How-To: Fix IntelliJ / Android Studio screen display corruption

With my NVidia 980M w/ Optimus graphics card, Android Studio (which is IntelliJ-based) would often get itself in a state and the screen would get corrupted, which was incredibly frustrating to work with. Luckily there seems to be a pretty simple solution:

1 – Find your user folder

If you want to make this change on a per-user basis, then you’ll need to create a vmoptions file in the relevant user-directory. I’m doing this fix on Windows running 64-bit Android Studio so I’ve created the file: %USERPROFILE%\.{FOLDER_NAME}\studio64.exe.vmoptions

Depending on your operating system, the filename and locations are:

Windows:
%USERPROFILE%\.{FOLDER_NAME}\studio.exe.vmoptions and/or %USERPROFILE%\.{FOLDER_NAME}\studio64.exe.vmoptions

Mac:
~/Library/Preferences/{FOLDER_NAME}/studio.vmoptions

Linux:
~/.{FOLDER_NAME}/studio.vmoptions and/or ~/.{FOLDER_NAME}/studio64.vmoptions

Where FOLDER_NAME is something like AndroidStudio1.5 or such.

If you want to make the change on a global basis (although the config file doesn’t recommend this), then you can modify the studio.exe.vmoptions configuration file in the bin folder located wherever Android Studio is installed (on Windows this is likely to be “Program Files” for 64-bit or “Program Files (x86)” for 32-bit Android Studio). So for me the ‘global’ config file is: C:\Program Files\Android\Android Studio\bin\studio64.exe.vmoptions

Source: http://tools.android.com/tech-docs/configuration

2 – Add this switch

-Dsun.java2d.d3d=false

Save the file then restart Android Studio and the display corruption should be fixed!

Source: http://stackoverflow.com/a/27768329.

Wrap up and secondary workaround

This worked fine for me in Windows, but as the settings affect Direct3D, I’m somewhat doubtful that it’ll work in Linux or Mac. However, I did read about a workaround technique where you go into the NVidia Settings panel, select your java runtime and force it to always work in maximum performance mode, thus bypassing any use of Optimus which may also be causing the screen corruption – so should the above fix not work for you, then perhaps the workaround will.

Cheers!

The Caliko Inverse Kinematics Library

After around 18 months of work, I’ve finally submitted my first research paper today to the Journal of Open Research Software in the form of a software meta-paper. While the paper outlines what the library is and does, the real crux of the submission is the creation of the Caliko library itself as a ‘software artifact’.

I can’t do anything with the paper until it’s either accepted or rejected (hopefully the former!) – but if you’d like to see what the library is and does – then this video should explain things quite nicely:

And if you’d like to give the whole thing a spin, then it’s merely a click away at:
https://github.com/feduni/caliko

One down, five to go.

Onwards!

Oracle Java Certfication

I passed my 1Z0-803 Java SE 7 Programmer I exam the other day – and it was without doubt the hardest exam I’ve ever taken by a country mile.

The entire thing’s made of trick-questions, corner-cases and large ‘human-compiler’ questions which have you substituting multiple pieces of borderline-legal nonsensical code into large swathes of horribly structured and badly laid out code to mentally determine which ones result in a given set of output. Horrific.

Also, on top of having to race your way through 70 questions in two hours, there are an undisclosed number of “non-assessed questions” which don’t count towards your score – the only possible reason for these I can think of is to burn the clock and artificially inflate the fail rate, thus scoring Oracle ~$300 a pop on resits for people who need an Oracle cert for their work. What a complete and utter rort.

Java-Cert2

Nailed it – but the only way I’d ever do another Oracle certification would be if there was something big like a specific job riding on it. And even then I’d think twice about whether it’d be worth the grief.

Final rating: 0 out of 5 Rubber Chickens. Avoid like leprosy.

A Simple C++ OpenGL Shader Loader – Improved

I wrote one back in 2013, but I’ve learnt some things since then, so I’ve re-written it all with some changes. You can still load/compile shaders from strings or files, and then link/validate/use the resulting shader programs, only this time its all a little bit cleaner and more robust.

