1 // ImGui Renderer for: OpenGL3 (modern OpenGL with shaders / programmatic pipeline)
2 // This needs to be used along with a Platform Binding (e.g. GLFW, SDL, Win32, custom..)
3 // (Note: We are using GL3W as a helper library to access OpenGL functions since there is no standard header to access modern OpenGL functions easily. Alternatives are GLEW, Glad, etc..)
4
5 // Implemented features:
6 // [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
7
8 // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
9 // If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
10 // https://github.com/ocornut/imgui
11
12 // CHANGELOG
13 // (minor and older changes stripped away, please see git history for details)
14 // 2018-07-10: OpenGL: Support for more GLSL versions (based on the GLSL version string). Added error output when shaders fail to compile/link.
15 // 2018-06-08: Misc: Extracted imgui_impl_opengl3.cpp/.h away from the old combined GLFW/SDL+OpenGL3 examples.
16 // 2018-06-08: OpenGL: Use draw_data->DisplayPos and draw_data->DisplaySize to setup projection matrix and clipping rectangle.
17 // 2018-05-25: OpenGL: Removed unnecessary backup/restore of GL_ELEMENT_ARRAY_BUFFER_BINDING since this is part of the VAO state.
18 // 2018-05-14: OpenGL: Making the call to glBindSampler() optional so 3.2 context won't fail if the function is a NULL pointer.
19 // 2018-03-06: OpenGL: Added const char* glsl_version parameter to ImGui_ImplOpenGL3_Init() so user can override the GLSL version e.g. "#version 150".
20 // 2018-02-23: OpenGL: Create the VAO in the render function so the setup can more easily be used with multiple shared GL context.
21 // 2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplSdlGL3_RenderDrawData() in the .h file so you can call it yourself.
22 // 2018-01-07: OpenGL: Changed GLSL shader version from 330 to 150.
23 // 2017-09-01: OpenGL: Save and restore current bound sampler. Save and restore current polygon mode.
24 // 2017-05-01: OpenGL: Fixed save and restore of current blend func state.
25 // 2017-05-01: OpenGL: Fixed save and restore of current GL_ACTIVE_TEXTURE.
26 // 2016-09-05: OpenGL: Fixed save and restore of current scissor rectangle.
27 // 2016-07-29: OpenGL: Explicitly setting GL_UNPACK_ROW_LENGTH to reduce issues because SDL changes it. (#752)
28
29 //----------------------------------------
30 // OpenGL GLSL GLSL
31 // version version string
32 //----------------------------------------
33 // 2.0 110 "#version 110"
34 // 2.1 120
35 // 3.0 130
36 // 3.1 140
37 // 3.2 150 "#version 150"
38 // 3.3 330
39 // 4.0 400
40 // 4.1 410
41 // 4.2 420
42 // 4.3 430
43 // ES 2.0 100 "#version 100"
44 // ES 3.0 300 "#version 300 es"
45 //----------------------------------------
46
47 #if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
48 #define _CRT_SECURE_NO_WARNINGS
49 #endif
50
51 #include "imgui/imgui.h"
52 #include "imgui_impl_opengl3.h"
53 #include <stdio.h>
54 #if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier
55 #include <stddef.h> // intptr_t
56 #else
57 #include <stdint.h> // intptr_t
58 #endif
59
60 #include <epoxy/gl.h>
61 //#include "gl3w.h" // This example is using gl3w to access OpenGL functions. You may use another OpenGL loader/header such as: glew, glext, glad, glLoadGen, etc.
62 //#include <glew.h>
63 //#include <glext.h>
64 //#include <glad/glad.h>
65
66 // OpenGL Data
67 static char g_GlslVersionString[32] = "";
68 static GLuint g_FontTexture = 0;
69 static GLuint g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
70 static int g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;
71 static int g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_AttribLocationColor = 0;
72 static unsigned int g_VboHandle = 0, g_ElementsHandle = 0;
73
74 // Functions
ImGui_ImplOpenGL3_Init(const char * glsl_version)75 bool ImGui_ImplOpenGL3_Init(const char* glsl_version)
76 {
77 // Store GLSL version string so we can refer to it later in case we recreate shaders. Note: GLSL version is NOT the same as GL version. Leave this to NULL if unsure.
