Fix a crash if SampleBias is used with an unbound sampler on D3D11

renderdoc/driver/d3d11/d3d11_shaderdebug.cpp

@@ -1226,10 +1226,23 @@ bool D3D11DebugAPIWrapper::CalculateSampleGather(
   context->PSSetShaderResources(texSlot, 1, &usedSRV);
   if(opcode == OPCODE_SAMPLE_B && samplerData.bias != 0.0f)
   {
-    RDCASSERT(usedSamp);
+    D3D11_SAMPLER_DESC desc = {};
 
-    D3D11_SAMPLER_DESC desc;
-    usedSamp->GetDesc(&desc);
+    if(usedSamp)
+    {
+      usedSamp->GetDesc(&desc);
+    }
+    else
+    {
+      desc.Filter = D3D11_FILTER_MIN_MAG_MIP_LINEAR;
+      desc.AddressU = desc.AddressV = desc.AddressW = D3D11_TEXTURE_ADDRESS_CLAMP;
+      desc.MipLODBias = 0.0f;
+      desc.MaxAnisotropy = 1;
+      desc.ComparisonFunc = D3D11_COMPARISON_NEVER;
+      desc.BorderColor[0] = desc.BorderColor[1] = desc.BorderColor[2] = desc.BorderColor[3] = 1.0f;
+      desc.MinLOD = -FLT_MAX;
+      desc.MaxLOD = FLT_MAX;
+    }
 
     desc.MipLODBias = RDCCLAMP(desc.MipLODBias + samplerData.bias, -15.99f, 15.99f);
 

util/test/demos/d3d11/d3d11_shader_debug_zoo.cpp

@@ -124,6 +124,7 @@ RWTexture2D<float> unbounduav2 : register(u5);
 
 SamplerState linearclamp : register(s0);
 SamplerState linearwrap : register(s1);
+SamplerState unboundsamp : register(s2);
 
 float4 main(v2f IN) : SV_Target0
 {
@@ -740,6 +741,16 @@ float4 main(v2f IN) : SV_Target0
     float2 uv = posone * float2(1.81f, 0.48f);
     return smileyuint.Load(int3(uv*16,0));
   }
+  if(IN.tri == 91)
+  {
+    float2 uv = posone * float2(0.55f, 0.48f);
+    return smiley.Sample(unboundsamp, uv);
+  }
+  if(IN.tri == 92)
+  {
+    float2 uv = posone * float2(0.55f, 0.48f);
+    return smiley.SampleBias(unboundsamp, uv, 0.5f);
+  }
 
   return float4(0.4f, 0.4f, 0.4f, 0.4f);
 }