Read half->float RWTexture conversion (#1842)

* #include an absolute path didn't work - because paths were taken to always be relative.

* Fix for writing to RWTexture with half types on CUDA.

* CUDA half functionality doc updates.

* First pass support for sust.p RWTexture format conversion on write.

* Tidy up implementation of $C.
Made clamping mode #define able.

* A simple test for RWTexture CUDA format conversion.

* Add support for float2 and float4.

* WIP conversion testing.

* Use $E to fix byte addressing in X in CUDA.

* Do not scale when accessing via _convert versions of surface functions.

* Revert to previous test.

* Test with half/float convert write/read.

* More broad half->float read conversion testing.

* Improve documentation around half and RWTexture conversion.

3 files changed, 71 insertions, 1 deletions

diff --git a/tests/compute/half-rw-texture-convert.slang b/tests/compute/half-rw-texture-convert.slang
index cf6eea4ea..338f44454 100644
--- a/tests/compute/half-rw-texture-convert.slang
+++ b/tests/compute/half-rw-texture-convert.slang
@@ -25,6 +25,14 @@
 [format("r16f")]
 RWTexture2D<float> rwt2D;
 
+//TEST_INPUT: RWTexture2D(format=RG_Float16, size=4, content = one, mipMaps = 1):name rwt2D_2
+[format("rg16f")]
+RWTexture2D<float2> rwt2D_2;
+
+//TEST_INPUT: RWTexture2D(format=RGBA_Float16, size=4, content = one, mipMaps = 1):name rwt2D_4
+[format("rgba16f")]
+RWTexture2D<float4> rwt2D_4;
+
 //TEST_INPUT: ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
 RWStructuredBuffer<float> outputBuffer;
 
@@ -38,5 +46,9 @@ void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
     // Do a format converting write!
     rwt2D[uint2(idx, idx)] = val;    
     
+    rwt2D_2[uint2(idx, idx)] = float2(val * 2, val * 3);    
+    
+    rwt2D_4[uint2(idx, idx)] = float4(val + 1, val - 1, val * 4, val * -4);    
+    
     outputBuffer[idx] = val;
-}
+}
\ No newline at end of file
diff --git a/tests/compute/half-rw-texture-convert2.slang b/tests/compute/half-rw-texture-convert2.slang
new file mode 100644
index 000000000..e9b7200c4
--- /dev/null
+++ b/tests/compute/half-rw-texture-convert2.slang
@@ -0,0 +1,53 @@
+// Native half not supported on CPU currently
+//DISABLE_TEST(compute):COMPARE_COMPUTE_EX:-cpu -compute -output-using-type -shaderobj
+// Doesn't work on DX11 currently - locks up on binding
+//DISABLE_TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -output-using-type -shaderobj
+// Produces a different result on DX12 with DXBC than expected(!). So disabled for now
+//DISABLE_TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -dx12 -output-using-type -shaderobj
+//DISABLE_TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -dx12 -profile cs_6_0 -use-dxil -output-using-type -shaderobj
+// TODO(JS): Doesn't work on vk currently, because createTextureView not implemented on vk renderer
+//DIABLE_TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -output-using-type -shaderobj
+
+//TEST(compute):COMPARE_COMPUTE_EX:-cuda -compute -output-using-type -shaderobj -render-features half
+
+//TEST_INPUT: RWTexture2D(format=R_Float16, size=4, content = one, mipMaps = 1):name rwt2D
+[format("r16f")]
+RWTexture2D<float> rwt2D;
+
+//TEST_INPUT: RWTexture2D(format=RG_Float16, size=4, content = one, mipMaps = 1):name rwt2D_2
+[format("rg16f")]
+RWTexture2D<float2> rwt2D_2;
+
+//TEST_INPUT: RWTexture2D(format=RGBA_Float16, size=4, content = one, mipMaps = 1):name rwt2D_4
+[format("rgba16f")]
+RWTexture2D<float4> rwt2D_4;
+
+//TEST_INPUT: ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    int idx = dispatchThreadID.x;
+    
+    float val = 0;
+ 
+    // Do a format converting write2!
+    rwt2D[uint2(idx, idx)] = idx - 1;
+    rwt2D_2[uint2(idx, idx)] = float2(idx + idx, idx * idx);
+    rwt2D_4[uint2(idx, idx)] = float4(idx + 97, idx + 8, idx + 16, idx + 24);    
+    
+    // May not be strictly necessary
+    AllMemoryBarrierWithGroupSync();
+    
+    // Do read converting
+    // There is *only* CUDA support for half/float *converting* reads for 1d, 2d, 3d shapes for RWTexture/surface
+    
+    float4 v4 = rwt2D_4[uint2(idx, idx)];
+    float2 v2 = rwt2D_2[uint2(idx, idx)];
+    float v = rwt2D[uint2(idx, idx)];
+    
+    val += v4.x + v2.x + v;
+    
+    outputBuffer[idx] = val;
+}
diff --git a/tests/compute/half-rw-texture-convert2.slang.expected.txt b/tests/compute/half-rw-texture-convert2.slang.expected.txt
new file mode 100644
index 000000000..462941fda
--- /dev/null
+++ b/tests/compute/half-rw-texture-convert2.slang.expected.txt
@@ -0,0 +1,5 @@
+type: float
+96.000000
+100.000000
+104.000000
+108.000000