78 if (glsl_version == NULL)
79 glsl_version = "#version 130";
80 IM_ASSERT((int)strlen(glsl_version) + 2 < IM_ARRAYSIZE(g_GlslVersionString));
81 strcpy(g_GlslVersionString, glsl_version);
82 strcat(g_GlslVersionString, "\n");
83 return true;
84 }
85
ImGui_ImplOpenGL3_Shutdown()86 void ImGui_ImplOpenGL3_Shutdown()
87 {
88 ImGui_ImplOpenGL3_DestroyDeviceObjects();
89 }
90
ImGui_ImplOpenGL3_NewFrame()91 void ImGui_ImplOpenGL3_NewFrame()
92 {
93 if (!g_FontTexture)
94 ImGui_ImplOpenGL3_CreateDeviceObjects();
95 }
96
97 // OpenGL3 Render function.
98 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
99 // Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
ImGui_ImplOpenGL3_RenderDrawData(ImDrawData * draw_data)100 void ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
101 {
102 // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
103 ImGuiIO& io = ImGui::GetIO();
104 int fb_width = (int)(draw_data->DisplaySize.x * io.DisplayFramebufferScale.x);
105 int fb_height = (int)(draw_data->DisplaySize.y * io.DisplayFramebufferScale.y);
106 if (fb_width <= 0 || fb_height <= 0)
107 return;
108 draw_data->ScaleClipRects(io.DisplayFramebufferScale);
109
110 // Backup GL state
111 GLenum last_active_texture; glGetIntegerv(GL_ACTIVE_TEXTURE, (GLint*)&last_active_texture);
112 glActiveTexture(GL_TEXTURE0);
113 GLint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
114 GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
115 GLint last_sampler; glGetIntegerv(GL_SAMPLER_BINDING, &last_sampler);
116 GLint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
117 GLint last_vertex_array; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
118 GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
119 GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
120 GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
121 GLenum last_blend_src_rgb; glGetIntegerv(GL_BLEND_SRC_RGB, (GLint*)&last_blend_src_rgb);
122 GLenum last_blend_dst_rgb; glGetIntegerv(GL_BLEND_DST_RGB, (GLint*)&last_blend_dst_rgb);
123 GLenum last_blend_src_alpha; glGetIntegerv(GL_BLEND_SRC_ALPHA, (GLint*)&last_blend_src_alpha);
124 GLenum last_blend_dst_alpha; glGetIntegerv(GL_BLEND_DST_ALPHA, (GLint*)&last_blend_dst_alpha);
125 GLenum last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, (GLint*)&last_blend_equation_rgb);
126 GLenum last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, (GLint*)&last_blend_equation_alpha);
127 GLboolean last_enable_blend = glIsEnabled(GL_BLEND);
128 GLboolean last_enable_cull_face = glIsEnabled(GL_CULL_FACE);
129 GLboolean last_enable_depth_test = glIsEnabled(GL_DEPTH_TEST);
130 GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
131
132 // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
133 glEnable(GL_BLEND);
134 glBlendEquation(GL_FUNC_ADD);
135 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
136 glDisable(GL_CULL_FACE);
137 glDisable(GL_DEPTH_TEST);
138 glEnable(GL_SCISSOR_TEST);
139 glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
140
141 // Setup viewport, orthographic projection matrix
142 // Our visible imgui space lies from draw_data->DisplayPps (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is typically (0,0) for single viewport apps.
143 glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
144 float L = draw_data->DisplayPos.x;
145 float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
146 float T = draw_data->DisplayPos.y;
147 float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
148 const float ortho_projection[4][4] =
149 {
150 { 2.0f/(R-L), 0.0f, 0.0f, 0.0f },
151 { 0.0f, 2.0f/(T-B), 0.0f, 0.0f },
152 { 0.0f, 0.0f, -1.0f, 0.0f },
153 { (R+L)/(L-R), (T+B)/(B-T), 0.0f, 1.0f },
154 };
155 glUseProgram(g_ShaderHandle);
156 glUniform1i(g_AttribLocationTex, 0);
157 glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
158 if (glBindSampler) glBindSampler(0, 0); // We use combined texture/sampler state. Applications using GL 3.3 may set that otherwise.
