// license:BSD-3-Clause // copyright-holders:hap /* This thing is a generic helper for PWM(strobed) display elements, to prevent flickering and optionally handle perceived brightness levels. Common usecase is to call matrix(selmask, datamask), a collision between the 2 masks implies a powered-on display element (eg. a LED, or VFD sprite). The maximum matrix size is 64 by 64, simply due to uint64_t constraints. If a larger size is needed, create an array of pwm_display_device. If display elements are directly addressable, you can also use write_element or write_row to set them. Display element states are sent to output tags "y.x" where y is the matrix row number, x is the row bit. It is also sent to "y.a" for all rows. The output state is 0 for off, and >0 for on, depending on brightness level. If segmask is defined, it is also sent to "multiy.b" where b is brightness level, for use with multi-state elements. This usecase is not common though (one example is Coleco Quarterback where some digit segments are brighter). And when brightness level does not matter, it is also sent to "digity", for common 7seg leds. If you use this device in a slot, or use multiple of them (or just don't want to use the default output tags), set a callback. Brightness tresholds (0.0 to 1.0) indicate how long an element was powered on in the last frame, eg. 0.01 means a minimum on-time for 1%. Some games use two levels of brightness by strobing elements longer. TODO: - SVG screens and rendlay digit elements don't support multiple brightness levels, the latter can be worked around with by stacking digits on top of eachother */ #include "emu.h" #include "pwm.h" #include DEFINE_DEVICE_TYPE(PWM_DISPLAY, pwm_display_device, "pwm_display", "PWM Display") //------------------------------------------------- // constructor //------------------------------------------------- pwm_display_device::pwm_display_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) : device_t(mconfig, PWM_DISPLAY, tag, owner, clock), m_out_x(*this, "%u.%u", 0U, 0U), m_out_a(*this, "%u.a", 0U), m_out_multi(*this, "multi%u.%u", 0U, 0U), m_out_digit(*this, "digit%u", 0U), m_output_x_cb(*this), m_output_a_cb(*this), m_output_multi_cb(*this), m_output_digit_cb(*this) { // set defaults set_refresh(attotime::from_hz(60)); set_interpolation(0.5); set_bri_levels(0.01); set_bri_minimum(0); set_bri_maximum(0.0); set_size(0, 0); reset_segmask(); } //------------------------------------------------- // device_start/reset //------------------------------------------------- void pwm_display_device::device_start() { // resolve handlers m_external_output = !m_output_x_cb.isunset() || !m_output_a_cb.isunset() || !m_output_multi_cb.isunset() || !m_output_digit_cb.isunset(); if (!m_external_output) { m_out_x.resolve(); m_out_a.resolve(); m_out_multi.resolve(); m_out_digit.resolve(); } // initialize m_rowsel = 0; m_rowdata_last = 0; std::fill(std::begin(m_rowdata), std::end(m_rowdata), 0); for (auto &bri : m_bri) std::fill(std::begin(bri), std::end(bri), 0.0); m_frame_timer = timer_alloc(FUNC(pwm_display_device::frame_tick), this); m_sync_time = machine().time(); // register for savestates save_item(NAME(m_width)); save_item(NAME(m_height)); save_item(NAME(m_framerate_set)); save_item(NAME(m_framerate)); save_item(NAME(m_interpolation)); save_item(NAME(m_levels)); save_item(NAME(m_level_min)); save_item(NAME(m_level_max)); save_item(NAME(m_segmask)); save_item(NAME(m_rowsel)); save_item(NAME(m_rowdata)); save_item(NAME(m_rowdata_last)); save_item(NAME(m_bri)); save_item(NAME(m_sync_time)); save_item(NAME(m_acc)); } void pwm_display_device::device_reset() { if (m_height > 64 || m_width > 64) fatalerror("%s: Invalid size %d*%d, maximum is 64*64!