Image.cpp

#include "Miro.h"
#include "Image.h"
#include <stdio.h>
#include <string.h>
#include <math.h>

#ifdef _WIN32
	// disable useless warnings
	#pragma warning(disable:4996)
#endif

Image * g_image = 0;

Image::Image()
{
	m_pixels = 0;
	m_width = 1;
	m_height = 1;
}

Image::~Image()
{
	if (m_pixels) delete [] m_pixels;
}

void Image::resize(int width, int height)
{
	if (m_pixels) delete [] m_pixels;
	m_pixels = 0;
	m_pixels = new Pixel[width*height];
	memset(m_pixels, 0, width*height*sizeof(Pixel));
	m_width = width;
	m_height = height;
}

void Image::clear(const Vector3& c)
{
	// should be bg color
	for (int y=0; y<m_height; y++) 
	{
		for (int x=0; x<m_width; x++) 
		{
			setPixel(x, y, c);
		}
	}
}

// map floating point values to byte values for pixels
unsigned char Map(float r)
{
	float rMap = 255*r;
	unsigned char c = rMap>255?255:(unsigned char)rMap;
	return c;
}

void Image::setPixel(int x, int y, const Vector3& p)
{
	// do some tone mapping
	if (x >= 0 && x < m_width && y < m_height && y >= 0)
	{
		m_pixels[y*m_width+x].r = Map(p.x);
		m_pixels[y*m_width+x].g = Map(p.y);
		m_pixels[y*m_width+x].b = Map(p.z);
	}
}

void Image::setPixel(int x, int y, const Pixel& p)
{
	// do some tone mapping
	if (x >= 0 && x < m_width && y < m_height && y >= 0)
	{
		m_pixels[y*m_width+x]= p;
	}
}

void Image::drawScanline(int y)
{
	glRasterPos2f(-1, -1 + 2*y / (float)m_height);
	glDrawPixels(m_width, 1, GL_RGB, GL_UNSIGNED_BYTE, &m_pixels[y*m_width]);
}

void Image::draw()
{
	for (int i = 0; i < m_height; i++) 
	{
		drawScanline(i);
	}
}

void Image::writePPM(char* pcFile)
{
	writePPM(pcFile, (unsigned char*)m_pixels, m_width, m_height);
}

void Image::writePPM(char *pcFile, unsigned char *data, int width, int height)
{
	FILE *fp = fopen(pcFile, "wb");
	if (!fp)
		fprintf(stderr, "Couldn't open PPM file %s for writing\n", pcFile);
	else
	{
		fprintf(fp, "P6\n");
		fprintf(fp, "%d %d\n", width, height );
		fprintf(fp, "255\n" );

		// invert image
		int stride = width*3;
		for (int i = height-1; i >= 0; i--)
			fwrite(&data[stride*i], stride, 1, fp);
		fclose(fp);
	}
}