#ifndef _UTIL_H
#define _UTIL_H 1
+// Various utilities.
+
#include <stdio.h>
#include <stdlib.h>
#define BUFFER_OFFSET(i) ((char *)NULL + (i))
-// assumes h in [0, 2pi> or [-pi, pi>
+// Converts a HSV color to RGB. Assumes h in [0, 2pi> or [-pi, pi>
void hsv2rgb(float h, float s, float v, float *r, float *g, float *b);
// Column major (same as OpenGL).
typedef double Matrix3x3[9];
+// Read a file from disk and return its contents.
+// Dies if the file does not exist.
std::string read_file(const std::string &filename);
+
+// Compile the given GLSL shader (typically a vertex or fragment shader)
+// and return the object number.
GLuint compile_shader(const std::string &shader_src, GLenum type);
+
+// Compute a * b.
void multiply_3x3_matrices(const Matrix3x3 a, const Matrix3x3 b, Matrix3x3 result);
+
+// Compute m^-1. Result is undefined if the matrix is singular or near-singular.
void invert_3x3_matrix(const Matrix3x3 m, Matrix3x3 result);
+
+// Print a 3x3 matrix to standard output. Useful for debugging.
void print_3x3_matrix(const Matrix3x3 m);
#ifdef NDEBUG
#ifndef _WIDGETS_H
#define _WIDGETS_H 1
+// Some simple UI widgets for test use.
+
void draw_hsv_wheel(float y, float rad, float theta, float value);
void draw_saturation_bar(float y, float saturation);
void make_hsv_wheel_texture();