Deal with OpImageFetch without explicit LOD.

reference/opt/shaders-hlsl/asm/frag/texel-fetch-no-lod.asm.frag

@@ -0,0 +1,29 @@
+Texture2D<float4> uTexture : register(t0);
+SamplerState _uTexture_sampler : register(s0);
+
+static float4 gl_FragCoord;
+static float4 FragColor;
+
+struct SPIRV_Cross_Input
+{
+    float4 gl_FragCoord : SV_Position;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    FragColor = uTexture.Load(int3(int2(gl_FragCoord.xy), 0));
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    gl_FragCoord = stage_input.gl_FragCoord;
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}

reference/opt/shaders-hlsl/frag/tex-sampling-ms.frag

@@ -0,0 +1,33 @@
+Texture2DMS<float4> uTex : register(t0);
+SamplerState _uTex_sampler : register(s0);
+
+static float4 gl_FragCoord;
+static float4 FragColor;
+
+struct SPIRV_Cross_Input
+{
+    float4 gl_FragCoord : SV_Position;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    int2 _22 = int2(gl_FragCoord.xy);
+    FragColor = uTex.Load(_22, 0);
+    FragColor += uTex.Load(_22, 1);
+    FragColor += uTex.Load(_22, 2);
+    FragColor += uTex.Load(_22, 3);
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    gl_FragCoord = stage_input.gl_FragCoord;
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}

reference/opt/shaders-msl/asm/frag/texel-fetch-no-lod.asm.frag

@@ -0,0 +1,17 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    float4 FragColor [[color(0)]];
+};
+
+fragment main0_out main0(texture2d<float> uTexture [[texture(0)]], sampler uTextureSmplr [[sampler(0)]], float4 gl_FragCoord [[position]])
+{
+    main0_out out = {};
+    out.FragColor = uTexture.read(uint2(int2(gl_FragCoord.xy)), 0);
+    return out;
+}
+

reference/opt/shaders/asm/frag/texel-fetch-no-lod.asm.frag

@@ -0,0 +1,11 @@
+#version 450
+
+layout(binding = 0) uniform sampler2D uTexture;
+
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+    FragColor = texelFetch(uTexture, ivec2(gl_FragCoord.xy), 0);
+}
+

reference/shaders-hlsl/asm/frag/texel-fetch-no-lod.asm.frag

@@ -0,0 +1,29 @@
+Texture2D<float4> uTexture : register(t0);
+SamplerState _uTexture_sampler : register(s0);
+
+static float4 gl_FragCoord;
+static float4 FragColor;
+
+struct SPIRV_Cross_Input
+{
+    float4 gl_FragCoord : SV_Position;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    FragColor = uTexture.Load(int3(int2(gl_FragCoord.xy), 0));
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    gl_FragCoord = stage_input.gl_FragCoord;
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}

reference/shaders-hlsl/frag/tex-sampling-ms.frag

@@ -0,0 +1,32 @@
+Texture2DMS<float4> uTex : register(t0);
+SamplerState _uTex_sampler : register(s0);
+
+static float4 gl_FragCoord;
+static float4 FragColor;
+
+struct SPIRV_Cross_Input
+{
+    float4 gl_FragCoord : SV_Position;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    FragColor = uTex.Load(int2(gl_FragCoord.xy), 0);
+    FragColor += uTex.Load(int2(gl_FragCoord.xy), 1);
+    FragColor += uTex.Load(int2(gl_FragCoord.xy), 2);
+    FragColor += uTex.Load(int2(gl_FragCoord.xy), 3);
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    gl_FragCoord = stage_input.gl_FragCoord;
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}

reference/shaders-msl/asm/frag/texel-fetch-no-lod.asm.frag

@@ -0,0 +1,17 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    float4 FragColor [[color(0)]];
+};
+
+fragment main0_out main0(texture2d<float> uTexture [[texture(0)]], sampler uTextureSmplr [[sampler(0)]], float4 gl_FragCoord [[position]])
+{
+    main0_out out = {};
+    out.FragColor = uTexture.read(uint2(int2(gl_FragCoord.xy)), 0);
+    return out;
+}
+

reference/shaders/asm/frag/texel-fetch-no-lod.asm.frag

@@ -0,0 +1,11 @@
+#version 450
+
+layout(binding = 0) uniform sampler2D uTexture;
+
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+    FragColor = texelFetch(uTexture, ivec2(gl_FragCoord.xy), 0);
+}
+

