#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>

#include <GL/glew.h>
#include <GL/glfw.h>

//Declare vectors for gcc.
typedef float v4f __attribute__ ((vector_size (16)));
typedef float rgba __attribute__ ((vector_size (16)));
typedef float v2f __attribute__ ((vector_size (8)));

//Used by the report function defined below.
#define REPORT_TIMESTAMP
#define DEBUG
#define FAIL 1
#define WARN 2
#define INFO 4
#define PASS 8
#define REPORT_SHOW (FAIL|WARN|INFO|PASS)
void report(unsigned char level, const char* format, ...){//A "fancy-smancy printf replacer" for debugging purposes.
  if(REPORT_SHOW & level){
    va_list args;
    va_start (args, format);
#ifdef REPORT_TIMESTAMP
    fprintf(stderr, "\033[1;37m[%7.4f]",glfwGetTime());
#endif
    if(level & FAIL)//critical failure
      fputs("\033[1;31m[FAIL]\033[0m", stderr);
    else if(level & PASS)//something went right
      fputs("\033[1;32m[PASS]\033[0m", stderr);
    else if(level &WARN)//Watch out for this.
      fputs("\033[0;31m[WARN]\033[0m", stderr);
    else if(level & INFO) //Information.
      fputs("\033[1;34m[INFO]\033[0m", stderr);
    vfprintf(stderr, format, args);
    fputs("\n",stderr);
  va_end(args);
  }
}
GLuint shaderFromFilename(char *File,GLenum shaderType){
  GLenum glError;
  GLuint shader = glCreateShader(shaderType);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Failed to create shader.");
    return -1;
  }
  FILE * fp;
  unsigned long fileSize;
  GLchar* source;
  fp = fopen(File, "r");
  if(fp == NULL){
    report(FAIL, "Couldn't open shader file!");
    return 0;
  }
  fseek(fp, 0, SEEK_END);
  fileSize = ftell(fp);
  rewind(fp); //be kind, rewind.
  source = malloc((fileSize+1)*sizeof(char));
  if(source == NULL){
    report(FAIL, "Couldn't allocate earth for shader!");
    return 0;
  }
  if(fread(source,1,fileSize,fp) != fileSize){
    report(FAIL, "Couldn't read the opend shader file!");
    return 0;
  }
  source[fileSize] = '\0';
  glShaderSource(shader,1,(const GLchar**)&source,NULL);
  glCompileShader(shader);
  return shader;
}
void reportShaderLog(GLuint shader){
  GLsizei logLength;
  glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logLength);
  if(logLength != 1){
    GLchar *shaderLog = malloc(logLength);
    glGetShaderInfoLog(shader,logLength,NULL,shaderLog);
    report(WARN, "Shader log:\n %s",shaderLog);
    free(shaderLog);
  }
}
GLuint createProgramFromFilenames(char *vertexShader, char *fragmentShader){//simple wrapper for vertex+frag shader program creation.
  GLenum glError;
  GLuint vs = shaderFromFilename(vertexShader,GL_VERTEX_SHADER);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Failed everything!" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  GLint isCompiled;
  glGetShaderiv(vs,GL_COMPILE_STATUS,&isCompiled);
  isCompiled == GL_TRUE? report(PASS,"Compiled %s", vertexShader) : report(FAIL, "Couldn't compile %s",vertexShader);
  reportShaderLog(vs);
  GLuint fs = shaderFromFilename(fragmentShader,GL_FRAGMENT_SHADER);
  glGetShaderiv(fs,GL_COMPILE_STATUS,&isCompiled);
  isCompiled == GL_TRUE? report(PASS,"Compiled %s", fragmentShader) : report(FAIL, "Couldn't compile %s",fragmentShader);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Failed to compile everything!" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  reportShaderLog(fs);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "what!" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  GLuint shaderProgram = glCreateProgram();
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Couldn't create program!" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  glAttachShader(shaderProgram, fs);
  glAttachShader(shaderProgram,vs);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Couldn't prepare linking %s and %s, error:" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  glLinkProgram(shaderProgram);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Couldn't link %s and %s, error:" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  report(PASS, "Linked %s and %s", vertexShader, fragmentShader);
  return shaderProgram;
}
void GLFWCALL My_Key_Callback(int key, int action){
  if(key == GLFW_KEY_SPACE && action == GLFW_PRESS)
    exit(EXIT_SUCCESS);
}
int initialize(){
  glewExperimental = GL_TRUE;
  GLenum err;
  if( glfwInit() != GL_TRUE){
    report(FAIL, "Couldn't Initialize GLFW!");
    return -1;
  }
//Start by initializing OpenGL,
  glfwOpenWindowHint(GLFW_OPENGL_VERSION_MAJOR,3);
  glfwOpenWindowHint(GLFW_OPENGL_VERSION_MINOR,0);
  //glfwOpenWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
  { //Scope block because we don't need this anywhere else and it's to little to warrant a function.
    int major,minor,rev;
    glfwGetVersion(&major,&minor,&rev);
    report(INFO, "Using GLFW version %d.%d, revision %d.", major,minor,rev);
  }
  if( glfwOpenWindow( 600,600, 0,0,0,0,0,0, GLFW_WINDOW ) != GL_TRUE){
    report(FAIL, "Couldn't create window!");
    glfwTerminate();
    return -2;
  }
  err = glGetError();
  if(err != GL_NO_ERROR){
    report(FAIL, "Error on opening window!");
  }
  //Initialize GLEW so we can use our extensions.
  err = glewInit();
  if(err !=GLEW_OK){
    report(FAIL,"Couldn't initialze GLEW: %s", glewGetErrorString(err));
    return -3;
  }
  report(INFO, "Using GLEW %s", glewGetString(GLEW_VERSION));
  err = glGetError();
  if(err != GL_NO_ERROR){
    report(WARN, "Glew set GL_ERROR, should be fine though!");
  }
  //glfwSwapInterval(0); //vsync off
//Report some information about the window if wanted./*
  report(INFO,"Using OpenGL Version %d.%d.",glfwGetWindowParam(GLFW_OPENGL_VERSION_MAJOR), glfwGetWindowParam(GLFW_OPENGL_VERSION_MINOR));
  report(INFO,"Using (%d,%d,%d)RGB bit-depth.",glfwGetWindowParam(GLFW_RED_BITS),glfwGetWindowParam(GLFW_GREEN_BITS),glfwGetWindowParam(GLFW_BLUE_BITS));
  report(INFO,"Hardware acceleration: %s.", glfwGetWindowParam(GLFW_ACCELERATED) == GL_TRUE? "Supported": "Unsupported");
  report(INFO,"Refresh Rate: %dHz.", glfwGetWindowParam(GLFW_REFRESH_RATE));
  report(PASS, "Intialized.");
  glfwSetKeyCallback(My_Key_Callback);
  return 0;
}

