1 // ImGui Platform Binding for: FreeGLUT
2 // This needs to be used along with a Renderer (e.g. OpenGL2)
3
4 // Issues:
5 // [ ] Platform: GLUT is unable to distinguish e.g. Backspace from CTRL+H or TAB from CTRL+I
6
7 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
8 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
9 // https://github.com/ocornut/imgui
10
11 // CHANGELOG
12 // (minor and older changes stripped away, please see git history for details)
13 // 2018-03-22: Added FreeGLUT Platform binding.
14
15 #include "imgui.h"
16 #include "imgui_impl_freeglut.h"
17 #include <GL/freeglut.h>
18
19 #ifdef _MSC_VER
20 #pragma warning (disable: 4505) // unreferenced local function has been removed (stb stuff)
21 #endif
22
23 static int g_Time = 0; // Current time, in milliseconds
24
ImGui_ImplFreeGLUT_Init()25 bool ImGui_ImplFreeGLUT_Init()
26 {
27 ImGuiIO& io = ImGui::GetIO();
28 g_Time = 0;
29
30 // Glut has 1 function for characters and one for "special keys". We map the characters in the 0..255 range and the keys above.
31 io.KeyMap[ImGuiKey_Tab] = '\t'; // == 9 == CTRL+I
32 io.KeyMap[ImGuiKey_LeftArrow] = 256 + GLUT_KEY_LEFT;
33 io.KeyMap[ImGuiKey_RightArrow] = 256 + GLUT_KEY_RIGHT;
34 io.KeyMap[ImGuiKey_UpArrow] = 256 + GLUT_KEY_UP;
35 io.KeyMap[ImGuiKey_DownArrow] = 256 + GLUT_KEY_DOWN;
36 io.KeyMap[ImGuiKey_PageUp] = 256 + GLUT_KEY_PAGE_UP;
37 io.KeyMap[ImGuiKey_PageDown] = 256 + GLUT_KEY_PAGE_DOWN;
38 io.KeyMap[ImGuiKey_Home] = 256 + GLUT_KEY_HOME;
39 io.KeyMap[ImGuiKey_End] = 256 + GLUT_KEY_END;
40 io.KeyMap[ImGuiKey_Insert] = 256 + GLUT_KEY_INSERT;
41 io.KeyMap[ImGuiKey_Delete] = 127;
42 io.KeyMap[ImGuiKey_Backspace] = 8; // == CTRL+H
43 io.KeyMap[ImGuiKey_Space] = ' ';
44 io.KeyMap[ImGuiKey_Enter] = 13; // == CTRL+M
45 io.KeyMap[ImGuiKey_Escape] = 27;
46 io.KeyMap[ImGuiKey_A] = 'A';
47 io.KeyMap[ImGuiKey_C] = 'C';
48 io.KeyMap[ImGuiKey_V] = 'V';
49 io.KeyMap[ImGuiKey_X] = 'X';
50 io.KeyMap[ImGuiKey_Y] = 'Y';
51 io.KeyMap[ImGuiKey_Z] = 'Z';
52
53 return true;
54 }
55
ImGui_ImplFreeGLUT_InstallFuncs()56 void ImGui_ImplFreeGLUT_InstallFuncs()
57 {
58 glutReshapeFunc(ImGui_ImplFreeGLUT_ReshapeFunc);
59 glutMotionFunc(ImGui_ImplFreeGLUT_MotionFunc);
60 glutPassiveMotionFunc(ImGui_ImplFreeGLUT_MotionFunc);
61 glutMouseFunc(ImGui_ImplFreeGLUT_MouseFunc);
62 glutMouseWheelFunc(ImGui_ImplFreeGLUT_MouseWheelFunc);
63 glutKeyboardFunc(ImGui_ImplFreeGLUT_KeyboardFunc);
64 glutKeyboardUpFunc(ImGui_ImplFreeGLUT_KeyboardUpFunc);
65 glutSpecialFunc(ImGui_ImplFreeGLUT_SpecialFunc);
66 glutSpecialUpFunc(ImGui_ImplFreeGLUT_SpecialUpFunc);
67 }
68
ImGui_ImplFreeGLUT_Shutdown()69 void ImGui_ImplFreeGLUT_Shutdown()
70 {
71 }
72
ImGui_ImplFreeGLUT_NewFrame()73 void ImGui_ImplFreeGLUT_NewFrame()
74 {
75 // Setup time step
76 ImGuiIO& io = ImGui::GetIO();
77 int current_time = glutGet(GLUT_ELAPSED_TIME);
78 io.DeltaTime = (current_time - g_Time) / 1000.0f;
79 g_Time = current_time;
80
81 // Start the frame
82 ImGui::NewFrame();
83 }
84
ImGui_ImplFreeGLUT_UpdateKeyboardMods()85 static void ImGui_ImplFreeGLUT_UpdateKeyboardMods()
86 {
87 ImGuiIO& io = ImGui::GetIO();
88 int mods = glutGetModifiers();
89 io.KeyCtrl = (mods & GLUT_ACTIVE_CTRL) != 0;
90 io.KeyShift = (mods & GLUT_ACTIVE_SHIFT) != 0;
91 io.KeyAlt = (mods & GLUT_ACTIVE_ALT) != 0;
92 }
93
ImGui_ImplFreeGLUT_KeyboardFunc(unsigned char c,int x,int y)94 void ImGui_ImplFreeGLUT_KeyboardFunc(unsigned char c, int x, int y)
95 {
96 // Send character to imgui
97 //printf("char_down_func %d '%c'\n", c, c);
98 ImGuiIO& io = ImGui::GetIO();
99 if (c >= 32)
100 io.AddInputCharacter(c);
101
102 // Store letters in KeysDown[] array as both uppercase and lowercase + Handle GLUT translating CTRL+A..CTRL+Z as 1..26.
