initial commit

.gitignore

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+o/*
+*/*.o
+*.o
+librenderer.so.1
+librenderer.a

Makefile

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+include config.mk
+
+all: shared static
+
+# --- librenderer library ---
+shared: librenderer.so.1
+static: librenderer.a
+
+librenderer.o: librenderer.c
+	$(CC) -fPIC -lm $(CFLAGS) -o librenderer.o -c librenderer.c
+
+librenderer.so.1: librenderer.o
+	$(CC) -lm -shared $(CFLAGS) -o librenderer.so.1 librenderer.o
+
+librenderer.a: librenderer.o
+	$(AR) rcs librenderer.a librenderer.o
+
+# --- Examples & related ---
+util.o: util.c
+	$(CC) -c -lsodium $(CFLAGS) -o util.o util.c
+
+examples: o/bball o/randpix o/randline o/cosgraph
+
+examples/bball.o: examples/bball.c
+	$(CC) -c -lsodium $(CFLAGS) -o examples/bball.o examples/bball.c
+
+o/bball: examples/bball.o util.o librenderer.a
+	$(CC) -lsodium $(CFLAGS) -o o/bball examples/bball.o util.o librenderer.a
+
+examples/randpix.o: examples/randpix.c
+	$(CC) -c -lsodium $(CFLAGS) -o examples/randpix.o examples/randpix.c
+
+o/randpix: examples/randpix.o util.o librenderer.a
+	$(CC) -lsodium $(CFLAGS) -o o/randpix examples/randpix.o util.o librenderer.a
+
+examples/randline.o: examples/randline.c
+	$(CC) -c -lsodium $(CFLAGS) -o examples/randline.o examples/randline.c
+
+o/randline: examples/randline.o util.o librenderer.a
+	$(CC) -lsodium $(CFLAGS) -o o/randline examples/randline.o util.o librenderer.a
+
+examples/cosgraph.o: examples/cosgraph.c
+	$(CC) -c $(CFLAGS) -o examples/cosgraph.o examples/cosgraph.c
+
+o/cosgraph: examples/cosgraph.o librenderer.a
+	$(CC) $(CFLAGS) -o o/cosgraph examples/cosgraph.o librenderer.a -lm
+
+clean:
+	rm -rf *.o examples/*.o *.so* *.a o/*
+
+.PHONY: clean examples shared static

TODO

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+fix mkpixel x y orientation
+cosgraph example
+add to git repo

config.h

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+#ifndef CONFIG_H
+#define CONFIG_H
+
+static const int cols = 80;
+static const int rows = 25;
+
+#endif

config.mk

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+CC = cc
+AR = ar
+CFLAGS = -O2 -std=c99 -Wall -Wextra -Wpedantic 

examples/bball.c

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+#define _XOPEN_SOURCE   600
+#define _POSIX_C_SOURCE 200112L
+
+/// Useful includes
+#include <stdio.h>
+//#include <stdlib.h>
+//#include <getopt.h>
+//#include <unistd.h>
+//#include <string.h>
+#include "../librenderer.h"
+#include "../util.h"
+
+int main(void) {
+  if(sodium_init() == -1) {
+    fprintf(stderr, "sodium_init() failed\n");
+    return 2;
+  }
+
+  char pixelmap[rows][cols];
+  init_pxmap(pixelmap);
+
+  printf("\033[s"); // save cursor position
+
+  int x_pos = 12; // set initial x position
+  int y_pos = 40; // set initial y position
+  int speed_x = randint(-3,3); // set initial horizontal speed
+  int speed_y = randint(-3,3); // set initial vertical speed
+
+  /* TODO draw initial ball here */
+  add_pixel(pixelmap, x_pos, y_pos, 1.0);
+  render_pixelmap(pixelmap);
+  usleep(800000);
+
+  while(1) {
+    if(x_pos >= 0 || x_pos < cols || y_pos >= 0 || y_pos < rows)
+      add_pixel(pixelmap, x_pos, y_pos, 0.0);
+    x_pos += speed_x; y_pos += speed_y; // move
+    if(x_pos >= 0 || x_pos < cols || y_pos >= 0 || y_pos < rows)
+      add_pixel(pixelmap, x_pos, y_pos, 1.0);
+    render_pixelmap(pixelmap);
+    if(x_pos <= 0 || x_pos >= rows)
+      speed_x = -speed_x; // bounce of the wall (horizontal) 
+    if(y_pos <= 0 || y_pos >= cols)
+      speed_y = -speed_y; // bounce of the wall (vertical) 
+    usleep(30000);
+  }
+  return 0;
+}