The main deficiencies of the previous incarnation were:

  • The Shader class wasn’t required for what I was using this stuff for, so I stripped it out – now you just create a ShaderProgram directly,
  • Error logs weren’t shown for any shader or shader program errors,
  • The shader program didn’t get validated,
  • Abuse of exit(-1) rather than throwing unchecked runtime_errors,
  • Inclusion of using clauses in headers, and
  • Possible wonky static declaration and initialisation of const_iterator error in uniform location getter meant that it might have only “got” the uniform location correcty on first run, when the const_iterator was declared – but in practice I haven’t seen any issues, perhaps because I spotted and fixed it but forgot to update article though…

Anyway, below is an improved version that fixes all of the above – here’s how you use it…

Usage

// Start by declaring a pointer to a ShaderProgram. A ShaderProgram can only be instantiated when there
// is a valid OpenGL context (i.e. window) - so you may like to declare the ShaderProgram globally, then
// instantiate it later on when you have an OpenGL context.
ShaderProgram *shaderProgram;
 
// ...later on when we have a OpenGL context...
shaderProgram = new ShaderProgram();
 
// To provide the source code for the vertex and fragment shaders you can either initialise from strings or from files:
shaderProgram->initFromStrings(vertexShaderString, fragmentShaderString);
shaderProgram->initFromFiles(vertexShaderFilename, fragmentShaderFilename);
 
// Add attributes to suit
shaderProgram->addAttribute("vertexLocation");
shaderProgram->addAttribute("vertexColour");
 
// Add uniforms to suit
shaderProgram->addUniform("mvpMatrix");
 
// Enable attributes
// 1.) Create and bind to a vertex array object (VAO)...
// 2.) Create and bind to a vertex buffer object (VBO) and specify your vertex attrib pointers
// 3.) Provide geometry data then unbind from the VBO
// --- Now you can enable vertex attributes with, for example:
             glEnableVertexAttribArray( shaderProgram->attribute("vertexLocation") );
             glEnableVertexAttribArray( shaderProgram->attribute("vertexColour") );
// 5.) Unbind from VAO
 
// Finally, to draw the geometry using the shader program you can use code similar to this:
// Note: This code assumes you're using GLM for your matrices, modify as appropriate if not. Also
// note that to use glm::value_ptr you must "#include <glm/gtc/type_ptr.hpp>"
shaderProgram->use();
             glUniformMatrix4fv(shaderProgram->uniform("mvpMatrix"), 1, GL_FALSE, glm::value_ptr(mvpMatrix) );
             <YOUR-DRAW-CALL-HERE> i.e. glDrawArrays(GL_TRIANGLES, 0, 100) etc.
shaderProgram->disable();

ShaderProgram Class Source Code

Here’s the code for the class itself:

/***
author     : r3dux
version    : 0.3 - 15/01/2014
description: Gets GLSL source code either provided as strings or can load from filenames,
             compiles the shaders, creates a shader program which the shaders are linked
             to, then the program is validated and is ready for use via myProgram.use(),
             <draw-stuff-here> then calling myProgram.disable();
 
             Attributes and uniforms are stored in <string, int> maps and can be added
             via calls to addAttribute(<name-of-attribute>) and then the attribute
             index can be obtained via myProgram.attribute(<name-of-attribute>) - Uniforms
             work in the exact same way.
***/
 
#ifndef SHADER_PROGRAM_HPP
#define SHADER_PROGRAM_HPP
 
#include <iostream>
#include <fstream>
#include <sstream>
#include <map>
 
class ShaderProgram
{
private:
	// static DEBUG flag - if set to false then, errors aside, we'll run completely silent
	static const bool DEBUG = true;
 
	// We'll use an enum to differentiate between shaders and shader programs when querying the info log
	enum class ObjectType
	{
		SHADER, PROGRAM
	};
 
	// Shader program and individual shader Ids
	GLuint programId;
	GLuint vertexShaderId;
	GLuint fragmentShaderId;
 
	// How many shaders are attached to the shader program
	GLuint shaderCount;
 
	// Map of attributes and their binding locations
	std::map<std::string, int> attributeMap;
 
	// Map of uniforms and their binding locations
	std::map<std::string, int> uniformMap;
 
	// Has this shader program been initialised?
	bool initialised;
 
	// ---------- PRIVATE METHODS ----------
 
	// Private method to compile a shader of a given type
	GLuint compileShader(std::string shaderSource, GLenum shaderType)
	{
		std::string shaderTypeString;
		switch (shaderType)
		{
			case GL_VERTEX_SHADER:
				shaderTypeString = "GL_VERTEX_SHADER";
				break;
			case GL_FRAGMENT_SHADER:
				shaderTypeString = "GL_FRAGMENT_SHADER";
				break;
			case GL_GEOMETRY_SHADER:
				throw std::runtime_error("Geometry shaders are unsupported at this time.");
				break;
			default:
				throw std::runtime_error("Bad shader type enum in compileShader.");
				break;
		}
 
