From: Michael Georgoulopoulos <mgeorgoulopoulos@gmail.com>
Date: Fri, 2 Sep 2016 21:23:10 +0000 (+0300)
Subject: Added normalmap + parallax scrolling
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=dosdemo;a=commitdiff_plain;h=c78787f699686cb064504ae8a83844afeb388040

Added normalmap + parallax scrolling
---

diff --git a/src/mike.c b/src/mike.c
index cf1ed73..411592a 100644
--- a/src/mike.c
+++ b/src/mike.c
@@ -12,6 +12,14 @@
 #define MIN_SCROLL 32
 #define MAX_SCROLL (backgroundW - fb_width - MIN_SCROLL)
 
+#define FAR_SCROLL_SPEED 50.0f
+#define NEAR_SCROLL_SPEED 400.0f
+
+#define HORIZON_HEIGHT 100
+#define REFLECTION_HEIGHT (240 - HORIZON_HEIGHT)
+
+#define NORMALMAP_SCANLINE 372
+
 static int init(void);
 static void destroy(void);
 static void start(long trans_time);
@@ -19,11 +27,22 @@ static void stop(long trans_time);
 static void draw(void);
 
 static void convert32To16(unsigned int *src32, unsigned short *dst16, unsigned int pixelCount);
+static void processNormal();
+static void initScrollTables();
+static void updateScrollTables(float dt);
 
 static unsigned short *background = 0;
 static unsigned int backgroundW = 0;
 static unsigned int backgroundH = 0;
 
+static unsigned int lastFrameTime = 0;
+static float lastFrameDuration = 0.0f;
+
+static float scrollSpeedTable[REFLECTION_HEIGHT];
+static float scrollTable[REFLECTION_HEIGHT];
+static int scrollTableRounded[REFLECTION_HEIGHT];
+static int scrollModTable[REFLECTION_HEIGHT];
+
 static struct screen scr = {
 	"mike",
 	init,
@@ -47,7 +66,11 @@ static int init(void)
 	}
 
 	/* Convert to 16bpp */
-	convert32To16((unsigned int*)background, background, backgroundW * backgroundH);
+	convert32To16((unsigned int*)background, background, backgroundW * NORMALMAP_SCANLINE); /* Normalmap will keep its 32 bit color */
+
+	processNormal();
+
+	initScrollTables();
 
 	return 0;
 }
@@ -59,7 +82,7 @@ static void destroy(void)
 
 static void start(long trans_time)
 {
-
+	lastFrameTime = time_msec;
 }
 
 static void stop(long trans_time)
@@ -70,15 +93,30 @@ static void draw(void)
 {	
 	int scroll = MIN_SCROLL + (MAX_SCROLL - MIN_SCROLL) * mouse_x / fb_width;
 	unsigned short *dst = fb_pixels;
-	unsigned short *src = background + 2 * scroll;
+	unsigned short *src = background + scroll;
 	int scanline = 0;
-	
+	int i = 0;
+
+	lastFrameDuration = (time_msec - lastFrameTime) / 1000.0f;
+	lastFrameTime = time_msec;
 
 	for (scanline = 0; scanline < fb_height; scanline++) {
 		memcpy(dst, src, fb_width * 2);
 		src += backgroundW;
 		dst += fb_width;
 	}
+	
+	updateScrollTables(lastFrameDuration);
+
+	dst = fb_pixels;
+	dst += 100 * fb_width;
+	src = background + NORMALMAP_SCANLINE * backgroundW * 2;
+	for (scanline = 0; scanline < REFLECTION_HEIGHT; scanline++) {
+		for (i = 0; i < fb_width; i++) {
+			*dst++ = src[(i + scrollTableRounded[scanline]) % scrollModTable[scanline]];
+		}
+		src += backgroundW;
+	}
 }
 
 /* src and dst can be the same */
@@ -93,4 +131,45 @@ static void convert32To16(unsigned int *src32, unsigned short *dst16, unsigned i
 	}
 }
 
+/* Normal map preprocessing */
+/* Scale normal with depth and unpack R component (horizontal component) */
+static void processNormal() {
+	int scanline;
+	unsigned int *normalmap = (unsigned int*)background;
+	normalmap += NORMALMAP_SCANLINE * backgroundW;
+	unsigned short *dst = normalmap;
+	float scale;
+	int i;
+	int x;
+
+	for (scanline = 0; scanline < REFLECTION_HEIGHT; scanline++) {
+		scale = 2.0f - (float)scanline / ((float)REFLECTION_HEIGHT - 1);
+		scrollModTable[scanline] = (int) (backgroundW / scale + 0.5f);
+		for (i = 0; i < backgroundW; i++) {
+			x = (int)(i * scale + 0.5f);
+			*dst++ = x < backgroundW ? normalmap[x] & 0xFF : 0;
+		}
+		normalmap += backgroundW;
+	}
+}
+
+static void initScrollTables() {
+	int i = 0;
+	float scrollSpeed = FAR_SCROLL_SPEED;
+	float speedIncrement = (NEAR_SCROLL_SPEED - FAR_SCROLL_SPEED) / ((float) (REFLECTION_HEIGHT - 1));
+	for (i = 0; i < REFLECTION_HEIGHT; i++) {
+		scrollSpeedTable[i] = scrollSpeed;
+		scrollSpeed += speedIncrement;
+		scrollTable[i] = 0.0f;
+		scrollTableRounded[i] = 0;
+	}
+}
 
+
+static void updateScrollTables(float dt) {
+	int i = 0;
+	for (i = 0; i < REFLECTION_HEIGHT; i++) {
+		scrollTable[i] += scrollSpeedTable[i] * dt;
+		scrollTableRounded[i] = (int)(scrollTable[i] + 0.5f) % scrollModTable[i];
+	}
+}
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