From 6246ecb19b407d85768a5b1cbba2244ae5624a5d Mon Sep 17 00:00:00 2001
From: Vito Caputo <vcaputo@pengaru.com>
Date: Tue, 21 Nov 2023 21:39:07 -0800
Subject: modules/mixer: introduce style=interlace
Another mixing variant. Similar cost to style=blend in that it
must render both [ab]_module every frame, but doesn't have the
overhead of interpolating the pixels.
As-implemented this always interlaces by horizontal line
granularity. It'd be nice to be able to vary that with a runtime
setting to make it potentially chunkier.
---
src/modules/mixer/mixer.c | 45 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 44 insertions(+), 1 deletion(-)
diff --git a/src/modules/mixer/mixer.c b/src/modules/mixer/mixer.c
index ecaa2b5..b6cc16c 100644
--- a/src/modules/mixer/mixer.c
+++ b/src/modules/mixer/mixer.c
@@ -16,9 +16,15 @@
/* This implements a rudimentary mixing module for things like fades */
+/*
+ * TODO:
+ * - make interlace line granularity configurable instead of always 1 pixel
+ */
+
typedef enum mixer_style_t {
MIXER_STYLE_BLEND,
MIXER_STYLE_FLICKER,
+ MIXER_STYLE_INTERLACE,
} mixer_style_t;
typedef struct mixer_input_t {
@@ -26,6 +32,11 @@ typedef struct mixer_input_t {
/* XXX: it's expected that inputs will get more settable attributes to stick in here */
} mixer_input_t;
+typedef struct mixer_seed_t {
+ char __padding[256]; /* prevent seeds sharing a cache line */
+ unsigned state;
+} mixer_seed_t;
+
typedef struct mixer_context_t {
til_module_context_t til_module_context;
@@ -41,6 +52,7 @@ typedef struct mixer_context_t {
mixer_input_t inputs[2];
til_fb_fragment_t *snapshots[2];
+ mixer_seed_t seeds[];
} mixer_context_t;
typedef struct mixer_setup_input_t {
@@ -74,7 +86,7 @@ static til_module_context_t * mixer_create_context(const til_module_t *module, t
assert(setup);
- ctxt = til_module_context_new(module, sizeof(mixer_context_t), stream, seed, ticks, n_cpus, setup);
+ ctxt = til_module_context_new(module, sizeof(mixer_context_t) * (sizeof(mixer_seed_t) * n_cpus), stream, seed, ticks, n_cpus, setup);
if (!ctxt)
return NULL;
@@ -131,6 +143,11 @@ static void mixer_prepare_frame(til_module_context_t *context, til_stream_t *str
til_module_render(ctxt->inputs[i].module_ctxt, stream, ticks, &fragment);
break;
+ case MIXER_STYLE_INTERLACE:
+ for (int i = 0; i < context->n_cpus; i++)
+ ctxt->seeds[i].state = rand_r(&context->seed);
+ /* fallthrough */
+
case MIXER_STYLE_BLEND: {
float T = ctxt->vars.T;
@@ -264,6 +281,31 @@ static void mixer_render_fragment(til_module_context_t *context, til_stream_t *s
break;
}
+ case MIXER_STYLE_INTERLACE: {
+ til_fb_fragment_t *snapshot_a, *snapshot_b;
+ float T = ctxt->vars.T;
+
+ if (T <= 0.f || T >= 1.f)
+ break;
+
+ assert(ctxt->snapshots[0]);
+ assert(ctxt->snapshots[1]);
+
+ snapshot_a = ctxt->snapshots[0];
+ snapshot_b = ctxt->snapshots[1];
+
+ for (unsigned y = 0; y < fragment->height; y++) {
+ float r = randf(&ctxt->seeds[cpu].state);
+
+ if (r > T) {
+ til_fb_fragment_copy(fragment, 0, fragment->x, fragment->y + y, fragment->width, 1, snapshot_b);
+ } else {
+ til_fb_fragment_copy(fragment, 0, fragment->x, fragment->y + y, fragment->width, 1, snapshot_a);
+ }
+ }
+ break;
+ }
+
default:
assert(0);
}
@@ -352,6 +394,7 @@ static int mixer_setup(const til_settings_t *settings, til_setting_t **res_setti
const char *style_values[] = {
"blend",
"flicker",
+ "interlace",
NULL
};
til_setting_t *style;
--
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