Function fillBuffer

src/platforms/esp/32/drivers/i2s/clockless_i2s_esp32.h:227–268

Fill DMA buffer * * This is where the real work happens: take a row of pixels (one * from each strip), transpose and encode the bits, and store * them in the DMA buffer for the I2S peripheral to read. */

     *  them in the DMA buffer for the I2S peripheral to read.
     */
    static void fillBuffer() FL_NOEXCEPT {
        // -- Alternate between buffers
        volatile u32 *buf = (u32 *)dmaBuffers[gCurBuffer]->buffer;
        gCurBuffer = (gCurBuffer + 1) % NUM_DMA_BUFFERS;

        // -- Get the requested pixel from each controller. Store the
        //    data for each color channel in a separate array.
        u32 has_data_mask = 0;
        for (int i = 0; i < gNumControllers; ++i) {
            // -- Store the pixels in reverse controller order starting at index
            // 23
            //    This causes the bits to come out in the right position after
            //    we transpose them.
            int bit_index = 23 - i;
            ClocklessI2S *pController =
                static_cast<ClocklessI2S *>(gControllers[i]);
            if (pController->mPixels->has(1)) {
                gPixelRow[0][bit_index] = pController->mPixels->loadAndScale0();
                gPixelRow[1][bit_index] = pController->mPixels->loadAndScale1();
                gPixelRow[2][bit_index] = pController->mPixels->loadAndScale2();
                pController->mPixels->advanceData();
                pController->mPixels->stepDithering();

                // -- Record that this controller still has data to send
                has_data_mask |= (1 << (i + 8));
            }
        }

        // -- None of the strips has data? We are done.
        if (has_data_mask == 0) {
            gDoneFilling = true;
            return;
        }
#if FASTLED_ESP32_I2S_NUM_DMA_BUFFERS > 2
        gCntBuffer++;
#endif
        // -- Transpose and encode the pixel data for the DMA buffer
        // int buf_index = 0;
        for (int channel = 0; channel < NUM_COLOR_CHANNELS; ++channel) {
            i2s_transpose_and_encode(channel, has_data_mask, buf);
        }
    }

    // -- Show pixels
    //    This is the main entry point for the controller.