This is useful for doing rendering where the only useful output is the fragment's depth, and you want to use the depth computed by the system, rather than some other depth. However, the depth and stencil values for the output fragment have the same values as the inputs. If no fragment shader is used, then the color values of the output Fragment have undefined values. The output of a fragment shader is a depth value, a possible stencil value (unmodified by the fragment shader), and zero or more color values to be potentially written to the buffers in the current framebuffers.įragment shaders take a single fragment as input and produce a single fragment as output.įragment shaders are technically an optional shader stage. Each fragment has a Window Space position, a few other values, and it contains all of the interpolated per-vertex output values from the last Vertex Processing stage. For each sample of the pixels covered by a primitive, a 'fragment' is generated. The fragment shader is the OpenGL pipeline stage after a primitive is rasterized. (GL20.A Fragment Shader is the Shader stage that will process a Fragment generated by the Rasterization into a set of colors and a single depth value. One thing, I've left out FBOs, but that shouldn't make a difference. If you want to use stenciling with SpriteBatch, you'll need to break up the batch drawing.

While drawing to a SpriteBatch, state changes are ignored, until end() is called. Instead of something like this: (Ignore the windows sizes and colour tones) ToDrawHeart = new Image(new TextureRegion(fbo1.getColorBufferTexture())) Here is the code: (0, 0, 0, 0) įrameBuffer.clearAllFrameBuffers(Gdx.app) UPDATE: I have also tried producing something of the same kind using glColorMask. It would be very helpful if anyone can shed some light on these two. How am I supposed to do this using Stencil Buffers? I am also facing some difficulty understanding glStencilFunc and glStencilOp. (GL20.GL_KEEP, GL20.GL_KEEP, GL20.GL_KEEP) īackground.draw(stage.getSpriteBatch(), 1) //Draws the background such that the background is not rendered on the required pattern, leaving that area black.

Enables the ColorMask and DepthMask to resume normal rendering RHeart.draw(stage.getSpriteBatch(), 1) //Draws the required pattern on the stencil buffer (GL20.GL_REPLACE, GL20.GL_REPLACE, GL20.GL_REPLACE) Disables ColorMask and DepthMask so that all the rendering is done on the Stencil Buffer I am using Frame Buffer Object and Stencil Buffer to achieve this kind of effect. 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.

Opengl es 2.0 stencil buffer