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Backends: GLUT: Update to use io.AddEventKey() will full key map (#2625
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…, #4858)
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thedmd authored and ocornut committed Jan 10, 2022
1 parent 1bfe4a7 commit da1864d
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185 changes: 134 additions & 51 deletions backends/imgui_impl_glut.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -5,19 +5,22 @@
// !!! If someone or something is teaching you GLUT today, you are being abused. Please show some resistance. !!!
// !!! Nowadays, prefer using GLFW or SDL instead!

// Implemented features:
// [X] Platform: Partial keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy GLUT values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
// Issues:
// [ ] Platform: GLUT is unable to distinguish e.g. Backspace from CTRL+H or TAB from CTRL+I
// [ ] Platform: Missing mouse cursor shape/visibility support.
// [ ] Platform: Missing clipboard support (not supported by Glut).
// [ ] Platform: Missing gamepad support.

// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs

// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
// 2022-01-10: Inputs: calling new io.AddKeyEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
// 2019-04-03: Misc: Renamed imgui_impl_freeglut.cpp/.h to imgui_impl_glut.cpp/.h.
// 2019-03-25: Misc: Made io.DeltaTime always above zero.
// 2018-11-30: Misc: Setting up io.BackendPlatformName so it can be displayed in the About Window.
Expand All @@ -37,6 +40,120 @@

static int g_Time = 0; // Current time, in milliseconds

// Glut has 1 function for characters and one for "special keys". We map the characters in the 0..255 range and the keys above.
static ImGuiKey ImGui_ImplGLUT_KeyToImGuiKey(int key)
{
switch (key)
{
case '\t': return ImGuiKey_Tab;
case 256 + GLUT_KEY_LEFT: return ImGuiKey_LeftArrow;
case 256 + GLUT_KEY_RIGHT: return ImGuiKey_RightArrow;
case 256 + GLUT_KEY_UP: return ImGuiKey_UpArrow;
case 256 + GLUT_KEY_DOWN: return ImGuiKey_DownArrow;
case 256 + GLUT_KEY_PAGE_UP: return ImGuiKey_PageUp;
case 256 + GLUT_KEY_PAGE_DOWN: return ImGuiKey_PageDown;
case 256 + GLUT_KEY_HOME: return ImGuiKey_Home;
case 256 + GLUT_KEY_END: return ImGuiKey_End;
case 256 + GLUT_KEY_INSERT: return ImGuiKey_Insert;
case 127: return ImGuiKey_Delete;
case 8: return ImGuiKey_Backspace;
case ' ': return ImGuiKey_Space;
case 13: return ImGuiKey_Enter;
case 27: return ImGuiKey_Escape;
case 39: return ImGuiKey_Apostrophe;
case 44: return ImGuiKey_Comma;
case 45: return ImGuiKey_Minus;
case 46: return ImGuiKey_Period;
case 47: return ImGuiKey_Slash;
case 59: return ImGuiKey_Semicolon;
case 61: return ImGuiKey_Equal;
case 91: return ImGuiKey_LeftBracket;
case 92: return ImGuiKey_Backslash;
case 93: return ImGuiKey_RightBracket;
case 96: return ImGuiKey_GraveAccent;
//case 0: return ImGuiKey_CapsLock;
//case 0: return ImGuiKey_ScrollLock;
case 256 + 0x006D: return ImGuiKey_NumLock;
//case 0: return ImGuiKey_PrintScreen;
//case 0: return ImGuiKey_Pause;
//case '0': return ImGuiKey_Keypad0;
//case '1': return ImGuiKey_Keypad1;
//case '2': return ImGuiKey_Keypad2;
//case '3': return ImGuiKey_Keypad3;
//case '4': return ImGuiKey_Keypad4;
//case '5': return ImGuiKey_Keypad5;
//case '6': return ImGuiKey_Keypad6;
//case '7': return ImGuiKey_Keypad7;
//case '8': return ImGuiKey_Keypad8;
//case '9': return ImGuiKey_Keypad9;
//case 46: return ImGuiKey_KeypadDecimal;
//case 47: return ImGuiKey_KeypadDivide;
case 42: return ImGuiKey_KeypadMultiply;
//case 45: return ImGuiKey_KeypadSubtract;
case 43: return ImGuiKey_KeypadAdd;
//case 13: return ImGuiKey_KeypadEnter;
//case 0: return ImGuiKey_KeypadEqual;
case 256 + 0x0070: return ImGuiKey_LeftShift;
case 256 + 0x0072: return ImGuiKey_LeftControl;
case 256 + 0x0074: return ImGuiKey_LeftAlt;
//case 0: return ImGuiKey_LeftSuper;
case 256 + 0x0071: return ImGuiKey_RightShift;
case 256 + 0x0073: return ImGuiKey_RightControl;
case 256 + 0x0075: return ImGuiKey_RightAlt;
//case 0: return ImGuiKey_RightSuper;
//case 0: return ImGuiKey_Menu;
case '0': return ImGuiKey_0;
case '1': return ImGuiKey_1;
case '2': return ImGuiKey_2;
case '3': return ImGuiKey_3;
case '4': return ImGuiKey_4;
case '5': return ImGuiKey_5;
case '6': return ImGuiKey_6;
case '7': return ImGuiKey_7;
case '8': return ImGuiKey_8;
case '9': return ImGuiKey_9;
case 'A': case 'a': return ImGuiKey_A;
case 'B': case 'b': return ImGuiKey_B;
case 'C': case 'c': return ImGuiKey_C;
case 'D': case 'd': return ImGuiKey_D;
case 'E': case 'e': return ImGuiKey_E;
case 'F': case 'f': return ImGuiKey_F;
case 'G': case 'g': return ImGuiKey_G;
case 'H': case 'h': return ImGuiKey_H;
case 'I': case 'i': return ImGuiKey_I;
case 'J': case 'j': return ImGuiKey_J;
case 'K': case 'k': return ImGuiKey_K;
case 'L': case 'l': return ImGuiKey_L;
case 'M': case 'm': return ImGuiKey_M;
case 'N': case 'n': return ImGuiKey_N;
case 'O': case 'o': return ImGuiKey_O;
case 'P': case 'p': return ImGuiKey_P;
case 'Q': case 'q': return ImGuiKey_Q;
case 'R': case 'r': return ImGuiKey_R;
case 'S': case 's': return ImGuiKey_S;
case 'T': case 't': return ImGuiKey_T;
case 'U': case 'u': return ImGuiKey_U;
case 'V': case 'v': return ImGuiKey_V;
case 'W': case 'w': return ImGuiKey_W;
case 'X': case 'x': return ImGuiKey_X;
case 'Y': case 'y': return ImGuiKey_Y;
case 'Z': case 'z': return ImGuiKey_Z;
case 256 + GLUT_KEY_F1: return ImGuiKey_F1;
case 256 + GLUT_KEY_F2: return ImGuiKey_F2;
case 256 + GLUT_KEY_F3: return ImGuiKey_F3;
case 256 + GLUT_KEY_F4: return ImGuiKey_F4;
case 256 + GLUT_KEY_F5: return ImGuiKey_F5;
case 256 + GLUT_KEY_F6: return ImGuiKey_F6;
case 256 + GLUT_KEY_F7: return ImGuiKey_F7;
case 256 + GLUT_KEY_F8: return ImGuiKey_F8;
case 256 + GLUT_KEY_F9: return ImGuiKey_F9;
case 256 + GLUT_KEY_F10: return ImGuiKey_F10;
case 256 + GLUT_KEY_F11: return ImGuiKey_F11;
case 256 + GLUT_KEY_F12: return ImGuiKey_F12;
default: return ImGuiKey_None;
}
}