		// Generate a shader id
		// Note: Shader id will be non-zero if successfully created.
		GLuint shaderId = glCreateShader(shaderType);
		if (shaderId == 0)
		{
			// Display the shader log via a runtime_error
			throw std::runtime_error("Could not create shader of type " + shaderTypeString + ": " + getInfoLog(ObjectType::SHADER, shaderId) );
		}
 
		// Get the source string as a pointer to an array of characters
		const char *shaderSourceChars = shaderSource.c_str();
 
		// Attach the GLSL source code to the shader
		// Params: GLuint shader, GLsizei count, const GLchar **string, const GLint *length
		// Note: The pointer to an array of source chars will be null terminated, so we don't need to specify the length and can instead use NULL.
		glShaderSource(shaderId, 1, &shaderSourceChars, NULL);
 
		// Compile the shader
		glCompileShader(shaderId);
 
		// Check the compilation status and throw a runtime_error if shader compilation failed
		GLint shaderStatus;
		glGetShaderiv(shaderId, GL_COMPILE_STATUS, &shaderStatus);
		if (shaderStatus == GL_FALSE)
		{
			throw std::runtime_error(shaderTypeString + " compilation failed: " + getInfoLog(ObjectType::SHADER, shaderId) );
		}
		else
		{
			if (DEBUG)
			{
				std::cout << shaderTypeString << " shader compilation successful." << std::endl;
			}
		}
 
		// If everything went well, return the shader id
		return shaderId;
	}
 
	// Private method to compile/attach/link/verify the shaders.
	// Note: Rather than returning a boolean as a success/fail status we'll just consider
	// a failure here to be an unrecoverable error and throw a runtime_error.
	void initialise(std::string vertexShaderSource, std::string fragmentShaderSource)
	{
		// Compile the shaders and return their id values
		vertexShaderId   = compileShader(vertexShaderSource,   GL_VERTEX_SHADER);
		fragmentShaderId = compileShader(fragmentShaderSource, GL_FRAGMENT_SHADER);
 
		// Attach the compiled shaders to the shader program
		glAttachShader(programId, vertexShaderId);
		glAttachShader(programId, fragmentShaderId);
 
		// Link the shader program - details are placed in the program info log
		glLinkProgram(programId);
 
		// Once the shader program has the shaders attached and linked, the shaders are no longer required.
		// If the linking failed, then we're going to abort anyway so we still detach the shaders.
		glDetachShader(programId, vertexShaderId);
		glDetachShader(programId, fragmentShaderId);
 
		// Check the program link status and throw a runtime_error if program linkage failed.
		GLint programLinkSuccess = GL_FALSE;
		glGetProgramiv(programId, GL_LINK_STATUS, &programLinkSuccess);
		if (programLinkSuccess == GL_TRUE)
		{
			if (DEBUG)
			{
				std::cout << "Shader program link successful." << std::endl;
			}
		}
		else
		{
			throw std::runtime_error("Shader program link failed: " + getInfoLog(ObjectType::PROGRAM, programId) );
		}
 
		// Validate the shader program
		glValidateProgram(programId);
 
		// Check the validation status and throw a runtime_error if program validation failed
		GLint programValidatationStatus;
		glGetProgramiv(programId, GL_VALIDATE_STATUS, &programValidatationStatus);
		if (programValidatationStatus == GL_TRUE)
		{
			if (DEBUG)
			{
				std::cout << "Shader program validation successful." << std::endl;
			}
		}
		else
		{
			throw std::runtime_error("Shader program validation failed: " + getInfoLog(ObjectType::PROGRAM, programId) );
		}
 
		// Finally, the shader program is initialised
		initialised = true;
	}
 
	// Private method to load the shader source code from a file
	std::string loadShaderFromFile(const std::string filename)
	{
		// Create an input filestream and attempt to open the specified file
		std::ifstream file( filename.c_str() );
 
		// If we couldn't open the file we'll bail out
		if ( !file.good() )
		{
			throw std::runtime_error("Failed to open file: " + filename);
		}
 
