stencil-buffer

currently im drawing a background, then a transparent triangle into the stencil buffer, then a blue square where the triangle isnt being drawn. i was hoping the effect would be a blue square with a trianglular hole exposing the background. but all im getting is a black triangle drawn over everything else. i think im getting the desired effect on the square but the stencil is also being applied to the background. my question is how can i adjust the following code to allow the background to be displayed through a triangular hole in the square? static void Draw(void) { glClear(GL_COLOR_BUFFER_BIT

This is a continuation of my previous problem and post, seen here . Thanks to the answer I received there I feel I was able to get a little closer to my goal, as well as further my learning of OpenGL, but shortly after figuring out the basics of working with stencil buffers, I've run into a problem. It seems that when I draw a sprite to the stencil buffer, it draws the entire square area, rather than just the pixels that aren't fully transparent as I had ignorantly hoped. I vaguely understand why it happens that way, but I am not sure where the solution lies. I have experimented with the

I am trying to figure out a way to cut out a certain region of a background texture such that a certain custom pattern is not rendered on the screen for that background. For example: This square can be any pattern. I am using Frame Buffer Object and Stencil Buffer to achieve this kind of effect. Here is the code: fbo.begin(); //Disables ColorMask and DepthMask so that all the rendering is done on the Stencil Buffer Gdx.gl20.glColorMask(false, false, false, false); Gdx.gl20.glDepthMask(false); Gdx.gl20.glEnable(GL20.GL_STENCIL_TEST); Gdx.gl20.glStencilFunc(GL20.GL_ALWAYS, 1, 0xFFFFFFFF); Gdx

I'm having issues when drawing using the stencil test in OpenGL on mac. When I first draw the scene, the stencil works fine. I draw a semi-transparent black rectangle in the middle, with writing to the stencil buffer enabled, and then a larger blue rectangle with writing to the stencil buffer disabled. I get the right result when the window first pops up, which looks like this: However, when I resize the window, and the rendering function gets called again, I get a result which looks like: or Sometimes the weird white space follows the middle rectangle, other times the white snaps between

The documentation in OpenGL reference pdf (both OpenGL 3.3 and 4.5 specs) is not much clear about what happens to the stored stencil value when a mask is applied. In example If I have the following mask: glStencilMask( 0x06); and stored in the stencil buffer there is already this value: 0x06 If the stencil operation is GL_INCR_WRAP what should happens when StencilOp is correctly invoked on that pixel? Basically I have the mask: 00000110 and the value 00000110 and I try to increment it, is it wrapped? 00000010 or is it just zeroed? (00000110 + 1) & mask 00000000 derhass Section 17.4.2 "Fine

Can I have Stencil prepared with a texture (Image) in OpenGL 2.0 So that some part of the Image will be transparent and as a result it will be transfered as is to Stencil buffer and then will use this use this stencil buffer for further drawing. EDIT by datenwolf to account for OPs question update in a answer: By @InfiniteLoop: @datenwolf thanks a lot for ur reply but no success :( here is my code - (void)render { [EAGLContext setCurrentContext:context]; glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer); glUseProgram(program); glClearColor(0, 104.0/255.0, 55.0/255.0, 1.0); glViewport(0, 0,