int main(int argc, char **argv)
{
  GLenum glError;
  if(initialize()) //basic initialisation
   exit(EXIT_FAILURE);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Failed to init!");
    return -1;
  }
//create the shaders
  GLuint shaderProgram = createProgramFromFilenames("./shaders/pointPath.vert", "./shaders/spritePoint.frag");
  glUseProgram (shaderProgram);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "An error occured while building the shader program!");
  else
    report(PASS, "Succesfully using shaders");

//Create and set first texture.
  v2f path[] = {{-0.5,0.5},//A path "t -> (x,y)" along which we will place our sprites
    {-0.5,-0.5},
    {0.5,-0.5},
    {0.5,0.5}};
  glActiveTexture(GL_TEXTURE0);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Couldn't activate texture!");
  GLuint pathTex;
  glGenTextures(1, &pathTex); //create a new texture
  glBindTexture(GL_TEXTURE_1D, pathTex); //start using it as a 1D texture
  glTexImage1D(GL_TEXTURE_1D,0,GL_RG32F, sizeof(path)/sizeof(v2f),0,GL_RG,GL_FLOAT,path); //store the coordinates of path in the texture so that we can interpolate our path in the shader.
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_BASE_LEVEL, 0);//We need these two lines
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAX_LEVEL, 0);//because we don't have mipmaps.
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);//We want the path to be linearly filtered
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);//Set the min filter just to be safe.
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Something went wrong setting up pathTex");
  GLint uniformLoc = glGetUniformLocation(shaderProgram, "pathTexture"); //locate the uniform
  uniformLoc >= 0?glUniform1i(uniformLoc, 0):report(FAIL, "found uniform spriteTexture at %d", uniformLoc); //and set it to "0" because we're using GL_TEXTURE0
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Couldn't set uniform!");
  report(PASS, "Setup texture for path");
//create and set second texture
  rgba sprite[] = {{1.0,0,0,1},{0,1.0,0,1},{0,0,1.0,1},{1,1,0,1}}; //our sprite, a simple "red,green,blue,yellow" square.
  glActiveTexture(GL_TEXTURE0+1); //use texUnit 1 now.
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Couldn't activate texture!");
  GLuint spriteTex;
  glGenTextures(1, &spriteTex); //create a new texture
  glBindTexture(GL_TEXTURE_2D, spriteTex); //start using it as a 2D texture
  glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA, 2,2,0,GL_RGBA,GL_FLOAT,sprite); //load the data again. 2x2 sprite.
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);//We need these two lines
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);//because we don't have mipmaps.
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);//We want our sprites to be filtered to
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);//the nearest pixel, not interpolated.
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Something went wrong setting up pathTex");
  uniformLoc = glGetUniformLocation(shaderProgram, "spriteTexture"); //locates and set the second sampler.
  uniformLoc >= 0?glUniform1i(uniformLoc, 1):report(FAIL, "found uniform spriteTexture at %d", uniformLoc);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Couldn't set uniform!");
  report(PASS, "Setup texture for sprite");

