This is a simple tool that generates a PPM file using some basic raytracing along with some linear interpolation to generate a gradient image which transitions from one colour to another.

You end up with something that looks like this:

The above image is gradient of white to blue.

The image can be changed by changing the attributes in the config file which is located in include/Config.h directory

The Config.h has some settings that can be changed by the user to alter the output:

typedef struct CONFIG_STRUCT {
  // Colour gradient options (RGB)
  double beginRed = 256;
  double beginGreen = 256;
  double beginBlue = 256;

  double endRed = 128;
  double endGreen = 179.2;
  double endBlue = 256;

  // Image settings
  double aspect_ratio = 16.0 / 9.0;
  int image_width = 900; // Image height is calculated according to width

  // Camera settings
  double viewportHeight = 2.0;
  double focalLength = 1.0;
  double originX = 0;
  double originY = 0;
  double originZ = 0;

  // Renderer settings
  std::ostream &out = std::cout;
} Config;

This project uses the PPM (Portable Pixelmap Format) file format, this allows us to write RGB values to a file in plaintext format and then open using a typical image viewer.

A typical PPM file looks like this:

P3 # Means this is a RGB color image in ASCII
3 2 # width * height
255 # Max colour value

255 0 0 # RGB triplets
0 255 0
0 0 255
255 255 0
255 255 255
0 0 0

After changing the config file to your preference, you can simply run the following in your terminal of choice

To compile the file and export data to image file in res/image.ppm

$ make

To open the image after compiling

$ make open-image

To do all of the above in one statement

$ make create-image

This project was designed to use no dependencies except the C++ standard library, this is a C++11 project because we are using constexpr to speed up some of the vector operations.