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stm32_business_card/recon/mandelbrot_tests/c/main.c

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C
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#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <raylib.h>
#include <raymath.h>
#include <limits.h>
#include <complex.h>
#include <string.h>
#define WINDOW_SIZE_X 1600
#define WINDOW_SIZE_Y 800
#define RES_X 1600
#define RES_Y 800
#define DEFAULT_CENTER_X 0
#define DEFAULT_CENTER_Y 0
#define MOUSE_BUTTON 0
#define STEP_SIZE .1
#define ZOOM_SIZE .1
#define DECIMAL_LOC 28
#define DOUBLE_SCALER (1 << DECIMAL_LOC)
#define DOUBLE_TO_FIXED(val) (int32_t)((val) * DOUBLE_SCALER)
#define FIXED_MULTIPLY(x,y) ((((uint64_t)(x))*(y)) >> DECIMAL_LOC)
#define FIXED_TO_DOUBLE(val) ((val) / (double)DOUBLE_SCALER)
#define INFTY 2
#define INFTY_SQR INFTY * INFTY
#define ITERS 255
#define INFTY_SQR_FIXED DOUBLE_TO_FIXED(INFTY_SQR)
//#define SHIP
//#undef SHIP
#ifdef SHIP
Color get_color(int i) {
if(i == ITERS) return (Color){0, 0, 0, 255};
if(i == 0) return (Color){0, 0, 0, 255};
return (Color) {
2*(i - 128)+255,
0,
0,
255
};
}
#else
Color get_color(int i) {
// if((i == ITERS) || (i == 0)) return (Color){0, 0, 0, 255};
if(i == ITERS) return (Color){0,0,0,255};
if(i == 0) return (Color){0,0,1,255};
if(i < 128) {
return (Color) {
(8*(i - 128)+255) & 0xff,
0,
(16*(i - 64)+255) & 0xff,
255
};
}
return (Color) {
0,
0,
((unsigned int)-2*(i - 128)+255) & 0xff,
255
};
}
#endif
struct camera {
double min_r, min_i, max_r, max_i;
};
typedef struct {
int32_t r; int32_t i;
} FixedCord;
static inline int iterate(FixedCord c) {
int32_t z_i = 0;
int32_t z_r = 0;
int32_t z_r_2, z_i_2, zn_r, zn_i;
for(int it = 0; it < ITERS; it++) {
z_r_2 = FIXED_MULTIPLY(z_r, z_r);
z_i_2 = FIXED_MULTIPLY(z_i, z_i);
zn_r = z_r_2 - z_i_2 + c.r;
#ifdef SHIP
zn_i = abs(FIXED_MULTIPLY((DOUBLE_TO_FIXED(2)), (FIXED_MULTIPLY(z_r, z_i)))) + c.i;
#else
zn_i = (FIXED_MULTIPLY((DOUBLE_TO_FIXED(2)), (FIXED_MULTIPLY(z_r, z_i)))) + c.i;
#endif
z_i = zn_i;
z_r = zn_r;
if(z_i_2 + z_r_2 > INFTY_SQR_FIXED) return it;
}
return ITERS;
}
//blllluuuuurg, matracies and vectors in raylib are floats and we need doubles
void shift_cam(struct camera *cam, double step_r, double step_i) {
double i_offset = (cam->max_i - cam->min_i) * step_i;
double r_offset = (cam->max_r - cam->min_r) * step_r;
cam->min_i += i_offset;
cam->max_i += i_offset;
cam->min_r += r_offset;
cam->max_r += r_offset;
}
void zoom_cam(struct camera *cam, double zoom) {
double i_scale = (cam->max_i - cam->min_i) * zoom;
double r_scale = (cam->max_r - cam->min_r) * zoom;
cam->min_i += i_scale;
cam->max_i -= i_scale;
cam->min_r += r_scale;
cam->max_r -= r_scale;
}
enum DIRECTIONS {
N, NE, E, SE, S, SW, W, NW
};
//we can inline these if needed
inline bool bitarray_check(uint8_t *array, size_t i) {
return array[i/8] & (1 << (i%8));
}
inline void bitarray_set(uint8_t *array, size_t i) {
array[i/8] |= (1 << (i%8));
}
inline FixedCord get_neighbor_coord(FixedCord from_coord, int direction, FixedCord step) {
if((direction == NW) || (direction < E)) from_coord.i += step.i;
