Added const qualifier support for function arguments in shaders

drivers/gles2/shader_compiler_gles2.cpp

@@ -247,6 +247,9 @@ void ShaderCompilerGLES2::_dump_function_deps(SL::ShaderNode *p_node, const Stri
 		for (int i = 0; i < fnode->arguments.size(); i++) {
 			if (i > 0)
 				header += ", ";
+			if (fnode->arguments[i].is_const) {
+				header += "const ";
+			}
 			if (fnode->arguments[i].type == SL::TYPE_STRUCT) {
 				header += _qualstr(fnode->arguments[i].qualifier) + _mkid(fnode->arguments[i].type_str) + " " + _mkid(fnode->arguments[i].name);
 			} else {

servers/rendering/rasterizer_rd/shader_compiler_rd.cpp

@@ -399,6 +399,9 @@ void ShaderCompilerRD::_dump_function_deps(const SL::ShaderNode *p_node, const S
 			if (i > 0) {
 				header += ", ";
 			}
+			if (fnode->arguments[i].is_const) {
+				header += "const ";
+			}
 			if (fnode->arguments[i].type == SL::TYPE_STRUCT) {
 				header += _qualstr(fnode->arguments[i].qualifier) + _mkid(fnode->arguments[i].type_str) + " " + _mkid(fnode->arguments[i].name);
 			} else {

servers/rendering/shader_language.cpp

@@ -982,6 +982,9 @@ bool ShaderLanguage::_find_identifier(const BlockNode *p_block, bool p_allow_rea
 				if (r_struct_name) {
 					*r_struct_name = function->arguments[i].type_str;
 				}
+				if (r_is_const) {
+					*r_is_const = function->arguments[i].is_const;
+				}
 				return true;
 			}
 		}
@@ -3553,7 +3556,7 @@ ShaderLanguage::Node *ShaderLanguage::_parse_expression(BlockNode *p_block, cons
 							for (int i = 0; i < call_function->arguments.size(); i++) {
 								int argidx = i + 1;
 								if (argidx < func->arguments.size()) {
-									if (call_function->arguments[i].qualifier == ArgumentQualifier::ARGUMENT_QUALIFIER_OUT || call_function->arguments[i].qualifier == ArgumentQualifier::ARGUMENT_QUALIFIER_INOUT) {
+									if (call_function->arguments[i].is_const || call_function->arguments[i].qualifier == ArgumentQualifier::ARGUMENT_QUALIFIER_OUT || call_function->arguments[i].qualifier == ArgumentQualifier::ARGUMENT_QUALIFIER_INOUT) {
 										bool error = false;
 										Node *n = func->arguments[argidx];
 										if (n->type == Node::TYPE_CONSTANT || n->type == Node::TYPE_OPERATOR) {
@@ -6780,15 +6783,29 @@ Error ShaderLanguage::_parse_shader(const Map<StringName, FunctionInfo> &p_funct
 						break;
 					}
 
+					bool is_const = false;
+					if (tk.type == TK_CONST) {
+						is_const = true;
+						tk = _get_token();
+					}
+
 					ArgumentQualifier qualifier = ARGUMENT_QUALIFIER_IN;
 
 					if (tk.type == TK_ARG_IN) {
 						qualifier = ARGUMENT_QUALIFIER_IN;
 						tk = _get_token();
 					} else if (tk.type == TK_ARG_OUT) {
+						if (is_const) {
+							_set_error("'out' qualifier cannot be used within a function parameter declared with 'const'.");
+							return ERR_PARSE_ERROR;
+						}
 						qualifier = ARGUMENT_QUALIFIER_OUT;
 						tk = _get_token();
 					} else if (tk.type == TK_ARG_INOUT) {
+						if (is_const) {
+							_set_error("'inout' qualifier cannot be used within a function parameter declared with 'const'.");
+							return ERR_PARSE_ERROR;
+						}
 						qualifier = ARGUMENT_QUALIFIER_INOUT;
 						tk = _get_token();
 					}
@@ -6877,6 +6894,7 @@ Error ShaderLanguage::_parse_shader(const Map<StringName, FunctionInfo> &p_funct
 					arg.tex_builtin_check = false;
 					arg.tex_argument_filter = FILTER_DEFAULT;
 					arg.tex_argument_repeat = REPEAT_DEFAULT;
+					arg.is_const = is_const;
 
 					func_node->arguments.push_back(arg);
 
@@ -7273,6 +7291,10 @@ Error ShaderLanguage::complete(const String &p_code, const Map<StringName, Funct
 							calltip += CharType(0xFFFF);
 						}
 
+						if (shader->functions[i].function->arguments[j].is_const) {
+							calltip += "const ";
+						}
+
 						if (shader->functions[i].function->arguments[j].qualifier != ArgumentQualifier::ARGUMENT_QUALIFIER_IN) {
 							if (shader->functions[i].function->arguments[j].qualifier == ArgumentQualifier::ARGUMENT_QUALIFIER_OUT) {
 								calltip += "out ";

servers/rendering/shader_language.h

@@ -554,6 +554,7 @@ public:
 			TextureRepeat tex_argument_repeat;
 			bool tex_builtin_check;
 			StringName tex_builtin;
+			bool is_const;
 
 			Map<StringName, Set<int>> tex_argument_connect;
 		};