GLSL 'include' support

res/shaders/background.glslf

@@ -1,5 +1,3 @@
-#version 330 core
-
 in vec3 v_coord;
 out vec4 f_color;
 

res/shaders/background.glslv

@@ -1,5 +1,3 @@
-#version 330 core
-
 layout (location = 0) in vec2 v_position;
 
 out vec3 v_coord;

res/shaders/lib/commons.glsl

@@ -0,0 +1,11 @@
+// Example of a GLSL library
+
+vec4 decompress_light(float compressed_light) {
+	vec4 result;
+    int compressed = floatBitsToInt(compressed_light);
+    result.r = ((compressed >> 24) & 0xFF) / 255.f;
+    result.g = ((compressed >> 16) & 0xFF) / 255.f;
+    result.b = ((compressed >> 8) & 0xFF) / 255.f;
+    result.a = (compressed & 0xFF) / 255.f;
+	return result;
+}

res/shaders/lines.glslf

@@ -1,5 +1,3 @@
-#version 330 core
-
 in vec4 v_color;
 out vec4 f_color;
 

res/shaders/lines.glslv

@@ -1,5 +1,3 @@
-#version 330 core
-
 layout (location = 0) in vec3 a_position;
 layout (location = 1) in vec4 a_color;
 

res/shaders/main.glslf

@@ -1,5 +1,3 @@
-#version 330 core
-
 in vec4 a_color;
 in vec2 a_texCoord;
 in float a_distance;

res/shaders/main.glslv

@@ -1,4 +1,4 @@
-#version 330 core
+#include <commons>
 
 layout (location = 0) in vec3 v_position;
 layout (location = 1) in vec2 v_texCoord;
@@ -22,15 +22,6 @@ uniform float u_torchlightDistance;
 
 #define SKY_LIGHT_MUL 2.5
 
-vec4 decompress_light(float compressed_light) {
-	vec4 result;
-    int compressed = floatBitsToInt(compressed_light);
-    result.r = ((compressed >> 24) & 0xFF) / 255.f;
-    result.g = ((compressed >> 16) & 0xFF) / 255.f;
-    result.b = ((compressed >> 8) & 0xFF) / 255.f;
-    result.a = (compressed & 0xFF) / 255.f;
-	return result;
-}
 
 void main(){
 	vec2 pos2d = (u_model * vec4(v_position, 1.0)).xz-u_cameraPos.xz;

res/shaders/skybox_gen.glslf

@@ -22,8 +22,6 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 */
 
-#version 330 core
-
 // first, lets define some constants to use (planet radius, position, and scattering coefficients)
 #define PLANET_POS vec3(0.0) /* the position of the planet */
 #define PLANET_RADIUS 6371e3 /* radius of the planet */

res/shaders/skybox_gen.glslv

@@ -1,5 +1,3 @@
-#version 330 core
-
 layout (location = 0) in vec2 v_position;
 
 out vec2 v_coord;

res/shaders/ui.glslf

@@ -1,5 +1,3 @@
-#version 330 core
-
 in vec2 a_textureCoord;
 in vec4 a_color;
 out vec4 f_color;

res/shaders/ui.glslv

@@ -1,5 +1,3 @@
-#version 330 core
-
 layout (location = 0) in vec2 v_position;
 layout (location = 1) in vec2 v_textureCoord;
 layout (location = 2) in vec4 v_color;

src/assets/AssetsLoader.cpp

@@ -48,7 +48,7 @@ bool AssetsLoader::loadNext() {
 #include "../graphics/Font.h"
 
 bool _load_shader(Assets* assets, const path& filename, const std::string& name) {
-	Shader* shader = load_shader(filename.string() + ".glslv", filename.string() + ".glslf");
+	Shader* shader = Shader::loadShader(filename.string() + ".glslv", filename.string() + ".glslf");
 	if (shader == nullptr) {
 		std::cerr << "failed to load shader '" << name << "'" << std::endl;
 		return false;