		// Otherwise, create a string stream...
		std::stringstream stream;
 
		// ...and dump the contents of the file into it.
		stream << file.rdbuf();
 
		// Now that we've read the file we can close it
		file.close();
 
		// Finally, convert the stringstream into a string and return it
		return stream.str();
	}
 
	// Private method to return the current shader program info log as a string
	std::string getInfoLog(ObjectType type, int id)
	{
		GLint infoLogLength;
		if (type == ObjectType::SHADER)
		{
			glGetShaderiv(id, GL_INFO_LOG_LENGTH, &infoLogLength);
		}
		else // type must be ObjectType::PROGRAM
		{
			glGetProgramiv(id, GL_INFO_LOG_LENGTH, &infoLogLength);
		}
 
		GLchar *infoLog = new GLchar[infoLogLength + 1];
		if (type == ObjectType::SHADER)
		{
			glGetShaderInfoLog(id, infoLogLength, NULL, infoLog);
		}
		else // type must be ObjectType::PROGRAM
		{
			glGetProgramInfoLog(id, infoLogLength, NULL, infoLog);
		}
 
		// Convert the info log to a string
		std::string infoLogString(infoLog);
 
		// Delete the char array version of the log
		delete[] infoLog;
 
		// Finally, return the string version of the info log
		return infoLogString;
	}
 
public:
	// Constructor
	ShaderProgram()
	{
		// We start in a non-initialised state - calling initFromFiles() or initFromStrings() will
		// initialise us.
		initialised = false;
 
		// Generate a unique Id / handle for the shader program
		// Note: We MUST have a valid rendering context before generating the programId or we'll segfault!
		programId = glCreateProgram();
		glUseProgram(programId);
 
		// Initially, we have zero shaders attached to the program
		shaderCount = 0;
	}
 
	// Destructor
	~ShaderProgram()
	{
		// Delete the shader program from the graphics card memory to
		// free all the resources it's been using
		glDeleteProgram(programId);
	}
 
	// Method to initialise a shader program from shaders provided as files
	void initFromFiles(std::string vertexShaderFilename, std::string fragmentShaderFilename)
	{
		// Get the shader file contents as strings
		std::string vertexShaderSource   = loadShaderFromFile(vertexShaderFilename);
		std::string fragmentShaderSource = loadShaderFromFile(fragmentShaderFilename);
 
		initialise(vertexShaderSource, fragmentShaderSource);
	}
 
	// Method to initialise a shader program from shaders provided as strings
	void initFromStrings(std::string vertexShaderSource, std::string fragmentShaderSource)
	{
		initialise(vertexShaderSource, fragmentShaderSource);
	}
 
	// Method to enable the shader program - we'll suggest this for inlining
	inline void use()
	{
		// Santity check that we're initialised and ready to go...
		if (initialised)
		{
			glUseProgram(programId);
		}
		else
		{
			std::string msg = "Shader program " + programId;
			msg += " not initialised - aborting.";
			throw std::runtime_error(msg);
		}
	}
 
	// Method to disable the shader - we'll also suggest this for inlining
	inline void disable()
	{
		glUseProgram(0);
	}
 
	// Method to return the bound location of a named attribute, or -1 if the attribute was not found
	GLuint attribute(const std::string attributeName)
	{
		// You could do this method with the single line:
		//
		//		return attributeMap[attribute];
		//
		// BUT, if you did, and you asked it for a named attribute which didn't exist
		// like: attributeMap["FakeAttrib"] then the method would return an invalid
		// value which will likely cause the program to segfault. So we're making sure
		// the attribute asked for exists, and if it doesn't then we alert the user & bail.
 
		// Create an iterator to look through our attribute map (only create iterator on first run -
		// reuse it for all further calls).
		static std::map<std::string, int>::const_iterator attributeIter;
 
		// Try to find the named attribute
		attributeIter = attributeMap.find(attributeName);
 
		// Not found? Bail.
		if ( attributeIter == attributeMap.end() )
		{
			throw std::runtime_error("Could not find attribute in shader program: " + attributeName);
		}
 
		// Otherwise return the attribute location from the attribute map
		return attributeMap[attributeName];
	}
 
	// Method to returns the bound location of a named uniform
	GLuint uniform(const std::string uniformName)
	{
		// Note: You could do this method with the single line:
		//
		// 		return uniformLocList[uniform];
		//
		// But we're not doing that. Explanation in the attribute() method above.
 