\n", tag(), m_height, m_width); schedule_frame(); m_sync_time = machine().time(); } //------------------------------------------------- // public handlers (most of the interface is in the .h file) //------------------------------------------------- pwm_display_device &pwm_display_device::set_bri_levels(double l0, double l1, double l2, double l3) { // init brightness level(s) (if you need to set more than 4, use set_bri_one) reset_bri_levels(); set_bri_one(0, l0); set_bri_one(1, l1); set_bri_one(2, l2); set_bri_one(3, l3); return *this; } pwm_display_device &pwm_display_device::set_segmask(u64 digits, u64 mask) { // set a segment mask per selected digit, but leave unselected ones alone for (int y = 0; y < m_height; y++) { if (digits & 1) m_segmask[y] = mask; digits >>= 1; } return *this; } void pwm_display_device::matrix_partial(u8 start, u8 height, u64 rowsel, u64 rowdata) { sync(); u64 selmask = (u64(1) << height) - 1; rowsel &= selmask; selmask <<= start; m_rowsel = (m_rowsel & ~selmask) | (rowsel << start); // update selected rows u64 rowmask = (u64(1) << m_width) - 1; m_rowdata_last = rowdata & rowmask; for (int y = start; y < (start + height) && y < m_height; y++) { m_rowdata[y] = (rowsel & 1) ? (rowdata & rowmask) : 0; rowsel >>= 1; } } //------------------------------------------------- // internal handlers //------------------------------------------------- void pwm_display_device::schedule_frame() { std::fill_n(*m_acc, m_height * std::size(m_acc[0]), attotime::zero); m_framerate = m_framerate_set; m_frame_timer->adjust(m_framerate); } TIMER_CALLBACK_MEMBER(pwm_display_device::frame_tick) { const double frame_time = m_framerate.as_double(); const double factor0 = m_interpolation; const double factor1 = 1.0 - factor0; // determine brightness cutoff u8 max_levels = 1; for (; m_levels[max_levels] < 1.0; max_levels++) { ; } double cutoff = m_level_max; if (cutoff == 0.0) cutoff = 4 * m_levels[max_levels - 1]; if (cutoff > 1.0) cutoff = 1.0; sync(); // final timeslice for (int y = 0; y < m_height; y++) { u64 multi_row[0x40]; std::fill(std::begin(multi_row), std::end(multi_row), 0); for (int x = 0; x <= m_width; x++) { // determine brightness level double bri = m_bri[y][x] * factor1 + (m_acc[y][x].as_double() / frame_time) * factor0; if (bri > cutoff) bri = cutoff; m_bri[y][x] = bri; u8 level; for (level = 0; bri > m_levels[level]; level++) { ; } // output to y.x, or y.a when always-on if (x != m_width) { multi_row[level] |= (u64(1) << x); if (m_external_output) m_output_x_cb(x << 6 | y, level); else m_out_x[y][x] = level; } else { if (m_external_output) m_output_a_cb(y, level); else m_out_a[y] = level; } } // multi-state outputs if (m_segmask[y] != 0) { u64 digit_row = 0; for (int b = 0; b <= max_levels; b++) { multi_row[b] &= m_segmask[y]; if (b > m_level_min) digit_row |= multi_row[b]; // output to multiy.b if (m_external_output) m_output_multi_cb(b << 6 | y, digit_row); else m_out_multi[y][b] = multi_row[b]; } // output to digity (single brightness level) if (m_external_output) m_output_digit_cb(y, digit_row); else m_out_digit[y] = digit_row; } } schedule_frame(); } void pwm_display_device::sync() { const attotime now = machine().time(); const attotime last = m_sync_time; if (last >= now) return; m_sync_time = now; const attotime diff = now - last; u64 sel = m_rowsel; // accumulate active time for (int y = 0; y < m_height; y++) { u64 row = m_rowdata[y]; if (sel & 1) m_acc[y][m_width] += diff; for (int x = 0; x < m_width; x++) { if (row & 1) m_acc[y][x] += diff; row >>= 1; } sel >>= 1; } }