feat: tiled grayscale rendering to drop the storeBwBuffer peak (#2106)
Tiled grayscale rendering to drop the storeBwBuffer peak largest contiguous free block (the value that actually drives OOM on the C3) from ~114 KB to ~82-90 KB. This renders each grayscale plane band-by-band into a small (~8 KB) scratch and streams each band straight to controller RAM (community-sdk writeGrayscalePlaneStrip), leaving the BW framebuffer intact. No save, no restore; controller RAM is re-synced for the next differential turn directly from the live framebuffer. Three writers honor the active band target so per-band re-rendering stays cheap and correct: - drawPixel (text) redirects writes to the band scratch and clips to it. - renderCharImpl skips glyphs whose physical y-extent is outside the band before the bitmap decode (glyphIntersectsStrip), so the per-band re-render doesn't pay N x glyph decode. - DirectPixelWriter (images) writes the band scratch via getWriteTarget instead of the framebuffer. Without this, image pixels wrote the live BW frame directly and cleanup re-synced that corruption, leaving thin outlines after navigating away from an image. Controller specifics live in the SDK (X4 setRamArea windowing, X3 PTL); the reader checks supportsStripGrayscale() and is otherwise controller-agnostic. Measured on hardware (X4 and X3, text and images, visually correct): - Grayscale scratch ~8 KB vs ~50 KB save; largest contiguous free block held at full size during grayscale instead of dropping ~25-32 KB. - X4 text page about +25 ms/page; X3 page time is dominated by its intrinsic grayscale refresh, not tiling. Depends on community-sdk #13 (the writeGrayscalePlaneStrip API). The submodule bump here points at that branch, so until #13 merges the submodule won't resolve from upstream and CI will fail there; keeping this a draft until then. Will rebase onto master and re-point the submodule to the merged SDK commit once #13 lands. Did you use AI tools to help write this code? partial
This commit is contained in:
Jeremy Klein
@@ -8,6 +8,7 @@
|
||||
#include <HalStorage.h>
|
||||
#include <I18n.h>
|
||||
#include <Logging.h>
|
||||
#include <Memory.h>
|
||||
#include <esp_system.h>
|
||||
|
||||
#include <functional>
|
||||
@@ -909,50 +910,105 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
|
||||
}
|
||||
const auto tDisplay = millis();
|
||||
|
||||
// Save bw buffer to reset buffer state after grayscale data sync
|
||||
renderer.storeBwBuffer();
|
||||
const auto tBwStore = millis();
|
||||
// Tiled grayscale: render each plane band-by-band into a small scratch and
|
||||
// stream straight to the controller, leaving the BW framebuffer intact so no
|
||||
// full-frame storeBwBuffer is needed; controller RAM is re-synced from the
|
||||
// live framebuffer afterward. The page is re-rendered ceil(H/STRIP_ROWS) times
|
||||
// per plane, but renderCharImpl culls out-of-band glyphs before decode so the
|
||||
// cost stays close to one render. Both text (drawPixel) and images
|
||||
// (DirectPixelWriter) honor the active strip target.
|
||||
if (SETTINGS.textAntiAliasing && renderer.supportsStripGrayscale()) {
|
||||
constexpr int STRIP_ROWS = 80;
|
||||
const int gh = renderer.getDisplayHeight();
|
||||
const int gwBytes = renderer.getDisplayWidthBytes();
|
||||
|
||||
// grayscale rendering
|
||||
// TODO: Only do this if font supports it
|
||||
if (SETTINGS.textAntiAliasing) {
|
||||
renderer.clearScreen(0x00);
|
||||
renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
|
||||
page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
|
||||
renderer.copyGrayscaleLsbBuffers();
|
||||
const auto tGrayLsb = millis();
|
||||
auto scratch = makeUniqueNoThrow<uint8_t[]>(static_cast<size_t>(gwBytes) * STRIP_ROWS);
|
||||
if (!scratch) {
|
||||
LOG_ERR("ERS", "OOM: grayscale strip scratch (%d bytes); skipping AA this page", gwBytes * STRIP_ROWS);
|
||||
} else {
|
||||
// Bands may be streamed in any order: X4 windows each via setRamArea, X3
|
||||
// via PTL.
|
||||
renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
|
||||
for (int y = 0; y < gh; y += STRIP_ROWS) {
|
||||
const int rows = (gh - y < STRIP_ROWS) ? (gh - y) : STRIP_ROWS;
|
||||
renderer.beginStripTarget(scratch.get(), y, rows);
|
||||
renderer.clearScreen(0x00);
|
||||
page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
|
||||
renderer.endStripTarget();
|
||||
renderer.writeGrayscalePlaneStrip(true, scratch.get(), y, rows);
|
||||
}
|
||||
const auto tGrayLsb = millis();
|
||||
|
||||
// Render and copy to MSB buffer
|
||||
renderer.clearScreen(0x00);
|
||||
renderer.setRenderMode(GfxRenderer::GRAYSCALE_MSB);
|
||||
page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
|
||||
renderer.copyGrayscaleMsbBuffers();
|
||||
const auto tGrayMsb = millis();
|
||||
// MSB plane.
