roto: add modular forms of original renderer

2 files changed, 240 insertions, 0 deletions

diff --git a/modules/roto/roto.c b/modules/roto/roto.c
new file mode 100644
index 0000000..21e68b7
--- /dev/null
+++ b/modules/roto/roto.c
@@ -0,0 +1,231 @@
+#include <stdint.h>
+#include <inttypes.h>
+#include <math.h>
+
+#include "fb.h"
+#include "rototiller.h"
+
+/* Copyright (C) 2016 Vito Caputo <vcaputo@pengaru.com> */
+
+/* Some defines for the fixed-point stuff in render(). */
+#define FIXED_TRIG_LUT_SIZE	4096	/* size of the cos/sin look-up tables */
+#define FIXED_BITS		12	/* fractional bits */
+#define FIXED_EXP		4096	/* 2^FIXED_BITS */
+#define FIXED_COS(_rad)		costab[_rad % FIXED_TRIG_LUT_SIZE]
+#define FIXED_SIN(_rad)		sintab[_rad % FIXED_TRIG_LUT_SIZE]
+#define FIXED_MULT(_a, _b)	((_a * _b) >> FIXED_BITS)
+#define FIXED_NEW(_i)		(_i << FIXED_BITS)
+#define FIXED_TO_INT(_f)	((_f) >> FIXED_BITS)
+
+
+/* Draw a rotating checkered 256x256 texture into fragment. (32-bit version) */
+static void roto32(fb_fragment_t *fragment)
+{
+	static int32_t	costab[FIXED_TRIG_LUT_SIZE], sintab[FIXED_TRIG_LUT_SIZE];
+	static uint8_t	texture[256][256];
+	static int	initialized;
+	static uint32_t	colors[2];
+	static unsigned	r, rr;
+
+	int		y_cos_r, y_sin_r, x_cos_r, x_sin_r, x_cos_r_init, x_sin_r_init, cos_r, sin_r;
+	int		x, y, stride = fragment->stride / 4, width = fragment->width, height = fragment->height;
+	uint8_t		tx, ty; /* 256x256 texture; 8 bit texture indices to modulo via overflow. */
+	uint32_t	*buf = fragment->buf;
+
+	if (!initialized) {
+		int i;
+
+		initialized = 1;
+
+		/* Generate simple checker pattern texture, nothing clever, feel free to play! */
+		/* If you modify texture on every frame instead of only @ initialization you can
+		 * produce some neat output.  These values are indexed into colors[] below. */
+		for (y = 0; y < 128; y++) {
+			for (x = 0; x < 128; x++)
+				texture[y][x] = 1;
+			for (; x < 256; x++)
+				texture[y][x] = 0;
+		}
+		for (; y < 256; y++) {
+			for (x = 0; x < 128; x++)
+				texture[y][x] = 0;
+			for (; x < 256; x++)
+				texture[y][x] = 1;
+		}
+
+		/* Generate fixed-point cos & sin LUTs. */
+		for (i = 0; i < FIXED_TRIG_LUT_SIZE; i++) {
+			costab[i] = ((cos((double)2*M_PI*i/FIXED_TRIG_LUT_SIZE))*FIXED_EXP);
+			sintab[i] = ((sin((double)2*M_PI*i/FIXED_TRIG_LUT_SIZE))*FIXED_EXP);
+		}
+	}
+
+	/* This is all done using fixed-point in the hopes of being faster, and yes assumptions
+	 * are being made WRT the overflow of tx/ty as well, only tested on x86_64. */
+	cos_r = FIXED_COS(r);
+	sin_r = FIXED_SIN(r);
+
+	/* Vary the colors, this is just a mashup of sinusoidal rgb values. */
+	colors[0] =	((FIXED_TO_INT(FIXED_MULT(FIXED_COS(rr), FIXED_NEW(127))) + 128) << 16) |