		// Create an iterator to look through our uniform map (only create iterator on first run -
		// reuse it for all further calls).
		static std::map<std::string, int>::const_iterator uniformIter;
 
		// Try to find the named uniform
		uniformIter = uniformMap.find(uniformName);
 
		// Found it? Great - pass it back! Didn't find it? Alert user and halt.
		if ( uniformIter == uniformMap.end() )
		{
			throw std::runtime_error("Could not find uniform in shader program: " + uniformName);
		}
 
		// Otherwise return the attribute location from the uniform map
		return uniformMap[uniformName];
	}
 
	// Method to add an attribute to the shader and return the bound location
	int addAttribute(const std::string attributeName)
	{
		// Add the attribute location value for the attributeName key
		attributeMap[attributeName] = glGetAttribLocation( programId, attributeName.c_str() );
 
		// Check to ensure that the shader contains an attribute with this name
		if (attributeMap[attributeName] == -1)
		{
			throw std::runtime_error("Could not add attribute: " + attributeName + " - location returned -1.");
		}
		else // Valid attribute location? Inform user if we're in debug mode.
		{
			if (DEBUG)
			{
				std::cout << "Attribute " << attributeName << " bound to location: " << attributeMap[attributeName] << std::endl;
			}
		}
 
		// Return the attribute location
		return attributeMap[attributeName];
	}
 
	// Method to add a uniform to the shader and return the bound location
	int addUniform(const std::string uniformName)
	{
		// Add the uniform location value for the uniformName key
		uniformMap[uniformName] = glGetUniformLocation( programId, uniformName.c_str() );
 
		// Check to ensure that the shader contains a uniform with this name
		if (uniformMap[uniformName] == -1)
		{
			throw std::runtime_error("Could not add uniform: " + uniformName + " - location returned -1.");
		}
		else // Valid uniform location? Inform user if we're in debug mode.
		{
			if (DEBUG)
			{
				std::cout << "Uniform " << uniformName << " bound to location: " << uniformMap[uniformName] << std::endl;
			}
		}
 
		// Return the uniform location
		return uniformMap[uniformName];
	}
 
}; // End of class
 
#endif // SHADER_PROGRAM_HPP

Note: I’m not convinced that the compiler will even consider inlining the use() and disable() methods when the program is built as a hpp – I think I’d have to break it into .h and .cpp files for that… other than that I’m thinking the above code is pretty clean, robust and usable.

GLFW3 Basecode with FPS Camera Controls

Basecode is funny thing – when you start a new project, do you really start from scratch? A complete blank slate? Or do you make a copy of the last project you worked on which is similar and modify it? Often, you’re going to want to start from some pre-existing functional base, but what’s stable and functional enough? Do you really want to go with a framework like Cinder or Processing to hold your code? Or go with a full-on engine like Unity or Unreal Engine 4 or some other engine?

I’m going to write a game at some point in the future, and I want to go it (almost) alone – I don’t want to be locked into someone elses constructs and patterns, or drag-and-drop functionality in which I have absolutely no idea how it works – I want to think for myself and create what’s basically my own engine, where I understand how it fits together and how each piece works. This doesn’t necessarily mean that everything needs to be worked out from first principles, but it should be possible to make all the important architectural decisions. This means that I want precise control over:

  • At least one OpenGL window, with controllable context details (preferably multiple windows with a shared projection)
  • Painless keyboard and mouse handlers
  • File handling of common types (load and use this 3D model/sound file/settings file)
  • Help with prototyping via simple drawing calls

Which brings us back to basecode being a funny thing – you get to make the architectural decisions, and live with the consequences. If you decide to go with an engine, then you’re going to learn the engine – not the fundamental technologies or aspects of the code that make the engine work. So if you grab some fantastic engine and you go:

  1. Load this spaceship model, which is made of these different materials,
  2. There’s a light which is at (1000, 200, 300) in world space (and perhaps a dozen other lights),
  3. Draw the spaceship from my (i.e the camera’s) location.

But what does that actually teach you, as a developer? How do you load the model from file? How is the lighting model applied to the vertices? Where the hell is the spaceship in relation to you, let alone the surface normals of the spaceship with regard to the light-source(s) with regard to the camera? In an engine, you don’t care – you let the engine work it out for you, and you learn nothing. Or maybe you learn the engine – which means you learn to trust someone else to think instead of you having to think for yourself.