103 // 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.
104 if (c >= 1 && c <= 26)
105 io.KeysDown[c] = io.KeysDown[c - 1 + 'a'] = io.KeysDown[c - 1 + 'A'] = true;
106 else if (c >= 'a' && c <= 'z')
107 io.KeysDown[c] = io.KeysDown[c - 'a' + 'A'] = true;
108 else if (c >= 'A' && c <= 'Z')
109 io.KeysDown[c] = io.KeysDown[c - 'A' + 'a'] = true;
110 else
111 io.KeysDown[c] = true;
112 ImGui_ImplFreeGLUT_UpdateKeyboardMods();
113 (void)x; (void)y; // Unused
114 }
115
ImGui_ImplFreeGLUT_KeyboardUpFunc(unsigned char c,int x,int y)116 void ImGui_ImplFreeGLUT_KeyboardUpFunc(unsigned char c, int x, int y)
117 {
118 //printf("char_up_func %d '%c'\n", c, c);
119 ImGuiIO& io = ImGui::GetIO();
120 if (c >= 1 && c <= 26)
121 io.KeysDown[c] = io.KeysDown[c - 1 + 'a'] = io.KeysDown[c - 1 + 'A'] = false;
122 else if (c >= 'a' && c <= 'z')
123 io.KeysDown[c] = io.KeysDown[c - 'a' + 'A'] = false;
124 else if (c >= 'A' && c <= 'Z')
125 io.KeysDown[c] = io.KeysDown[c - 'A' + 'a'] = false;
126 else
127 io.KeysDown[c] = false;
128 ImGui_ImplFreeGLUT_UpdateKeyboardMods();
129 (void)x; (void)y; // Unused
130 }
131
ImGui_ImplFreeGLUT_SpecialFunc(int key,int x,int y)132 void ImGui_ImplFreeGLUT_SpecialFunc(int key, int x, int y)
133 {
134 //printf("key_down_func %d\n", key);
135 ImGuiIO& io = ImGui::GetIO();
136 if (key + 256 < IM_ARRAYSIZE(io.KeysDown))
137 io.KeysDown[key + 256] = true;
138 ImGui_ImplFreeGLUT_UpdateKeyboardMods();
139 (void)x; (void)y; // Unused
140 }
141
ImGui_ImplFreeGLUT_SpecialUpFunc(int key,int x,int y)142 void ImGui_ImplFreeGLUT_SpecialUpFunc(int key, int x, int y)
143 {
144 //printf("key_up_func %d\n", key);
145 ImGuiIO& io = ImGui::GetIO();
146 if (key + 256 < IM_ARRAYSIZE(io.KeysDown))
147 io.KeysDown[key + 256] = false;
148 ImGui_ImplFreeGLUT_UpdateKeyboardMods();
149 (void)x; (void)y; // Unused
150 }
151
ImGui_ImplFreeGLUT_MouseFunc(int glut_button,int state,int x,int y)152 void ImGui_ImplFreeGLUT_MouseFunc(int glut_button, int state, int x, int y)
153 {
154 ImGuiIO& io = ImGui::GetIO();
155 io.MousePos = ImVec2((float)x, (float)y);
156 int button = -1;
157 if (glut_button == GLUT_LEFT_BUTTON) button = 0;
158 if (glut_button == GLUT_RIGHT_BUTTON) button = 1;
159 if (glut_button == GLUT_MIDDLE_BUTTON) button = 2;
160 if (button != -1 && state == GLUT_DOWN)
161 io.MouseDown[button] = true;
162 if (button != -1 && state == GLUT_UP)
163 io.MouseDown[button] = false;
164 }
165
ImGui_ImplFreeGLUT_MouseWheelFunc(int button,int dir,int x,int y)166 void ImGui_ImplFreeGLUT_MouseWheelFunc(int button, int dir, int x, int y)
167 {
168 ImGuiIO& io = ImGui::GetIO();
169 io.MousePos = ImVec2((float)x, (float)y);
170 if (dir > 0)
171 io.MouseWheel += 1.0;
172 else if (dir < 0)
173 io.MouseWheel -= 1.0;
174 (void)button; // Unused
175 }
176
ImGui_ImplFreeGLUT_ReshapeFunc(int w,int h)177 void ImGui_ImplFreeGLUT_ReshapeFunc(int w, int h)
178 {
179 ImGuiIO& io = ImGui::GetIO();
180 io.DisplaySize = ImVec2((float)w, (float)h);
181 }
182
ImGui_ImplFreeGLUT_MotionFunc(int x,int y)183 void ImGui_ImplFreeGLUT_MotionFunc(int x, int y)
184 {
185 ImGuiIO& io = ImGui::GetIO();
186 io.MousePos = ImVec2((float)x, (float)y);
187 }
188