+			((FIXED_TO_INT(FIXED_MULT(FIXED_SIN(rr / 2), FIXED_NEW(127))) + 128) << 8) |
+			((FIXED_TO_INT(FIXED_MULT(FIXED_COS(rr / 3), FIXED_NEW(127))) + 128));
+
+	colors[1] =	((FIXED_TO_INT(FIXED_MULT(FIXED_SIN(rr / 2), FIXED_NEW(127))) + 128) << 16) |
+			((FIXED_TO_INT(FIXED_MULT(FIXED_COS(rr / 2), FIXED_NEW(127))) + 128)) << 8 |
+			((FIXED_TO_INT(FIXED_MULT(FIXED_SIN(rr), FIXED_NEW(127))) + 128) );
+
+	/* The dimensions are cut in half and negated to center the rotation. */
+	/* The [xy]_{sin,cos}_r variables are accumulators to replace multiplication with addition. */
+	x_cos_r_init = FIXED_MULT(-FIXED_NEW((width / 2)), cos_r);
+	x_sin_r_init = FIXED_MULT(-FIXED_NEW((width / 2)), sin_r);
+
+	y_cos_r = FIXED_MULT(-FIXED_NEW((height / 2)), cos_r);
+	y_sin_r = FIXED_MULT(-FIXED_NEW((height / 2)), sin_r);
+
+	for (y = 0; y < height; y++) {
+
+		x_cos_r = x_cos_r_init;
+		x_sin_r = x_sin_r_init;
+
+		for (x = 0; x < width; x++, buf++) {
+
+			tx = FIXED_TO_INT(x_sin_r - y_cos_r);
+			ty = FIXED_TO_INT(y_sin_r + x_cos_r);
+
+			*buf = colors[texture[ty][tx]];
+
+			x_cos_r += cos_r;
+			x_sin_r += sin_r;
+		}
+
+		buf += stride;
+		y_cos_r += cos_r;
+		y_sin_r += sin_r;
+	}
+
+	// This governs the rotation and color cycle.
+	r += FIXED_TO_INT(FIXED_MULT(FIXED_SIN(rr), FIXED_NEW(16)));
+	rr += 2;
+}
+
+
+/* Draw a rotating checkered 256x256 texture into fragment. (64-bit version) */
+static void roto64(fb_fragment_t *fragment)
+{
+	static int32_t	costab[FIXED_TRIG_LUT_SIZE], sintab[FIXED_TRIG_LUT_SIZE];
+	static uint8_t	texture[256][256];
+	static int	initialized;
+	static uint32_t	colors[2];
+	static unsigned	r, rr;
+
+	int		y_cos_r, y_sin_r, x_cos_r, x_sin_r, x_cos_r_init, x_sin_r_init, cos_r, sin_r;
+	int		x, y, stride = fragment->stride / 8, width = fragment->width, height = fragment->height;
+	uint8_t		tx, ty; /* 256x256 texture; 8 bit texture indices to modulo via overflow. */
+	uint64_t	*buf = (uint64_t *)fragment->buf;
+
+	if (!initialized) {
+		int i;
+
+		initialized = 1;
+
+		/* Generate simple checker pattern texture, nothing clever, feel free to play! */
+		/* If you modify texture on every frame instead of only @ initialization you can
+		 * produce some neat output.  These values are indexed into colors[] below. */
+		for (y = 0; y < 128; y++) {
+			for (x = 0; x < 128; x++)
+				texture[y][x] = 1;
+			for (; x < 256; x++)
+				texture[y][x] = 0;
+		}
+		for (; y < 256; y++) {
+			for (x = 0; x < 128; x++)
+				texture[y][x] = 0;
+			for (; x < 256; x++)
+				texture[y][x] = 1;
+		}
+
+		/* Generate fixed-point cos & sin LUTs. */
+		for (i = 0; i < FIXED_TRIG_LUT_SIZE; i++) {
+			costab[i] = ((cos((double)2*M_PI*i/FIXED_TRIG_LUT_SIZE))*FIXED_EXP);
+			sintab[i] = ((sin((double)2*M_PI*i/FIXED_TRIG_LUT_SIZE))*FIXED_EXP);
