X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=censuslogo;a=blobdiff_plain;f=src%2Flogo.c;fp=src%2Flogo.c;h=b36473d2b4ba8803d930d35083f5b436fe8e7d3f;hp=0000000000000000000000000000000000000000;hb=0dd87713321a351d6f14167c35ff6e3afcfe8ac4;hpb=fc0cfd2c7c9f5efddddb21fc94a15cc42685ca1d

diff --git a/src/logo.c b/src/logo.c
new file mode 100644
index 0000000..b36473d
--- /dev/null
+++ b/src/logo.c
@@ -0,0 +1,140 @@
+#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);
+}