framebuffer.cpp

#include <float.h>
#include <stdlib.h>

#include <fstream>
#include <iostream>
using namespace std;

#include "framebuffer.h"

FrameBuffer::FrameBuffer(int w, int h) {
  if ((w < 0) || (w > 2048) || (h < 0) || (h > 2048)) {
    // Stops incorrectly formatted constructions of the grame buffer class
    // not good practice, but force a stop anyway.
    exit(-1);
  }

  this->framebuffer = new Pixel[w * h];

  if (!this->framebuffer) {
    exit(-2);
  }

  this->width = w;
  this->height = h;

  // Sets initial rgb + depth values for each pixel to 0.0f
  for (int i = 0; i < w * h; i += 1) {
    this->framebuffer[i].red = 0.0f;
    this->framebuffer[i].green = 0.0f;
    this->framebuffer[i].blue = 0.0f;
    this->framebuffer[i].depth = 0.0f;
  }

  return;
}

// Plots rgb values to a pixel
int FrameBuffer::plotPixel(int x, int y, float red, float green, float blue) {
  // Prevents plotting pixel to undefined widths or heights
  if ((x < 0) || (x >= this->width) || (y < 0) || (y >= this->height)) {
    return -1;
  }
  //  if ((red > 1.0f) || (red < 0.0f)) cerr<<"out of range\n";

  // 1D array indexing
  this->framebuffer[y * this->width + x].red = red;
  this->framebuffer[y * this->width + x].green = green;
  this->framebuffer[y * this->width + x].blue = blue;

  return 0;
}

// Plots depth values to a pixel
int FrameBuffer::plotDepth(int x, int y, float depth) {
  // Prevents plotting pixel to undefined widths or heights
  if ((x < 0) || (x >= this->width) || (y < 0) || (y >= this->height)) {
    return -1;
  }
  // 1D array indexing
  this->framebuffer[y * this->width + x].depth = depth;

  return 0;
}

// Returns the depth value of a input pixel
int FrameBuffer::getDepth(int x, int y, float &depth) {
  // Prevents plotting pixel to undefined widths or heights
  if ((x < 0) || (x >= this->width) || (y < 0) || (y >= this->height)) {
    return -1;
  }

  // 1D array indexing
  depth = this->framebuffer[y * this->width + x].depth;

  return 0;
}

// Returns the rgb values for a input pixel
int FrameBuffer::getPixel(int x, int y, float &red, float &green, float &blue) {
  // Prevents plotting pixel to undefined widths or heights
  if ((x < 0) || (x >= this->width) || (y < 0) || (y >= this->height)) {
    return -1;
  }

  // 1D array indexing
  red = this->framebuffer[y * this->width + x].red;
  green = this->framebuffer[y * this->width + x].green;
  blue = this->framebuffer[y * this->width + x].blue;

  return 0;
}

// Write RGB values stores in the frame buffer in PPM format
int FrameBuffer::writeRGBFile(char *filename) {
  float min = 0.0f;
  float max = 0.0f;

  ofstream outfile;

  outfile.open(filename, ofstream::binary);

  if (!outfile.is_open()) {
    return -1;
  }
  // Loop through each pixel in frame buffer and get the range between the rgb
  // values
  for (int i = 0; i < this->width * this->height; i += 1) {
    if (this->framebuffer[i].red > max) max = this->framebuffer[i].red;
    if (this->framebuffer[i].green > max) max = this->framebuffer[i].green;
    if (this->framebuffer[i].blue > max) max = this->framebuffer[i].blue;
    if (this->framebuffer[i].red < min) min = this->framebuffer[i].red;
    if (this->framebuffer[i].green < min) min = this->framebuffer[i].green;
    if (this->framebuffer[i].blue < min) min = this->framebuffer[i].blue;
  }

  // Calculate the range of colours, to normalize RGB values
  float diff = max - min;
  if (diff == 0.0f) diff = 1.0f;

  // Writes the PPM header
  outfile << "P6\n";
  outfile << this->width << " " << this->height << "\n255\n";

  // For each pixel write its normalized RGB value using three unsigned 8-bit
  // integers
  for (int j = 0; j < this->width * this->height; j += 1) {
    outfile << (unsigned char)(((this->framebuffer[j].red - min) / diff) *
                               255.0);
    outfile << (unsigned char)(((this->framebuffer[j].green) / diff) * 255.0);
    outfile << (unsigned char)(((this->framebuffer[j].blue) / diff) * 255.0);
  }

  // Return 0 when successful
  outfile.close();
  return 0;
}

// Write RGB values stores in the frame buffer in PPM format
int FrameBuffer::writeDepthFile(char *filename) {
  float max = 0;
  float min = FLT_MAX;

  ofstream outfile;

  outfile.open(filename, ofstream::binary);

  if (!outfile.is_open()) {
    return -1;
  }
  // Loop through each pixel in the frame buffer and calcualte the depth range
  for (int i = 0; i < this->width * this->height; i += 1) {
    if (this->framebuffer[i].depth > max) max = this->framebuffer[i].depth;
    if (this->framebuffer[i].depth < min) min = this->framebuffer[i].depth;
  }

  float diff = max - min;
  if (diff == 0.0f) diff = 1.0f;

  //  cerr << "Min/max/diff" << min << "/" << max << "/" << diff << endl;

  // Writes the PPM header
  outfile << "P6\n";
  outfile << this->width << " " << this->height << "\n255\n";

  // For each pixel write its normalized depth value using an unsigned 8-bit
  // integer (creats a grayscale)
  for (int j = 0; j < this->width * this->height; j += 1) {
    unsigned char pd =
        (unsigned char)(((this->framebuffer[j].depth - min) / diff) * 255.0);
    outfile << pd << pd << pd;
  }

  outfile.close();
  return 0;
}