#include <GL/gl.h>
+#define BUFFER_OFFSET(i) ((char *)NULL + (i))
+
// 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];
+
std::string read_file(const std::string &filename);
-GLhandleARB compile_shader(const std::string &shader_src, GLenum type);
+GLuint compile_shader(const std::string &shader_src, GLenum type);
+void multiply_3x3_matrices(const Matrix3x3 a, const Matrix3x3 b, Matrix3x3 result);
+void invert_3x3_matrix(const Matrix3x3 m, Matrix3x3 result);
+void print_3x3_matrix(const Matrix3x3 m);
#ifdef NDEBUG
#define check_error()