From 39bc663b26d55d4f0c8e7cf320f6e8c5b76230db Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Sun, 9 Mar 2025 13:45:53 -0500
Subject: [PATCH] introduce pixel schedules

---
 src/include/piomatter/matrixmap.h       | 31 ++++++++++++++++++++++---
 src/include/piomatter/protomatter.pio.h |  2 +-
 src/include/piomatter/render.h          | 22 ++++++------------
 3 files changed, 36 insertions(+), 19 deletions(-)

diff --git a/src/include/piomatter/matrixmap.h b/src/include/piomatter/matrixmap.h
index 98b184d..47885f1 100644
--- a/src/include/piomatter/matrixmap.h
+++ b/src/include/piomatter/matrixmap.h
@@ -81,6 +81,24 @@ matrix_map make_matrixmap(size_t width, size_t height, size_t n_addr_lines,
     return result;
 }
 
+struct schedule_entry {
+    uint32_t shift, active_time;
+};
+
+using schedule = std::vector<schedule_entry>;
+
+schedule make_simple_schedule(int n_planes, int pixels_across) {
+    schedule result;
+    uint32_t max_count = 1 << n_planes;
+    while (max_count < pixels_across)
+        max_count <<= 1;
+
+    for (int i = 0; i < n_planes; i++) {
+        result.emplace_back(10 - i, max_count >> i);
+    }
+    return result;
+}
+
 struct matrix_geometry {
     template <typename Cb>
     matrix_geometry(size_t pixels_across, size_t n_addr_lines, int n_planes,
@@ -91,9 +109,16 @@ struct matrix_geometry {
 
     matrix_geometry(size_t pixels_across, size_t n_addr_lines, int n_planes,
                     size_t width, size_t height, matrix_map map, size_t n_lanes)
+        : matrix_geometry(pixels_across, n_addr_lines, width, height, map,
+                          n_lanes,
+                          make_simple_schedule(n_planes, pixels_across)) {}
+
+    matrix_geometry(size_t pixels_across, size_t n_addr_lines, size_t width,
+                    size_t height, matrix_map map, size_t n_lanes,
+                    const std::vector<schedule_entry> schedule)
         : pixels_across(pixels_across), n_addr_lines(n_addr_lines),
-          n_lanes(n_lanes), n_planes(n_planes), width(width), height(height),
-          map(map) {
+          n_lanes(n_lanes), width(width), height(height),
+          map(map), schedule{schedule} {
         size_t pixels_down = n_lanes << n_addr_lines;
         if (map.size() != pixels_down * pixels_across) {
             throw std::range_error(
@@ -102,7 +127,7 @@ struct matrix_geometry {
     }
 
     size_t pixels_across, n_addr_lines, n_lanes;
-    int n_planes;
+    std::vector<schedule_entry> schedule;
     size_t width, height;
     matrix_map map;
 };
diff --git a/src/include/piomatter/protomatter.pio.h b/src/include/piomatter/protomatter.pio.h
index 73485e2..ee5e74a 100644
--- a/src/include/piomatter/protomatter.pio.h
+++ b/src/include/piomatter/protomatter.pio.h
@@ -3,7 +3,7 @@
 const int protomatter_wrap = 4;
 const int protomatter_wrap_target = 0;
 const int protomatter_sideset_pin_count = 1;
-const bool protomatter_sideset_enable = true;
+const bool protomatter_sideset_enable = 1;
 const uint16_t protomatter[] = {
     // ; data format (out-shift-right):
     // ; MSB ... LSB
diff --git a/src/include/piomatter/render.h b/src/include/piomatter/render.h
index 59ae2d1..c8bc059 100644
--- a/src/include/piomatter/render.h
+++ b/src/include/piomatter/render.h
@@ -183,32 +183,22 @@ void protomatter_render_rgb10(std::vector<uint32_t> &result,
         return data;
     };
 
-    int last_bit = 0;
     // illuminate the right row for data in the shift register (the previous
     // address)
 
     const size_t n_addr = 1u << matrixmap.n_addr_lines;
-    const int n_planes = matrixmap.n_planes;
     constexpr size_t n_bits = 10u;
-    unsigned offset = n_bits - n_planes;
     const size_t pixels_across = matrixmap.pixels_across;
 
     size_t prev_addr = n_addr - 1;
     uint32_t addr_bits = calc_addr_bits(prev_addr);
 
     for (size_t addr = 0; addr < n_addr; addr++) {
-        // printf("addr=%zu/%zu\n", addr, n_addr);
-        for (int bit = n_planes - 1; bit >= 0; bit--) {
-            // printf("bit=%d/%d\n", bit, n_planes);
-            uint32_t r_mask = 1 << (20 + offset + bit);
-            uint32_t g_mask = 1 << (10 + offset + bit);
-            uint32_t b_mask = 1 << (0 + offset + bit);
-
-            // the shortest /OE we can do is one DATA_OVERHEAD...
-            // TODO: should make sure desired duration of MSB is at least
-            // `pixels_across`
-            active_time = 1 << last_bit;
-            last_bit = bit;
+        uint32_t active_time = matrixmap.schedule.back().active_time;
+        for (auto &schedule_ent : matrixmap.schedule) {
+            uint32_t r_mask = 1 << (20 + schedule_ent.shift);
+            uint32_t g_mask = 1 << (10 + schedule_ent.shift);
+            uint32_t b_mask = 1 << (0 + schedule_ent.shift);
 
             prep_data(pixels_across);
             auto mapiter = matrixmap.map.begin() +
@@ -242,6 +232,8 @@ void protomatter_render_rgb10(std::vector<uint32_t> &result,
             do_data_delay(addr_bits | pinout::oe_inactive | pinout::lat_bit,
                           pinout::post_latch_delay);
 
+            active_time = schedule_ent.active_time;
+
             // with oe inactive, set address bits to illuminate THIS line
             if (addr != prev_addr) {
                 addr_bits = calc_addr_bits(addr);