126 lines
2.2 KiB
C
126 lines
2.2 KiB
C
#include <math.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#define uint unsigned int
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#define ON 'x'
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#define OFF '.'
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typedef struct Canvas {
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int x;
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int y;
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char* data;
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} Canvas;
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// Function Declarations
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void clear();
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void render(Canvas* c);
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void line(Canvas* c, uint start_x, uint start_y, uint end_x, uint end_y);
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void dot(Canvas* c, uint x, uint y);
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/*
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* main
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*/
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int main(){
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char *data = malloc(40*40);
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Canvas c = {40, 40, data};
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memset(c.data, OFF, c.x * c.y);
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//line(&c, 1, 1, 8, 8);
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//line(&c, 8, 8, 1, 1);
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//line(&c, 0, 5, 8, 8);
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line(&c, 8, 8, 35, 39);
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render(&c);
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return 0;
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}
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/*
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* Renders canvas* c on screen and adds line numbers on left and bottom
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*/
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void render(Canvas* c){
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clear();
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putchar('\n');
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for(int i=0; i < c->y; i++){
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printf("%2i ", i); //horizontal line numbers
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for(int j=0; j < c->x; j++){
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putchar(c->data[i*(c->x)+j]);
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putchar(' ');
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}
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putchar('\n');
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}
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// vertical line numbers
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printf(" ");
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for(int i=0; i<(c->x); i+=2){
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printf("%2i ", i);
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}
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}
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/*
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* Sets pixel at x,y to ON
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*/
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void dot(Canvas* c, uint x, uint y){
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c->data[ y*(c->x) + x] = ON;
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}
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/*
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* Draws a line from (start_x, start_y) to (end_x, end_y)
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* This is the naive line drawing algorithm and is sub-optimal due to the use of floating point calculations
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*/
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void line(Canvas* c, uint start_x, uint start_y, uint end_x, uint end_y){
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int dx = end_x - start_x;
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int dy = end_y - start_y;
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if (dx<0) dx *= -1;
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if (dy<0) dy *= -1;
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if((dx>=dy && start_x>end_x) || ( dx<dy && start_y>end_y)){
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int temp;
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temp = end_x;
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end_x = start_x;
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start_x = temp;
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temp = end_y;
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end_y = start_y;
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start_y = temp;
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}
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int direction_x = start_x < end_x ? 1 : -1;
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int direction_y = start_y < end_y ? 1 : -1;
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if(dx>=dy){
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float small = direction_y * (float)dy/(float)dx;
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for(int i=0; i<dx; i++){
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dot(c, start_x + i*direction_x, start_y + nearbyintf(i*small));
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}
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}else{
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float small = direction_x * (float)dx/(float)dy;
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for(int i=0; i<dy; i++){
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dot(c, start_x + nearbyintf(i*small), start_y + i*direction_y);
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}
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}
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dot(c, end_x, end_y);
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}
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//TODO: find escape sequence for clearing screen
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void clear(){
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printf("function clear() not implemented yet");
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}
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