//Create our sprite locations
#define Npoints 1024 //any number > the number of path points will do.
  GLfloat points[Npoints]; //the location in "t-space" of our sprites, i.e. the texture coordinate for our path texture.
  for(size_t i = 0; i < Npoints;i++)
    points[i] = (float)i/(float)Npoints; //fill it from 0 to 1.
  report(PASS, "generated points array.");
//set-up a our buffers.
  unsigned int vaSprites;
  glGenVertexArrays(1,&vaSprites);
  report(PASS, "Generated vertex array");
  unsigned int vbSprites;
  glGenBuffers(1, &vbSprites);
  glBindBuffer(GL_ARRAY_BUFFER, vbSprites);
  glBufferData (GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Something went wrong generating the vbSprites!");
  glBindVertexArray(vaSprites);
  GLint inputAttrib = glGetAttribLocation(shaderProgram, "t");
  glEnableVertexAttribArray(inputAttrib);
  glVertexAttribPointer (inputAttrib, 1, GL_FLOAT, GL_FALSE, 0, (GLubyte*)NULL);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Something went wrong generating the vaSprites!");
  else
    report(PASS, "Set-up vaSprites.");

  glEnable(GL_POINT_SPRITE); //We need this (on Nvidia atleast) for obvious reasons.
  glPointSize(64);


  while(1){ //our main loop,it's broken by hitting space.
    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glDrawArrays(GL_POINTS,0, Npoints);
    glfwSwapBuffers();
   }
  return 0;
}
	#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>

#include <GL/glew.h>
#include <GL/glfw.h>

//Declare vectors for gcc.
typedef float v4f __attribute__ ((vector_size (16)));
typedef float rgba __attribute__ ((vector_size (16)));
typedef float v2f __attribute__ ((vector_size (8)));

