Applied modernize rules and fixed build.

Applied clang-tidy modernize rules and fixed the CMakeLists.txt
file so that it also linked against the SDL2 library.

10 files changed, 39 insertions, 26 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f084702c..b92ec79a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -67,16 +67,16 @@ endif()
 # find libraries
 find_package(OpenGL REQUIRED)
 find_package(GLEW REQUIRED)
+include(FindPkgConfig)
+pkg_search_module(SDL2 REQUIRED sdl2)
 
 # set include directory
-include_directories(${YAGE_INCLUDE_DIR}
-  ${YAGE_INCLUDE_DIR}/Physics/
-  ${YAGE_INCLUDE_DIR}/Math/)
+include_directories(${YAGE_INCLUDE_DIR})
 
 # make it a static library
 add_library(${PROJECT_NAME} ${YAGE_SOURCES})
 
-set(YAGE_LIB_DEP_L "yage;${OPENGL_LIBRARIES};${GLEW_LIBRARIES};${SDL2_LIBRAIRES}")
+set(YAGE_LIB_DEP_L "yage;${OPENGL_LIBRARIES};${GLEW_LIBRARIES};${SDL2_LIBRARIES}")
 
 message("${YAGE_LIB_DEP_L}")
 
diff --git a/README.md b/README.md
index 17176786..96a0ad70 100644
--- a/README.md
+++ b/README.md
@@ -1,14 +1,25 @@
 YAGE
 ====
 
-YAGE stands for Yet Another Game Engine. It is a game engine that I am developing for a game called [Arider](https://github.com/ymherklotz/Arider). 
+Introduction
+------------
 
-YAGE uses OpenGL and SDL2 for the window creation and management and graphics.
+YAGE stands for Yet Another Game Engine. It is a game engine that I am
+developing for a game called [Arider](https://github.com/ymherklotz/Arider).
+It uses OpenGL and SDL2 for the window creation and management and graphics.
 