|
||||
renderer.setRenderMode(GfxRenderer::GRAYSCALE_MSB);
|
||||
for (int y = 0; y < gh; y += STRIP_ROWS) {
|
||||
const int rows = (gh - y < STRIP_ROWS) ? (gh - y) : STRIP_ROWS;
|
||||
renderer.beginStripTarget(scratch.get(), y, rows);
|
||||
renderer.clearScreen(0x00);
|
||||
page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
|
||||
renderer.endStripTarget();
|
||||
renderer.writeGrayscalePlaneStrip(false, scratch.get(), y, rows);
|
||||
}
|
||||
const auto tGrayMsb = millis();
|
||||
|
||||
// display grayscale part
|
||||
renderer.displayGrayBuffer();
|
||||
const auto tGrayDisplay = millis();
|
||||
renderer.setRenderMode(GfxRenderer::BW);
|
||||
// restore the bw data
|
||||
renderer.restoreBwBuffer();
|
||||
const auto tBwRestore = millis();
|
||||
renderer.setRenderMode(GfxRenderer::BW);
|
||||
renderer.displayGrayBuffer();
|
||||
const auto tGrayDisplay = millis();
|
||||
|
||||
const auto tEnd = millis();
|
||||
LOG_DBG("ERS",
|
||||
"Page render: prewarm=%lums bw_render=%lums display=%lums bw_store=%lums "
|
||||
"gray_lsb=%lums gray_msb=%lums gray_display=%lums bw_restore=%lums total=%lums",
|
||||
tPrewarm - t0, tBwRender - tPrewarm, tDisplay - tBwRender, tBwStore - tDisplay, tGrayLsb - tBwStore,
|
||||
tGrayMsb - tGrayLsb, tGrayDisplay - tGrayMsb, tBwRestore - tGrayDisplay, tEnd - t0);
|
||||
// BW framebuffer is intact; re-sync controller RAM for the next
|
||||
// differential page turn directly from it.
|
||||
renderer.cleanupGrayscaleWithFrameBuffer();
|
||||
const auto tCleanup = millis();
|
||||
|
||||
const auto tEnd = millis();
|
||||
LOG_DBG("ERS",
|
||||
"Page render (tiled): prewarm=%lums bw_render=%lums display=%lums gray_lsb=%lums "
|
||||
"gray_msb=%lums gray_display=%lums cleanup=%lums total=%lums",
|
||||
tPrewarm - t0, tBwRender - tPrewarm, tDisplay - tBwRender, tGrayLsb - tDisplay, tGrayMsb - tGrayLsb,
|
||||
tGrayDisplay - tGrayMsb, tCleanup - tGrayDisplay, tEnd - t0);
|
||||
}
|
||||
} else {
|
||||
// restore the bw data
|
||||
renderer.restoreBwBuffer();
|
||||
const auto tBwRestore = millis();
|
||||
// Fallback path for a controller without strip support. grayscale rendering
|
||||
// TODO: Only do this if font supports it
|
||||
if (SETTINGS.textAntiAliasing) {
|
||||
// Save the BW frame before the grayscale passes overwrite it, restore
|
||||
// after. Only needed when grayscale actually renders.
|
||||
renderer.storeBwBuffer();
|
||||
const auto tBwStore = millis();
|
||||
|
||||
const auto tEnd = millis();
|
||||
LOG_DBG("ERS",
|
||||
"Page render: prewarm=%lums bw_render=%lums display=%lums bw_store=%lums bw_restore=%lums total=%lums",
|
||||
tPrewarm - t0, tBwRender - tPrewarm, tDisplay - tBwRender, tBwStore - tDisplay, tBwRestore - tBwStore,
|
||||
tEnd - t0);
|
||||
renderer.clearScreen(0x00);
|
||||
renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
|
||||
page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
|
||||
renderer.copyGrayscaleLsbBuffers();
|
||||
const auto tGrayLsb = millis();
|
||||
|
||||
// Render and copy to MSB buffer
|
||||
renderer.clearScreen(0x00);
|
||||
renderer.setRenderMode(GfxRenderer::GRAYSCALE_MSB);
|
||||
page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
|
||||
renderer.copyGrayscaleMsbBuffers();
|
||||
const auto tGrayMsb = millis();
|
||||
|
||||
// display grayscale part
|
||||
renderer.displayGrayBuffer();
|
||||
const auto tGrayDisplay = millis();
|
||||
renderer.setRenderMode(GfxRenderer::BW);
|
||||
renderer.restoreBwBuffer();
|
||||
const auto tBwRestore = millis();
|
||||
|
||||
const auto tEnd = millis();
|
||||
LOG_DBG("ERS",
|
||||
"Page render: prewarm=%lums bw_render=%lums display=%lums bw_store=%lums "
|
||||
"gray_lsb=%lums gray_msb=%lums gray_display=%lums bw_restore=%lums total=%lums",
|
||||
tPrewarm - t0, tBwRender - tPrewarm, tDisplay - tBwRender, tBwStore - tDisplay, tGrayLsb - tBwStore,
|
||||
tGrayMsb - tGrayLsb, tGrayDisplay - tGrayMsb, tBwRestore - tGrayDisplay, tEnd - t0);
|
||||
} else {
|
||||
// No anti-aliasing: BW frame already displayed above, no grayscale to
|
||||
// render, so no save/restore.
|
||||
const auto tEnd = millis();
|
||||
LOG_DBG("ERS", "Page render: prewarm=%lums bw_render=%lums display=%lums total=%lums", tPrewarm - t0,
|
||||
tBwRender - tPrewarm, tDisplay - tBwRender, tEnd - t0);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
Reference in New Issue
Block a user