Added intermediate buffer to be able to alter the reflected image before applying...

diff --git a/src/mike.c b/src/mike.c
index 333a4aa..5ab5276 100644 (file)
--- a/src/mike.c
+++ b/src/mike.c
@@ -11,7 +11,12 @@
 
 #define BG_FILENAME "data/grise.png"
 
-#define MIN_SCROLL 32
+#define BB_SIZE 512    /* Let's use a power of 2. Maybe we'll zoom/rotate the effect */
+
+/* Every backBuffer scanline is guaranteed to have that many dummy pixels before and after */
+#define PIXEL_PADDING 32
+
+#define MIN_SCROLL PIXEL_PADDING
 #define MAX_SCROLL (backgroundW - fb_width - MIN_SCROLL)
 
 #define FAR_SCROLL_SPEED 50.0f
@@ -42,6 +47,8 @@ static float lastFrameDuration = 0.0f;
 
 static short *displacementMap;
 
+static unsigned short *backBuffer;
+
 static float scrollScaleTable[REFLECTION_HEIGHT];
 static float scrollTable[REFLECTION_HEIGHT];
 static int scrollTableRounded[REFLECTION_HEIGHT];
@@ -65,6 +72,9 @@ struct screen *mike_screen(void)
 
 static int init(void)
 {
+       /* Allocate back buffer */
+       backBuffer = (unsigned short*) malloc(BB_SIZE * BB_SIZE * sizeof(unsigned short));
+
        if (!(background = img_load_pixels(BG_FILENAME, &backgroundW, &backgroundH, IMG_FMT_RGBA32))) {
                fprintf(stderr, "failed to load image " BG_FILENAME "\n");
                return -1;
@@ -82,7 +92,10 @@ static int init(void)
 
 static void destroy(void)
 {
-       //img_free_pixels(background);
+       free(backBuffer);
+       backBuffer = 0;
+
+       img_free_pixels(background);
 }
 
 static void start(long trans_time)
@@ -97,34 +110,47 @@ static void stop(long trans_time)
 static void draw(void)
 {      
        int scroll = MIN_SCROLL + (MAX_SCROLL - MIN_SCROLL) * mouse_x / fb_width;
-       unsigned short *dst = fb_pixels;
+       unsigned short *dst = backBuffer + PIXEL_PADDING;
        unsigned short *src = background + scroll;
        int scanline = 0;
        int i = 0;
-       short *disp;
+       short *dispScanline;
        int d;
 
        lastFrameDuration = (time_msec - lastFrameTime) / 1000.0f;
        lastFrameTime = time_msec;
 
-       for (scanline = 0; scanline < fb_height; scanline++) {
+       /* First, render the horizon */
+       for (scanline = 0; scanline < HORIZON_HEIGHT; scanline++) {
                memcpy(dst, src, fb_width * 2);
                src += backgroundW;
-               dst += fb_width;
+               dst += BB_SIZE;
        }
        
+       /* Create scroll opffsets for all scanlines of the normalmap */
        updateScrollTables(lastFrameDuration);
 
-       dst = (unsigned short*) fb_pixels + HORIZON_HEIGHT * fb_width;
+       /* Then, render the reflection under the horizon */
+       /* dst is already in place */
        src = background + HORIZON_HEIGHT * backgroundW;
-       disp = displacementMap;
+       dispScanline = displacementMap;
        for (scanline = 0; scanline < REFLECTION_HEIGHT; scanline++) {
                for (i = 0; i < fb_width; i++) {
-                       d = disp[(i + scrollTableRounded[scanline]) % scrollModTable[scanline]];
+                       d = dispScanline[(i + scrollTableRounded[scanline]) % scrollModTable[scanline]];
                        *dst++ = src[i + scroll + d];
                }
                src += backgroundW;
-               disp += backgroundW;
+               dst += BB_SIZE - fb_width;
+               dispScanline += backgroundW;
+       }
+
+       /* Blit effect to framebuffer */
+       src = backBuffer + PIXEL_PADDING;
+       dst = fb_pixels;
+       for (scanline = 0; scanline < fb_height; scanline++) {
+               memcpy(dst, src, fb_width * 2);
+               src += BB_SIZE;
+               dst += fb_width;
        }
 }