Add Derivatives Instructions.

include/sirit/sirit.h

@@ -823,6 +823,52 @@ public:
     /// of the pixel specified by offset.
     Id OpInterpolateAtOffset(Id result_type, Id interpolant, Id offset);
 
+    // Derivatives
+
+    /// Same result as either OpDPdxFine or OpDPdxCoarse on the input.
+    /// Selection of which one is based on external factors.
+    Id OpDPdx(Id result_type, Id operand);
+
+    /// Same result as either OpDPdyFine or OpDPdyCoarse on the input.
+    /// Selection of which one is based on external factors.
+    Id OpDPdy(Id result_type, Id operand);
+
+    /// Result is the same as computing the sum of the absolute values of OpDPdx and OpDPdy
+    /// on the input.
+    Id OpFwidth(Id result_type, Id operand);
+
+    /// Result is the partial derivative of the input with respect to the window x coordinate.
+    /// Uses local differencing based on the value of the input for the current fragment and
+    /// its immediate neighbor(s).
+    Id OpDPdxFine(Id result_type, Id operand);
+
+    /// Result is the partial derivative of the input with respect to the window y coordinate.
+    /// Uses local differencing based on the value of the input for the current fragment and
+    /// its immediate neighbor(s).
+    Id OpDPdyFine(Id result_type, Id operand);
+
+    /// Result is the same as computing the sum of the absolute values of OpDPdxFine and OpDPdyFine
+    /// on the input.
+    Id OpFwidthFine(Id result_type, Id operand);
+
+    /// Result is the partial derivative of the input with respect to the window x coordinate.
+    /// Uses local differencing based on the value of the input for the current fragment's
+    /// neighbors, and possibly, but not necessarily, includes the value of the input for the
+    /// current fragment. That is, over a given area, the implementation can compute x derivatives
+    /// in fewer unique locations than would be allowed for OpDPdxFine.
+    Id OpDPdxCoarse(Id result_type, Id operand);
+
+    /// Result is the partial derivative of the input with respect to the window y coordinate.
+    /// Uses local differencing based on the value of the input for the current fragment's
+    /// neighbors, and possibly, but not necessarily, includes the value of the input for the
+    /// current fragment. That is, over a given area, the implementation can compute y derivatives
+    /// in fewer unique locations than would be allowed for OpDPdyFine.
+    Id OpDPdyCoarse(Id result_type, Id operand);
+
+    /// Result is the same as computing the sum of the absolute values of OpDPdxCoarse and
+    /// OpDPdyCoarse on the input.
+    Id OpFwidthCoarse(Id result_type, Id operand);
+
     // Image
 
     /// Create a sampled image, containing both a sampler and an image.

src/CMakeLists.txt

@@ -8,6 +8,7 @@ add_library(sirit
     instructions/function.cpp
     instructions/flow.cpp
     instructions/debug.cpp
+    instructions/derivatives.cpp
     instructions/memory.cpp
     instructions/annotation.cpp
     instructions/misc.cpp

src/instructions/derivatives.cpp

@@ -0,0 +1,29 @@
+/* This file is part of the sirit project.
+ * Copyright (c) 2021 sirit
+ * This software may be used and distributed according to the terms of the
+ * 3-Clause BSD License
+ */
+
+#include "sirit/sirit.h"
+
+#include "stream.h"
+
+namespace Sirit {
+
+#define DEFINE_UNARY(funcname, opcode)                                                             \
+    Id Module::funcname(Id result_type, Id operand) {                                              \
+        code->Reserve(4);                                                                          \
+        return *code << OpId{opcode, result_type} << operand << EndOp{};                           \
+    }
+
+DEFINE_UNARY(OpDPdx, spv::Op::OpDPdx)
+DEFINE_UNARY(OpDPdy, spv::Op::OpDPdy)
+DEFINE_UNARY(OpFwidth, spv::Op::OpFwidth)
+DEFINE_UNARY(OpDPdxFine, spv::Op::OpDPdxFine)
+DEFINE_UNARY(OpDPdyFine, spv::Op::OpDPdyFine)
+DEFINE_UNARY(OpFwidthFine, spv::Op::OpFwidthFine)
+DEFINE_UNARY(OpDPdxCoarse, spv::Op::OpDPdxCoarse)
+DEFINE_UNARY(OpDPdyCoarse, spv::Op::OpDPdyCoarse)
+DEFINE_UNARY(OpFwidthCoarse, spv::Op::OpFwidthCoarse)
+
+} // namespace Sirit