horizontal scrolling

diff --git a/globals.h b/globals.h
index ae1bb1c..35c77f5 100644 (file)
--- a/globals.h
+++ b/globals.h
@@ -26,7 +26,7 @@ struct enginedots {
 struct spacedot {
        // Space dots are harmless background items
        // All are active. When one falls off the edge, another is created at the start.
-       float x,y,dx;
+       float x,y,z;
        Uint16 color;
 };
 
@@ -61,6 +61,7 @@ extern struct shape shipshape;
 extern float shipx,shipy;      // X position, 0..XSIZE
 extern float shipdx,shipdy;    // Change in X position per tick.
 extern float screendx, screendy;
+extern float xscroll, yscroll;
 extern float gamerate;  // this controls the speed of everything that moves.
 extern float yscroll;
 extern float scrollvel;

diff --git a/main.c b/main.c
index bd0c158..6b575bd 100644 (file)
--- a/main.c
+++ b/main.c
@@ -68,7 +68,7 @@ char topline[1024];
 char *initerror = "";
 
 struct shape shipshape;
-float shipx,shipy = 240.0;     // X position, 0..XSIZE
+float shipx = 320.0, shipy = 240.0;    // X position, 0..XSIZE
 float shipdx,shipdy;   // Change in X position per tick.
 float screendx = 7.5, screendy = 0.0;
 float xscroll, yscroll;
@@ -128,25 +128,18 @@ init_engine_dots() {
 
 void
 init_space_dots() {
-       int i,intensity;
+       int i,b;
        for(i = 0; i<MAXSPACEDOTS; i++) {
-               float r;
-
                sdot[i].x = rnd()*(XSIZE-5);
                sdot[i].y = rnd()*(YSIZE-5);
-
-               r = rnd()*rnd();
-
-               sdot[i].dx = -r*4;
-               // -1/((1-r) + .3);
-               intensity = (int)(r*180 + 70);
-               sdot[i].color = SDL_MapRGB(surf_screen->format,intensity,intensity,intensity);
-
+               sdot[i].z = 4*rnd();
+               b = (4 - sdot[i].z) * 255.0 / 4;
+               sdot[i].color = SDL_MapRGB(surf_screen->format, b, b, b);
        }
 }
 
 void
-makebangdots(int xbang, int ybang, int dx, int dy, SDL_Surface *s, int power) {
+make_bang_dots(int xbang, int ybang, int dx, int dy, SDL_Surface *s, int power) {
 
        // TODO - stop generating dots after a certain amount of time has passed, to cope with slower CPUs.
        // TODO - generate and display dots in a circular buffer
@@ -226,8 +219,8 @@ draw_bang_dots(SDL_Surface *s) {
                        //last_i = i + 1;
                        rawpixel[(int)(s->pitch/2*(int)(bdot[i].y)) + (int)(bdot[i].x)] = bdot[i].c ? bdot[i].c : heatcolor[(int)(bdot[i].life*3)];
                        bdot[i].life -= bdot[i].decay;
-                       bdot[i].x += bdot[i].dx*gamerate;
-                       bdot[i].y += bdot[i].dy*gamerate-yscroll;
+                       bdot[i].x += bdot[i].dx*gamerate - xscroll;
+                       bdot[i].y += bdot[i].dy*gamerate - yscroll;
 
                        if(bdot[i].life<0)
                        bdot[i].active = 0;
@@ -257,16 +250,12 @@ draw_space_dots(SDL_Surface *s) {
                        sdot[i].y = 0;
                }
                rawpixel[(int)(s->pitch/2*(int)sdot[i].y) + (int)(sdot[i].x)] = sdot[i].color;
-               sdot[i].x += sdot[i].dx*gamerate;
-               sdot[i].y -= yscroll;
-               if(sdot[i].y > YSIZE) {
-                       sdot[i].y -= YSIZE;
-               } else if(sdot[i].y < 0) {
-                       sdot[i].y += YSIZE;
-               }
-               if(sdot[i].x<0) {
-                       sdot[i].x = XSIZE;
-               }
+               sdot[i].x -= xscroll / (1 + sdot[i].z);
+               sdot[i].y -= yscroll / (1 + sdot[i].z);
+               if(sdot[i].y >= XSIZE) sdot[i].x -= XSIZE;
+               else if(sdot[i].x < 0) sdot[i].x = XSIZE-1;
+               if(sdot[i].y > YSIZE) sdot[i].y -= YSIZE;
+               else if(sdot[i].y < 0) sdot[i].y += YSIZE-1;
        }
 }
 
