From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 16 Oct 2016 11:30:51 +0000 (+0300)
Subject: Add a geometry flag to ProgramBuilder
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=f9d27a44f11dcb2980ea7c65d410e9002098487f;p=libs%2Fgl.git

Add a geometry flag to ProgramBuilder

It does not generate a geometry shader yet but allows one to be manually
inserted into the program.
---

diff --git a/source/programbuilder.cpp b/source/programbuilder.cpp
index 829691b6..affc4cc3 100644
--- a/source/programbuilder.cpp
+++ b/source/programbuilder.cpp
@@ -162,11 +162,12 @@ const ProgramBuilder::VariableDefinition ProgramBuilder::standard_variables[] =
 	{ NO_SCOPE, 0, 0, 0, 0 }
 };
 
-const char ProgramBuilder::interfaces[] = { 0, 0, 0, 0, 0, 'v', 0 };
+const char ProgramBuilder::interfaces[] = { 0, 0, 0, 0, 0, 'v', 'g', 0 };
 
 ProgramBuilder::ProgramBuilder(const StandardFeatures &f):
 	features(f),
 	feature_flags(features.create_flags()),
+	enabled_scopes((1<<N_SCOPES)-1),
 	optimize(true)
 {
 	if(!features.custom.empty())
@@ -259,6 +260,9 @@ ProgramBuilder::ProgramBuilder(const StandardFeatures &f):
 		}
 	}
 
+	if(!features.geometry)
+		enabled_scopes &= ~(1<<GEOMETRY);
+
 	if(!features.legacy)
 	{
 		aliases["texture1D"] = "texture";
@@ -469,7 +473,7 @@ string ProgramBuilder::create_source(const list<ShaderVariable *> &variables, Va
 		if(iface&INPUT)
 		{
 			const char *qualifier = (features.legacy ? scope==VERTEX ? "attribute" : "varying" : "in");
-			source += format("%s %s;\n", qualifier, (*i)->create_declaration(interfaces[scope-1]));
+			source += format("%s %s;\n", qualifier, (*i)->create_declaration(interfaces[previous_scope(scope, enabled_scopes)]));
 		}
 
 		if(iface&OUTPUT)
@@ -743,9 +747,21 @@ string ProgramBuilder::replace_identifiers(const char *expression, const map<str
 	return result;
 }
 
+ProgramBuilder::VariableScope ProgramBuilder::previous_scope(VariableScope scope, unsigned enabled_scopes)
+{
+	while(scope!=NO_SCOPE)
+	{
+		scope = static_cast<VariableScope>(scope-1);
+		if(enabled_scopes&(1<<scope))
+			break;
+	}
+
+	return scope;
+}
+
 string ProgramBuilder::create_expression(const ShaderVariable &var, const char *loop) const
 {
-	string expr = var.create_expression(loop);
+	string expr = var.create_expression(enabled_scopes, loop);
 	return replace_identifiers(expr.c_str(), aliases, true);
 }
 
@@ -762,7 +778,8 @@ ProgramBuilder::StandardFeatures::StandardFeatures():
 	shadow(false),
 	reflection(false),
 	clipping(false),
-	max_clip_planes(1)
+	max_clip_planes(1),
+	geometry(false)
 {
 	if(get_gl_api()==OPENGL_ES2)
 		legacy = !(get_glsl_version()>=Version(3, 0));
@@ -1075,18 +1092,19 @@ string ProgramBuilder::ShaderVariable::create_declaration(char iface, bool loop)
 		return format("%s %s%s", variable->type, resolved_name, array);
 }
 
