1 // dear imgui: Renderer Backend for modern OpenGL with shaders / programmatic pipeline
2 // - Desktop GL: 2.x 3.x 4.x
3 // - Embedded GL: ES 2.0 (WebGL 1.0), ES 3.0 (WebGL 2.0)
4 // This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
5
6 // Implemented features:
7 // [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
8 // [x] Renderer: Desktop GL only: Support for large meshes (64k+ vertices) with 16-bit indices.
9
10 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
11 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
12 // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
13 // Read online: https://github.com/ocornut/imgui/tree/master/docs
14
15 // CHANGELOG
16 // (minor and older changes stripped away, please see git history for details)
17 // 2021-08-23: OpenGL: Fixed ES 3.0 shader ("#version 300 es") use normal precision floats to avoid wobbly rendering at HD resolutions.
18 // 2021-08-19: OpenGL: Embed and use our own minimal GL loader (imgui_impl_opengl3_loader.h), removing requirement and support for third-party loader.
19 // 2021-06-29: Reorganized backend to pull data from a single structure to facilitate usage with multiple-contexts (all g_XXXX access changed to bd->XXXX).
20 // 2021-06-25: OpenGL: Use OES_vertex_array extension on Emscripten + backup/restore current state.
21 // 2021-06-21: OpenGL: Destroy individual vertex/fragment shader objects right after they are linked into the main shader.
22 // 2021-05-24: OpenGL: Access GL_CLIP_ORIGIN when "GL_ARB_clip_control" extension is detected, inside of just OpenGL 4.5 version.
23 // 2021-05-19: OpenGL: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
24 // 2021-04-06: OpenGL: Don't try to read GL_CLIP_ORIGIN unless we're OpenGL 4.5 or greater.
25 // 2021-02-18: OpenGL: Change blending equation to preserve alpha in output buffer.
26 // 2021-01-03: OpenGL: Backup, setup and restore GL_STENCIL_TEST state.
27 // 2020-10-23: OpenGL: Backup, setup and restore GL_PRIMITIVE_RESTART state.
28 // 2020-10-15: OpenGL: Use glGetString(GL_VERSION) instead of glGetIntegerv(GL_MAJOR_VERSION, ...) when the later returns zero (e.g. Desktop GL 2.x)
29 // 2020-09-17: OpenGL: Fix to avoid compiling/calling glBindSampler() on ES or pre 3.3 context which have the defines set by a loader.
30 // 2020-07-10: OpenGL: Added support for glad2 OpenGL loader.
31 // 2020-05-08: OpenGL: Made default GLSL version 150 (instead of 130) on OSX.
32 // 2020-04-21: OpenGL: Fixed handling of glClipControl(GL_UPPER_LEFT) by inverting projection matrix.
33 // 2020-04-12: OpenGL: Fixed context version check mistakenly testing for 4.0+ instead of 3.2+ to enable ImGuiBackendFlags_RendererHasVtxOffset.
34 // 2020-03-24: OpenGL: Added support for glbinding 2.x OpenGL loader.
35 // 2020-01-07: OpenGL: Added support for glbinding 3.x OpenGL loader.
36 // 2019-10-25: OpenGL: Using a combination of GL define and runtime GL version to decide whether to use glDrawElementsBaseVertex(). Fix building with pre-3.2 GL loaders.
37 // 2019-09-22: OpenGL: Detect default GL loader using __has_include compiler facility.
38 // 2019-09-16: OpenGL: Tweak initialization code to allow application calling ImGui_ImplOpenGL3_CreateFontsTexture() before the first NewFrame() call.
39 // 2019-05-29: OpenGL: Desktop GL only: Added support for large mesh (64K+ vertices), enable ImGuiBackendFlags_RendererHasVtxOffset flag.
40 // 2019-04-30: OpenGL: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
41 // 2019-03-29: OpenGL: Not calling glBindBuffer more than necessary in the render loop.
42 // 2019-03-15: OpenGL: Added a GL call + comments in ImGui_ImplOpenGL3_Init() to detect uninitialized GL function loaders early.
43 // 2019-03-03: OpenGL: Fix support for ES 2.0 (WebGL 1.0).
44 // 2019-02-20: OpenGL: Fix for OSX not supporting OpenGL 4.5, we don't try to read GL_CLIP_ORIGIN even if defined by the headers/loader.
45 // 2019-02-11: OpenGL: Projecting clipping rectangles correctly using draw_data->FramebufferScale to allow multi-viewports for retina display.
46 // 2019-02-01: OpenGL: Using GLSL 410 shaders for any version over 410 (e.g. 430, 450).
47 // 2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
48 // 2018-11-13: OpenGL: Support for GL 4.5's glClipControl(GL_UPPER_LEFT) / GL_CLIP_ORIGIN.
49 // 2018-08-29: OpenGL: Added support for more OpenGL loaders: glew and glad, with comments indicative that any loader can be used.