bool ImGui_ImplGLUT_Init()
{
ImGuiIO& io = ImGui::GetIO();
Expand All @@ -46,33 +163,8 @@ bool ImGui_ImplGLUT_Init()
#else
io.BackendPlatformName = "imgui_impl_glut";
#endif

g_Time = 0;

// Glut has 1 function for characters and one for "special keys". We map the characters in the 0..255 range and the keys above.
io.KeyMap[ImGuiKey_Tab] = '\t'; // == 9 == CTRL+I
io.KeyMap[ImGuiKey_LeftArrow] = 256 + GLUT_KEY_LEFT;
io.KeyMap[ImGuiKey_RightArrow] = 256 + GLUT_KEY_RIGHT;
io.KeyMap[ImGuiKey_UpArrow] = 256 + GLUT_KEY_UP;
io.KeyMap[ImGuiKey_DownArrow] = 256 + GLUT_KEY_DOWN;
io.KeyMap[ImGuiKey_PageUp] = 256 + GLUT_KEY_PAGE_UP;
io.KeyMap[ImGuiKey_PageDown] = 256 + GLUT_KEY_PAGE_DOWN;
io.KeyMap[ImGuiKey_Home] = 256 + GLUT_KEY_HOME;
io.KeyMap[ImGuiKey_End] = 256 + GLUT_KEY_END;
io.KeyMap[ImGuiKey_Insert] = 256 + GLUT_KEY_INSERT;
io.KeyMap[ImGuiKey_Delete] = 127;
io.KeyMap[ImGuiKey_Backspace] = 8; // == CTRL+H
io.KeyMap[ImGuiKey_Space] = ' ';
io.KeyMap[ImGuiKey_Enter] = 13; // == CTRL+M
io.KeyMap[ImGuiKey_Escape] = 27;
io.KeyMap[ImGuiKey_KeypadEnter] = 13; // == CTRL+M
io.KeyMap[ImGuiKey_A] = 'A';
io.KeyMap[ImGuiKey_C] = 'C';
io.KeyMap[ImGuiKey_V] = 'V';
io.KeyMap[ImGuiKey_X] = 'X';
io.KeyMap[ImGuiKey_Y] = 'Y';
io.KeyMap[ImGuiKey_Z] = 'Z';

