borgware-2d/animations/fpmath_patterns.c

134 lines
3.5 KiB
C

#include <math.h> // Floating point math is dog slow on AVR, but I don't care.
#include <string.h>
#include <stdint.h>
#include "../config.h"
#include "../pixel.h"
#include "../util.h"
#include "fpmath_patterns.h"
#define DOUBLE_BUFFERING
#ifdef DOUBLE_BUFFERING
#define BUFFER pixmap_buffer
#else
#define BUFFER pixmap
#endif
/**
* Pointer to a function which return a value depending on two-dimensional
* coordinates and a "step" value.
* @param x x-coordinate
* @param y y-coordinate
* @param t a step value which changes for each frame, allowing for animations
* @return
*/
typedef unsigned char (*fpmath_pattern_func_t)(unsigned char const x,
unsigned char const y,
double t);
/**
* Calculates the distance between two points.
* @param x1 x coordinate of the first point
* @param y1 y coordinate of the first point
* @param x2 x coordinate of the second point
* @param y2 y coordinate of the second point
* @return distance between the points
*/
static double dist(double x1, double y1, double x2, double y2)
{
return sqrt(((x1 - x2) * (x1 - x2)) + ((y1 - y2) * (y1 - y2)));
}
/**
* Draws an animated two dimensional graph for a given function f(x,y,t).
* @param t_start start value for the function's time variable
* @param t_stop stop value for the function's time variable
* @param t_delta value by which the function's timing variable gets incremented
* @param frame_delay frame delay in ms
* @param fpPattern function which generates a pattern depending on x, y, t
*/
static void fpmath_pattern(double const t_start,
double const t_stop,
double const t_delta,
unsigned int const frame_delay,
fpmath_pattern_func_t fpPattern)
{
#ifdef DOUBLE_BUFFERING
// double buffering to reduce half painted pictures
unsigned char pixmap_buffer[NUMPLANE][NUM_ROWS][LINEBYTES];
#endif
for (double t = t_start; t < t_stop; t += t_delta)
{
for (unsigned char y = 0; y < NUM_ROWS; ++y)
{
for (unsigned char x = 0; x < NUM_COLS; ++x)
{
unsigned char const mask = shl_table[x % 8U];
unsigned char const x8 = x / 8u;
unsigned char const color = fpPattern(x, y, t);
for (uint8_t p = 0; p < NUMPLANE; ++p)
{
if (p <= (color - 1))
{
BUFFER[p][y][x8] |= mask;
}
else
{
BUFFER[p][y][x8] &= ~mask;
}
}
}
}
#ifdef DOUBLE_BUFFERING
memcpy(pixmap, pixmap_buffer, sizeof(pixmap));
#endif
wait(frame_delay);
}
}
#ifdef ANIMATION_PLASMA
#define PLASMA_X (1.0 / (NUM_COLS / (2.0 * M_PI)))
/**
* Draws a simple plasma like pattern.
*/
static unsigned char fpmath_plasma(unsigned char x, unsigned char y, double t)
{
return (sin(x * PLASMA_X + t) + sin(dist(x, y, NUM_COLS * sin(t) + NUM_COLS,
NUM_ROWS * cos(t) + NUM_ROWS) * PLASMA_X) + 2) * (NUMPLANE - 1) / 2;
}
void plasma(void)
{
#ifndef __AVR__
fpmath_pattern(0.0, 75, 0.1, 80, fpmath_plasma);
#else
fpmath_pattern(0.0, 60.0, 0.1, 1, fpmath_plasma);
#endif
}
#endif
#ifdef ANIMATION_PSYCHEDELIC
/**
* Draws flowing circular waves with a rotating center.
*/
static unsigned char fpmath_psycho(unsigned char x, unsigned char y, double t)
{
return (sin(dist(x, y, NUM_COLS * cos(t), NUM_ROWS * sin(t)) - t * 10) + 1)
* (NUMPLANE - 1);
}
void psychedelic(void)
{
#ifndef __AVR__
fpmath_pattern(0.0, 75, 0.1, 80, fpmath_psycho);
#else
fpmath_pattern(0.0, 60.0, 0.1, 1, fpmath_psycho);
#endif
}
#endif