X-Git-Url: https://jasonwoof.com/gitweb/?a=blobdiff_plain;ds=sidebyside;f=dust.c;fp=dust.c;h=691649d412b821b42f83766a3af059a361b6a4c3;hb=841f94c4182f8dff0253db9bae4922c3c9039a5f;hp=0000000000000000000000000000000000000000;hpb=3ef599c7104a20c4f5268dbefb6590aa3e285663;p=vor.git

diff --git a/dust.c b/dust.c
new file mode 100644
index 0000000..691649d
--- /dev/null
+++ b/dust.c
@@ -0,0 +1,51 @@
+#include <SDL.h>
+#include <math.h>
+
+#include "config.h"
+#include "globals.h"
+#include "dust.h"
+#include "mt.h"
+
+struct dust_mote {
+	float x,y,z;
+	Uint16 color;
+};
+
+struct dust_mote motes[N_DUST_MOTES];
+
+void
+init_dust(void)
+{
+	int i, b;
+	for(i=0; i<N_DUST_MOTES; i++) {
+		motes[i].x = frnd()*(XSIZE-5);
+		motes[i].y = frnd()*(YSIZE-5);
+		motes[i].z = MAX_DUST_DEPTH*sqrt(frnd());
+		b = (MAX_DUST_DEPTH - motes[i].z) * 255.0 / MAX_DUST_DEPTH;
+		motes[i].color = SDL_MapRGB(surf_screen->format, b, b, b);
+	}
+}
+
+void
+move_dust(void)
+{
+	int i;
+	for(i=0; i<N_DUST_MOTES; i++) {
+		motes[i].x -= xscroll / (1.3 + motes[i].z);
+		motes[i].y -= yscroll / (1.3 + motes[i].z);
+		if(motes[i].y >= XSIZE) motes[i].x -= XSIZE;
+		else if(motes[i].x < 0) motes[i].x += XSIZE;
+		if(motes[i].y > YSIZE) motes[i].y -= YSIZE;
+		else if(motes[i].y < 0) motes[i].y += YSIZE;
+	}
+}
+
+void
+draw_dust(SDL_Surface *s)
+{
+	int i;
+	uint16_t *pixels = s->pixels;
+	for(i=0; i<N_DUST_MOTES; i++) {
+		pixels[s->pitch/2*(int)motes[i].y + (int)motes[i].x] = motes[i].color;
+	}
+}