159
160 // Recreate the VAO every time
161 // (This is to easily allow multiple GL contexts. VAO are not shared among GL contexts, and we don't track creation/deletion of windows so we don't have an obvious key to use to cache them.)
162 GLuint vao_handle = 0;
163 glGenVertexArrays(1, &vao_handle);
164 glBindVertexArray(vao_handle);
165 glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
166 glEnableVertexAttribArray(g_AttribLocationPosition);
167 glEnableVertexAttribArray(g_AttribLocationUV);
168 glEnableVertexAttribArray(g_AttribLocationColor);
169 glVertexAttribPointer(g_AttribLocationPosition, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
170 glVertexAttribPointer(g_AttribLocationUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
171 glVertexAttribPointer(g_AttribLocationColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
172
173 // Draw
174 ImVec2 pos = draw_data->DisplayPos;
175 for (int n = 0; n < draw_data->CmdListsCount; n++)
176 {
177 const ImDrawList* cmd_list = draw_data->CmdLists[n];
178 const ImDrawIdx* idx_buffer_offset = 0;
179
180 glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
181 glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)cmd_list->VtxBuffer.Size * sizeof(ImDrawVert), (const GLvoid*)cmd_list->VtxBuffer.Data, GL_STREAM_DRAW);
182
183 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
184 glBufferData(GL_ELEMENT_ARRAY_BUFFER, (GLsizeiptr)cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx), (const GLvoid*)cmd_list->IdxBuffer.Data, GL_STREAM_DRAW);
185
186 for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
187 {
188 const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
189 if (pcmd->UserCallback)
190 {
191 // User callback (registered via ImDrawList::AddCallback)
192 pcmd->UserCallback(cmd_list, pcmd);
193 }
194 else
195 {
196 ImVec4 clip_rect = ImVec4(pcmd->ClipRect.x - pos.x, pcmd->ClipRect.y - pos.y, pcmd->ClipRect.z - pos.x, pcmd->ClipRect.w - pos.y);
197 if (clip_rect.x < fb_width && clip_rect.y < fb_height && clip_rect.z >= 0.0f && clip_rect.w >= 0.0f)
198 {
199 // Apply scissor/clipping rectangle
200 glScissor((int)clip_rect.x, (int)(fb_height - clip_rect.w), (int)(clip_rect.z - clip_rect.x), (int)(clip_rect.w - clip_rect.y));
201
202 // Bind texture, Draw
203 glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
204 glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer_offset);
205 }
206 }
207 idx_buffer_offset += pcmd->ElemCount;
208 }
209 }
210 glDeleteVertexArrays(1, &vao_handle);
211
212 // Restore modified GL state
213 glUseProgram(last_program);
214 glBindTexture(GL_TEXTURE_2D, last_texture);
215 if (glBindSampler) glBindSampler(0, last_sampler);
216 glActiveTexture(last_active_texture);
217 glBindVertexArray(last_vertex_array);
218 glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
219 glBlendEquationSeparate(last_blend_equation_rgb, last_blend_equation_alpha);
220 glBlendFuncSeparate(last_blend_src_rgb, last_blend_dst_rgb, last_blend_src_alpha, last_blend_dst_alpha);
221 if (last_enable_blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
222 if (last_enable_cull_face) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
223 if (last_enable_depth_test) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
224 if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
225 glPolygonMode(GL_FRONT_AND_BACK, (GLenum)last_polygon_mode[0]);
226 glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
227 glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
228 }
229
ImGui_ImplOpenGL3_CreateFontsTexture()230 bool ImGui_ImplOpenGL3_CreateFontsTexture()
231 {
232 // Build texture atlas
233 ImGuiIO& io = ImGui::GetIO();
234 unsigned char* pixels;
235 int width, height;
236 io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); // Load as RGBA 32-bits (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
237
238 // Upload texture to graphics system
239 GLint last_texture;
240 glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
241 glGenTextures(1, &g_FontTexture);
242 glBindTexture(GL_TEXTURE_2D, g_FontTexture);
243 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
244 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
245 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
246 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
247
248 // Store our identifier
249 io.Fonts->TexID = (void *)(intptr_t)g_FontTexture;
250
251 // Restore state
252 glBindTexture(GL_TEXTURE_2D, last_texture);
253
254 return true;
255 }
256
ImGui_ImplOpenGL3_DestroyFontsTexture()257 void ImGui_ImplOpenGL3_DestroyFontsTexture()
258 {
259 if (g_FontTexture)
260 {
261 ImGuiIO& io = ImGui::GetIO();
262 glDeleteTextures(1, &g_FontTexture);
263 io.Fonts->TexID = 0;
264 g_FontTexture = 0;
265 }
266 }
267
268 // If you get an error please report on github. You may try different GL context version or GLSL version.
