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