examples/cosgraph.c

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+#define _XOPEN_SOURCE   600
+#define _POSIX_C_SOURCE 200112L
+
+/// Useful includes
+#include <stdio.h>
+//#include <stdlib.h>
+//#include <getopt.h>
+//#include <unistd.h>
+//#include <string.h>
+#include <math.h>
+#include "../librenderer.h"
+
+int main(void) {
+  char pixelmap[rows][cols];
+  init_pxmap(pixelmap);
+
+  printf("\033[s"); // save cursor position
+
+  // TODO for every x from 0 to 'cols', graph the cos(x)
+
+  add_pixel(pixelmap, 1,0,1.0f);
+  render_pixelmap(pixelmap);
+
+  /*
+  for(int x = 0; x < cols; x++) {
+    add_pixel(pixelmap, (int)(cos(x)*5), (int)rows/2, 1.0f);
+    render_pixelmap(pixelmap);
+  }
+  */
+  return 0;
+}

examples/randline.c

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+#define _XOPEN_SOURCE   600
+#define _POSIX_C_SOURCE 200112L
+
+/// Useful includes
+#include <stdio.h>
+//#include <stdlib.h>
+//#include <getopt.h>
+//#include <unistd.h>
+//#include <string.h>
+#include "../librenderer.h"
+#include "../util.h"
+
+int main(void) {
+  if(sodium_init() == -1) {
+    fprintf(stderr, "sodium_init() failed\n");
+    return 2;
+  }
+
+  char pixelmap[rows][cols];
+  init_pxmap(pixelmap);
+
+  printf("\033[s"); // save cursor position
+
+  // TODO these lines segfault
+  //mkline(pixelmap,15,58,4,15);
+  //mkline(pixelmap,14,13,20,73);
+  //mkline(pixelmap,5,29,11,66);
+  //mkline(pixelmap,0,25,80,0);
+
+  mkline(pixelmap,3,35,13,6);
+  mkline(pixelmap,0,0,80,25);
+  int a,b,c,d;
+  while(1) {
+    a = randint(1,rows-1); b = randint(1,cols-1);
+    c = randint(1,rows-1); d = randint(1,cols-1);
+    render_pixelmap(pixelmap);
+    printf("\n\n    (%d;%d) -> (%d;%d)      \n",a,b,c,d);
+    mkline(pixelmap,a,b,c,d);
+    usleep(200000);
+  }
+  return 0;
+}

examples/randpix.c

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+#define _XOPEN_SOURCE   600
+#define _POSIX_C_SOURCE 200112L
+
+/// Useful includes
+#include <stdio.h>
+//#include <stdlib.h>
+//#include <getopt.h>
+//#include <unistd.h>
+//#include <string.h>
+#include "../librenderer.h"
+#include "../util.h"
+
+int main(void) {
+  if(sodium_init() == -1) {
+    fprintf(stderr, "sodium_init() failed\n");
+    return 2;
+  }
+
+  char pixelmap[rows][cols];
+  init_pxmap(pixelmap);
+
+  printf("\033[s"); // save cursor position
+
+  while(1) {
+    render_pixelmap(pixelmap);
+    add_pixel(pixelmap, randint(0,rows), randint(0,cols), randfloat(0.0,1.0));
+    usleep(20000);
+  }
+  return 0;
+}