src/coders/GLSLExtension.cpp

@@ -0,0 +1,145 @@
+#include "GLSLExtension.h"
+#include <iostream>
+#include <sstream>
+#include <stdexcept>
+#include "../util/stringutil.h"
+#include "../typedefs.h"
+#include "../files/files.h"
+
+using std::string;
+using std::filesystem::path;
+namespace fs = std::filesystem;
+
+path GLSLExtension::getHeaderPath(string name) {
+    return libFolder/path(name+".glsl");
+}
+
+void GLSLExtension::setLibFolder(path folder) {
+    this->libFolder = folder;
+}
+
+void GLSLExtension::setVersion(string version) {
+    this->version = version;
+}
+
+void GLSLExtension::loadHeader(string name) {
+    path file = getHeaderPath(name);
+    string source = files::read_string(file);
+    addHeader(name, source);
+}
+
+void GLSLExtension::addHeader(string name, string source) {
+    headers[name] = source;
+}
+
+void GLSLExtension::define(string name, string value) {
+    defines[name] = value;
+}
+
+const string& GLSLExtension::getHeader(const string name) const {
+    auto found = headers.find(name);
+    if (found == headers.end()) {
+        throw std::runtime_error("no header '"+name+"' loaded");
+    }
+    return found->second;
+}
+
+const string GLSLExtension::getDefine(const string name) const {
+    auto found = defines.find(name);
+    if (found == defines.end()) {
+        return "";
+    }
+    return found->second;
+}
+
+bool GLSLExtension::hasDefine(const string name) const {
+    return defines.find(name) != defines.end();
+}
+
+bool GLSLExtension::hasHeader(const string name) const {
+    return headers.find(name) != headers.end();
+}
+
+void GLSLExtension::undefine(string name) {
+    if (hasDefine(name)) {
+        defines.erase(name);
+    }
+}
+
+inline std::runtime_error parsing_error(
+        const path& file, 
+        uint linenum, 
+        const string message) {
+    return std::runtime_error("file "+file.string()+": "+message+
+                          " at line "+std::to_string(linenum));
+}
+
+inline void parsing_warning(
+        const path& file, 
+        uint linenum, const 
+        string message) {
+    std::cerr << "file "+file.string()+": warning: "+message+
+             " at line "+std::to_string(linenum) << std::endl;
+}
+
+inline void source_line(std::stringstream& ss, const path& file, uint linenum) {
+    ss << "#line " << linenum << " " << file << '\n';
+}
+
+const string GLSLExtension::process(const path file, const string& source) {
+    std::stringstream ss;
+    size_t pos = 0;
+    uint linenum = 1;
+    ss << "#version " << version << '\n';
+    for (auto& entry : defines) {
+        ss << "#define " << entry.first << " " << entry.second << '\n';
+    }
+    source_line(ss, file, linenum);
+    while (pos < source.length()) {
+        size_t endline = source.find('\n', pos);
+        if (endline == string::npos) {
+            endline = source.length();
+        }
+        // parsing preprocessor directives
+        if (source[pos] == '#') {
+            string line = source.substr(pos+1, endline-pos);
+            util::trim(line);
+            // parsing 'include' directive
+            if (line.find("include") != string::npos) {
+                line = line.substr(7);
+                util::trim(line);
+                if (line.length() < 3) {
+                    throw parsing_error(file, linenum, 
+                        "invalid 'include' syntax");
+                }
+                if (line[0] != '<' || line[line.length()-1] != '>') {
+                    throw parsing_error(file, linenum,
+                        "expected '#include <filename>' syntax");
+                }
+                string name = line.substr(1, line.length()-2);
+                path hfile = getHeaderPath(name);
+                if (!hasHeader(name)) {
+                    loadHeader(name);
+                }
+                source_line(ss, hfile, 1);
+                ss << getHeader(name) << '\n';
+                pos = endline+1;
+                linenum++;
+                source_line(ss, file, linenum);
+                continue;
+            } 
+            // removing extra 'include' directives
+            else if (line.find("version") != string::npos) {
+                parsing_warning(file, linenum, "removed #version directive");
+                pos = endline+1;
+                linenum++;
+                source_line(ss, file, linenum);
+                continue;
+            }
+        }
+        linenum++;
+        ss << source.substr(pos, endline+1-pos);
+        pos = endline+1;
+    }
+    return ss.str();    
+}

src/coders/GLSLExtension.h

@@ -0,0 +1,33 @@
+#ifndef CODERS_GLSL_EXTESION_H_
+#define CODERS_GLSL_EXTESION_H_
+
+#include <string>
+#include <unordered_map>
+#include <filesystem>
+
+class GLSLExtension {
+    std::unordered_map<std::string, std::string> headers;
+    std::unordered_map<std::string, std::string> defines;
+    std::filesystem::path libFolder;
+    std::string version = "330 core";
+
+    void loadHeader(std::string name);
+    std::filesystem::path getHeaderPath(std::string name);
+public:
+    void setLibFolder(std::filesystem::path folder);
+    void setVersion(std::string version);
+
+    void define(std::string name, std::string value);
+    void undefine(std::string name);
+    void addHeader(std::string name, std::string source);
+
+    const std::string& getHeader(const std::string name) const;
+    const std::string getDefine(const std::string name) const;
+
+    bool hasHeader(const std::string name) const;
+    bool hasDefine(const std::string name) const;
+
+    const std::string process(const std::filesystem::path file, const std::string& source);
+};
+
+#endif // CODERS_GLSL_EXTESION_H_

src/engine.cpp

@@ -15,6 +15,7 @@
 #include "window/Camera.h"
 #include "window/input.h"
 #include "graphics/Batch2D.h"
+#include "graphics/Shader.h"
 #include "graphics/ImageData.h"
 #include "frontend/gui/GUI.h"
 #include "frontend/screens.h"
@@ -22,6 +23,7 @@
 
 #include "coders/json.h"
 #include "coders/png.h"
+#include "coders/GLSLExtension.h"
 #include "files/files.h"
 #include "files/engine_paths.h"
 