shaders-hlsl/asm/frag/texel-fetch-no-lod.asm.frag

@@ -0,0 +1,46 @@
+; SPIR-V
+; Version: 1.0
+; Generator: Khronos Glslang Reference Front End; 6
+; Bound: 26
+; Schema: 0
+               OpCapability Shader
+          %1 = OpExtInstImport "GLSL.std.450"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint Fragment %main "main" %FragColor %gl_FragCoord
+               OpExecutionMode %main OriginUpperLeft
+               OpSource GLSL 450
+               OpName %main "main"
+               OpName %FragColor "FragColor"
+               OpName %uTexture "uTexture"
+               OpName %gl_FragCoord "gl_FragCoord"
+               OpDecorate %FragColor Location 0
+               OpDecorate %uTexture DescriptorSet 0
+               OpDecorate %uTexture Binding 0
+               OpDecorate %gl_FragCoord BuiltIn FragCoord
+       %void = OpTypeVoid
+          %3 = OpTypeFunction %void
+      %float = OpTypeFloat 32
+    %v4float = OpTypeVector %float 4
+%_ptr_Output_v4float = OpTypePointer Output %v4float
+  %FragColor = OpVariable %_ptr_Output_v4float Output
+         %10 = OpTypeImage %float 2D 0 0 0 1 Unknown
+         %11 = OpTypeSampledImage %10
+%_ptr_UniformConstant_11 = OpTypePointer UniformConstant %11
+   %uTexture = OpVariable %_ptr_UniformConstant_11 UniformConstant
+%_ptr_Input_v4float = OpTypePointer Input %v4float
+%gl_FragCoord = OpVariable %_ptr_Input_v4float Input
+    %v2float = OpTypeVector %float 2
+        %int = OpTypeInt 32 1
+      %v2int = OpTypeVector %int 2
+      %int_0 = OpConstant %int 0
+       %main = OpFunction %void None %3
+          %5 = OpLabel
+         %14 = OpLoad %11 %uTexture
+         %18 = OpLoad %v4float %gl_FragCoord
+         %19 = OpVectorShuffle %v2float %18 %18 0 1
+         %22 = OpConvertFToS %v2int %19
+         %24 = OpImage %10 %14
+         %25 = OpImageFetch %v4float %24 %22
+               OpStore %FragColor %25
+               OpReturn
+               OpFunctionEnd

shaders-hlsl/frag/tex-sampling-ms.frag

@@ -0,0 +1,16 @@
+#version 450
+
+layout(location = 0) out vec4 FragColor;
+layout(binding = 0) uniform sampler2DMS uTex;
+
+void main()
+{
+	FragColor =
+		texelFetch(uTex, ivec2(gl_FragCoord.xy), 0);
+	FragColor +=
+		texelFetch(uTex, ivec2(gl_FragCoord.xy), 1);
+	FragColor +=
+		texelFetch(uTex, ivec2(gl_FragCoord.xy), 2);
+	FragColor +=
+		texelFetch(uTex, ivec2(gl_FragCoord.xy), 3);
+}

shaders-msl/asm/frag/texel-fetch-no-lod.asm.frag

@@ -0,0 +1,46 @@
+; SPIR-V
+; Version: 1.0
+; Generator: Khronos Glslang Reference Front End; 6
+; Bound: 26
+; Schema: 0
+               OpCapability Shader
+          %1 = OpExtInstImport "GLSL.std.450"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint Fragment %main "main" %FragColor %gl_FragCoord
+               OpExecutionMode %main OriginUpperLeft
+               OpSource GLSL 450
+               OpName %main "main"
+               OpName %FragColor "FragColor"
+               OpName %uTexture "uTexture"
+               OpName %gl_FragCoord "gl_FragCoord"
+               OpDecorate %FragColor Location 0
+               OpDecorate %uTexture DescriptorSet 0
+               OpDecorate %uTexture Binding 0
+               OpDecorate %gl_FragCoord BuiltIn FragCoord
+       %void = OpTypeVoid
+          %3 = OpTypeFunction %void
+      %float = OpTypeFloat 32
+    %v4float = OpTypeVector %float 4
+%_ptr_Output_v4float = OpTypePointer Output %v4float
+  %FragColor = OpVariable %_ptr_Output_v4float Output
+         %10 = OpTypeImage %float 2D 0 0 0 1 Unknown
+         %11 = OpTypeSampledImage %10
+%_ptr_UniformConstant_11 = OpTypePointer UniformConstant %11
+   %uTexture = OpVariable %_ptr_UniformConstant_11 UniformConstant
+%_ptr_Input_v4float = OpTypePointer Input %v4float
+%gl_FragCoord = OpVariable %_ptr_Input_v4float Input
+    %v2float = OpTypeVector %float 2
+        %int = OpTypeInt 32 1
+      %v2int = OpTypeVector %int 2
+      %int_0 = OpConstant %int 0
+       %main = OpFunction %void None %3
+          %5 = OpLabel
+         %14 = OpLoad %11 %uTexture
+         %18 = OpLoad %v4float %gl_FragCoord
+         %19 = OpVectorShuffle %v2float %18 %18 0 1
+         %22 = OpConvertFToS %v2int %19
+         %24 = OpImage %10 %14
+         %25 = OpImageFetch %v4float %24 %22
+               OpStore %FragColor %25
+               OpReturn
+               OpFunctionEnd

