*: move source into src/ subdir

Restoring some organizational sanity since adopting autotools.

1 files changed, 305 insertions, 0 deletions

diff --git a/src/modules/roto/roto.c b/src/modules/roto/roto.c
new file mode 100644
index 0000000..d789f85
--- /dev/null
+++ b/src/modules/roto/roto.c
@@ -0,0 +1,305 @@
+#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		11			/* fractional bits */
+#define FIXED_EXP		(1 << FIXED_BITS)	/* 2^FIXED_BITS */
+#define FIXED_MASK		(FIXED_EXP - 1)		/* fractional part mask */
+#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)
+
+typedef struct color_t {
+	int	r, g, b;
+} color_t;
+
+
+/* linearly interpolate between two colors, alpha is fixed-point value 0-FIXED_EXP. */
+static inline color_t lerp_color(color_t *a, color_t *b, int alpha)
+{
+	/* TODO: This could be done without multiplies with a bit of effort,
+	 * maybe a simple table mapping integer color deltas to shift values
+	 * for shifting alpha which then gets simply added?  A table may not even
+	 * be necessary, use the order of the delta to derive how much to shift
+	 * alpha?
+	 */
+	color_t	c = {
+			.r = a->r + FIXED_MULT(alpha, b->r - a->r),
+			.g = a->g + FIXED_MULT(alpha, b->g - a->g),
+			.b = a->b + FIXED_MULT(alpha, b->b - a->b),
+		};
+
+	return c;
+}
+
+
+/* Return the bilinearly interpolated color palette[texture[ty][tx]] (Anti-Aliasing) */
+/* tx, ty are fixed-point for fractions, palette colors are also in fixed-point format. */
+static uint32_t bilerp_color(uint8_t texture[256][256], color_t *palette, int tx, int ty)
+{
+	uint8_t	itx = FIXED_TO_INT(tx), ity = FIXED_TO_INT(ty);
+	color_t	n_color, s_color, color;
+	int	x_alpha, y_alpha;
+	uint8_t	nw, ne, sw, se;
+
+	/* We need the 4 texels constituting a 2x2 square pattern to interpolate.
+	 * A point tx,ty can only intersect one texel; one corner of the 2x2 square.
+	 * Where relative to the corner's center the intersection occurs determines which corner has been intersected,
+	 * and the other corner texels may then be addressed relative to that corner.
+	 * Alpha values must also be determined for both axis, these values describe the position between
+	 * the 2x2 texel centers the intersection occurred, aka the weight or bias.
+	 * Once the two alpha values are known, linear interpolation between the texel colors is trivial.
+	 */
+
+	if ((ty & FIXED_MASK) > (FIXED_EXP >> 1)) {
+		y_alpha = ty & (FIXED_MASK >> 1);
+
+		if ((tx & (FIXED_MASK)) > (FIXED_EXP >> 1)) {
+			nw = texture[ity][itx];
+			ne = texture[ity][(uint8_t)(itx + 1)];
+			sw = texture[(uint8_t)(ity + 1)][itx];
+			se = texture[(uint8_t)(ity + 1)][(uint8_t)(itx + 1)];
+
+			x_alpha = tx & (FIXED_MASK >> 1);
+		} else {
+			ne = texture[ity][itx];
+			nw = texture[ity][(uint8_t)(itx - 1)];
+			se = texture[(uint8_t)(ity + 1)][itx];
+			sw = texture[(uint8_t)(ity + 1)][(uint8_t)(itx - 1)];
+
+			x_alpha = (FIXED_EXP >> 1) + (tx & (FIXED_MASK >> 1));
+		}
+	} else {
+		y_alpha = (FIXED_EXP >> 1) + (ty & (FIXED_MASK >> 1));
+
+		if ((tx & (FIXED_MASK)) > (FIXED_EXP >> 1)) {
+			sw = texture[ity][itx];
+			se = texture[ity][(uint8_t)(itx + 1)];
+			nw = texture[(uint8_t)(ity - 1)][itx];
+			ne = texture[(uint8_t)(ity - 1)][(uint8_t)(itx + 1)];
+
+			x_alpha = tx & (FIXED_MASK >> 1);
+		} else {
+			se = texture[ity][itx];
+			sw = texture[ity][(uint8_t)(itx - 1)];
+			ne = texture[(uint8_t)(ity - 1)][itx];
+			nw = texture[(uint8_t)(ity - 1)][(uint8_t)(itx - 1)];