//Used by the report function defined below.
#define REPORT_TIMESTAMP
#define DEBUG
#define FAIL 1
#define WARN 2
#define INFO 4
#define PASS 8
#define REPORT_SHOW (FAIL|WARN|INFO|PASS)
void report(unsigned char level, const char* format, ...){//A "fancy-smancy printf replacer" for debugging purposes.
  if(REPORT_SHOW & level){
    va_list args;
    va_start (args, format);
#ifdef REPORT_TIMESTAMP
    fprintf(stderr, "\033[1;37m[%7.4f]",glfwGetTime());
#endif
    if(level & FAIL)//critical failure
      fputs("\033[1;31m[FAIL]\033[0m", stderr);
    else if(level & PASS)//something went right
      fputs("\033[1;32m[PASS]\033[0m", stderr);
    else if(level &WARN)//Watch out for this.
      fputs("\033[0;31m[WARN]\033[0m", stderr);
    else if(level & INFO) //Information.
      fputs("\033[1;34m[INFO]\033[0m", stderr);
    vfprintf(stderr, format, args);
    fputs("\n",stderr);
  va_end(args);
  }
}
GLuint shaderFromFilename(char *File,GLenum shaderType){
  GLenum glError;
  GLuint shader = glCreateShader(shaderType);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Failed to create shader.");
    return -1;
  }
  FILE * fp;
  unsigned long fileSize;
  GLchar* source;
  fp = fopen(File, "r");
  if(fp == NULL){
    report(FAIL, "Couldn't open shader file!");
    return 0;
  }
  fseek(fp, 0, SEEK_END);
  fileSize = ftell(fp);
  rewind(fp); //be kind, rewind.
  source = malloc((fileSize+1)*sizeof(char));
  if(source == NULL){
    report(FAIL, "Couldn't allocate earth for shader!");
    return 0;
  }
  if(fread(source,1,fileSize,fp) != fileSize){
    report(FAIL, "Couldn't read the opend shader file!");
    return 0;
  }
  source[fileSize] = '\0';
  glShaderSource(shader,1,(const GLchar**)&source,NULL);
  glCompileShader(shader);
  return shader;
}
void reportShaderLog(GLuint shader){
  GLsizei logLength;
  glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logLength);
  if(logLength != 1){
    GLchar *shaderLog = malloc(logLength);
    glGetShaderInfoLog(shader,logLength,NULL,shaderLog);
    report(WARN, "Shader log:\n %s",shaderLog);
    free(shaderLog);
  }
}
GLuint createProgramFromFilenames(char *vertexShader, char *fragmentShader){//simple wrapper for vertex+frag shader program creation.
  GLenum glError;
  GLuint vs = shaderFromFilename(vertexShader,GL_VERTEX_SHADER);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Failed everything!" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  GLint isCompiled;
  glGetShaderiv(vs,GL_COMPILE_STATUS,&isCompiled);
  isCompiled == GL_TRUE? report(PASS,"Compiled %s", vertexShader) : report(FAIL, "Couldn't compile %s",vertexShader);
  reportShaderLog(vs);
  GLuint fs = shaderFromFilename(fragmentShader,GL_FRAGMENT_SHADER);
  glGetShaderiv(fs,GL_COMPILE_STATUS,&isCompiled);
  isCompiled == GL_TRUE? report(PASS,"Compiled %s", fragmentShader) : report(FAIL, "Couldn't compile %s",fragmentShader);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Failed to compile everything!" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  reportShaderLog(fs);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "what!" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  GLuint shaderProgram = glCreateProgram();
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Couldn't create program!" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  glAttachShader(shaderProgram, fs);
  glAttachShader(shaderProgram,vs);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Couldn't prepare linking %s and %s, error:" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  glLinkProgram(shaderProgram);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Couldn't link %s and %s, error:" ,vertexShader, fragmentShader,glError);
    return -1;
  }
  report(PASS, "Linked %s and %s", vertexShader, fragmentShader);
  return shaderProgram;
}
void GLFWCALL My_Key_Callback(int key, int action){
  if(key == GLFW_KEY_SPACE && action == GLFW_PRESS)
    exit(EXIT_SUCCESS);
}
int initialize(){
  glewExperimental = GL_TRUE;
  GLenum err;
  if( glfwInit() != GL_TRUE){
    report(FAIL, "Couldn't Initialize GLFW!");
    return -1;
  }
//Start by initializing OpenGL,
  glfwOpenWindowHint(GLFW_OPENGL_VERSION_MAJOR,3);
  glfwOpenWindowHint(GLFW_OPENGL_VERSION_MINOR,0);
  //glfwOpenWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
  { //Scope block because we don't need this anywhere else and it's to little to warrant a function.
    int major,minor,rev;
    glfwGetVersion(&major,&minor,&rev);
    report(INFO, "Using GLFW version %d.%d, revision %d.", major,minor,rev);
  }
  if( glfwOpenWindow( 600,600, 0,0,0,0,0,0, GLFW_WINDOW ) != GL_TRUE){
    report(FAIL, "Couldn't create window!");
    glfwTerminate();
    return -2;
  }
  err = glGetError();
  if(err != GL_NO_ERROR){
    report(FAIL, "Error on opening window!");
  }
  //Initialize GLEW so we can use our extensions.
  err = glewInit();
  if(err !=GLEW_OK){
    report(FAIL,"Couldn't initialze GLEW: %s", glewGetErrorString(err));
    return -3;
  }
  report(INFO, "Using GLEW %s", glewGetString(GLEW_VERSION));
  err = glGetError();
  if(err != GL_NO_ERROR){
    report(WARN, "Glew set GL_ERROR, should be fine though!");
  }
  //glfwSwapInterval(0); //vsync off
//Report some information about the window if wanted./*
  report(INFO,"Using OpenGL Version %d.%d.",glfwGetWindowParam(GLFW_OPENGL_VERSION_MAJOR), glfwGetWindowParam(GLFW_OPENGL_VERSION_MINOR));
  report(INFO,"Using (%d,%d,%d)RGB bit-depth.",glfwGetWindowParam(GLFW_RED_BITS),glfwGetWindowParam(GLFW_GREEN_BITS),glfwGetWindowParam(GLFW_BLUE_BITS));
  report(INFO,"Hardware acceleration: %s.", glfwGetWindowParam(GLFW_ACCELERATED) == GL_TRUE? "Supported": "Unsupported");
  report(INFO,"Refresh Rate: %dHz.", glfwGetWindowParam(GLFW_REFRESH_RATE));
  report(PASS, "Intialized.");
  glfwSetKeyCallback(My_Key_Callback);
  return 0;
}

int main(int argc, char **argv)
{
  GLenum glError;
  if(initialize()) //basic initialisation
   exit(EXIT_FAILURE);
  glError = glGetError();
  if(glError != GL_NO_ERROR){
    report(FAIL, "Failed to init!");
    return -1;
  }
//create the shaders
  GLuint shaderProgram = createProgramFromFilenames("./shaders/pointPath.vert", "./shaders/spritePoint.frag");
  glUseProgram (shaderProgram);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "An error occured while building the shader program!");
  else
    report(PASS, "Succesfully using shaders");

