Curve subdivision!

main.c

@@ -26,7 +26,7 @@
 
 #define PER_PIXEL 0
 #define PER_ROW 0
-#define DEBUG_SHOW_POINTS 1
+#define DEBUG_SHOW_POINTS 0
 
 /*
 int total_hits = 0;
@@ -408,8 +408,8 @@ render_glyph(struct glyph g, struct line_contour *lines,
     
     int x0 = 0; // g.xmin * scale;
     
-    int gwidth  = (g.xmax - g.xmin) * scale + 2;
+    int gwidth  = (g.xmax - g.xmin) * scale;
-    int gheight = (g.ymax - g.ymin) * scale + 2;
+    int gheight = (g.ymax - g.ymin) * scale + 1;
     
     pixels = pixels + width * 100 + 100;
     
@@ -480,6 +480,7 @@ outline_to_lines(struct glyph g, f32 scale, struct line_contour *dest, int *cnt)
 {
     int nlines = 0;
     int points_from = 0;
+    int curve_segments = 5;
     
     for (int c = 0; c < g.ncontours; ++c) {
         for (int p = points_from; p < g.end_pts_of_contours[c] + 1; ++p) {
@@ -513,22 +514,43 @@ outline_to_lines(struct glyph g, f32 scale, struct line_contour *dest, int *cnt)
                 f32 x3 = (nextnextgp.x - g.xmin) * scale;
                 f32 y3 = nextnextgp.y * scale;
                 
-                if (gp.y != nextgp.y) {
+                /* P(t) = P0*t^2 + P1*2*t*(1-t) + P2*(1-t)^2 */
-                    if (dest->data) {
+                f32 t_step = 1.0f / curve_segments;
-                        dest->data[nlines].a = (struct v2f) { x1, y1 };
+                f32 x_prev = x1;
-                        dest->data[nlines].b = (struct v2f) { x2, y2 };
+                f32 y_prev = y1;
-                    }
+                
-                    ++nlines;
+                /* s = 1 for exact beginning */
+                for (int s = 1; s <= curve_segments; ++s) {
+                    f32 t_now = t_step * s;
+                    f32 x_now;
+                    f32 y_now;
+                    
+                    if (s < curve_segments) {
+                        x_now = x3 * t_now * t_now 
+                            + x2 * 2.0f * t_now * (1.0f - t_now) 
+                            + x1 * (1.0f - t_now) * (1.0f - t_now);
+                        
+                        y_now = y3 * t_now * t_now 
+                            + y2 * 2.0f * t_now * (1.0f - t_now) 
+                            + y1 * (1.0f - t_now) * (1.0f - t_now);
+                    } else {
+                        /* For exact match between neighbours */
+                        x_now = x3;
+                        y_now = y3;
                     }
                     
-                if (nextgp.y != nextnextgp.y) {
+                    if (abs_f32(y_now - y_prev) > F32EPS) {
                         if (dest->data) {
-                        dest->data[nlines].a = (struct v2f) { x2, y2 };
+                            dest->data[nlines].a = (struct v2f) { x_prev, y_prev };
-                        dest->data[nlines].b = (struct v2f) { x3, y3 };
+                            dest->data[nlines].b = (struct v2f) { x_now, y_now };
                         }
                         ++nlines;
                     }
                     
+                    x_prev = x_now;
+                    y_prev = y_now;
+                }
+                
                 ++p;
             }
         }
@@ -604,11 +626,11 @@ main(int argc, char **argv)
     printf("Loaded font\n");
     
     //struct glyph g = get_outline(&font, 0x046C);
-    int codepoint = 0x0431;
+    int codepoint = 0x0020;
     struct glyph g = get_outline(&font, codepoint);
     int nlines = 0;
     
-    u32 px_size = 120;
+    u32 px_size = 20;
     u32 *pixels = hc_vram;
     int t = 0;
     
@@ -629,7 +651,7 @@ main(int argc, char **argv)
         render_glyph(g, &lines, font, px_size, pixels, width, height);
         XPutImage(display, window, default_gc, xwindow_buffer, 0, 0, 0, 0, width, height);
         
-#if 0
+#if 1
         //printf("%d\n", px_size);
         ++px_size;