if((direction > N) && (direction < S)) from_coord.r += step.r;
if((direction > E) && (direction < W)) from_coord.i -= step.i;
if(direction > S) from_coord.r -= step.r;
return from_coord;
}
FixedCord get_neighbor_coord(FixedCord from_coord, int direction, FixedCord step);
size_t get_neighbor_index(size_t from_pixel, int direction) {
const size_t neighbor_index_accl[8] =
{-RES_X, -RES_X + 1, 1, RES_X + 1, RES_X, RES_X - 1, -1, -RES_X - 1};
from_pixel += neighbor_index_accl[direction];
//canidate for optimization; lots of branches. maybe inline
return from_pixel;
}
bool bitarray_check(uint8_t *array, size_t i);
void bitarray_set(uint8_t *array, size_t i);
#define BITARRAY_SET(array, i) ((array)[(i)/8] |= (1 << ((i) % 8)))
#define BITARRAY_CLEAR(array, i) ((array)[(i)/8] &= ~(1 << ((i) % 8)))
#define BITARRAY_CHECK(array, i) ((array)[(i)/8] & (1 << ((i) % 8)))
#define PRESORT_UNSOLVED (1 << 0)
#define PRESORT_VISITED (1 << VISITED)
//#define PRESORT_INTERIOR (1 << INTERIOR) //in set, NOT an edge
//#define PRESORT_BACKTRACKED (1 << BACKTRACED)
//#define PRESORT_EXTERIOR (1 <<
//we'll be storing info in the green channel to utalize all available memory.
//the following is bitmasks to do so
#define GCHAN_RENDERED (1 << 0)
#define GCHAN_VISITED (1 << 1)
#define GCHAN_BLOCKED (1 << 2) //interior element or backtrack
#define GCHAN_DEBUG (1 << 3) //extra, not nessesary
/**
void switch_pixel(coord &this_coord, const coord step, size_t this_index, int dir) {
}
**/
unsigned int mandelbrot_bordertrace(struct camera *cam, Color *pixels) {
//these lookup tables r cheap cuz on the stm32f1, 1 memory read is 1 instruction
FixedCord scale = {
.r = DOUBLE_TO_FIXED((cam->max_r - cam->min_r) / (double)RES_X),
.i = DOUBLE_TO_FIXED((cam->max_i - cam->min_i) / (double)RES_Y)};
FixedCord c = {.r = 0, .i = DOUBLE_TO_FIXED(cam->max_i)};
unsigned int total_iters = 0;
size_t on_pixel = 0;
//having these r kinda gross, will restructure later
int32_t cam_bord_fixed_n = DOUBLE_TO_FIXED(cam->min_i);
int32_t cam_bord_fixed_s = DOUBLE_TO_FIXED(cam->max_i);
int32_t cam_bord_fixed_e = DOUBLE_TO_FIXED(cam->max_r);
int32_t cam_bord_fixed_w = DOUBLE_TO_FIXED(cam->min_r);
/**
//for keeping track of border only. will organize later
uint8_t set[(160*80)/8] = {0};
uint8_t unset[(160*80)/8] = {0};
**/
for(int y = 0; y < RES_Y; y++) {
c.r = DOUBLE_TO_FIXED(cam->min_r);
for(int x = 0; x < RES_X; x++) {
int i = iterate(c);
total_iters += i;
pixels[on_pixel] = get_color(i);
/**
const Color debug_colors[] =
{ (Color) {0xff, 0x00, 0x00, 0xff},
(Color) {0xff, 0x00, 0xff, 0xff},
(Color) {0x00, 0xff, 0x00, 0xff},
(Color) {0x00, 0x00, 0xff, 0xff},
(Color) {0x6a, 0x00, 0xff, 0xff}
};
static int on_dbg_color = 0;
**/
if(i == ITERS) {
FixedCord this_coord = c;
size_t this_index = on_pixel;
int nei_priority[8];
int last_nei_priority[8];
//only really need to zero green channel
bzero(pixels, RES_X * RES_Y * sizeof(*pixels));
int last_direction = W;
int nei_presort[8] = {0};
//this is so fucking knarly
while(true) {
//step 1: check pixels around us, fill in neighbors.