+
+			x_alpha = (FIXED_EXP >> 1) + (tx & (FIXED_MASK >> 1));
+		}
+	}
+
+	/* Skip interpolation of same colors, a substantial optimization with plain textures like the checker pattern */
+	if (nw == ne) {
+		if (ne == sw && sw == se) {
+			return (FIXED_TO_INT(palette[sw].r) << 16) | (FIXED_TO_INT(palette[sw].g) << 8) | FIXED_TO_INT(palette[sw].b);
+		}
+		n_color = palette[nw];
+	} else {
+		n_color = lerp_color(&palette[nw], &palette[ne], x_alpha);
+	}
+
+	if (sw == se) {
+		s_color = palette[sw];
+	} else {
+		s_color = lerp_color(&palette[sw], &palette[se], x_alpha);
+	}
+
+	color = lerp_color(&n_color, &s_color, y_alpha);
+
+	return (FIXED_TO_INT(color.r) << 16) | (FIXED_TO_INT(color.g) << 8) | FIXED_TO_INT(color.b);
+}
+
+
+static void init_roto(uint8_t texture[256][256], int32_t *costab, int32_t *sintab)
+{
+	int	x, y, i;
+
+	/* 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 palette[] 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);
+	}
+}
+
+
+/* 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 color_t	palette[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;
+	uint32_t	*buf = fragment->buf;
+
+	if (!initialized) {
+		initialized = 1;
+
+		init_roto(texture, costab, sintab);
+	}
+
+	/* 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. */
+	palette[0].r = (FIXED_MULT(FIXED_COS(rr), FIXED_NEW(127)) + FIXED_NEW(128));
+	palette[0].g = (FIXED_MULT(FIXED_SIN(rr / 2), FIXED_NEW(127)) + FIXED_NEW(128));
+	palette[0].b = (FIXED_MULT(FIXED_COS(rr / 3), FIXED_NEW(127)) + FIXED_NEW(128));
+
+	palette[1].r = (FIXED_MULT(FIXED_SIN(rr / 2), FIXED_NEW(127)) + FIXED_NEW(128));
+	palette[1].g = (FIXED_MULT(FIXED_COS(rr / 2), FIXED_NEW(127)) + FIXED_NEW(128));
+	palette[1].b = (FIXED_MULT(FIXED_SIN(rr), FIXED_NEW(127)) + FIXED_NEW(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++) {
+			*buf = bilerp_color(texture, palette, x_sin_r - y_cos_r, y_sin_r + x_cos_r);
+
+			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 color_t	palette[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;
+	uint64_t	*buf = (uint64_t *)fragment->buf;
+
+	if (!initialized) {
+		initialized = 1;
+
+		init_roto(texture, costab, sintab);
+	}
+
+	/* 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. */
+	palette[0].r = (FIXED_MULT(FIXED_COS(rr), FIXED_NEW(127)) + FIXED_NEW(128));
+	palette[0].g = (FIXED_MULT(FIXED_SIN(rr / 2), FIXED_NEW(127)) + FIXED_NEW(128));
+	palette[0].b = (FIXED_MULT(FIXED_COS(rr / 3), FIXED_NEW(127)) + FIXED_NEW(128));
+
+	palette[1].r = (FIXED_MULT(FIXED_SIN(rr / 2), FIXED_NEW(127)) + FIXED_NEW(128));
+	palette[1].g = (FIXED_MULT(FIXED_COS(rr / 2), FIXED_NEW(127)) + FIXED_NEW(128));
+	palette[1].b = (FIXED_MULT(FIXED_SIN(rr), FIXED_NEW(127)) + FIXED_NEW(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;
+
+			p = bilerp_color(texture, palette, x_sin_r - y_cos_r, y_sin_r + x_cos_r);
+
+			x_cos_r += cos_r;
+			x_sin_r += sin_r;
+
+			p |= (uint64_t)(bilerp_color(texture, palette, x_sin_r - y_cos_r, y_sin_r + x_cos_r)) << 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 = "Anti-aliased tiled texture rotation (32-bit)",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.license = "GPLv2",
+};
+
+
+rototiller_renderer_t	roto64_renderer = {
+	.render = roto64,
+	.name = "roto64",
+	.description = "Anti-aliased tiled texture rotation (64-bit)",
+	.author = "Vito Caputo <vcaputo@pengaru.com>",
+	.license = "GPLv2",
+};