预期行为:中音 C 在一台 MIDI 乐器上演奏,然后在另一台上演奏。实际行为:DL 弃用警告且没有声音。运行 Windows 7。
代码:
require "dl/import"
class LiveMIDI
ON = 0x90
OFF =0x80
PC = 0xc0
def initialize
open
end
def note_on(channel, note, velocity=64)
message(ON | channel, note, velocity)
end
def note_off(channel, note, velocity=64)
message(OFF | channel, note, velocity)
end
def program_change(channel, preset)
message(PC | channel, preset)
end
module C
extend DL::Importer
dlload "winmm"
extern "int midiOutOpen(HMIDIOUT*, int, int, int, int)"
extern "int midiOutClose(int)"
extern "int midiOutShortMsg(int, int)"
end
def open
@device = DL.malloc(DL::Importer.sizeof("int"))
C.midiOutOpen(@device, -1, 0, 0, 0)
end
def close
C.midiOutClose(@device.ptr.to_i)
end
def message(one, two=0, three=0)
message = one + (two << 8) + (three << 16)
C.midiOutShortMsg(DL::CPtr.to_ptr(@device).to_i, message)
end
end
midi = LiveMIDI.new
midi.note_on(0, 60, 100)
sleep(1)
midi.note_off(0, 60)
midi.program_change(1, 40)
midi.note_on(1, 60, 100)
sleep(1)
midi.note_off(1, 60)
摘自《实用 Ruby 项目》一书。根据第 2 章中页面上的数字 11-15。代码稍作修改以处理 Ruby 1.9 中对 Ruby DL 的更改。
最佳答案
你必须写
DL::CPtr.malloc(DL::Importer.sizeof("int")
而不是
DL.malloc(DL::Importer.sizeof("int"))
创建一个指针对象(DL::CPtr
),而不仅仅是获取整数地址。
还有
DL::CPtr.to_ptr(@device).to_i
必须是
@device.ptr.to_i
或者甚至
@device.ptr
这是使用 DL 替换 Fiddle 的代码的修复版本:
require 'fiddle/import'
require 'fiddle/types'
class LiveMIDI
ON = 0x90
OFF = 0x80
PC = 0xc0
def initialize
open
end
def note_on(channel, note, velocity = 64)
message(ON | channel, note, velocity)
end
def note_off(channel, note, velocity = 64)
message(OFF | channel, note, velocity)
end
def program_change(channel, preset)
message(PC | channel, preset)
end
module C
extend Fiddle::Importer
dlload 'winmm'
# defines a few Windows-specific types such as DWORD or UINT
include Fiddle::Win32Types
# some other types not defined by the previous line
typealias 'HMIDIOUT', 'void*'
typealias 'LPHMIDIOUT', 'HMIDIOUT*'
typealias 'DWORD_PTR', 'uintptr_t'
typealias 'MMRESULT', 'UINT'
extern 'MMRESULT midiOutOpen(LPHMIDIOUT, UINT, DWORD_PTR, DWORD_PTR, DWORD)'
extern 'MMRESULT midiOutClose(HMIDIOUT)'
extern 'MMRESULT midiOutShortMsg(HMIDIOUT, DWORD)'
end
def open
@device = Fiddle::Pointer.malloc(Fiddle::SIZEOF_VOIDP)
C.midiOutOpen(@device, -1, 0, 0, 0)
end
def close
C.midiOutClose(@device.ptr)
end
def message(one, two = 0, three = 0)
message = one + (two << 8) + (three << 16)
C.midiOutShortMsg(@device.ptr, message)
end
end
除了我根据the documentation on MSDN添加或更正的类型内容之外,它或多或少是相同的。 。错误的类型可能会导致不明显的问题。
关于c - 没有声音。通过 RubyDL 使用 Ruby 和 winmm,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/32622432/