X-Git-Url: https://jasonwoof.com/gitweb/?p=vor.git;a=blobdiff_plain;f=shape.c;fp=shape.c;h=9d0501c24485ae6539af2c340b2daf1efee38fc6;hp=0000000000000000000000000000000000000000;hb=8193e09e49bc571f9c61e6e3adf45010271c08d5;hpb=05bfe1eca8ec4981dc087a97b7dfaa74eb1de59e

diff --git a/shape.c b/shape.c
new file mode 100644
index 0000000..9d0501c
--- /dev/null
+++ b/shape.c
@@ -0,0 +1,63 @@
+#include <stdlib.h>
+#include "shape.h"
+
+void
+get_shape(SDL_Surface *img, struct shape *s)
+{
+	int x, y;
+	uint16_t *px, transp;
+	uint32_t bits;
+
+	if(img->format->BytesPerPixel != 2) {
+		fprintf(stderr, "get_shape(): not a 16-bit image!\n");
+		exit(1);
+	}
+
+	s->w = img->w; s->h = img->h;
+	s->mw = ((img->w+31)>>5) * img->h;
+	s->mask = malloc(4*s->mw);
+	if(!s->mask) {
+		fprintf(stderr, "can't malloc bitmask");
+		exit(1);
+	}
+
+	SDL_LockSurface(img);
+	px = img->pixels;
+	transp = img->format->colorkey;
+	bits = 0;
+	for(y=0; y<img->h; y++) {
+		for(x=0; x<img->w; x++) {
+			if(*px++ != transp) bits |= 1;
+			if(x == img->w-1 || !(x+1)%32) {
+				*(s->mask++) = bits;
+				bits = 0;
+			} else bits = bits << 1;
+		}
+		px = (uint16_t *) ((uint8_t *) px + img->pitch - 2*img->w);
+	}
+	SDL_UnlockSurface(img);
+}
+
+#ifndef max
+#define max(a, b) ((a) > (b) ? (a) : (b))
+#endif
+
+#ifndef min
+#define min(a, b) ((a) < (b) ? (a) : (b))
+#endif
+
+int
+collide(int xdiff, int ydiff, struct shape *r, struct shape *s)
+{
+	int xov, yov;
+
+	if(xdiff >= 0) xov = max(min(r->w-xdiff, s->w), 0);
+	else xov = -max(min(s->w+xdiff, r->w), 0);
+
+	if(ydiff >= 0) yov = max(min(r->h-ydiff, s->h), 0);
+	else yov = -max(min(s->h+ydiff, r->h), 0);
+
+	if(xov == 0 && yov == 0) return 0;
+
+	return 0;
+}