CheckShader(GLuint handle,const char * desc)269 static bool CheckShader(GLuint handle, const char* desc)
270 {
271 GLint status = 0, log_length = 0;
272 glGetShaderiv(handle, GL_COMPILE_STATUS, &status);
273 glGetShaderiv(handle, GL_INFO_LOG_LENGTH, &log_length);
274 if (status == GL_FALSE)
275 fprintf(stderr, "ERROR: ImGui_ImplOpenGL3_CreateDeviceObjects: failed to compile %s!\n", desc);
276 if (log_length > 0)
277 {
278 ImVector<char> buf;
279 buf.resize((int)(log_length + 1));
280 glGetShaderInfoLog(handle, log_length, NULL, (GLchar*)buf.begin());
281 fprintf(stderr, "%s\n", buf.begin());
282 }
283 return status == GL_TRUE;
284 }
285
286 // If you get an error please report on github. You may try different GL context version or GLSL version.
CheckProgram(GLuint handle,const char * desc)287 static bool CheckProgram(GLuint handle, const char* desc)
288 {
289 GLint status = 0, log_length = 0;
290 glGetProgramiv(handle, GL_LINK_STATUS, &status);
291 glGetProgramiv(handle, GL_INFO_LOG_LENGTH, &log_length);
292 if (status == GL_FALSE)
293 fprintf(stderr, "ERROR: ImGui_ImplOpenGL3_CreateDeviceObjects: failed to link %s!\n", desc);
294 if (log_length > 0)
295 {
296 ImVector<char> buf;
297 buf.resize((int)(log_length + 1));
298 glGetProgramInfoLog(handle, log_length, NULL, (GLchar*)buf.begin());
299 fprintf(stderr, "%s\n", buf.begin());
300 }
301 return status == GL_TRUE;
302 }
303
ImGui_ImplOpenGL3_CreateDeviceObjects()304 bool ImGui_ImplOpenGL3_CreateDeviceObjects()
305 {
306 // Backup GL state
307 GLint last_texture, last_array_buffer, last_vertex_array;
308 glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
309 glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
310 glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
311
312 // Parse GLSL version string
313 int glsl_version = 130;
314 sscanf(g_GlslVersionString, "#version %d", &glsl_version);
315
316 const GLchar* vertex_shader_glsl_120 =
317 "uniform mat4 ProjMtx;\n"
318 "attribute vec2 Position;\n"
319 "attribute vec2 UV;\n"
320 "attribute vec4 Color;\n"
321 "varying vec2 Frag_UV;\n"
322 "varying vec4 Frag_Color;\n"
323 "void main()\n"
324 "{\n"
325 " Frag_UV = UV;\n"
326 " Frag_Color = Color;\n"
327 " gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
328 "}\n";
329
330 const GLchar* vertex_shader_glsl_130 =
331 "uniform mat4 ProjMtx;\n"
332 "in vec2 Position;\n"
333 "in vec2 UV;\n"
334 "in vec4 Color;\n"
335 "out vec2 Frag_UV;\n"
336 "out vec4 Frag_Color;\n"
337 "void main()\n"
338 "{\n"
339 " Frag_UV = UV;\n"
340 " Frag_Color = Color;\n"
341 " gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
342 "}\n";
343
344 const GLchar* fragment_shader_glsl_120 =
345 "#ifdef GL_ES\n"
346 " precision mediump float;\n"
347 "#endif\n"
348 "uniform sampler2D Texture;\n"
349 "varying vec2 Frag_UV;\n"
350 "varying vec4 Frag_Color;\n"
351 "void main()\n"
352 "{\n"
353 " gl_FragColor = Frag_Color * texture2D(Texture, Frag_UV.st);\n"
354 "}\n";
355