+		}
+	}
+
+	/* This is all done using fixed-point in the hopes of being faster, and yes assumptions
+	 * are being made WRT the overflow of tx/ty as well, only tested on x86_64. */
+	cos_r = FIXED_COS(r);
+	sin_r = FIXED_SIN(r);
+
+	/* Vary the colors, this is just a mashup of sinusoidal rgb values. */
+	colors[0] =	((FIXED_TO_INT(FIXED_MULT(FIXED_COS(rr), FIXED_NEW(127))) + 128) << 16) |
+			((FIXED_TO_INT(FIXED_MULT(FIXED_SIN(rr / 2), FIXED_NEW(127))) + 128) << 8) |
+			((FIXED_TO_INT(FIXED_MULT(FIXED_COS(rr / 3), FIXED_NEW(127))) + 128));
+
+	colors[1] =	((FIXED_TO_INT(FIXED_MULT(FIXED_SIN(rr / 2), FIXED_NEW(127))) + 128) << 16) |
+			((FIXED_TO_INT(FIXED_MULT(FIXED_COS(rr / 2), FIXED_NEW(127))) + 128)) << 8 |
+			((FIXED_TO_INT(FIXED_MULT(FIXED_SIN(rr), FIXED_NEW(127))) + 128) );
+
+	/* The dimensions are cut in half and negated to center the rotation. */
+	/* The [xy]_{sin,cos}_r variables are accumulators to replace multiplication with addition. */
+	x_cos_r_init = FIXED_MULT(-FIXED_NEW((width / 2)), cos_r);
+	x_sin_r_init = FIXED_MULT(-FIXED_NEW((width / 2)), sin_r);
+
+	y_cos_r = FIXED_MULT(-FIXED_NEW((height / 2)), cos_r);
+	y_sin_r = FIXED_MULT(-FIXED_NEW((height / 2)), sin_r);
+
+	width /= 2;	/* Since we're processing 64-bit words (2 pixels) at a time */
+
+	for (y = 0; y < height; y++) {
+
+		x_cos_r = x_cos_r_init;
+		x_sin_r = x_sin_r_init;
+
+		for (x = 0; x < width; x++, buf++) {
+			uint64_t	p;
+
+			tx = FIXED_TO_INT(x_sin_r - y_cos_r);
+			ty = FIXED_TO_INT(y_sin_r + x_cos_r);
+
+			p = colors[texture[ty][tx]];
+
+			x_cos_r += cos_r;
+			x_sin_r += sin_r;
+
+			tx = FIXED_TO_INT(x_sin_r - y_cos_r);
+			ty = FIXED_TO_INT(y_sin_r + x_cos_r);
+
+			p |= (uint64_t)colors[texture[ty][tx]] << 32;
+			
+			*buf = p;
+
+			x_cos_r += cos_r;
+			x_sin_r += sin_r;
+		}
+
+		buf += stride;
+		y_cos_r += cos_r;
+		y_sin_r += sin_r;
+	}
+
+	// This governs the rotation and color cycle.
+	r += FIXED_TO_INT(FIXED_MULT(FIXED_SIN(rr), FIXED_NEW(16)));
+	rr += 2;
+}
+
+
+rototiller_renderer_t	roto32_renderer = {
+	.render = roto32,
+	.name = "roto32",
+	.description = "Tiled texture rotation (32-bit)",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.license = "GPLv2",
+};
+
+
+rototiller_renderer_t	roto64_renderer = {
+	.render = roto64,
+	.name = "roto64",
+	.description = "Tiled texture rotation (64-bit)",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.license = "GPLv2",
+};
diff --git a/modules/roto/roto.h b/modules/roto/roto.h
new file mode 100644
index 0000000..84a66a9
--- /dev/null
+++ b/modules/roto/roto.h
@@ -0,0 +1,9 @@
+#ifndef _ROTO_H
+#define _ROTO_H
+
+#include "fb.h"
+
+void roto64(fb_fragment_t *fragment);
+void roto32(fb_fragment_t *fragment);
+
+#endif