-string ProgramBuilder::ShaderVariable::create_replacement(VariableScope from_scope, const char *loop) const
+string ProgramBuilder::ShaderVariable::create_replacement(VariableScope from_scope, unsigned enabled_scopes, const char *loop) const
 {
 	string replacement = resolved_name;
 	InterfaceFlags iface = NO_INTERFACE;
 	if(variable)
 	{
 		iface = get_interface_flags(from_scope);
-		if((iface&INPUT) && interfaces[from_scope-1])
-			replacement = format("%c_%s", interfaces[from_scope-1], replacement);
+		VariableScope prev_scope = previous_scope(from_scope, enabled_scopes);
+		if((iface&INPUT) && interfaces[prev_scope])
+			replacement = format("%c_%s", interfaces[prev_scope], replacement);
 		else if(inlined)
 		{
-			replacement = create_expression(loop);
+			replacement = create_expression(enabled_scopes, loop);
 			if(inline_parens)
 				replacement = "("+replacement+")";
 			return replacement;
@@ -1105,12 +1123,12 @@ string ProgramBuilder::ShaderVariable::create_replacement(VariableScope from_sco
 	return replacement;
 }
 
-string ProgramBuilder::ShaderVariable::create_expression(const char *loop) const
+string ProgramBuilder::ShaderVariable::create_expression(unsigned enabled_scopes, const char *loop) const
 {
 	map<string, string> replace_map;
 	for(list<ShaderVariable *>::const_iterator i=referenced_vars.begin(); i!=referenced_vars.end(); ++i)
 	{
-		string replacement = (*i)->create_replacement(variable->scope, loop);
+		string replacement = (*i)->create_replacement(variable->scope, enabled_scopes, loop);
 		if(replacement!=(*i)->name)
 			replace_map[(*i)->name] = replacement;
 	}
@@ -1128,6 +1146,7 @@ ProgramBuilder::StandardFeatures::Loader::Loader(StandardFeatures &f):
 	add("clipping",  &StandardFeatures::clipping);
 	add("custom",    &StandardFeatures::custom);
 	add("fog",       &StandardFeatures::fog);
+	add("geometry",  &StandardFeatures::geometry);
 	add("lighting",  &StandardFeatures::lighting);
 	add("material",  &StandardFeatures::material);
 	add("max_clip_planes", &StandardFeatures::max_clip_planes);
diff --git a/source/programbuilder.h b/source/programbuilder.h
index f2046e45..053eb567 100644
--- a/source/programbuilder.h
+++ b/source/programbuilder.h
@@ -104,6 +104,9 @@ public:
 		/** Number of clipping planes to process. */
 		unsigned max_clip_planes;
 
+		/** Use a geometry shader. */
+		bool geometry;
+
 		/** Force the use of legacy shaders conforming to GLSL 1.10.   Defaults
 		to true if the version of GLSL is less than 1.30, false otherwise. */
 		bool legacy;
@@ -125,7 +128,9 @@ private:
 		UNIFORM,
 		ATTRIBUTE,
 		VERTEX,
-		FRAGMENT
+		GEOMETRY,
+		FRAGMENT,
+		N_SCOPES
 	};
 
 	enum InterfaceFlags
@@ -177,8 +182,8 @@ private:
 		InterfaceFlags get_interface_flags(VariableScope) const;
 		std::string create_type_declaration() const;
 		std::string create_declaration(char = 0, bool = false) const;
-		std::string create_replacement(VariableScope, const char * = 0) const;
-		std::string create_expression(const char * = 0) const;
+		std::string create_replacement(VariableScope, unsigned, const char * = 0) const;
+		std::string create_expression(unsigned, const char * = 0) const;
 	};
 
 	enum MatchType
@@ -192,6 +197,7 @@ private:
 	StandardFeatures features;
 	std::list<VariableDefinition> custom_variables;
 	std::string feature_flags;
+	unsigned enabled_scopes;
 	std::map<std::string, std::string> aliases;
 	bool optimize;
 
@@ -218,6 +224,7 @@ private:
 	static bool parse_identifier(const char *, unsigned &, unsigned &);
 	static std::vector<std::string> extract_identifiers(const char *);
 	static std::string replace_identifiers(const char *, const std::map<std::string, std::string> &, bool = false);
+	static VariableScope previous_scope(VariableScope, unsigned);
 	std::string create_expression(const ShaderVariable &, const char * = 0) const;
 };