//Create and set first texture.
  v2f path[] = {{-0.5,0.5},//A path "t -> (x,y)" along which we will place our sprites
    {-0.5,-0.5},
    {0.5,-0.5},
    {0.5,0.5}};
  glActiveTexture(GL_TEXTURE0);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Couldn't activate texture!");
  GLuint pathTex;
  glGenTextures(1, &pathTex); //create a new texture
  glBindTexture(GL_TEXTURE_1D, pathTex); //start using it as a 1D texture
  glTexImage1D(GL_TEXTURE_1D,0,GL_RG32F, sizeof(path)/sizeof(v2f),0,GL_RG,GL_FLOAT,path); //store the coordinates of path in the texture so that we can interpolate our path in the shader.
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_BASE_LEVEL, 0);//We need these two lines
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAX_LEVEL, 0);//because we don't have mipmaps.
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);//We want the path to be linearly filtered
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);//Set the min filter just to be safe.
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Something went wrong setting up pathTex");
  GLint uniformLoc = glGetUniformLocation(shaderProgram, "pathTexture"); //locate the uniform
  uniformLoc >= 0?glUniform1i(uniformLoc, 0):report(FAIL, "found uniform spriteTexture at %d", uniformLoc); //and set it to "0" because we're using GL_TEXTURE0
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Couldn't set uniform!");
  report(PASS, "Setup texture for path");
//create and set second texture
  rgba sprite[] = {{1.0,0,0,1},{0,1.0,0,1},{0,0,1.0,1},{1,1,0,1}}; //our sprite, a simple "red,green,blue,yellow" square.
  glActiveTexture(GL_TEXTURE0+1); //use texUnit 1 now.
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Couldn't activate texture!");
  GLuint spriteTex;
  glGenTextures(1, &spriteTex); //create a new texture
  glBindTexture(GL_TEXTURE_2D, spriteTex); //start using it as a 2D texture
  glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA, 2,2,0,GL_RGBA,GL_FLOAT,sprite); //load the data again. 2x2 sprite.
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);//We need these two lines
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);//because we don't have mipmaps.
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);//We want our sprites to be filtered to
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);//the nearest pixel, not interpolated.
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Something went wrong setting up pathTex");
  uniformLoc = glGetUniformLocation(shaderProgram, "spriteTexture"); //locates and set the second sampler.
  uniformLoc >= 0?glUniform1i(uniformLoc, 1):report(FAIL, "found uniform spriteTexture at %d", uniformLoc);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Couldn't set uniform!");
  report(PASS, "Setup texture for sprite");

//Create our sprite locations
#define Npoints 1024 //any number > the number of path points will do.
  GLfloat points[Npoints]; //the location in "t-space" of our sprites, i.e. the texture coordinate for our path texture.
  for(size_t i = 0; i < Npoints;i++)
    points[i] = (float)i/(float)Npoints; //fill it from 0 to 1.
  report(PASS, "generated points array.");
//set-up a our buffers.
  unsigned int vaSprites;
  glGenVertexArrays(1,&vaSprites);
  report(PASS, "Generated vertex array");
  unsigned int vbSprites;
  glGenBuffers(1, &vbSprites);
  glBindBuffer(GL_ARRAY_BUFFER, vbSprites);
  glBufferData (GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Something went wrong generating the vbSprites!");
  glBindVertexArray(vaSprites);
  GLint inputAttrib = glGetAttribLocation(shaderProgram, "t");
  glEnableVertexAttribArray(inputAttrib);
  glVertexAttribPointer (inputAttrib, 1, GL_FLOAT, GL_FALSE, 0, (GLubyte*)NULL);
  if(glGetError() != GL_NO_ERROR)
    report(FAIL, "Something went wrong generating the vaSprites!");
  else
    report(PASS, "Set-up vaSprites.");

  glEnable(GL_POINT_SPRITE); //We need this (on Nvidia atleast) for obvious reasons.
  glPointSize(64);


  while(1){ //our main loop,it's broken by hitting space.
    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glDrawArrays(GL_POINTS,0, Npoints);
    glfwSwapBuffers();
   }
  return 0;
}