Which finally brings us back to basecode being a funny thing… I’ve been thinking about this for weeks, and below is the OpenGL/GLFW3 basecode I’ve written to open a window, draw some grids for orientation, and allow for ‘FPS-esque’ mouse and keyboard controls. The main.cpp is listed below, which shows you how the program itself runs – everything else you’ll need to look at for yourself – but I promise you this:

  • Every single piece of this code is clear in its use and serves a purpose.
  • Every single piece of this code performs its job in the simplest, most straight forward manner possible. If the option is to be clever or readable, then I pick readable every time. Saying that, I think I used an inline if-statement once i.e. “if (raining) ? putUpUmbrella() : keepUmbrellaDown();”. Honestly, when you see it, you’ll be okay.
  • Every single piece of this code is documented to explain not only WHAT the code is doing, but (where appropriate) WHY it is doing it. When I used to work as as Subsystem Integration and Test engineer, we would write software build instructions with the goal that your Mum should be able to build the software image from the simple, accurate, non-ambiguous instructions. If you didn’t think your Mum could build it, then you re-worked the instructions until you thought that she could.

I’ll add some additional utility classes to this over time, but for now, this basecode will get a window with FPS controls up and running and display some grids via shaders for orientation – and everything should be simple, straight-forward and clear. Enjoy!

Code::Blocks projects for both Windows and Linux (libraries included for Windows) can be found here: GLFW3_Basecode_Nov_2014.7z.

Update – Feb 2015: There were issues using this code in Visual Studio 2010 as it doesn’t support strongly typed enums or the R” notation (although VS2012 onwards does), and the libraries packaged were the Code::Blocks versions (which was intended – the above version is specifically for Code::Blocks) – so here’s a modified & fully working Visual Studio 2010 version: GLFW3-Basecode-VS2010.7z.

/***
Project: GLFW3 Basecode
Version: 0.5
Author : r3dux
Date   : 21/1/2014
Purpose: Basecode to setup an OpenGL context with FPS camera controls and draw some grids.
***/
 
#include <iostream>
 
// Define that we're using the static version of GLEW (glew32s) so that it gets built
// into our final executable.
// NOTE: This MUST be defined before importing GLEW!
#define GLEW_STATIC
 
// Include the GL Extension Wrangler. Note: GLEW should always be the very first include
#include <GL/glew.h>
 
#include <GLFW/glfw3.h>                 // Include GL Framework. Note: This pulls in GL.h for us.
 
// Include the GL Mathematics library
#define GLM_FORCE_RADIANS               // We must work in radians in newer versions of GLM...
#include <glm/glm.hpp>                  // ...so now that's defined we can import GLM itself.
 
// Include our custom classes
#include "Camera.h"
#include "Grid.h"
#include "Utils.h"
 
// Save ourselves some typing...
using std::cout;
using std::endl;
using glm::vec3;
using glm::vec4;
using glm::mat4;
using glm::mat3;
 
// ---------- Global variables ----------
 
// Window and projection settings
GLsizei windowWidth       = 800;
GLsizei windowHeight      = 600;
float vertFieldOfViewDegs = 45.0f;
float nearClipDistance    = 1.0f;
float farClipDistance     = 2000.0f;
 
// Misc
int  frameCount = 0;              // How many frames we've drawn
int  frameRate  = 60;             // Target frame rate -we'll assume a 60Hz refresh for now
bool leftMouseButtonDown = false; // We'll only look around when the left mouse button is down
 
// Matricies
mat4 projectionMatrix; // The projection matrix is used to perform the 3D to 2D conversion i.e. it maps from eye space to clip space.
mat4 viewMatrix;       // The view matrix maps the world coordinate system into eye cordinates (i.e. world space to eye space)
mat4 modelMatrix;      // The model matrix maps an object's local coordinate system into world coordinates (i.e. model space to world space)
 
// Pointers to two grids
Grid *upperGrid, *lowerGrid;
 
// Camera. Params: location, rotation (degrees), window width & height
Camera camera(vec3(0.0f), vec3(0.0f), windowWidth, windowHeight);
 
// Callback function to resize the window and set the viewport to the correct size
void resizeWindow(GLFWwindow *window, GLsizei newWidth, GLsizei newHeight)
{
    // Keep track of the new width and height of the window
    windowWidth  = float(newWidth);
    windowHeight = float(newHeight);
 
