X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=src%2Fthunder.c;fp=src%2Fthunder.c;h=08c094e2052c1be77710e6030615e0d213170522;hb=5e15b0effd5e72dd8a6d8e141546f940e9f73b12;hp=0000000000000000000000000000000000000000;hpb=d8a130931d29a838871b4c720e0ee8201b9b3835;p=dosdemo

diff --git a/src/thunder.c b/src/thunder.c
new file mode 100644
index 0000000..08c094e
--- /dev/null
+++ b/src/thunder.c
@@ -0,0 +1,199 @@
+/* thunder. c */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <assert.h>
+#include "imago2.h"
+#include "demo.h"
+#include "screen.h"
+
+/* Render blur in half x half dimenstions. Add one pixel padding in all 
+ * directions (2 pixels horizontally, 2 pixels vertically).
+ */
+#define BLUR_BUFFER_WIDTH (320/2 + 2)
+#define BLUR_BUFFER_HEIGHT (240/2 + 2)
+#define BLUR_BUFFER_SIZE (BLUR_BUFFER_WIDTH * BLUR_BUFFER_HEIGHT)
+static unsigned char *blurBuffer, *blurBuffer2;
+
+#define THUNDER_RECT_SIZE 4
+#define THUNDER_RANDOMNESS 80
+#define THUNDER_SECONDS 0.1f
+
+/* TODO: Load palette from file */
+static unsigned short palette[256];
+
+void clearBlurBuffer();
+void drawPatternOnBlurBuffer(int seed);
+void applyBlur();
+void blitEffect();
+void thunder(int x0, int y0, int x1, int y1, int seed, int randomness, int depth);
+
+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 unsigned int lastFrameTime = 0;
+static float lastFrameDuration = 0.0f;
+static struct screen scr = {
+	"thunder",
+	init,
+	destroy,
+	start,
+	0,
+	draw
+};
+
+struct screen *thunder_screen(void)
+{
+	return &scr;
+}
+
+static int init(void)
+{
+	int i = 0;
+
+	blurBuffer = malloc(BLUR_BUFFER_SIZE);
+	blurBuffer2 = malloc(BLUR_BUFFER_SIZE);
+
+	clearBlurBuffer();
+
+	/* For now, map to blue */
+	for (i = 0; i < 256; i++) {
+		palette[i] = i >> 3;
+	}
+
+	return 0;
+}
+
+static void destroy(void)
+{
+	free(blurBuffer);
+	blurBuffer = 0;
+	
+	free(blurBuffer2);
+	blurBuffer2 = 0;
+}
+
+static void start(long trans_time)
+{
+	lastFrameTime = time_msec;
+}
+
+
+static float remainingThunderDuration = THUNDER_SECONDS;
+static int thunderPattern = 0;
+
+static void draw(void)
+{
+	lastFrameDuration = (time_msec - lastFrameTime) / 1000.0f;
+	lastFrameTime = time_msec;
+
+	remainingThunderDuration -= lastFrameDuration;
+	if (remainingThunderDuration <= 0) {
+		thunderPattern++;
+		remainingThunderDuration = THUNDER_SECONDS;
+	}
+	
+	
+	
+	drawPatternOnBlurBuffer(thunderPattern);
+	applyBlur();
+	blitEffect();
+
+	swap_buffers(0);
+}
+
+void clearBlurBuffer() {
+	/* Clear the whole buffer (including its padding ) */
+	memset(blurBuffer, 0, BLUR_BUFFER_SIZE);
+	memset(blurBuffer2, 0, BLUR_BUFFER_SIZE);
+}
+
+void drawPatternOnBlurBuffer(int seed) {
+	thunder(20, 20, 140, 100, seed, THUNDER_RANDOMNESS, 6);
+}
+
+void applyBlur() {
+	int i, j;
+	unsigned char *tmp;
+	unsigned char *src = blurBuffer + BLUR_BUFFER_WIDTH + 1;
+	unsigned char *dst = blurBuffer2 + BLUR_BUFFER_WIDTH + 1;
+
+	for (j = 0; j < 120; j++) {
+		for (i = 0; i < 160; i++) {
+			*dst = (*(src - 1) + *(src + 1) + *(src - BLUR_BUFFER_WIDTH) + *(src + BLUR_BUFFER_WIDTH)) >> 2;
+			if (*dst > 4) *dst -= 4;
+			else *dst = 0;
+			dst++;
+			src++;
+		}
+		/* Just skip the padding since we went through the scanline in the inner loop (except from the padding) */
+		src += 2;
+		dst += 2;
+	}
+
+	/* Swap blur buffers */
+	tmp = blurBuffer;
+	blurBuffer = blurBuffer2;
+	blurBuffer2 = tmp;
+}
+
+void blitEffect() {
+	unsigned int *dst1 = (unsigned int*) vmem_back;
+	unsigned int *dst2 = dst1 + 160; /* We're writing two pixels at once */
+	unsigned char *src1 = blurBuffer + BLUR_BUFFER_WIDTH + 1;
+	unsigned char *src2 = src1 + BLUR_BUFFER_WIDTH;
+	unsigned char tl, tr, bl, br;
+	int i, j;
+
+	for (j = 0; j < 120; j++) {
+		for (i = 0; i < 160; i++) {
+			tl = *src1;
+			tr = (*src1 + *(src1 + 1)) >> 1;
+			bl = (*src1 + *src2) >> 1;
+			br = tr + ((*src2 + *(src2 + 1)) >> 1) >> 1;
+
+			/* Pack 2 pixels in each 32 bit word */
+			*dst1 = (palette[tr] << 16) | palette[tl];
+			*dst2 = (palette[br] << 16) | palette[bl];
+
+			dst1++;
+			src1++;
+			dst2++;
+			src2++;
+		}
+		/* Again, skip padding */
+		src1 += 2;
+		src2 += 2;
+
+		/* For now, skip a scanline */
+		dst1 += 160;
+		dst2 += 160;
+	}
+
+}
+
+void thunder(int x0, int y0, int x1, int y1, int seed, int randomness, int depth) {
+	int mx = ((x0 + x1) >> 1) + rand() % randomness - randomness / 2;
+	int my = ((y0 + y1) >> 1) + rand() % randomness - randomness / 2;
+	int i, j;
+	unsigned char *dst = blurBuffer + BLUR_BUFFER_WIDTH + 1 + mx + my * BLUR_BUFFER_WIDTH;
+
+	if (depth <= 0) return;
+
+	srand(seed);
+
+	for (j = 0; j < THUNDER_RECT_SIZE; j++) {
+		memset(dst, 255, THUNDER_RECT_SIZE);
+		dst += BLUR_BUFFER_WIDTH;
+	}
+
+	thunder(x0, y0, mx, my, rand(), randomness >> 1, depth-1);
+	thunder(mx, my, x1, y1, rand(), randomness >> 1, depth - 1);
+}
+
+
+