From b415760d7f166eaad7fa27daa09edc9a8964c37e Mon Sep 17 00:00:00 2001 From: Tim Foley Date: Mon, 3 Feb 2020 17:36:32 -0800 Subject: Initial steps on GPU printing example (#1197) * Initial steps on GPU printing example This change is checkpointing work on a new Slang example that shows how a "GPU `printf()`" can be implemented almost entirely in user space thanks to a combination of Slang language and API features. The example is not perfect as it stands today due to limitations in our current handling of hashed string literals: * At call sites where a string literal is passed, we currently have to explicitly invoke `getStringHash()` to get the hash code, because we don't currently support `String` as a function argument/parameter type. * On the implementation side, because strings are passed as their `int` hash codes, we can't tell them apart from ordinary `int` arguments. The current code handles this by assuming an `int` is *always* a hashed string, which obviously isn't appropriate. There are plenty of other limitations in the implementation presented, but the above are the two main things I'd like to address in follow-up work. I would like to checkpoint this work on the application first, in order to keep work on the Slang implementation and the example as separate as possible. * typo --- examples/gpu-printing/kernels.slang | 38 +++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 examples/gpu-printing/kernels.slang (limited to 'examples/gpu-printing/kernels.slang') diff --git a/examples/gpu-printing/kernels.slang b/examples/gpu-printing/kernels.slang new file mode 100644 index 000000000..ec4533958 --- /dev/null +++ b/examples/gpu-printing/kernels.slang @@ -0,0 +1,38 @@ +// kernels.slang + +// This file demonstrates how ordinary shader code can make use of +// a standalone GPU printing library implemented in `printing.slang`. +// +// The first step for using a module of Slang code is to `import` it. +// +import printing; +// +// The `import` declaration above brings all the types and functions +// declared in the `printing` module (in `printing.slang`) into +// scope so that our code can use them. + +// For simplicity, we will define a single compute shader that does +// some simple printing. +// +[shader("compute")] +[numthreads(32)] +void computeMain(uint3 tid : SV_DispatchThreadID) +{ + // The `printing` module defines two main printing routines. + // + // The first is a `println` function in the style of Java, + // which takes zero or more arguments and prints them all + // followed by a newline. + // + // HACK: We are having to explicitly call `getStringHash` here + // because the print implementation wants to write out strings + // in terms of their hash code, and the current Slang implementation + // of `getStringHash` only applies to string literals. + // + println(getStringHash("hello from thread number "), tid.x); + + // The second facility supported by `printing.slang` is a C-style + // `printf()` function. + // + printf(getStringHash("printf from thread 0x%x\n"), tid.x); +} -- cgit v1.2.3