50 // 2018-08-09: OpenGL: Default to OpenGL ES 3 on iOS and Android. GLSL version default to "#version 300 ES".
51 // 2018-07-30: OpenGL: Support for GLSL 300 ES and 410 core. Fixes for Emscripten compilation.
52 // 2018-07-10: OpenGL: Support for more GLSL versions (based on the GLSL version string). Added error output when shaders fail to compile/link.
53 // 2018-06-08: Misc: Extracted imgui_impl_opengl3.cpp/.h away from the old combined GLFW/SDL+OpenGL3 examples.
54 // 2018-06-08: OpenGL: Use draw_data->DisplayPos and draw_data->DisplaySize to setup projection matrix and clipping rectangle.
55 // 2018-05-25: OpenGL: Removed unnecessary backup/restore of GL_ELEMENT_ARRAY_BUFFER_BINDING since this is part of the VAO state.
56 // 2018-05-14: OpenGL: Making the call to glBindSampler() optional so 3.2 context won't fail if the function is a NULL pointer.
57 // 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".
58 // 2018-02-23: OpenGL: Create the VAO in the render function so the setup can more easily be used with multiple shared GL context.
59 // 2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplSdlGL3_RenderDrawData() in the .h file so you can call it yourself.
60 // 2018-01-07: OpenGL: Changed GLSL shader version from 330 to 150.
61 // 2017-09-01: OpenGL: Save and restore current bound sampler. Save and restore current polygon mode.
62 // 2017-05-01: OpenGL: Fixed save and restore of current blend func state.
63 // 2017-05-01: OpenGL: Fixed save and restore of current GL_ACTIVE_TEXTURE.
64 // 2016-09-05: OpenGL: Fixed save and restore of current scissor rectangle.
65 // 2016-07-29: OpenGL: Explicitly setting GL_UNPACK_ROW_LENGTH to reduce issues because SDL changes it. (#752)
66
67 //----------------------------------------
68 // OpenGL GLSL GLSL
69 // version version string
70 //----------------------------------------
71 // 2.0 110 "#version 110"
72 // 2.1 120 "#version 120"
73 // 3.0 130 "#version 130"
74 // 3.1 140 "#version 140"
75 // 3.2 150 "#version 150"
76 // 3.3 330 "#version 330 core"
77 // 4.0 400 "#version 400 core"
78 // 4.1 410 "#version 410 core"
79 // 4.2 420 "#version 410 core"
80 // 4.3 430 "#version 430 core"
81 // ES 2.0 100 "#version 100" = WebGL 1.0
82 // ES 3.0 300 "#version 300 es" = WebGL 2.0
83 //----------------------------------------
84
85 #if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
86 #define _CRT_SECURE_NO_WARNINGS
87 #endif
88
89 #include "imgui.h"
90 #include "imgui_impl_opengl3.h"
91 #include <stdio.h>
92 #if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier
93 #include <stddef.h> // intptr_t
94 #else
95 #include <stdint.h> // intptr_t
96 #endif
97
98 // GL includes
99 #if defined(IMGUI_IMPL_OPENGL_ES2)
100 #include <GLES2/gl2.h>
101 #if defined(__EMSCRIPTEN__)
102 #ifndef GL_GLEXT_PROTOTYPES
103 #define GL_GLEXT_PROTOTYPES
104 #endif
105 #include <GLES2/gl2ext.h>
106 #endif
107 #elif defined(IMGUI_IMPL_OPENGL_ES3)
108 #if defined(__APPLE__)
109 #include <TargetConditionals.h>
110 #endif
111 #if (defined(__APPLE__) && (TARGET_OS_IOS || TARGET_OS_TV))
112 #include <OpenGLES/ES3/gl.h> // Use GL ES 3
113 #else
114 #include <GLES3/gl3.h> // Use GL ES 3
115 #endif
116 #elif !defined(IMGUI_IMPL_OPENGL_LOADER_CUSTOM)
117 // Modern desktop OpenGL doesn't have a standard portable header file to load OpenGL function pointers.
118 // Helper libraries are often used for this purpose! Here we are using our own minimal custom loader based on gl3w.
119 // In the rest of your app/engine, you can use another loader of your choice (gl3w, glew, glad, glbinding, glext, glLoadGen, etc.).
120 // If you happen to be developing a new feature for this backend (imgui_impl_opengl3.cpp):
121 // - You may need to regenerate imgui_impl_opengl3_loader.h to add new symbols. See https://github.com/dearimgui/gl3w_stripped
122 // - You can temporarily use an unstripped version. See https://github.com/dearimgui/gl3w_stripped/releases
123 // Changes to this backend using new APIs should be accompanied by a regenerated stripped loader version.
