From b0fb6b138099856c52c1fbdb76914eee0ee55d4a Mon Sep 17 00:00:00 2001
From: Scayze <manuel.strey@gmx.de>
Date: Mon, 27 Nov 2017 16:47:46 +0100
Subject: [PATCH] Added interpolation modifiers to shaderlang

---
 drivers/gles3/shader_compiler_gles3.cpp | 15 +++++++++++--
 servers/visual/shader_language.cpp      | 28 +++++++++++++++++++++++++
 servers/visual/shader_language.h        | 12 +++++++++++
 3 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/drivers/gles3/shader_compiler_gles3.cpp b/drivers/gles3/shader_compiler_gles3.cpp
index 325df8e4f10..05381da9b93 100644
--- a/drivers/gles3/shader_compiler_gles3.cpp
+++ b/drivers/gles3/shader_compiler_gles3.cpp
@@ -81,6 +81,16 @@ static int _get_datatype_size(SL::DataType p_type) {
 	ERR_FAIL_V(0);
 }
 
+static String _interpstr(SL::DataInterpolation p_interp) {
+
+	switch (p_interp) {
+		case SL::INTERPOLATION_FLAT: return "flat ";
+		case SL::INTERPOLATION_NO_PERSPECTIVE: return "noperspective ";
+		case SL::INTERPOLATION_SMOOTH: return "smooth ";
+	}
+	return "";
+}
+
 static String _prestr(SL::DataPrecision p_pres) {
 
 	switch (p_pres) {
@@ -383,12 +393,13 @@ String ShaderCompilerGLES3::_dump_node_code(SL::Node *p_node, int p_level, Gener
 			for (Map<StringName, SL::ShaderNode::Varying>::Element *E = pnode->varyings.front(); E; E = E->next()) {
 
 				String vcode;
+				String interp_mode = _interpstr(E->get().interpolation);
 				vcode += _prestr(E->get().precission);
 				vcode += _typestr(E->get().type);
 				vcode += " " + _mkid(E->key());
 				vcode += ";\n";
-				r_gen_code.vertex_global += "out " + vcode;
-				r_gen_code.fragment_global += "in " + vcode;
+				r_gen_code.vertex_global += interp_mode + "out " + vcode;
+				r_gen_code.fragment_global += interp_mode + "in " + vcode;
 			}
 
 			Map<StringName, String> function_code;
diff --git a/servers/visual/shader_language.cpp b/servers/visual/shader_language.cpp
index 4de902af588..e10a57c571b 100644
--- a/servers/visual/shader_language.cpp
+++ b/servers/visual/shader_language.cpp
@@ -254,6 +254,9 @@ const ShaderLanguage::KeyWord ShaderLanguage::keyword_list[] = {
 	{ TK_TYPE_ISAMPLER2D, "isampler2D" },
 	{ TK_TYPE_USAMPLER2D, "usampler2D" },
 	{ TK_TYPE_SAMPLERCUBE, "samplerCube" },
+	{ TK_INTERPOLATION_FLAT, "flat" },
+	{ TK_INTERPOLATION_NO_PERSPECTIVE, "noperspective" },
+	{ TK_INTERPOLATION_SMOOTH, "smooth" },
 	{ TK_PRECISION_LOW, "lowp" },
 	{ TK_PRECISION_MID, "mediump" },
 	{ TK_PRECISION_HIGH, "highp" },
@@ -658,6 +661,24 @@ ShaderLanguage::DataType ShaderLanguage::get_token_datatype(TokenType p_type) {
 	return DataType(p_type - TK_TYPE_VOID);
 }
 
+bool ShaderLanguage::is_token_interpolation(TokenType p_type) {
+
+	return (
+			p_type == TK_INTERPOLATION_FLAT ||
+			p_type == TK_INTERPOLATION_NO_PERSPECTIVE ||
+			p_type == TK_INTERPOLATION_SMOOTH);
+}
+
+ShaderLanguage::DataInterpolation ShaderLanguage::get_token_interpolation(TokenType p_type) {
+
+	if (p_type == TK_INTERPOLATION_FLAT)
+		return INTERPOLATION_FLAT;
+	else if (p_type == TK_INTERPOLATION_NO_PERSPECTIVE)
+		return INTERPOLATION_NO_PERSPECTIVE;
+	else
+		return INTERPOLATION_SMOOTH;
+}
+
 bool ShaderLanguage::is_token_precision(TokenType p_type) {
 
 	return (
@@ -3576,10 +3597,16 @@ Error ShaderLanguage::_parse_shader(const Map<StringName, FunctionInfo> &p_funct
 
 				bool uniform = tk.type == TK_UNIFORM;
 				DataPrecision precision = PRECISION_DEFAULT;
+				DataInterpolation interpolation = INTERPOLATION_SMOOTH;
 				DataType type;
 				StringName name;
 
 				tk = _get_token();
+				if (is_token_interpolation(tk.type)) {
+					interpolation = get_token_interpolation(tk.type);
+					tk = _get_token();
+				}
+
 				if (is_token_precision(tk.type)) {
 					precision = get_token_precision(tk.type);
 					tk = _get_token();
@@ -3777,6 +3804,7 @@ Error ShaderLanguage::_parse_shader(const Map<StringName, FunctionInfo> &p_funct
 					ShaderNode::Varying varying;
 					varying.type = type;
 					varying.precission = precision;
+					varying.interpolation = interpolation;
 					shader->varyings[name] = varying;
 
 					tk = _get_token();
diff --git a/servers/visual/shader_language.h b/servers/visual/shader_language.h
index 7a7f6dd71c2..e092bf931f1 100644
--- a/servers/visual/shader_language.h
+++ b/servers/visual/shader_language.h
@@ -72,6 +72,9 @@ public:
 		TK_TYPE_ISAMPLER2D,
 		TK_TYPE_USAMPLER2D,
 		TK_TYPE_SAMPLERCUBE,
+		TK_INTERPOLATION_FLAT,
+		TK_INTERPOLATION_NO_PERSPECTIVE,
+		TK_INTERPOLATION_SMOOTH,
 		TK_PRECISION_LOW,
 		TK_PRECISION_MID,
 		TK_PRECISION_HIGH,
@@ -192,6 +195,12 @@ public:
 		PRECISION_DEFAULT,
 	};
 
+	enum DataInterpolation {
+		INTERPOLATION_FLAT,
+		INTERPOLATION_NO_PERSPECTIVE,
+		INTERPOLATION_SMOOTH,
+	};
+
 	enum Operator {
 		OP_EQUAL,
 		OP_NOT_EQUAL,
@@ -431,6 +440,7 @@ public:
 
 		struct Varying {
 			DataType type;
+			DataInterpolation interpolation;
 			DataPrecision precission;
 		};
 
@@ -511,6 +521,8 @@ public:
 
 	static bool is_token_datatype(TokenType p_type);
 	static DataType get_token_datatype(TokenType p_type);
+	static bool is_token_interpolation(TokenType p_type);
+	static DataInterpolation get_token_interpolation(TokenType p_type);
 	static bool is_token_precision(TokenType p_type);
 	static DataPrecision get_token_precision(TokenType p_type);
 	static String get_datatype_name(DataType p_type);