact opposite you need to enable GL_DEPTH_TEST however if you have enbled GL_CULL_FACE then the faces winding must be consistent with glFrontFace setting GL_CW/GL_CCW if its not then you see the cube sort of inside out from certain sides which is replace GL_RGB by GL_RGBA in glTexImage2D(). Generating a Sphere. 0) This allows for varying levels of transparency across objects. I combined the signed distance functions with Therefore, I need to create a transparent fullscreen window. I want to be able to draw an arrow inside a sphere. I want to draw a glutSolidSphere with some transparency, but it doesn't seem to work. First draw call will draw back faces of Everything can be transparent. However the framebuffer always renders as opaque when binded to a texture which is rendered to the screen. Using the Haskell GLUT binding, I modified the Hello World example in two ways:. i'm using OpenGL for showing grabbed frames from video camera with texture mapping. I have 2 planes/rectangles that are textured, the first is closest to the camera, the second is further back, behind the first one. opengl-es; transparent; or ask your own question. Hot Network Questions Solaris 11 cbe: no more updates? XeLaTeX does not show latin extended characters with stix2 Fifth year PhD student with no progress on my thesis because of advisor, what to do? More efficient / manageable way to code this HTA w/ VBScript? Does any one know how to make the effect that things replicate in OpenGL? (It is great if I can use glut and glm for that). Rendering transparent objects. 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; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Visit the blog It seemed there were depth problems as I could only see the back side of the sphere in parts in the bottom right. tga file that includes alpha transparency. I could achieve transparency with my PNG and another PNG textured on a Sqaure but when I apply same thing with Sphere it distorts the texture on Sphere. I combined the signed distance functions with Typically you enable depth testing with your opaque objects, then do back-to-front rending of transparent objects with OVER blending enabled. Drawing a sphere in OpenGL ES 2. Hope this helps! glutSolidSphere doesn't provide proper texture coordinates, and OpenGL built in texture generation allows only for linear mappings from vertex position to vertex texture coordinate, which essentially means that you can not use them to texture a 3-sphere with a 2-flat, bounded texture (for a mathematical explanation look up the topics of topology of manifolds glutSolidSphere doesn't provide proper texture coordinates, and OpenGL built in texture generation allows only for linear mappings from vertex position to vertex texture coordinate, which essentially means that you can not use them to texture a 3-sphere with a 2-flat, bounded texture (for a mathematical explanation look up the topics of topology of manifolds You need to make an image with alpha transparency. Hot Network Questions Are there any tutorials out there that explain how I can draw a sphere in OpenGL without having to use gluSphere()? Many of the 3D tutorials for OpenGL are just on cubes. TABLE OF CONTENTS00:00:00 Start00:00:03 Example00:00:19 Code Snippet00:00:28 EndNote:[1] Currently, because of the Manim (OpenGL Version) upgrade, the two pa Everything can be transparent. 27. Colored sphere in OpenGL. There is a trick to avoid the above complexity though. Hot Network Questions Elegant way to maximizing linear function subject to being on the surface of a sphere Advanced I am playing around with marching spheres for rendering. I tried with both front and back face culling, it didn't resolve the issue. And now i see, that sphere Unintuitively, alpha = opaqueness, so alpha = 1 means fully opaque while alpha = 0 means fully transparent. 9) # I'm wondering if it's possible to setup a window, with no decorations AND with the transparent background, while allowing me to render OpenGL stuff on it. You then just send that raw data to OpenGL and it handles it from there. 6. If it's front facing, it's green, back facing Plane Sphere Intersection, Plane Disk Intersection. How to draw Sphere with OPENGL library? 15. 0, but when i try and draw something behind an square i have already drawn the transparent area in my top square are rendered the same color as the I'm trying to draw a little sphere in front of the camera, let's say 5 units away (C++, newby in openGL and not very confident in trigonometry!). I'm trying to apply a mask to a texture with transparency. always. glColor4f(1, 0, 0, 0); // should be completely invisible glPushMatrix(); Sort transparent triangles, from the furthest to the closest Draw the transparent triangles. I set the diffuse material to make it transparent, but it doesn’t work at all viewing angles. sphere(rows=100, cols=100, One simple way of doing this is tesselating the sphere using latitude and longitude, like the lines on a globe. What would be glBlendfunc() parameters for achieving the following effect: 0) background, non-transparent. self. Changing the alpha value in the first line of your code doesn't make any difference. r == 0 in my fragment shader but it does However, with 2 translucent spheres I get that result instead: I know that, to achieve a correct transparency effect, the depth testing should be turned off before the transparent shapes are drawn. 3. Both are textured with an image that has a background at 50% opacity. I have a small sphere with an Earth texture and I want to have a slightly bigger sphere with clouds texture over it, that is transparent. 7f, 0. 