Upgraded hid interface

src/commands.h

@@ -0,0 +1,35 @@
+#pragma once
+
+// Sent by host when connection is initiated.
+#define CMD_HELLO 0x00
+
+// Send keyboard state to host.
+//
+// Packet structure:
+// Data:		| cmd | anim state |
+// # of Bytes:	|  1  |     1      |
+//
+// anim state:
+// 0x00: RGBMatrix disabled
+// 0x01: normal animation, no HID data.
+// 0x02: FFT Animation
+#define CMD_SEND_STATE 0x01
+
+
+// Animation data. Sent by host.
+//
+// Packet structure:
+// Data:		| cmd | data type | data |
+// # of Bytes:	|  1  |     1     |  ?   |
+//
+// data type:
+// Which animation this data is for. These are defined below.
+//
+// data:
+// Animation data. Content depends on data type.
+#define CMD_ANIM_DATA 0x02
+
+// Data for FFT animation.
+// Data segment consists of 10 bits, each representing the height of a column.
+// Minimum height is 0, maximum is 250.
+#define CMD_ANIM_DATA_fft 0x00

src/config.h

@@ -0,0 +1,5 @@
+#pragma once
+
+// USB packet size, in bytes.
+// Usually 32, but depends on keyboard.
+#define RAW_EPSIZE 32

src/ergodox.cpp

@@ -1,7 +1,6 @@
 #include "ergodox.hpp"
 
 
-
 Ergodox::Ergodox(
 	unsigned short vendor_id,
 	unsigned short product_id,
@@ -64,6 +63,9 @@ Ergodox::~Ergodox() {
 Try to open this keyboard's hid device.
 Throws a runtime error if device is already open,
 or if we can't find a device with the given params.
+
+If we successfully open a device, this method sends a
+CMD_HELLO packet.
 */
 void Ergodox::open() {
 	if (handle != NULL) {
@@ -94,6 +96,10 @@ void Ergodox::open() {
 		hid_free_enumeration(devs);
 		throw std::runtime_error("Could not open hid device");
 	}
+
+	hid_set_nonblocking(handle, 1);
+
+	write(CMD_HELLO, NULL, 0);
 }
 
 
@@ -108,14 +114,64 @@ void Ergodox::close() {
 /*
 Send data to Ergodox.
 
+@param cmd Command byte
 @param data Data to send
-@param length How many bytes to send
-@returns Actual number of bytes written, or -1 on error.
+@returns data_len Data length. Must be shorter than packet_size.
 */
-int Ergodox::write(uint8_t* data, size_t length) const {
+int Ergodox::write(uint8_t cmd, const uint8_t* data, uint8_t data_len) const {
 	if (handle == NULL) {
 		throw std::runtime_error("Cannot write, device is not open!");
 	}
 
-	return hid_write(handle, data, length);
+	if (data_len > packet_size) {
+		throw std::runtime_error("Data length exceeds packet size");
+	}
+
+	if (data == NULL) {
+		data = {0x00};
+	}
+
+	uint8_t packet[packet_size];
+	packet[0] = 0x00; // Report number. Not seen by keyboard.
+	packet[1] = cmd;  // First byte is always command
+
+	// Copy data into rest of packet
+	std::copy(data, data + data_len, packet + 2);
+
+	return hid_write(handle, packet, packet_size + 1);
+}
+
+
+/*
+Read data from Ergodox into read_buf. If a CMD_SEND_STATE packet is received, process it and return false.
+
+@returns True if a new command was received, false otherwise.
+*/
+bool Ergodox::read() {
+	if (handle == NULL) {
+		throw std::runtime_error("Cannot write, device is not open!");
+	}
+	ssize_t res;
+	res = hid_read(handle, read_buf, packet_size);
+
+	if (res == 0) {
+		return false;
+	} else if (res < 0) {
+		throw std::runtime_error("Read failed.");
+	}
+
+	switch(read_buf[0]) {
+
+		// If keyboard sends a state packet, parse it.
+		case CMD_SEND_STATE:
+			if (animation_mode != read_buf[1]) {
+				wprintf(L"Mode set to %#x\n", read_buf[1]);
+				animation_mode = read_buf[1];
+			}
+
+			// Main code should not parse state packets.
+			return false;
+	}
+
+	return res > 0;
 }

src/ergodox.hpp

@@ -5,12 +5,24 @@
 #include <wchar.h>
 #include "hidapi.h"
 