    // Recalculate the projection matrix
    projectionMatrix = glm::perspective(vertFieldOfViewDegs, GLfloat(windowWidth) / GLfloat(windowHeight), nearClipDistance, farClipDistance);
 
    // Viewport is the entire window
    glViewport(0, 0, windowWidth, windowHeight);
 
    // Update the midpoint location in the camera class because it uses these values, too
    camera.updateWindowMidpoint(windowWidth, windowHeight);
}
 
// Callback function to handle keypresses
void handleKeypress(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    // User hit ESC? Set the window to close
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
    {
        glfwSetWindowShouldClose(window, GL_TRUE);
    }
    else
    {
        camera.handleKeypress(key, action);
    }
}
 
// Callback function to handle mouse movement
void handleMouseMove(GLFWwindow *window, double mouseX, double mouseY)
{
    // We'll only look around when the left mouse button is down
    if (leftMouseButtonDown)
    {
        camera.handleMouseMove(window, mouseX, mouseY);
    }
}
 
// Callback function to handle mouse button presses
void handleMouseButton(GLFWwindow *window, int button, int action, int mods)
{
    // Button press involves left mouse button?
    if (button == GLFW_MOUSE_BUTTON_1)
    {
        if (action == GLFW_PRESS)
        {
            glfwSetCursorPos(window, windowWidth / 2, windowHeight / 2);
            leftMouseButtonDown = true;
        }
        else // Action must be GLFW_RELEASE
        {
            leftMouseButtonDown = false;
        }
    }
}
 
// Function to set up our OpenGL rendering context
void initGL(GLFWwindow *window)
{
    // ---------- Initialise GLEW ----------
 
    // Enable glewExperimental which ensures that all extensions with valid entry points will be exposed.
    glewExperimental = true;
 
    // Note: We MUST have an OpenGL rendering context open to initialise GLEW successfully!
    GLenum err = glewInit();
    if (GLEW_OK != err)
    {
        cout << "GLEW error: " << glewGetErrorString(err) << endl;
        glfwTerminate();
    }
    cout << "GLEW intialised successfully. Using GLEW version: " << glewGetString(GLEW_VERSION) << endl << endl;
 
    // Depending on the OpenGL context settings, calling glewInit() can sometimes cause a GL_INVALID_ENUM error.
    // As this issue isn't really our code's fault, we'll check the error here to clear it.
    //
    // Cause: In a core profile context, GL_EXTENSIONS is an invalid constant to pass to glGetString (...). You
    // must use the new glGetStringi (...) function. GLEW does not do this by default, given a core context
    // without being informed to use glGetStringi (...), GLEW will use glGetString (...) and will cause GL to
    // generate a GL_INVALID_ENUM error. In order to get GLEW to use glGetStringi (...) (which you should ONLY
    // do in an OpenGL 3.0+ context), set glewExperimental = true; before calling glewInit (...).
    //
    // Source: http://stackoverflow.com/questions/19453439/solved-opengl-error-gl-invalid-enum-0x0500-while-glewinit
    checkGLError("glewInit - harmless / ignore");
 
    // ---------- Setup OpenGL Options ----------
 
    glViewport( 0, 0, GLsizei(windowWidth), GLsizei(windowHeight) ); // Viewport is entire window
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);                            // Clear to black with full alpha
    glEnable(GL_DEPTH_TEST);                                         // Enable depth testing
    glDepthFunc(GL_LEQUAL);                                          // Specify depth testing function
    glClearDepth(1.0);                                               // Clear the full extent of the depth buffer (default)
    glEnable(GL_CULL_FACE);                                          // Enable face culling
    glCullFace(GL_BACK);                                             // Cull back faces of polygons
    glFrontFace(GL_CCW);                                             // Counter-clockwise winding indicates a forward facing polygon (default)
 
    // ---------- Setup GLFW Callback Functions ----------
 
    glfwSetWindowSizeCallback(window, resizeWindow);                 // Register window resize functiom
    glfwSetKeyCallback(window, handleKeypress);                      // Register keyboard handler function
    glfwSetCursorPosCallback(window, handleMouseMove);               // Register mouse movement handler function
    glfwSetMouseButtonCallback(window, handleMouseButton);           // Register mouse button handler function
 