shaders/asm/frag/texel-fetch-no-lod.asm.frag

@@ -0,0 +1,46 @@
+; SPIR-V
+; Version: 1.0
+; Generator: Khronos Glslang Reference Front End; 6
+; Bound: 26
+; Schema: 0
+               OpCapability Shader
+          %1 = OpExtInstImport "GLSL.std.450"
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint Fragment %main "main" %FragColor %gl_FragCoord
+               OpExecutionMode %main OriginUpperLeft
+               OpSource GLSL 450
+               OpName %main "main"
+               OpName %FragColor "FragColor"
+               OpName %uTexture "uTexture"
+               OpName %gl_FragCoord "gl_FragCoord"
+               OpDecorate %FragColor Location 0
+               OpDecorate %uTexture DescriptorSet 0
+               OpDecorate %uTexture Binding 0
+               OpDecorate %gl_FragCoord BuiltIn FragCoord
+       %void = OpTypeVoid
+          %3 = OpTypeFunction %void
+      %float = OpTypeFloat 32
+    %v4float = OpTypeVector %float 4
+%_ptr_Output_v4float = OpTypePointer Output %v4float
+  %FragColor = OpVariable %_ptr_Output_v4float Output
+         %10 = OpTypeImage %float 2D 0 0 0 1 Unknown
+         %11 = OpTypeSampledImage %10
+%_ptr_UniformConstant_11 = OpTypePointer UniformConstant %11
+   %uTexture = OpVariable %_ptr_UniformConstant_11 UniformConstant
+%_ptr_Input_v4float = OpTypePointer Input %v4float
+%gl_FragCoord = OpVariable %_ptr_Input_v4float Input
+    %v2float = OpTypeVector %float 2
+        %int = OpTypeInt 32 1
+      %v2int = OpTypeVector %int 2
+      %int_0 = OpConstant %int 0
+       %main = OpFunction %void None %3
+          %5 = OpLabel
+         %14 = OpLoad %11 %uTexture
+         %18 = OpLoad %v4float %gl_FragCoord
+         %19 = OpVectorShuffle %v2float %18 %18 0 1
+         %22 = OpConvertFToS %v2int %19
+         %24 = OpImage %10 %14
+         %25 = OpImageFetch %v4float %24 %22
+               OpStore %FragColor %25
+               OpReturn
+               OpFunctionEnd

spirv_glsl.cpp

@@ -4078,6 +4078,11 @@ string CompilerGLSL::to_function_args(uint32_t img, const SPIRType &imgtype, boo
 			}
 		}
 	}
+	else if (is_fetch && imgtype.image.dim != DimBuffer && !imgtype.image.ms)
+	{
+		// Lod argument is optional in OpImageFetch, but we require a LOD value, pick 0 as the default.
+		farg_str += ", 0";
+	}
 
 	if (coffset)
 	{

spirv_hlsl.cpp

@@ -2714,8 +2714,9 @@ void CompilerHLSL::emit_texture_op(const Instruction &i)
 	if (op == OpImageFetch)
 	{
 		auto &coordtype = expression_type(coord);
-		if (imgtype.image.dim != DimBuffer)
-			coord_expr = join("int", coordtype.vecsize + 1, "(", coord_expr, ", ", to_expression(lod), ")");
+		if (imgtype.image.dim != DimBuffer && !imgtype.image.ms)
+			coord_expr =
+			    join("int", coordtype.vecsize + 1, "(", coord_expr, ", ", lod ? to_expression(lod) : string("0"), ")");
 	}
 	else
 		expr += ", ";

spirv_msl.cpp

@@ -2609,6 +2609,13 @@ string CompilerMSL::to_function_args(uint32_t img, const SPIRType &imgtype, bool
 			farg_str += ", level(" + to_expression(lod) + ")";
 		}
 	}
+	else if (is_fetch && !lod && imgtype.image.dim != Dim1D && imgtype.image.dim != DimBuffer && !imgtype.image.ms &&
+	         imgtype.image.sampled != 2)
+	{
+		// Lod argument is optional in OpImageFetch, but we require a LOD value, pick 0 as the default.
+		// Check for sampled type as well, because is_fetch is also used for OpImageRead in MSL.
+		farg_str += ", 0";
+	}
 
 	// Metal does not support LOD for 1D textures.
 	if ((grad_x || grad_y) && imgtype.image.dim != Dim1D)