+#include "config.h"
+#include "commands.h"
+
+
 /*
 A singleton Ergodox interface. Wraps all hidapi methods, including
 hid_init() and hid_exit().
 */
 class Ergodox {
 	public:
+
+		// USB Device paramaters
+		const unsigned short vendor_id;
+		const unsigned short product_id;
+		const unsigned short usage;
+		const unsigned short usage_page;
+		const uint8_t packet_size = RAW_EPSIZE;
+
 		static Ergodox& init(
 			unsigned short vendor_id,
 			unsigned short product_id,
@@ -20,11 +32,15 @@ class Ergodox {
 
 		~Ergodox();
 
-		int write(
-			uint8_t* data,
-			size_t length
-		) const;
+		int write(uint8_t cmd, const uint8_t* data, uint8_t data_len) const;
 
+		bool read();
+
+		// Read buffer, len = packet_size.
+		// Filled by read().
+		uint8_t read_buf[RAW_EPSIZE];
+
+		uint8_t get_animation_mode() const { return animation_mode; }
 
 	private:
 		Ergodox(
@@ -42,13 +58,11 @@ class Ergodox {
 		void open();
 		void close();
 
-		// USB Device paramaters
-		const unsigned short vendor_id;
-		const unsigned short product_id;
-		const unsigned short usage;
-		const unsigned short usage_page;
-
 		// HID device.
 		// NULL if not opened.
 		hid_device* handle;
+
+		// Keyboard state variables.
+		// Updated by read().
+		uint8_t animation_mode;
 };

src/test.cpp

@@ -2,7 +2,6 @@
 #include <cstdint>
 #include <vector>
 #include <stdexcept>
-
 // For reading FIFO
 #include <fcntl.h>
 #include <unistd.h>
@@ -12,6 +11,7 @@
 #include "utility/buffer.hpp"
 #include "signal_processing/fft.hpp"
 #include "ergodox.hpp"
+#include "commands.h"
 
 
 // TODO:
@@ -38,8 +38,19 @@ void draw_spectrum_bitmap(
 	}
 }
 
+
+
+// How many keys in a column * resolution per key.
+// this MUST fit inside a uint8_t.
+const uint8_t kb_resolution = 5 * 50;
+
+// How many resolution steps to skip at the top and bottom.
+const size_t bottom_skip = 25;
+const size_t top_skip = 50;
+
+
 const size_t width = 12;
-const size_t height = 150;
+const size_t height = bottom_skip + kb_resolution + top_skip;
 
 
 int main(int argc, char *argv[]) {
@@ -52,7 +63,7 @@ int main(int argc, char *argv[]) {
 	// FFT generator
 	FFT_Visualizer fft = FFT_Visualizer(
 		width, height,
-		100, 10000
+		100, 5000
 	);
 
 	// Audio buffer
@@ -70,24 +81,40 @@ int main(int argc, char *argv[]) {
 		0xFF60
 	);
 
-	// Data buffer
+	// Write buffer
 	uint8_t hid_buf[12];
 
-
 	while (1) {
-		buf.update();
-		fft.update(buf);
 
-		hid_buf[0] = 0x01;
-		hid_buf[1] = 0x02;
-		for (size_t i = 0; i < 10; i++) {
-			ssize_t h = fft.get_output()[i + 1] - 10;
-			h = h>100 ? 100 : h;
-			h = h<0 ? 0 : h;
-			hid_buf[i + 2] = h;
+
+		if (Dox.get_animation_mode() == 0x02) {
+			buf.update();
+			fft.update(buf);
+
+			hid_buf[0] = CMD_ANIM_DATA_fft;
+			for (size_t i = 0; i < 10; i++) {
+				// Get height from fft, apply bottom_skip
+				ssize_t h = fft.get_output()[i + 1] - bottom_skip;
+
+				// Enforce max and min
+				// max implicitly enforces top_skip
+				h = h>kb_resolution ? kb_resolution : h;
+				h = h<0 ? 0 : h;
+
+				hid_buf[i + 1] = h;
+			}
+			Dox.write(CMD_ANIM_DATA, hid_buf, 13);
 		}
 
-		Dox.write(hid_buf, 12);
+		// Read a packet if there is a packet to read
+		if (Dox.read()) {
+			uint8_t cmd = Dox.read_buf[0];
+
+			switch(cmd) {
+				case CMD_SEND_STATE:
+					break;
+			}
+		}
 	}
 
 	return 0;