//find if we're pushed against screen border.
//feels gross but I don't think there's a better way
if((this_coord.i - scale.i) < cam_bord_fixed_n) {
for(int nei_dir = SE; nei_dir <= SW; nei_dir++)
nei_presort[nei_dir] = GCHAN_BLOCKED;
}
else if((this_coord.i + scale.i) > cam_bord_fixed_s) {
nei_presort[NE] = GCHAN_BLOCKED;
nei_presort[N] = GCHAN_BLOCKED;
nei_presort[NW] = GCHAN_BLOCKED;
}
if((this_coord.r - scale.r) < cam_bord_fixed_w) {
for(int nei_dir = SW; nei_dir < NW; nei_dir++)
nei_presort[nei_dir] = GCHAN_BLOCKED;
}
else if((this_coord.r + scale.r) > cam_bord_fixed_e) {
for(int nei_dir = NE; nei_dir < SE; nei_dir++)
nei_presort[nei_dir] = GCHAN_BLOCKED;
}
/** now fill in neighbor info based on green channel,
* iterate if no info available.
* if this is to slow we could flatten this; it's predictable
* where there will be info
**/
//if this is too slow, get rid of all the modulos.
bool interior = true;
for(int nei_dir = 0; nei_dir < 8; nei_dir++) {
size_t nei_i;
uint8_t gchan_info;
nei_i = get_neighbor_index(this_index, nei_dir);
gchan_info = pixels[this_index].g;
//note that when we move this over, there will be no alpha channel.
//gchan_info will be extracted differently!!!
if(gchan_info & GCHAN_RENDERED) {
gchan_info &= ~(GCHAN_RENDERED);
gchan_info ^= GCHAN_BLOCKED << 1;
nei_presort[nei_i] = gchan_info;
if(!gchan_info) interior = false;
/**
if(gchan_info & GCHAN_BLOCKED) nei_presort[nei_dir] = -1;
else if(gchan_info & GCHAN_VISITED) nei_priority[nei_dir] = 12;
else if((pixels[nei_i].r | pixels[nei_i].b) == 0) //unvisited element
nei_priority[nei_dir] = 9;
else { //exterior
interior = false;
nei_priority[nei_dir] = -1;
}
**/
}
else {
int i = iterate(get_neighbor_coord(this_coord, nei_dir, scale));
pixels[nei_i] = get_color(i);
pixels[nei_i].g |= GCHAN_RENDERED;
if(i == ITERS) continue;
interior = false;
}
//TODO if interior true
/**
if((nei_priority[nei_dir] == 6) && (nei_i > 0)) {
if(last_nei_unvisited) {
nei_priority[nei_dir] = 3;
nei_priority[nei_dir-1] = 3;
}
else if(nei_priority[nei_dir-1] == 12)
nei_priority[nei_dir-1] = 6;
LAST_nei_unvisited = true;
}
else last_nei_unvisited = false;
**/
}
if(interior) {
memcpy(last_nei_priority, nei_priority, sizeof(nei_priority));
pixels[this_index].g |= GCHAN_BLOCKED;
this_index = get_neighbor_index(this_index, (last_direction + 4) % 8);
this_coord = get_neighbor_coord(
this_coord, (last_direction + 4) % 8, scale);
}
else {
for(int nei_dir = 0; nei_dir < 8; nei_dir++) {
int offset_cw = (last_direction - nei_dir) % 8;
int offset_ccw = (nei_dir - last_direction) % 8;
int forward_offset;
switch(nei_presort[nei_dir]) {
case GCHAN_VISITED:
nei_priority[nei_dir] = 12;
break;
case GCHAN_BLOCKED:
nei_priority[nei_dir] = -1;
break;
default: //unvisited element
if((nei_presort[(nei_dir - 1) % 8] == 0) ||
(nei_presort[(nei_dir + 1) % 8] == 0)) {
nei_priority[nei_dir] = 3;
break;
}
if((nei_presort[(nei_dir - 1) % 8] == GCHAN_VISITED) ||
(nei_presort[(nei_dir + 1) % 8] == GCHAN_VISITED)) {
nei_priority[nei_dir] = 6;
break;
}
nei_priority[nei_dir] = 9;
break;
}
forward_offset = (offset_cw < offset_ccw) ? offset_cw : offset_ccw;
if(forward_offset < 3) nei_priority[nei_dir] -= (3-forward_offset);
}
}
for(int priority = 0; priority < 12; priority++) {
for(int nei_dir = 0; nei_dir < 8; nei_dir++) {
if(nei_priority[nei_dir] != priority) continue;
//switch pixels!!!!1!!
