+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <assert.h>
+#include "imago2.h"
+#include "demo.h"
+#include "screen.h"
+
+/* APPROX. 170 FPS Minimum */
+
+#define BG_FILENAME "data/grise.png"
+
+#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
+#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);
+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 short *displacementMap;
+
+static unsigned short *backBuffer;
+
+static float scrollScaleTable[REFLECTION_HEIGHT];
+static float scrollTable[REFLECTION_HEIGHT];
+static int scrollTableRounded[REFLECTION_HEIGHT];
+static int scrollModTable[REFLECTION_HEIGHT];
+static float nearScrollAmount = 0.0f;
+
+static struct screen scr = {
+ "Galaxy rise",
+ init,
+ destroy,
+ start,
+ stop,
+ draw
+};
+
+struct screen *grise_screen(void)
+{
+ return &scr;
+}
+
+
+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;
+ }
+
+ /* Convert to 16bpp */
+ convert32To16((unsigned int*)background, background, backgroundW * NORMALMAP_SCANLINE); /* Normalmap will keep its 32 bit color */
+
+ initScrollTables();
+
+ processNormal();
+
+#ifdef MIKE_PC
+ return 0xCAFE;
+#else
+ return 0;
+#endif
+}
+
+static void destroy(void)
+{
+ free(backBuffer);
+ backBuffer = 0;
+
+ img_free_pixels(background);
+}
+
+static void start(long trans_time)
+{
+ lastFrameTime = time_msec;
+}
+
+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 = backBuffer + PIXEL_PADDING;
+ unsigned short *src = background + scroll;
+ int scanline = 0;
+ int i = 0;
+ short *dispScanline;
+ int d;
+
+ lastFrameDuration = (time_msec - lastFrameTime) / 1000.0f;
+ lastFrameTime = time_msec;
+
+ /* First, render the horizon */
+ for (scanline = 0; scanline < HORIZON_HEIGHT; scanline++) {
+ memcpy(dst, src, fb_width * 2);
+ src += backgroundW;
+ dst += BB_SIZE;
+ }
+
+ /* Create scroll opffsets for all scanlines of the normalmap */
+ updateScrollTables(lastFrameDuration);
+
+ /* Then, render the reflection under the horizon */
+ /* dst is already in place */
+ src = background + HORIZON_HEIGHT * backgroundW;
+ dispScanline = displacementMap;
+ for (scanline = 0; scanline < REFLECTION_HEIGHT; scanline++) {
+ for (i = 0; i < fb_width; i++) {
+ d = dispScanline[(i + scrollTableRounded[scanline]) % scrollModTable[scanline]];
+ *dst++ = src[i + scroll + d];
+ }
+ src += 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;
+ }
+}
+
+/* src and dst can be the same */
+static void convert32To16(unsigned int *src32, unsigned short *dst16, unsigned int pixelCount) {
+ unsigned int p;
+ while (pixelCount) {
+ p = *src32++;
+ *dst16++ = ((p << 8) & 0xF800) /* R */
+ | ((p >> 5) & 0x07E0) /* G */
+ | ((p >> 19) & 0x001F); /* B */
+ pixelCount--;
+ }
+}
+
+/* Normal map preprocessing */
+/* Scale normal with depth and unpack R component (horizontal component) */
+static void processNormal() {
+ int scanline;
+ int i;
+ int x;
+ short maxDisplacement = 0;
+ short minDisplacement = 256;
+ unsigned short *dst;
+ short *dst2;
+ unsigned int *normalmap = (unsigned int*)background;
+ normalmap += NORMALMAP_SCANLINE * backgroundW;
+ dst = (unsigned short*)normalmap;
+ displacementMap = (short*)dst;
+ dst2 = displacementMap;
+
+ for (scanline = 0; scanline < REFLECTION_HEIGHT; scanline++) {
+ scrollModTable[scanline] = (int) (backgroundW / scrollScaleTable[scanline] + 0.5f);
+ for (i = 0; i < backgroundW; i++) {
+ x = (int)(i * scrollScaleTable[scanline] + 0.5f);
+ if (x < backgroundW) {
+ *dst = (unsigned short)(normalmap[x] >> 8) & 0xFF;
+ if ((short)*dst > maxDisplacement) maxDisplacement = (short)(*dst);
+ if ((short)*dst < minDisplacement) minDisplacement = (short)(*dst);
+ } else {
+ *dst = 0;
+ }
+ dst++;
+ }
+ normalmap += backgroundW;
+ }
+
+ if (maxDisplacement == minDisplacement) {
+ printf("Warning: grise normalmap fucked up\n");
+ return;
+ }
+
+ /* Second pass - subtract half maximum displacement to displace in both directions */
+ for (scanline = 0; scanline < REFLECTION_HEIGHT; scanline++) {
+ for (i = 0; i < backgroundW; i++) {
+ /* Remember that MIN_SCROLL is the padding around the screen, so ti's the maximum displacement we can get (positive & negative) */
+ *dst2 = 2 * MIN_SCROLL * (*dst2 - minDisplacement) / (maxDisplacement - minDisplacement) - MIN_SCROLL;
+ *dst2 = (short)((float)*dst2 / scrollScaleTable[scanline] + 0.5f); /* Displacements must also scale with distance*/
+ dst2++;
+ }
+ }
+}
+
+static float distanceScale(int scanline) {
+ float farScale, t;
+ farScale = (float)NEAR_SCROLL_SPEED / (float)FAR_SCROLL_SPEED;
+ t = (float)scanline / ((float)REFLECTION_HEIGHT - 1);
+ return 1.0f / (1.0f / farScale + (1.0f - 1.0f / farScale) * t);
+}
+
+static void initScrollTables() {
+ int i = 0;
+ for (i = 0; i < REFLECTION_HEIGHT; i++) {
+ scrollScaleTable[i] = distanceScale(i);
+ scrollTable[i] = 0.0f;
+ scrollTableRounded[i] = 0;
+ }
+}
+
+
+static void updateScrollTables(float dt) {
+ int i = 0;
+
+ nearScrollAmount += dt * NEAR_SCROLL_SPEED;
+ nearScrollAmount = (float) fmod(nearScrollAmount, 512.0f);
+
+ for (i = 0; i < REFLECTION_HEIGHT; i++) {
+ scrollTable[i] = nearScrollAmount / scrollScaleTable[i];
+ scrollTableRounded[i] = (int)(scrollTable[i] + 0.5f) % scrollModTable[i];
+ }
+}