What is OpenGL template?
Advanced OpenGL/Stencil tests. A template buffer (typically) contains 8 bits per template value which amounts to a total of 256 different template values per pixel. We can set these template values to values of our liking and we can discard or keep fragments as long as a particular fragment has a certain template value.
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What is the OpenGL pipeline stage function called fragment shader?
A chunk shader is the shader stage that will process a chunk generated by rasterization into a set of colors and a single depth value. The fragment shader is the OpenGL pipeline stage after rasterizing a primitive. For each sample of the pixels covered by a primitive, a “chunk” is generated.
What is an OpenGL snippet?
From the OpenGL Wiki. A Fragment is a collection of values produced by the Rasterizer. Each chunk represents a sample-sized segment of a raster primitive.
What is the purpose of the fragment shader?
Fragment (or texture) shaders define the RGBA (red, green, blue, alpha) colors for each pixel being rendered; a single fragment shader is called once per pixel. The purpose of the fragment shader is to set the gl_FragColor variable. gl_FragColor is a built-in GLSL variable like gl_Position.
How often is fragment shader called?
A fragment shader is executed for each fragment once. A fragment is a pixel.
What is template shader unit?
In Unity, you can use a template buffer to mark pixels and then only render on pixels that pass the template operation. See in Glossary on the GPU. The template buffer stores an 8-bit integer value for each pixel. The pixel size depends on the resolution of your screen. Pixel illumination is calculated on each pixel on the screen.
What happens if the template test fails in OpenGL?
glStencilFunc can be used to set both face operations in a single call, if you don’t want to use GL_FRONT_AND_BACK . If the template test fails, the fragment is discarded. If the template test passes, other tests (such as the depth test) might drop the snippet. Normally, discarding a shard means that it has no visible effects.
When does a fragment pass the stencil test?
This tells OpenGL that as long as a fragment’s template value is equal (GL_EQUAL) to the reference value 1, the fragment passes the test and is drawn; otherwise, it is discarded. But glStencilFunconly describes whether OpenGL should pass or discard snippets based on the contents of the template buffer, not how we can update the buffer.
Why is there an early chunk test in OpenGL?
Fragment-first tests, like optimization, exist to avoid unnecessary executions of the Fragment Shader. If a fragment will be discarded based on the depth test (perhaps because it is behind other geometry), save performance to avoid running the fragment shader.
Why does OpenGL disable early depth testing?
Because this is hardware-based optimization, OpenGL has no direct controls to tell you whether to perform early depth tests. Similarly, if the fragment shader discards the fragment with the discard keyword, this will almost always disable the first depth tests on some hardware.