sub pixel rendering

config.h

@@ -3,12 +3,12 @@
 #define CONFIG_H_
 
 
-#define ON 'x'
+#define ON '#'
 #define OFF ' '
 #define HEIGHT 100
 #define WIDTH 100
 #define FRAMERATE 60
 #define GRAVITY 15.0f
-#define LINENUMBERS 1
+#define LINENUMBERS 0
 
 #endif

graphics.c

@@ -3,6 +3,7 @@
 #include <string.h>
 #include <stdio.h>
 #include "config.h"
+#include <locale.h>
 
 #define uint unsigned int
 
@@ -19,6 +20,7 @@ void clear();
 void render(Canvas* c);
 void line(Canvas* c, uint start_x, uint start_y, uint end_x, uint end_y);
 void dot(Canvas* c, const uint x, const uint y);
+void subpixel(int m1, int m2, int n1, int n2);
 
 
 /*
@@ -49,6 +51,34 @@ void render(Canvas* c){
 }
 
 
+/*
+ *	Renders canvas with subpixel rendering
+ * */
+void subpixel_render(Canvas* c){
+	setlocale(LC_ALL, "C.UTF-8");
+	clear();
+	putchar('\n');
+
+	for(int i=0; i < c->y; i+=2){
+#if LINENUMBERS
+		printf("%2i ", i*2); // horizontal line numbers
+#endif
+		for(int j=0; j < c->x; j+=2){
+			subpixel( 	c->data[i*(c->x) + j] == ON,     c->data[i*(c->x) + j+1] == ON,
+						c->data[(i+1)*(c->x) + j] == ON, c->data[(i+1)*(c->x) + j+1] == ON);
+		}
+		putchar('\n');
+	}
+
+#if 0
+	// vertical line numbers
+	for(int i=0; i<(c->x) / 2; i+=2){
+		printf("  %2i", i*2);
+	}
+#endif
+}
+
+
 /*
  * Sets pixel at x,y to ON
  */
@@ -100,9 +130,33 @@ void line(Canvas* c, uint start_x, uint start_y, uint end_x, uint end_y){
 }
 
 
-//TODO: find escape sequence for clearing screen
+/*
+ * Clears terminal (for ANSI like terminal emulation)
+ */
 void clear(){
 	printf("\033[2;2H");	
-	//printf("function clear() not implemented yet");
+}
+
+/*
+ * Print 4 pixels as unicode character
+ * pixel arrangement is like this:
+ * m1,m2           1  0
+ * n1,n2, example: 0  1  =  '▚'
+ */
+void subpixel(int m1, int m2, int n1, int n2){	
+	const wchar_t *quads[] = 
+	{
+	/*       00,  01,  10,  11*/
+	/*00*/	L" ", L"▝", L"▘", L"▀",
+	/*01*/	L"▗", L"▐", L"▚", L"▜",
+	/*10*/	L"▖", L"▞", L"▌", L"▛",
+	/*11*/	L"▄", L"▟", L"▙", L"█",
+	};
+
+	int x = !!m2 + (!!m1<<1); 
+	int y = !!n2 + (!!n1<<1);
+
+	printf("%ls", quads[y*4 + x]);
+	printf("%s", "" );
 }
 

graphics.h

@@ -10,6 +10,7 @@ typedef struct Canvas {
 
 void clear();
 void render(Canvas*);
+void subpixel_render(Canvas*);
 void line(Canvas*, unsigned int, unsigned int, unsigned int, unsigned int);
 void dot(Canvas*, const unsigned int, const unsigned int);
 

physics.c

@@ -43,31 +43,24 @@ void update_link(Link* l);
  * Main
  */
 int main(){
-#if 0
-	Point a = {0, 0};
-	Point b = {10, 10};
-	unit_vec(&a, &b);
-#endif
-
-#if 1
 	char *data = malloc(WIDTH*HEIGHT);
 	Canvas cnv = {WIDTH, HEIGHT, data};
 
 	// Add 4 points, link them, and add points and links to respective arrays
-	Point a = { 10.0, 10.0,
-				11.0, 10.0, 
+	Point a = { 20.0, 10.0,
+				21.0, 10.0, 
 				0.0, GRAVITY/(FRAMERATE*FRAMERATE)};
 
-	Point b = { 20.0, 10.0,
-				20.0, 10.0,
+	Point b = { 40.0, 10.0,
+				40.0, 10.0,
 				0.0, GRAVITY/(FRAMERATE*FRAMERATE)};
 
-	Point c = { 20.0, 20.0,
-				19.0, 20.0,
+	Point c = { 40.0, 30.0,
+				39.0, 30.0,
 				0.0, GRAVITY/(FRAMERATE*FRAMERATE)};
 
-	Point d = { 10.0, 20.0,
-				10.0, 20.0,
+	Point d = { 20.0, 30.0,
+				20.0, 30.0,
 				0.0, GRAVITY/(FRAMERATE*FRAMERATE)};
 
 	Link *l_ab = link_points(&a, &b);
@@ -98,10 +91,9 @@ int main(){
 		}
 
 		// then render and wait
-		render(&cnv);
+		subpixel_render(&cnv);
 		usleep(1000000/FRAMERATE);
 	}
-#endif
 
 	return 0;
 }