@@ -35,6 +37,7 @@ using gui::GUI;
 Engine::Engine(EngineSettings& settings, EnginePaths* paths, Content* content) 
 	   : settings(settings), content(content), paths(paths) {    
 	Window::initialize(settings.display);
+	Shader::preprocessor->setLibFolder(paths->getResources()/path("shaders/lib"));
 
 	assets = new Assets();
 	std::cout << "-- loading assets" << std::endl;

src/files/files.cpp

@@ -4,6 +4,7 @@
 #include <iostream>
 #include <memory>
 #include <stdint.h>
+#include <stdexcept>
 
 using std::ios;
 using std::string;
@@ -57,6 +58,9 @@ char* files::read_bytes(path filename, size_t& length) {
 std::string files::read_string(path filename) {
 	size_t size;
 	unique_ptr<char> chars (read_bytes(filename, size));
+	if (chars == nullptr) {
+		throw std::runtime_error("could not to load file '"+filename.string()+"'");
+	}
 	return string(chars.get(), size);
 }
 

src/graphics/Shader.cpp

@@ -10,6 +10,12 @@
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
 
+#include "../coders/GLSLExtension.h"
+
+using std::filesystem::path;
+
+GLSLExtension* Shader::preprocessor = new GLSLExtension();
+
 Shader::Shader(unsigned int id) : id(id){
 }
 
@@ -57,7 +63,7 @@ void Shader::uniform3f(std::string name, glm::vec3 xyz){
 }
 
 
-Shader* load_shader(std::string vertexFile, std::string fragmentFile) {
+Shader* Shader::loadShader(std::string vertexFile, std::string fragmentFile) {
 	// Reading Files
 	std::string vertexCode;
 	std::string fragmentCode;
@@ -84,6 +90,9 @@ Shader* load_shader(std::string vertexFile, std::string fragmentFile) {
 		std::cerr << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;
 		return nullptr;
 	}
+	vertexCode = preprocessor->process(path(vertexFile), vertexCode);
+	fragmentCode = preprocessor->process(path(fragmentFile), fragmentCode);
+
 	const GLchar* vShaderCode = vertexCode.c_str();
 	const GLchar* fShaderCode = fragmentCode.c_str();
 
@@ -98,7 +107,7 @@ Shader* load_shader(std::string vertexFile, std::string fragmentFile) {
 	glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);
 	if (!success){
 		glGetShaderInfoLog(vertex, 512, nullptr, infoLog);
-		std::cerr << "SHADER::VERTEX: compilation failed" << std::endl;
+		std::cerr << "SHADER::VERTEX: compilation failed: " << vertexFile << std::endl;
 		std::cerr << infoLog << std::endl;
 		return nullptr;
 	}
@@ -110,7 +119,7 @@ Shader* load_shader(std::string vertexFile, std::string fragmentFile) {
 	glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);
 	if (!success){
 		glGetShaderInfoLog(fragment, 512, nullptr, infoLog);
-		std::cerr << "SHADER::FRAGMENT: compilation failed" << std::endl;
+		std::cerr << "SHADER::FRAGMENT: compilation failed: " << vertexFile << std::endl;
 		std::cerr << infoLog << std::endl;
 		return nullptr;
 	}

src/graphics/Shader.h

@@ -4,8 +4,11 @@
 #include <string>
 #include <glm/glm.hpp>
 
+class GLSLExtension;
+
 class Shader {
 public:
+	static GLSLExtension* preprocessor;
 	unsigned int id;
 
 	Shader(unsigned int id);
@@ -19,8 +22,8 @@ public:
 	void uniform2f(std::string name, glm::vec2 xy);
 	void uniform3f(std::string name, float x, float y, float z);
 	void uniform3f(std::string name, glm::vec3 xyz);
+
+	static Shader* loadShader(std::string vertexFile, std::string fragmentFile);
 };
 
-extern Shader* load_shader(std::string vertexFile, std::string fragmentFile);
-
 #endif /* GRAPHICS_SHADER_H_ */

src/util/stringutil.cpp

@@ -4,6 +4,7 @@
 #include <locale>
 #include <sstream>
 #include <stdexcept>
+#include <algorithm>
 
 using std::vector;
 using std::string;
@@ -149,4 +150,21 @@ bool util::is_valid_filename(std::wstring name) {
         }
     }
     return true;
-}
+}
+
+void util::ltrim(std::string &s) {
+    s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](unsigned char ch) {
+        return !std::isspace(ch);
+    }));
+}
+
+void util::rtrim(std::string &s) {
+    s.erase(std::find_if(s.rbegin(), s.rend(), [](unsigned char ch) {
+        return !std::isspace(ch);
+    }).base(), s.end());
+}
+
+void util::trim(std::string &s) {
+    rtrim(s);
+    ltrim(s);
+}

src/util/stringutil.h

@@ -15,6 +15,10 @@ namespace util {
     extern bool is_integer(std::string text);
     extern bool is_integer(std::wstring text);
     extern bool is_valid_filename(std::wstring name);
+
+    extern void ltrim(std::string &s);
+    extern void rtrim(std::string &s);
+    extern void trim(std::string &s);
 }
 
 #endif // UTIL_STRINGUTIL_H_