356 const GLchar* fragment_shader_glsl_130 =
357 "uniform sampler2D Texture;\n"
358 "in vec2 Frag_UV;\n"
359 "in vec4 Frag_Color;\n"
360 "out vec4 Out_Color;\n"
361 "void main()\n"
362 "{\n"
363 " Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
364 "}\n";
365
366 // Select shaders matching our GLSL versions
367 const GLchar* vertex_shader = NULL;
368 const GLchar* fragment_shader = NULL;
369 if (glsl_version < 130)
370 {
371 vertex_shader = vertex_shader_glsl_120;
372 fragment_shader = fragment_shader_glsl_120;
373 }
374 else
375 {
376 vertex_shader = vertex_shader_glsl_130;
377 fragment_shader = fragment_shader_glsl_130;
378 }
379
380 // Create shaders
381 const GLchar* vertex_shader_with_version[2] = { g_GlslVersionString, vertex_shader };
382 g_VertHandle = glCreateShader(GL_VERTEX_SHADER);
383 glShaderSource(g_VertHandle, 2, vertex_shader_with_version, NULL);
384 glCompileShader(g_VertHandle);
385 CheckShader(g_VertHandle, "vertex shader");
386
387 const GLchar* fragment_shader_with_version[2] = { g_GlslVersionString, fragment_shader };
388 g_FragHandle = glCreateShader(GL_FRAGMENT_SHADER);
389 glShaderSource(g_FragHandle, 2, fragment_shader_with_version, NULL);
390 glCompileShader(g_FragHandle);
391 CheckShader(g_FragHandle, "fragment shader");
392
393 g_ShaderHandle = glCreateProgram();
394 glAttachShader(g_ShaderHandle, g_VertHandle);
395 glAttachShader(g_ShaderHandle, g_FragHandle);
396 glLinkProgram(g_ShaderHandle);
397 CheckProgram(g_ShaderHandle, "shader program");
398
399 g_AttribLocationTex = glGetUniformLocation(g_ShaderHandle, "Texture");
400 g_AttribLocationProjMtx = glGetUniformLocation(g_ShaderHandle, "ProjMtx");
401 g_AttribLocationPosition = glGetAttribLocation(g_ShaderHandle, "Position");
402 g_AttribLocationUV = glGetAttribLocation(g_ShaderHandle, "UV");
403 g_AttribLocationColor = glGetAttribLocation(g_ShaderHandle, "Color");
404
405 // Create buffers
406 glGenBuffers(1, &g_VboHandle);
407 glGenBuffers(1, &g_ElementsHandle);
408
409 ImGui_ImplOpenGL3_CreateFontsTexture();
410
411 // Restore modified GL state
412 glBindTexture(GL_TEXTURE_2D, last_texture);
413 glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
414 glBindVertexArray(last_vertex_array);
415
416 return true;
417 }
418
ImGui_ImplOpenGL3_DestroyDeviceObjects()419 void ImGui_ImplOpenGL3_DestroyDeviceObjects()
420 {
421 if (g_VboHandle) glDeleteBuffers(1, &g_VboHandle);
422 if (g_ElementsHandle) glDeleteBuffers(1, &g_ElementsHandle);
423 g_VboHandle = g_ElementsHandle = 0;
424
425 if (g_ShaderHandle && g_VertHandle) glDetachShader(g_ShaderHandle, g_VertHandle);
426 if (g_VertHandle) glDeleteShader(g_VertHandle);
427 g_VertHandle = 0;
428
429 if (g_ShaderHandle && g_FragHandle) glDetachShader(g_ShaderHandle, g_FragHandle);
430 if (g_FragHandle) glDeleteShader(g_FragHandle);
431 g_FragHandle = 0;
432
433 if (g_ShaderHandle) glDeleteProgram(g_ShaderHandle);
434 g_ShaderHandle = 0;
435
436 ImGui_ImplOpenGL3_DestroyFontsTexture();
437 }
438