    // ---------- Setup GLFW Options ----------
 
    glfwSwapInterval(1);                                             // Swap buffers every frame (i.e. lock to VSync)
    glfwSetInputMode(window, GLFW_CURSOR_DISABLED, GL_FALSE);        // Do not hide the mouse cursor
    glfwSetWindowPos(window, 200, 200);                              // Push the top-left of the window out from the top-left corner of the screen
    glfwSetCursorPos(window, windowWidth / 2, windowHeight / 2);     // Move the mouse cursor to the centre of the window
 
    checkGLError("InitGL");
}
 
// Function to perform our drawing
void drawFrame()
{
    // Move the camera
    camera.move(1.0f/ frameRate);
 
    // ---------- Matrix operations ----------
 
    // Reset our View matrix
    viewMatrix = mat4(1.0f);
 
    // Perform camera rotation
    viewMatrix = glm::rotate(viewMatrix, camera.getXRotationRads(), X_AXIS);
    viewMatrix = glm::rotate(viewMatrix, camera.getYRotationRads(), Y_AXIS);
 
    // Translate to our camera position
    viewMatrix = glm::translate(viewMatrix, -camera.getLocation() );
 
    // Create an identity matrix for the model matrix
    modelMatrix = mat4(1.0f);
 
    // ---------- Drawing operations ----------
 
    mat4 mvpMatrix = projectionMatrix * viewMatrix * modelMatrix;
    upperGrid->draw(mvpMatrix);
    lowerGrid->draw(mvpMatrix);
}
 
int main()
{
    // ----- Initialiise GLFW, specify window hints & open a context -----
 
    // IMPORTANT: glfwInit resets all window hints, so we must call glfwInit FIRST and THEN we supply window hints!
    if (!glfwInit())
    {
        cout << "glfwInit failed!" << endl;
        exit(-1);
    }
 
    // Further reading on GLFW window hints: http://www.glfw.org/docs/latest/window.html#window_hints
 
    // If we want to use a a core profile (i.e. no legacy fixed-pipeline functionality) or if we want to
    // use forward compatible mode (i.e. only non-deprecated features of a given OpenGL version available)
    // then we MUST specify the MAJOR.MINOR context version we want to use FIRST!
    //glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    //glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 4);
    //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
    //glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
    // Ask for 4x Anti-Aliasing
    glfwWindowHint(GLFW_SAMPLES, 4);
 
    // Create a window. Params: width, height, title, *monitor, *share
    GLFWwindow* window = glfwCreateWindow(GLsizei(windowWidth), GLsizei(windowHeight), "GLFW3 Basecode | Use WSAD to move & LMB to look around - Nov 2014 | r3dux.org ", NULL, NULL);
    if (!window)
    {
        cout << "Failed to create window - bad context MAJOR.MINOR version?" << endl;
        getKeypressThenExit();
    }
 
    // Make the current OpenGL context active
    glfwMakeContextCurrent(window);
 
    // Display the details of our OpenGL window
    displayWindowProperties(window);
 
    // -------------- Set up our OpenGL settings ---------------
 
    initGL(window);
 
    // ---------- Set up our grids ----------
 
    // Instantiate our grids. Params: Width, Depth, level (i.e. location of y-axis), number of grid lines
    upperGrid = new Grid(1000.0f, 1000.0f,  200.0f, 20);
    lowerGrid = new Grid(1000.0f, 1000.0f, -200.0f, 20);
 
    // ---------- Set up our matricies ----------
 
    // Specify the projection matrix
    projectionMatrix = glm::perspective(vertFieldOfViewDegs, GLfloat(windowWidth) / GLfloat(windowHeight), nearClipDistance, farClipDistance);
 
    // Reset the view and model and view matrices to identity
    viewMatrix  = mat4(1.0f);
    modelMatrix = mat4(1.0f);
 
    // ---------- Main loop ----------
 
    while ( !glfwWindowShouldClose(window) )
    {
        frameCount++;
 
        // Clear the screen and depth buffer
        glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
 
        // Draw our frame
        drawFrame();
 
        // Swap the back and front buffers to display the frame we just rendered
        glfwSwapBuffers(window);
 
        // Poll for input
        glfwPollEvents();
    }
 
    // Check the final error state
    // NOTE: This MUST be called while we still have a valid rendering context (i.e. before we call glfwTerminate() )
    checkGLError("End");
 
    // Destroy the window and exit
    glfwDestroyWindow(window);
    glfwTerminate();
 
    return 0;
}