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-rw-r--r--src/modules/roto/Makefile.am4
-rw-r--r--src/modules/roto/roto.c305
-rw-r--r--src/modules/roto/roto.h9
3 files changed, 318 insertions, 0 deletions
diff --git a/src/modules/roto/Makefile.am b/src/modules/roto/Makefile.am
new file mode 100644
index 0000000..08d8522
--- /dev/null
+++ b/src/modules/roto/Makefile.am
@@ -0,0 +1,4 @@
+noinst_LIBRARIES = libroto.a
+libroto_a_SOURCES = roto.c roto.h
+libroto_a_CFLAGS = @ROTOTILLER_CFLAGS@
+libroto_a_CPPFLAGS = @ROTOTILLER_CFLAGS@ -I../../
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",
+};
diff --git a/src/modules/roto/roto.h b/src/modules/roto/roto.h
new file mode 100644
index 0000000..84a66a9
--- /dev/null
+++ b/src/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
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