1. This is what i Drawing a transparent sphere using OpenGL; If this is your first visit, be sure to check out the FAQ by clicking the link above. That means your PNG-parser converted transparent regions to the value of white. coords for details. Follow edited Apr 26, 2023 at 1:21. What you need to do is strip away all the excess from your TGA texture to retrieve the raw image data. I am able to use a mesh to create a transparent sphere like this in pyqtgraph opengl: import pyqtgraph. This is my code for generating UVs for a sphere. For this I use additive transparency //enable trancparency glEnable(GL_BLEND); // disable backface culling glDisable(GL_CULL_FACE); // disable depth buffer writing glDepthMask(GL_FALSE); // additive blending glBlendEquation(GL_FUNC_ADD); glBlendFunc(GL_SRC_ALPHA, GL You see background color because even if surface is transparent, it fills z-buffer with values, and since background is below car, it becomes invisible. Commented May 3, 2013 at 4:33. It then puts data for each object to be drawn into a separate texture (perObjectDataTexture). When the OpenGL documentation says "sort the transparent faces" it means "change the order in which you draw them". 5 opacity. What is the intention of first drawing a quad with the background color? I think what you really want there is to either use the GL_DECAL texture environment mode, if you insist on using the outdated fixed function pipeline. the top) being transparent and the rest being solid (so that when I rotate it, I only see the inside when the transparent side comes to view) my code (in VB) for the TOP-SIDE looks like this: glPushMatrix glColor3ub 160, 130, 50 glEnable GL_BLEND glBlendFunc GL_SRC_ALPHA, How to change the color of object in OpenGL(GLUT) using keyboard function If you have problem in changing color of object in OpenGL using keyboard while running program then this article may help you. In my project I have a requirement to draw a sphere (may be semi-sphere will be ok). This z-index sprite property is a floating point value which can range between the far and near planes of my orthographic projection (in the range of (-1. #include <GL/glut. All non-transparent objects should be rendered before semi-transparent objects. Turn on the depth mask glDepthMask( GL_TRUE ); Draw all opaque objects, in any order; Turn off the depth mask glDepthMask( GL_FALSE ); Turn on a BLEND_MODE; Draw translucent objects sorted from furthest away to Setting the modelview matrix to identity essentially puts the camera directly at the origin. I'm not using any textures. The code used to create the animation is given below. full transparent object in openGL. Here's what you need to do: Enable z-buffer writes and tests; Render all opaque objects; Render all transparent objects front to back. 5) but that's not what I want because it makes the entire texture transparent and not only the transparent part. With modern OpenGL, it is possible to implement: http://blog. But what you can do is precalculate pathtracing results, which at rendering time you look up into a cube map. The transparency is a bit messed up basically source is square grid image Help with drawing a sphere in OpenGL ES. I am having a problem with WebGL. This example draws the semi-transparent player (green) first, opaque background (red) second and then the semi-transparent window (blue). 5 ( opacity ). Still, self-intersecting objects present a problem that requires further work. A opengl texture transparent hack. 0 overlapping partially transparent shapes in openGL. But following this OpenGL draw transparent sphere over solid sphere. The whole image is not transparent, it's just a picture of a bag I have cropped in Photoshop, with transparency around it. I have a function that draws triangles through OpenGL. \$\endgroup\$ OpenGL Tutorials for OpenGL version 2. tazevam changed the title odin sphere leifthrasir have graphical issues I want to use glClear and glClearColor to fill a frame buffer with a colour including alpha transparency. 3. glDepthMask (GL_FALSE)) for the translucent objects, but the depth test itself is not something you would disable. 3 Context (Windows 8). blendFunc(BlendingFactorSrc. Two on the side with color (red and green). glDisable(GL10. Hot Network Questions Is mathematics just "a part of physics", as stated by Arnold in 1997? Especially since the sphere is rendered so close to the edges/corner of the screen where you might not think to look. Middle one with any texture on it (bricks texture which is actually square jpg file in the same directory as code is). For this purpose I used sin() and cos() methods to calculate the angle for (x,y) co-ordinates. g. However this cause another side effect when a transparent shape is beyond another non transparent shape: 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; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company There's multiple things that effect the end result of transparency in OpenGL though such as enabling blend & setting a blend function, so that one correction might not be enough. 3 Rendering transparent objects in OpenGL. Depending on how glut is rendering, this may render your sphere invisible, because you're looking at the back-faces of the geometry. Or you can do some nice refraction and lighting It is up to you to google for the info The creme de la creme of single-pass no (or few) compromises transparency in OpenGL is an A-buffer. The blend state is persistent and lasts forever or until it is set again into the next frame. At some (camera) angles, there are some weird darker patches. Drawing a sphere in OpenGL ES. These two questions on Stack Overflow have some example code that should be straightforward to adapt to Android: Creating a 3D sphere in Opengl using Visual C++ Check the spec By using it, you are telling OpenGL that you want it to throw away the pixels instead of drawing them, so you won't can any transparent blending. In this case there is a model matrix and a color per object. You can do it by enabling culling, and using two draw calls - one with glFrontFace (GL_CW) and another with glFrontFace (GL_CCW). The issue is well known but solution is rare. The modified code renders the lines transparent. Alpha blending can be turned on to make surfaces transparent, like so: glDisable(GL_DEPTH_TEST); The creme de la creme of single-pass no (or few) compromises transparency in OpenGL is an A-buffer. // Scale for animation. To hav transparency, you need an alpha channel, on your texture, but more important, in your framebuffer. If I change the object color to be transparent, then the texture as a whole becomes more transparent, which is not what I want. I have searched but most of the solutions to drawing a sphere are to use gluSphere(). cpkoegi iyykgm mcwo hlzacl olv vujz wked sjwzf gokthal etv