-Installation and Usage
+Installation and usage
 ----------------------
 
-To compile YAGE, create a build directory from the base directory. Then call cmake and point it to the directory containing [CMakeLists.txt](/CMakeLists.txt).
+To use YAGE for your own game, you should link it as a static library and
+include the [yage.hpp](/include/YAGE/yage.hpp) header in your project.
+
+Build and Testing
+-----------------
+
+To compile YAGE, create a build directory from the base directory. Then call
+cmake and point it to the directory containing.
+[CMakeLists.txt](/CMakeLists.txt).
 
 ``` shell
 mkdir build
diff --git a/include/YAGE/Physics/body.hpp b/include/YAGE/Physics/body.hpp
index fab28fc1..efeedb64 100644
--- a/include/YAGE/Physics/body.hpp
+++ b/include/YAGE/Physics/body.hpp
@@ -46,7 +46,7 @@ public:
 
 protected:
 	// protected constructor to initialize member variables
-	Body(const Vector2d& position = Vector2d(0, 0), double mass = 1, const Vector2d& velocity = Vector2d(0, 0), bool gravity = false);
+	Body(Vector2d  position = Vector2d(0, 0), double mass = 1, Vector2d  velocity = Vector2d(0, 0), bool gravity = false);
 };
 }  // namespace yage
 
diff --git a/src/body.cpp b/src/body.cpp
index a17f6ee3..9c8babf1 100644
--- a/src/body.cpp
+++ b/src/body.cpp
@@ -6,6 +6,8 @@
  * ----------------------------------------------------------------------------
  */
 
+#include <utility>
+
 #include "Physics/body.hpp"
 
 namespace yage {
@@ -16,11 +18,11 @@ double Body::xPosition() const { return position_[0]; }
 
 double Body::yPosition() const { return position_[1]; }
 
-Body::Body(const Vector2d& position, double mass, const Vector2d& velocity,
+Body::Body(Vector2d  position, double mass, Vector2d  velocity,
            bool gravity)
-    : position_(position),
+    : position_(std::move(position)),
       mass_(mass),
-      velocity_(velocity),
+      velocity_(std::move(velocity)),
       gravity_(gravity) {}
 
 }  // yage
diff --git a/src/glslprogram.cpp b/src/glslprogram.cpp
index a5f95ad5..6d0a60b2 100644
--- a/src/glslprogram.cpp
+++ b/src/glslprogram.cpp
@@ -38,7 +38,7 @@ void GlslProgram::compileShader(const GLuint& shader,
 
     // cast source to a c string to get the address of it and input it for
     // compilation
-    const GLchar* vertex_source = (const GLchar*)content.c_str();
+    const auto* vertex_source = (const GLchar*)content.c_str();
     glShaderSource(shader, 1, &vertex_source, nullptr);
     glCompileShader(shader);
 
diff --git a/src/picopng.cpp b/src/picopng.cpp
index 6fe9c1f7..f75390de 100644
--- a/src/picopng.cpp
+++ b/src/picopng.cpp
@@ -466,7 +466,7 @@ int decodePNG(std::vector<unsigned char>& out_image, unsigned long& image_width,
         void decode(std::vector<unsigned char>& out, const unsigned char* in,
                     size_t size, bool convert_to_rgba32) {
             error = 0;
-            if (size == 0 || in == 0) {
+            if (size == 0 || in == nullptr) {
                 error = 48;
                 return;
             }  // the given data is empty
@@ -543,7 +543,7 @@ int decodePNG(std::vector<unsigned char>& out_image, unsigned long& image_width,
                             return;
                         }  // error: this chunk must be 2 bytes for greyscale
                            // image
-                        info.key_defined = 1;
+                        info.key_defined = true;
                         info.key_r = info.key_g = info.key_b =
                             256 * in[pos] + in[pos + 1];
                         pos += 2;
@@ -552,7 +552,7 @@ int decodePNG(std::vector<unsigned char>& out_image, unsigned long& image_width,
                             error = 41;
                             return;
                         }  // error: this chunk must be 6 bytes for RGB image
-                        info.key_defined = 1;
+                        info.key_defined = true;
                         info.key_r = 256 * in[pos] + in[pos + 1];
                         pos += 2;
                         info.key_g = 256 * in[pos] + in[pos + 1];
@@ -590,7 +590,7 @@ int decodePNG(std::vector<unsigned char>& out_image, unsigned long& image_width,
                    outlength = (info.height * info.width * bpp + 7) / 8;
             out.resize(outlength);  // time to fill the out buffer
             unsigned char* out_ =
-                outlength ? &out[0] : 0;  // use a regular pointer to the
+                outlength ? &out[0] : nullptr;  // use a regular pointer to the
                                           // std::vector for faster code if
                                           // compiled without optimization
             if (info.interlaceMethod == 0)  // no interlace, just filter
@@ -603,7 +603,7 @@ int decodePNG(std::vector<unsigned char>& out_image, unsigned long& image_width,
                     for (unsigned long y = 0; y < info.height; y++) {
                         unsigned long filterType = scanlines[linestart];
                         const unsigned char* prevline =
-                            (y == 0) ? 0
+                            (y == 0) ? nullptr
                                      : &out_[(y - 1) * info.width * bytewidth];
                         unFilterScanline(&out_[linestart - y],
                                          &scanlines[linestart + 1], prevline,
@@ -619,7 +619,7 @@ int decodePNG(std::vector<unsigned char>& out_image, unsigned long& image_width,
                     for (size_t y = 0, obp = 0; y < info.height; y++) {
                         unsigned long filterType = scanlines[linestart];
                         const unsigned char* prevline =
-                            (y == 0) ? 0
+                            (y == 0) ? nullptr
                                      : &out_[(y - 1) * info.width * bytewidth];
                         unFilterScanline(&templine[0],
                                          &scanlines[linestart + 1], prevline,
@@ -788,7 +788,7 @@ int decodePNG(std::vector<unsigned char>& out_image, unsigned long& image_width,
                    linelength = 1 + ((bpp * passw + 7) / 8);
             for (unsigned long y = 0; y < passh; y++) {
                 unsigned char filterType = in[y * linelength],
-                              *prevline = (y == 0) ? 0 : lineo;
+                              *prevline = (y == 0) ? nullptr : lineo;
                 unFilterScanline(linen, &in[y * linelength + 1], prevline,
                                  bytewidth, filterType, (w * bpp + 7) / 8);
                 if (error) return;
@@ -876,7 +876,7 @@ int decodePNG(std::vector<unsigned char>& out_image, unsigned long& image_width,
             out.resize(numpixels * 4);
             unsigned char* out_ =
                 out.empty()
-                    ? 0
+                    ? nullptr
                     : &out[0];  // faster if compiled without optimization
             if (infoIn.bitDepth == 8 && infoIn.colorType == 0)  // greyscale
                 for (size_t i = 0; i < numpixels; i++) {
diff --git a/src/sprite.cpp b/src/sprite.cpp
index e3d74982..4cdd2ecf 100644
--- a/src/sprite.cpp
+++ b/src/sprite.cpp
@@ -14,7 +14,7 @@
 
 namespace yage {
 
-Sprite::Sprite() {}
+Sprite::Sprite() = default;
 
 Sprite::~Sprite() {
     if (vbo_id_ != 0) glDeleteBuffers(1, &vbo_id_);
@@ -50,7 +50,7 @@ void Sprite::init(float x, float y, float width, float height,
     vertex_data[5].setPosition(x + width, y);
     vertex_data[5].setUv(1.f, 0.f);
 
-    for (int i = 0; i < 6; ++i) vertex_data[i].setColor(255, 0, 255, 255);
+    for (auto & i : vertex_data) i.setColor(255, 0, 255, 255);
 
     vertex_data[1].setColor(0, 255, 255, 255);
     vertex_data[4].setColor(255, 0, 0, 255);
diff --git a/src/spritebatch.cpp b/src/spritebatch.cpp
index 8e64aa5e..f4767829 100644
--- a/src/spritebatch.cpp
+++ b/src/spritebatch.cpp
@@ -28,7 +28,7 @@ Glyph::Glyph(GLuint texture, float depth, const Vertex& top_left,
 RenderBatch::RenderBatch(GLint offset, GLsizei num_vertices, GLuint texture)
     : num_vertices_(num_vertices), offset_(offset), texture_(texture) {}
 
-SpriteBatch::SpriteBatch() {}
+SpriteBatch::SpriteBatch() = default;
 
 SpriteBatch::~SpriteBatch() {
     if (vao_ != 0) glDeleteVertexArrays(1, &vao_);
diff --git a/src/texturecache.cpp b/src/texturecache.cpp
index 6d10b209..09ac2639 100644
--- a/src/texturecache.cpp
+++ b/src/texturecache.cpp
@@ -13,7 +13,7 @@ namespace yage
 {
 
 TextureCache::TextureCache()
-{}
+= default;
 
 Texture TextureCache::getTexture(const std::string &texture_path)
 {
diff --git a/src/window.cpp b/src/window.cpp
index 7a00b0c9..959cacb3 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -15,7 +15,7 @@
 
 namespace yage {
 
-Window::Window() {}
+Window::Window() = default;
 
 Window::~Window() { SDL_DestroyWindow(window_); }