librenderer.c

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+#define _POSIX_C_SOURCE 200112L
+
+#include "librenderer.h"
+// int cols; defined in config.h; default 80
+// int rows; defined in config.h; default 25
+
+void swap(int* a, int* b) {
+  int tmp = *a;
+  *a = *b;
+  *b = tmp;
+}
+
+float fract_part(float x) {
+  if(x > 0) return x - (int)x;
+  else return x - ((int)x+1);
+}
+
+char opacity2ch(float opac) {
+  // ._:-=+*n#%@
+  if(opac <= 0.0f) {
+    return ' ';
+  } else if(opac > 0.0f && opac <= 0.1f) {
+    return '.';
+  } else if(opac > 0.1f && opac <= 0.2f) {
+    return '_';
+  } else if(opac > 0.2f && opac <= 0.3f) {
+    return ':';
+  } else if(opac > 0.3f && opac <= 0.4f) {
+    return '-';
+  } else if(opac > 0.4f && opac <= 0.5f) {
+    return '=';
+  } else if(opac > 0.5f && opac <= 0.6f) {
+    return '+';
+  } else if(opac > 0.6f && opac <= 0.7f) {
+    return '*';
+  } else if(opac > 0.7f && opac <= 0.8f) {
+    return 'n';
+  } else if(opac > 0.8f && opac <= 0.9f) {
+    return '#';
+  } else if(opac > 0.9f && opac < 1.0f) {
+    return '%';
+  } else if(opac >= 1.0f){
+    return '@';
+  }
+  return '\0'; // default; should never run idealy
+}
+
+void add_pixel(char pxmap[rows][cols], int x, int y, float opac) {
+  pxmap[x][y] = opacity2ch(opac);
+}
+
+void render_pixelmap(char pxmap[rows][cols]) {
+  printf("\033[u"); // restore cursor position
+  for(int i=0; i<rows; i++) {
+    for(int j=0; j<cols; j++) {
+      printf("%c", pxmap[i][j]);
+    }
+    printf("\n");
+  }
+}
+
+void mkline(char pxmap[rows][cols], int x0, int y0, int x1, int y1) {
+  int steep = abs(y1-y0) > abs(x1-x0);
+
+  if(steep) {
+    swap(&x0,&y0);
+    swap(&x1,&y1);
+  }
+  if(x0 > x1) {
+    swap(&x0,&x1);
+    swap(&y0,&y1);
+  }
+
+  float dx = x1-x0;
+  float dy = y1-y0;
+  float m;
+  if(dx == 0.0f)
+    m = 1;
+  else
+    m = dy/dx;
+
+  int xpxl1 = x0;
+  int xpxl2 = x1;
+  float intersect_y = y0;
+
+  steep = 1;
+  if(steep) {
+    int x;
+    for(x = xpxl1; x <= xpxl2; x++) {
+      add_pixel(pxmap,
+                (int)intersect_y, x,
+                1 - fract_part(intersect_y)
+               );
+      add_pixel(pxmap,
+                (int)intersect_y - 1, x,
+                fract_part(intersect_y)
+               );
+      intersect_y += m;
+    }
+  } else { // not steep
+    int x;
+    for(x = xpxl1; x <= xpxl2; x++) {
+      add_pixel(pxmap,
+                x, (int)intersect_y,
+                1 - fract_part(intersect_y)
+               );
+      add_pixel(pxmap,
+                x, (int)intersect_y - 1,
+                fract_part(intersect_y)
+               );
+      intersect_y += m;
+    }
+  }
+}
+
+void init_pxmap(char pxmap[rows][cols]) { // initialize pixelmap with spaces
+  for(int i=0; i<rows; i++) {
+    for(int j=0; j<cols; j++) {
+      pxmap[i][j] = ' ';
+    }
+  }
+}
+

librenderer.h

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+#ifndef LIBRENDERER_H
+#define LIBRENDERER_H
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <math.h>
+#include <stdint.h>
+
+#include "config.h"
+
+void swap(int* a, int* b);
+float fract_part(float x);
+char opacity2ch(float opac);
+void add_pixel(char pxmap[rows][cols], int x, int y, float opac);
+void render_pixelmap(char pxmap[rows][cols]);
+void mkline(char pxmap[rows][cols], int x0, int y0, int x1, int y1);
+void init_pxmap(char pxmap[rows][cols]);
+
+#endif

util.c

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+#define _POSIX_C_SOURCE 200112L
+
+#include "util.h"
+
+uint32_t randint(uint32_t min, uint32_t max) {
+  return randombytes_uniform(max-min) + min;
+}
+
+float randfloat(float min, float max) {
+  max = max*1000; min = min*1000;
+  return (randombytes_uniform(max-min) + min) / 1000;
+}
+

util.h

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+#define _POSIX_C_SOURCE 200112L
+#ifndef UTIL_H
+#define UTIL_H
+#include <sodium.h>
+
+uint32_t randint(uint32_t min, uint32_t max);
+float randfloat(float min, float max);
+
+#endif