Check for legal lod id

And avoid passing superfluous has_lod parameter.

spirv_glsl.cpp

@@ -2417,7 +2417,7 @@ bool CompilerGLSL::check_explicit_lod_allowed(uint32_t lod)
 {
 	auto &execution = get_entry_point();
 	bool allowed = !is_legacy_es() || execution.model == ExecutionModelFragment;
-	if (!allowed)
+	if (!allowed && lod != 0)
 	{
 		auto *lod_constant = maybe_get<SPIRConstant>(lod);
 		if (!lod_constant || lod_constant->scalar_f32() != 0.0f)
@@ -2809,7 +2809,7 @@ void CompilerGLSL::emit_texture_op(const Instruction &i)
 	string expr;
 	bool forward = false;
 	expr += to_function_name(img, imgtype, !!fetch, !!gather, !!proj, !!coffsets, (!!coffset || !!offset),
-	                         (!!grad_x || !!grad_y), !!lod, !!dref, lod);
+	                         (!!grad_x || !!grad_y), !!dref, lod);
 	expr += "(";
 	expr += to_function_args(img, imgtype, fetch, gather, proj, coord, coord_components, dref, grad_x, grad_y, lod,
 	                         coffset, offset, bias, comp, sample, &forward);
@@ -2821,7 +2821,7 @@ void CompilerGLSL::emit_texture_op(const Instruction &i)
 // Returns the function name for a texture sampling function for the specified image and sampling characteristics.
 // For some subclasses, the function is a method on the specified image.
 string CompilerGLSL::to_function_name(uint32_t, const SPIRType &imgtype, bool is_fetch, bool is_gather, bool is_proj,
-                                      bool has_array_offsets, bool has_offset, bool has_grad, bool has_lod, bool, uint32_t lod)
+                                      bool has_array_offsets, bool has_offset, bool has_grad, bool, uint32_t lod)
 {
 	string fname;
 
@@ -2839,7 +2839,7 @@ string CompilerGLSL::to_function_name(uint32_t, const SPIRType &imgtype, bool is
 			fname += "Proj";
 		if (has_grad)
 			fname += "Grad";
-		if (has_lod)
+		if (!!lod)
 			fname += "Lod";
 	}
 

spirv_glsl.hpp

@@ -170,7 +170,7 @@ protected:
 	virtual std::string to_func_call_arg(uint32_t id);
 	virtual std::string to_function_name(uint32_t img, const SPIRType &imgtype, bool is_fetch, bool is_gather,
 	                                     bool is_proj, bool has_array_offsets, bool has_offset, bool has_grad,
-	                                     bool has_lod, bool has_dref, uint32_t lod);
+	                                     bool has_dref, uint32_t lod);
 	virtual std::string to_function_args(uint32_t img, const SPIRType &imgtype, bool is_fetch, bool is_gather,
 	                                     bool is_proj, uint32_t coord, uint32_t coord_components, uint32_t dref,
 	                                     uint32_t grad_x, uint32_t grad_y, uint32_t lod, uint32_t coffset,

spirv_msl.cpp

@@ -989,7 +989,7 @@ void CompilerMSL::emit_function_prototype(SPIRFunction &func, uint64_t)
 
 // Returns the texture sampling function string for the specified image and sampling characteristics.
 string CompilerMSL::to_function_name(uint32_t img, const SPIRType &, bool is_fetch, bool is_gather, bool, bool, bool,
-                                     bool, bool, bool has_dref, uint32_t)
+                                     bool, bool has_dref, uint32_t)
 {
 	// Texture reference
 	string fname = to_expression(img) + ".";

spirv_msl.hpp

@@ -139,8 +139,8 @@ protected:
 	std::string to_func_call_arg(uint32_t id) override;
 	std::string to_name(uint32_t id, bool allow_alias = true) const override;
 	std::string to_function_name(uint32_t img, const SPIRType &imgtype, bool is_fetch, bool is_gather, bool is_proj,
-	                             bool has_array_offsets, bool has_offset, bool has_grad, bool has_lod,
+	                             bool has_array_offsets, bool has_offset, bool has_grad, bool has_dref,
-	                             bool has_dref, uint32_t lod) override;
+	                             uint32_t lod) override;
 	std::string to_function_args(uint32_t img, const SPIRType &imgtype, bool is_fetch, bool is_gather, bool is_proj,
 	                             uint32_t coord, uint32_t coord_components, uint32_t dref, uint32_t grad_x,
 	                             uint32_t grad_y, uint32_t lod, uint32_t coffset, uint32_t offset, uint32_t bias,