--- /dev/null
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <ctype.h>
+#include <cgmath/cgmath.h>
+#include "logo.h"
+
+struct cpnode {
+ cgm_vec2 p;
+ struct cpnode *next;
+};
+
+#define CPLERP(res, a, b, t) \
+ do { \
+ (res).x = (a).x + ((b).x - (a).x) * (t); \
+ (res).y = (a).y + ((b).y - (a).y) * (t); \
+ } while(0)
+
+static cgm_vec2 *cp;
+static int numcp;
+
+int init_logo(const char *fname)
+{
+ FILE *fp;
+ char buf[256];
+ struct cpnode *cpn, *cplist = 0, *cptail = 0;
+ int idx;
+
+ if(!(fp = fopen(fname, "rb"))) {
+ fprintf(stderr, "failed to load logo curve: %s\n", fname);
+ return -1;
+ }
+ fgets(buf, sizeof buf, fp);
+ if(memcmp(buf, "GCURVES", 7) != 0) {
+ fprintf(stderr, "invalid logo file: %s\n", fname);
+ fclose(fp);
+ return -1;
+ }
+
+ numcp = 0;
+ while(fgets(buf, sizeof buf, fp)) {
+ char *ptr;
+ cgm_vec2 v;
+
+ ptr = buf;
+ while(*ptr && isspace(*ptr)) ptr++;
+
+ if(sscanf(ptr, "cp %f %f", &v.x, &v.y) == 2) {
+ if(!(cpn = malloc(sizeof *cpn))) {
+ continue;
+ }
+
+ cpn->p.x = v.x;
+ cpn->p.y = v.y;
+ cpn->next = 0;
+
+ if(cplist) {
+ cptail->next = cpn;
+ cptail = cpn;
+ } else {
+ cplist = cptail = cpn;
+ }
+ numcp++;
+ }
+ }
+ fclose(fp);
+
+ if(numcp < 4) {
+ fprintf(stderr, "invalid logo file, found %d control points\n", numcp);
+ return -1;
+ }
+
+ if(!(cp = malloc(numcp * sizeof *cp))) {
+ fprintf(stderr, "failed to allocate curve of %d control points\n", numcp);
+ while(cplist) {
+ cpn = cplist;
+ cplist = cplist->next;
+ free(cpn);
+ }
+ return -1;
+ }
+
+ idx = 0;
+ while(cplist) {
+ cpn = cplist;
+ cplist = cplist->next;
+ cp[idx++] = cpn->p;
+ free(cpn);
+ }
+
+ return 0;
+}
+
+static void eval_seg(float *res, int a, int b, float t)
+{
+ int prev, next;
+
+ if(numcp == 2) {
+ res[0] = cp[a].x + (cp[b].x - cp[a].x) * t;
+ res[1] = cp[a].y + (cp[b].y - cp[a].y) * t;
+ return;
+ }
+
+ prev = a <= 0 ? a : a - 1;
+ next = b >= numcp - 1 ? b : b + 1;
+
+ res[0] = cgm_bspline(cp[prev].x, cp[a].x, cp[b].x, cp[next].x, t);
+ res[1] = cgm_bspline(cp[prev].y, cp[a].y, cp[b].y, cp[next].y, t);
+}
+
+void eval_logo(float *res, float t)
+{
+ int idx0, idx1;
+ float t0, t1, dt;
+
+ if(!cp || numcp <= 0) {
+ res[0] = res[1] = 0;
+ return;
+ }
+ if(numcp == 1) {
+ res[0] = cp[0].x;
+ res[1] = cp[0].y;
+ return;
+ }
+
+ if(t < 0.0f) t = 0.0f;
+ if(t > 1.0f) t = 1.0f;
+
+ idx0 = (int)floor(t * (numcp - 1));
+ if(idx0 > numcp - 2) idx0 = numcp - 2;
+ idx1 = idx0 + 1;
+
+ dt = 1.0f / (float)(numcp - 1);
+ t0 = (float)idx0 * dt;
+ t1 = (float)idx1 * dt;
+ t = (t - t0) / (t1 - t0);
+
+ eval_seg(res, idx0, idx1, t);
+}