diff options
Diffstat (limited to 'src/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp')
| -rw-r--r-- | src/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/src/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp b/src/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp index 383643e..2bb4da0 100644 --- a/src/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp +++ b/src/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp @@ -705,7 +705,20 @@ void MatrixPanel_I2S_DMA::brtCtrlOEv2(uint8_t brt, const int _buff_id) { // let's set OE control bits for specific pixels in each color_index subrows uint8_t colouridx = dma_buff.rowBits[row_idx]->colour_depth; do { - int brightness_in_x_pixels = PIXELS_PER_ROW * brt >> 8 + max( ( dma_buff.rowBits[row_idx]->colour_depth - colouridx - 2 ), 0); + // Multiply brightness according to index of bitplane (color index subrow) + // in respect of accumulating LED intensities with Binary-Coded Modulation: + // bitplane 0 is 1/1 of total brightness; bitplane 1 is 1/2; bitplane 2 is 1/4, etc + // accumulating all of them together means we will get only ~1/4 of the total brightness. + + // During the DMA, assume bitplane 0 shown for 4 subrows; bitplane 1 shown for 2 subrows; + // bitplane 2 and the rest shown for one subrow, would give us ~2/3 of the total brightness, + // which is good balance for the depth, brightness, while the flickers still less noticeable: + // row 0 (blanking)\ row 1 (blanking)\ row 2 (blanking)\ .. + // bitplane : ... 0 0 0 0 1 1 2 3 4 5 6 7 \- 0 0 0 0 1 1 2 3 4 5 6 7 \- 0 0 0 0 1 1 2 3 4 5 6 7 \- .. + // rightshift: ... 0 0 0 0 0 0 0 1 2 3 4 5 -\ 0 0 0 0 0 0 0 1 2 3 4 5 -\ 0 0 0 0 0 0 0 1 2 3 4 5 -\ .. + char bitplane = dma_buff.rowBits[row_idx]->colour_depth-colouridx; + char rightshift = std::max(bitplane-2,0); + int brightness_in_x_pixels = PIXELS_PER_ROW * brt >> 8 + rightshift; --colouridx; // switch pointer to a row for a specific color index |