memcpy(last_nei_priority, nei_priority, sizeof(nei_priority));
last_direction = nei_dir;
this_index = get_neighbor_index(this_index, nei_dir);
this_coord = get_neighbor_coord(this_coord, nei_dir, scale);
goto drunkaloneandunemployed;
}
}
drunkaloneandunemployed:
}
}
on_pixel++;
c.r += scale.r;
}
c.i -= scale.i;
}
return total_iters;
}
unsigned int mandelbrot_unoptimized(struct camera *cam, Color *pixels) {
FixedCord scale = { .r = DOUBLE_TO_FIXED((cam->max_r - cam->min_r) / (double)RES_X), .i = DOUBLE_TO_FIXED((cam->max_i - cam->min_i) / (double)RES_Y) };
FixedCord c = { .r = 0, .i = DOUBLE_TO_FIXED(cam->max_i) };
unsigned int total_iters = 0;
for(int y = 0; y < RES_Y; y++) {
c.r = DOUBLE_TO_FIXED(cam->min_r);
for(int x = 0; x < RES_X; x++) {
int i = iterate(c);
total_iters += i;
pixels[((y * RES_X) + x)] = get_color(i);
c.r += scale.r;
}
c.i -= scale.i;
}
return total_iters;
}
void test() {
uint8_t bitarray[(160*80)/8] = {0};
int test_i = 9;
BITARRAY_SET(bitarray, test_i);
printf("%s\n", BITARRAY_CHECK(bitarray, 9) ? "true" : "false");
}
int main() {
//test();
//return 0;
Color *pixels = malloc(RES_X * RES_Y * sizeof(Color));
struct camera cam = {
.min_r = -1,
.max_r = 1,
// .min_i = -1,
// .max_i = 1
};
cam.min_i = ((double)RES_Y / RES_X) * cam.min_r;
cam.max_i = ((double)RES_Y / RES_X) * cam.max_r;
InitWindow(WINDOW_SIZE_X, WINDOW_SIZE_Y, "mandelbrot fixed point test");
Image img = GenImageColor(RES_X, RES_Y, BLUE);
Texture tex = LoadTextureFromImage(img);
UnloadImage(img);
SetTargetFPS(0);
while(!WindowShouldClose()) {
switch(GetKeyPressed()) {
case KEY_UP:
shift_cam(&cam, 0, STEP_SIZE);
break;
case KEY_DOWN:
shift_cam(&cam, 0, -STEP_SIZE);
break;
case KEY_RIGHT:
shift_cam(&cam, STEP_SIZE, 0);
break;
case KEY_LEFT:
shift_cam(&cam, -STEP_SIZE, 0);
break;
case KEY_W:
zoom_cam(&cam, ZOOM_SIZE);
break;
case KEY_S:
zoom_cam(&cam, -ZOOM_SIZE);
break;
default:
BeginDrawing();
EndDrawing();
continue;
break;
}
printf("(%.21f, %.21f) - (%.21f, %.21f)\n", cam.min_r, cam.min_i, cam.max_r, cam.max_i);
printf("Unoptimized: %u iterations\n", mandelbrot_unoptimized(&cam, pixels));
printf("Border tracing: %u iterations\n", mandelbrot_bordertrace(&cam, pixels));
BeginDrawing();
UpdateTexture(tex, pixels);
DrawTextureEx(tex, (Vector2){0,0}, 0, (float)GetRenderWidth()/RES_X, WHITE);
EndDrawing();
}
return 0;
}
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