rasterizer.cpp File Reference

Implementation of the rasterization process (coloring, shading, and image generation). More...

#include "rasterizer.hpp"
#include "quadtree.hpp"
#include <algorithm>
#include <cmath>
#include <fstream>
#include <iostream>
#include <limits>

Include dependency graph for rasterizer.cpp:

Classes
struct	Color

Functions
Color	getColor (double z, double minZ, double maxZ)
	Maps an altitude to a color using a Haxby-like colormap.
double	interpolateZ (double px, double py, const Point &p1, const Point &p2, const Point &p3)
	Computes the Z coordinate at point (px, py) within a triangle using barycentric interpolation.
double	calculateShade (const Point &p1, const Point &p2, const Point &p3)
	Calculates a shading factor based on the triangle's normal and a fixed light source.
void	generateImage (const std::string &filename, int width, const Mesh &mesh)
	Generates a colorized raster image (PPM) from the triangulated mesh.

Detailed Description

Implementation of the rasterization process (coloring, shading, and image generation).

Function Documentation

calculateShade()

double calculateShade	(	const Point &	p1,
		const Point &	p2,
		const Point &	p3
	)

Calculates a shading factor based on the triangle's normal and a fixed light source.

Computes the normal vector of the triangle (cross product of edges) and takes the dot product with a fixed light direction (from NW).

Parameters

p1	First vertex.
p2	Second vertex.
p3	Third vertex.

Returns

double Shading factor (0.4 to 1.0).

generateImage()

void generateImage	(	const std::string &	filename,
		int	width,
		const Mesh &	mesh
	)

Generates a colorized raster image (PPM) from the triangulated mesh.

Rasterizes the mesh into a PPM image of the specified width. The height is calculated automatically to maintain aspect ratio. Altitude is visualized using a color map.

Parameters

filename	The output filename (e.g., "output.ppm").
width	The desired width of the output image in pixels.
mesh	The triangulated mesh to rasterize.

Here is the call graph for this function:

getColor()

Color getColor	(	double	z,
		double	minZ,
		double	maxZ
	)

Maps an altitude to a color using a Haxby-like colormap.

Parameters

z	Current altitude.
minZ	Minimum altitude in the dataset.
maxZ	Maximum altitude in the dataset.

Returns

Color The corresponding RGB color.

interpolateZ()

double interpolateZ	(	double	px,
		double	py,
		const Point &	p1,
		const Point &	p2,
		const Point &	p3
	)

Computes the Z coordinate at point (px, py) within a triangle using barycentric interpolation.

Parameters

px	X coordinate of the target point.
py	Y coordinate of the target point.
p1	First vertex of the triangle.
p2	Second vertex of the triangle.
p3	Third vertex of the triangle.

Returns

double The interpolated altitude (Z).