stencil-buffer

问题 I'm using WebGL 1.0. I drew a circle to the stencil buffer, and now I want to use this stencil buffer multiple times without clearing it. The first time I use it, I enable stencil testing with: gl.enable(GL.STENCIL_TEST); Then, I perform my drawing to the color buffer. After this, at some later date, I want to draw again , but this time I want to clip to the inverse of what is in the stencil buffer. I know that I can draw to the stencil buffer again, but since I didn't use gl.stencilOp(GL

问题 How I can use to stencil buffer for my easiest program? I have read many different themes about it, but I not found a detailed guide about it. I want to cut out for hole each side in a created tetrahedron. Please explain to me step by step use stencil buffer? Link for my program 回答1: To use the stencil buffer you have to first request it when you create the webgl context const gl = someCanvasElement.getContext('webgl', {stencil: true}); Then you turn on the stencil test gl.enable(gl.STENCIL

问题 I am using a stencil mask on a 3d object using the hello ar java demo however i am running into some unexpected behaviour. My stencil mask correctly occludes the plane renderer but the 3d object (andy) does not seem to react expectedly. Instead he seems to get flipped as shown in the picture. I am not sure how to approach fixing this issue. Attached is the code snippet doing the stencil masking Image of stencil correctly working on plane buffer but failing on 3d model GLES20.glClear ( GLES20

问题 I want to create a wall with a window inside, using stencil buffer. My code looks like this: glEnable(GL_STENCIL_TEST); glClearStencil(0); glClear(GL_STENCIL_BUFFER_BIT); glStencilMask(1); glStencilFunc(GL_ALWAYS, 1, 1); glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE); glDisable(GL_DEPTH_TEST); glColor3f(1,1,1); //Window glBegin(GL_POLYGON); glVertex3d(-5,0,-20); glVertex3d(-5,0,40); glVertex3d(-20,0,40); glVertex3d(-20,0,-20); glEnd(); glEnable(GL_DEPTH_TEST); glStencilFunc(GL_NOTEQUAL, 1, 1

问题 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);

问题 In reference to the problem diskussed in article OpenGL clipping a new question arises. I am implementing the clipping for a node based 2D scene graph. Whenever the clipping boxes are axis aligned I am using the glScissor like proposed in OpenGL clipping. I have sucessfully implemented node clipping of boxes that are axis aligned. It turns out that each node has to intersect it's clipping rectangle with the ones of it's ancestors that use clipping. (That is necessary in case of siblings that

问题 I have this texture that I want to use as as mask using the Stencil buffer : Then I want to draw an image IMG on the screen which should appear only where the above image is visible (where there's color), thus excluding transparent pixels above the top edge and below the gradient. 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. So I thought about using the ALPHA_TEST but it's gone in the

问题 I'm facing very strange behaviour on my android device when I am trying to use stencil buffer feature. (GLES20.glEnable(GLES20.GL_STENCIL_TEST);) here is my code: GLES20.glEnable(GLES20.GL_STENCIL_TEST); GLES20.glStencilFunc(GLES20.GL_GEQUAL, 1, 0xff); GLES20.glStencilOp(GLES20.GL_KEEP, GLES20.GL_INCR, GLES20.GL_INCR); GLES20.glStencilMask(0xff); m_index_buffer.position(start_index); GLES20.glDrawElements(GLES20.GL_TRIANGLE_STRIP, n_indicies, GLES20.GL_UNSIGNED_SHORT, m_index_buffer); GLES20

问题 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

问题 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,