@@ -278,7 +267,7 @@ draw_engine_dots(SDL_Surface *s) {
 
        for(i = 0; i<MAXENGINEDOTS; i++) {
                if(edot[i].active) {
-                       edot[i].x += edot[i].dx*gamerate;
+                       edot[i].x += edot[i].dx*gamerate - xscroll;
                        edot[i].y += edot[i].dy*gamerate - yscroll;
                        if((edot[i].life -= gamerate*3)<0 || edot[i].y<0 || edot[i].y>YSIZE) {
                                edot[i].active = 0;
@@ -738,15 +727,23 @@ gameloop() {
 
                        // SCROLLING
                        tmp = shipy - (YSIZE / 2);
-                       tmp += 25 * shipdy;
+                       tmp += shipdy * 25;
                        tmp /= -25;
                        tmp = ((screendy * (gamerate - 12)) + (tmp * gamerate)) / 12;
                        screendy = -tmp;
+                       if(state == GAMEPLAY) {
+                               tmp = shipx - (XSIZE / 2);
+                               tmp += shipdx * 25;
+                               tmp /= -25;
+                               tmp = ((screendx * (gamerate - 12)) + (tmp * gamerate)) / 12;
+                               screendx = -tmp;
+                       } else screendx = 7.5;
+
                        xscroll = screendx * gamerate;
                        yscroll = screendy * gamerate;
 
                        // INERTIA
-                       shipx += shipdx*gamerate;
+                       shipx += shipdx*gamerate - xscroll;
                        shipy += shipdy*gamerate - yscroll;
                        
                        move_rocks();
@@ -770,8 +767,8 @@ gameloop() {
                        if(draw() && state == GAMEPLAY) {
                                // Play the explosion sound
                                play_sound(0);
-                               makebangdots(shipx,shipy,shipdx,shipdy,surf_ship,30);
-                               shipdx = 0;
+                               make_bang_dots(shipx,shipy,shipdx,shipdy,surf_ship,30);
+                               shipdx = screendx;
                                shipdy = 0;
                                if(--nships <= 0) {
                                        gameover = 1;
@@ -800,9 +797,9 @@ gameloop() {
                                play_tune(1);
 
                                gameover = 0;
-                               shipx = 0;
+                               shipx = 2*XSIZE/3;
                                shipy = YSIZE/2;
-                               shipdx = -1;
+                               shipdx = screendx;
                                shipdy = 0;
                        }
 

diff --git a/rocks.c b/rocks.c
index 2a9c906..5653979 100644 (file)
--- a/rocks.c
+++ b/rocks.c
@@ -107,7 +107,6 @@ new_rocks(void)
 {
        int i,j;
        float ti[4];
-       float x, y;
 
        rock_timer_increments(ti);
 
@@ -143,16 +142,8 @@ new_rocks(void)
                                                break;
                                }
 
-                               j=0;
-                               do {
-                                       rockptr->dx = RDX*crnd();
-                                       rockptr->dy = RDY*crnd();
-                                       x = (rockptr->dx-screendx)*gamerate;
-                                       y = (rockptr->dy-screendy)*gamerate;
-                                       j++;
-                               } while(x < -rockptr->image->w || x >= XSIZE
-                                               || y < -rockptr->image->h || y >= YSIZE);
-                               if(j > 1) fprintf(stderr, "had to try %d times.\n", j);
+                               rockptr->dx = RDX*crnd();
+                               rockptr->dy = RDY*crnd();
 
                                rockptr->active = 1;
                        }