return true;
}

Expand Down Expand Up @@ -117,6 +209,14 @@ static void ImGui_ImplGLUT_UpdateKeyboardMods()
io.KeyCtrl = (mods & GLUT_ACTIVE_CTRL) != 0;
io.KeyShift = (mods & GLUT_ACTIVE_SHIFT) != 0;
io.KeyAlt = (mods & GLUT_ACTIVE_ALT) != 0;
io.KeySuper = false;
}

static void ImGui_ImplGLUT_AddKeyEvent(ImGuiKey key, bool down, int native_keycode)
{
ImGuiIO& io = ImGui::GetIO();
io.AddKeyEvent(key, down);
io.SetKeyEventNativeData(key, native_keycode, -1); // To support legacy indexing (<1.87 user code)
}

void ImGui_ImplGLUT_KeyboardFunc(unsigned char c, int x, int y)
Expand All @@ -127,52 +227,35 @@ void ImGui_ImplGLUT_KeyboardFunc(unsigned char c, int x, int y)
if (c >= 32)
io.AddInputCharacter((unsigned int)c);

// Store letters in KeysDown[] array as both uppercase and lowercase + Handle GLUT translating CTRL+A..CTRL+Z as 1..26.
// This is a hacky mess but GLUT is unable to distinguish e.g. a TAB key from CTRL+I so this is probably the best we can do here.
if (c >= 1 && c <= 26)
io.KeysDown[c] = io.KeysDown[c - 1 + 'a'] = io.KeysDown[c - 1 + 'A'] = true;
else if (c >= 'a' && c <= 'z')
io.KeysDown[c] = io.KeysDown[c - 'a' + 'A'] = true;
else if (c >= 'A' && c <= 'Z')
io.KeysDown[c] = io.KeysDown[c - 'A' + 'a'] = true;
else
io.KeysDown[c] = true;
ImGuiKey key = ImGui_ImplGLUT_KeyToImGuiKey(c);
ImGui_ImplGLUT_AddKeyEvent(key, true, c);
ImGui_ImplGLUT_UpdateKeyboardMods();
(void)x; (void)y; // Unused
}

void ImGui_ImplGLUT_KeyboardUpFunc(unsigned char c, int x, int y)
{
//printf("char_up_func %d '%c'\n", c, c);
ImGuiIO& io = ImGui::GetIO();
if (c >= 1 && c <= 26)
io.KeysDown[c] = io.KeysDown[c - 1 + 'a'] = io.KeysDown[c - 1 + 'A'] = false;
else if (c >= 'a' && c <= 'z')
io.KeysDown[c] = io.KeysDown[c - 'a' + 'A'] = false;
else if (c >= 'A' && c <= 'Z')
io.KeysDown[c] = io.KeysDown[c - 'A' + 'a'] = false;
else
io.KeysDown[c] = false;
ImGuiKey key = ImGui_ImplGLUT_KeyToImGuiKey(c);
ImGui_ImplGLUT_AddKeyEvent(key, false, c);
ImGui_ImplGLUT_UpdateKeyboardMods();
(void)x; (void)y; // Unused
}

void ImGui_ImplGLUT_SpecialFunc(int key, int x, int y)
{
//printf("key_down_func %d\n", key);
ImGuiIO& io = ImGui::GetIO();
if (key + 256 < IM_ARRAYSIZE(io.KeysDown))
io.KeysDown[key + 256] = true;
ImGuiKey imgui_key = ImGui_ImplGLUT_KeyToImGuiKey(key + 256);
ImGui_ImplGLUT_AddKeyEvent(imgui_key, true, key + 256);
ImGui_ImplGLUT_UpdateKeyboardMods();
(void)x; (void)y; // Unused
}

void ImGui_ImplGLUT_SpecialUpFunc(int key, int x, int y)
{
//printf("key_up_func %d\n", key);
ImGuiIO& io = ImGui::GetIO();
if (key + 256 < IM_ARRAYSIZE(io.KeysDown))
io.KeysDown[key + 256] = false;
ImGuiKey imgui_key = ImGui_ImplGLUT_KeyToImGuiKey(key + 256);
ImGui_ImplGLUT_AddKeyEvent(imgui_key, false, key + 256);
ImGui_ImplGLUT_UpdateKeyboardMods();
(void)x; (void)y; // Unused
}
Expand Down
4 changes: 3 additions & 1 deletion backends/imgui_impl_glut.h
Original file line number Diff line number Diff line change
Expand Up @@ -5,13 +5,15 @@
// !!! If someone or something is teaching you GLUT today, you are being abused. Please show some resistance. !!!
// !!! Nowadays, prefer using GLFW or SDL instead!

// Implemented features:
// [X] Platform: Partial keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy GLUT values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
// Issues:
// [ ] Platform: GLUT is unable to distinguish e.g. Backspace from CTRL+H or TAB from CTRL+I
// [ ] Platform: Missing mouse cursor shape/visibility support.
// [ ] Platform: Missing clipboard support (not supported by Glut).
// [ ] Platform: Missing gamepad support.

// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs
Expand Down

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