124 #define IMGL3W_IMPL
125 #include "imgui_impl_opengl3_loader.h"
126 #endif
127
128 // Vertex arrays are not supported on ES2/WebGL1 unless Emscripten which uses an extension
129 #ifndef IMGUI_IMPL_OPENGL_ES2
130 #define IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
131 #elif defined(__EMSCRIPTEN__)
132 #define IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
133 #define glBindVertexArray glBindVertexArrayOES
134 #define glGenVertexArrays glGenVertexArraysOES
135 #define glDeleteVertexArrays glDeleteVertexArraysOES
136 #define GL_VERTEX_ARRAY_BINDING GL_VERTEX_ARRAY_BINDING_OES
137 #endif
138
139 // Desktop GL 2.0+ has glPolygonMode() which GL ES and WebGL don't have.
140 #ifdef GL_POLYGON_MODE
141 #define IMGUI_IMPL_HAS_POLYGON_MODE
142 #endif
143
144 // Desktop GL 3.2+ has glDrawElementsBaseVertex() which GL ES and WebGL don't have.
145 #if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_2)
146 #define IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
147 #endif
148
149 // Desktop GL 3.3+ has glBindSampler()
150 #if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_3)
151 #define IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
152 #endif
153
154 // Desktop GL 3.1+ has GL_PRIMITIVE_RESTART state
155 #if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_1)
156 #define IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
157 #endif
158
159 // Desktop GL use extension detection
160 #if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3)
161 #define IMGUI_IMPL_OPENGL_MAY_HAVE_EXTENSIONS
162 #endif
163
164 // OpenGL Data
165 struct ImGui_ImplOpenGL3_Data
166 {
167 GLuint GlVersion; // Extracted at runtime using GL_MAJOR_VERSION, GL_MINOR_VERSION queries (e.g. 320 for GL 3.2)
168 char GlslVersionString[32]; // Specified by user or detected based on compile time GL settings.
169 GLuint FontTexture;
170 GLuint ShaderHandle;
171 GLint AttribLocationTex; // Uniforms location
172 GLint AttribLocationProjMtx;
173 GLuint AttribLocationVtxPos; // Vertex attributes location
174 GLuint AttribLocationVtxUV;
175 GLuint AttribLocationVtxColor;
176 unsigned int VboHandle, ElementsHandle;
177 bool HasClipOrigin;
178
ImGui_ImplOpenGL3_DataImGui_ImplOpenGL3_Data179 ImGui_ImplOpenGL3_Data() { memset(this, 0, sizeof(*this)); }
180 };
181
182 // Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
183 // It is STRONGLY preferred that you use docking branch with multi-viewports (== single Dear ImGui context + multiple windows) instead of multiple Dear ImGui contexts.
ImGui_ImplOpenGL3_GetBackendData()184 static ImGui_ImplOpenGL3_Data* ImGui_ImplOpenGL3_GetBackendData()
185 {
186 return ImGui::GetCurrentContext() ? (ImGui_ImplOpenGL3_Data*)ImGui::GetIO().BackendRendererUserData : NULL;
187 }
188
189 // Functions
ImGui_ImplOpenGL3_Init(const char * glsl_version)190 bool ImGui_ImplOpenGL3_Init(const char* glsl_version)
191 {
192 ImGuiIO& io = ImGui::GetIO();
193 IM_ASSERT(io.BackendRendererUserData == NULL && "Already initialized a renderer backend!");
194
195 // Initialize our loader
196 #if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && !defined(IMGUI_IMPL_OPENGL_LOADER_CUSTOM)
197 if (imgl3wInit() != 0)
198 {
199 fprintf(stderr, "Failed to initialize OpenGL loader!\n");
200 return false;
201 }
202 #endif
203
204 // Setup backend capabilities flags
205 ImGui_ImplOpenGL3_Data* bd = IM_NEW(ImGui_ImplOpenGL3_Data)();
206 io.BackendRendererUserData = (void*)bd;
207 io.BackendRendererName = "imgui_impl_opengl3";
208
209 // Query for GL version (e.g. 320 for GL 3.2)
210 #if !defined(IMGUI_IMPL_OPENGL_ES2)
211 GLint major = 0;
212 GLint minor = 0;
213 glGetIntegerv(GL_MAJOR_VERSION, &major);
214 glGetIntegerv(GL_MINOR_VERSION, &minor);
215 if (major == 0 && minor == 0)
216 {
217 // Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
218 const char* gl_version = (const char*)glGetString(GL_VERSION);
219 sscanf(gl_version, "%d.%d", &major, &minor);
220 }
221 bd->GlVersion = (GLuint)(major * 100 + minor * 10);
222 #else
223 bd->GlVersion = 200; // GLES 2
224 #endif
225
226 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
227 if (bd->GlVersion >= 320)
228 io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset; // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
229 #endif
230
231 // Store GLSL version string so we can refer to it later in case we recreate shaders.
232 // Note: GLSL version is NOT the same as GL version. Leave this to NULL if unsure.
233 if (glsl_version == NULL)
234 {
235 #if defined(IMGUI_IMPL_OPENGL_ES2)
236 glsl_version = "#version 100";
237 #elif defined(IMGUI_IMPL_OPENGL_ES3)
238 glsl_version = "#version 300 es";
239 #elif defined(__APPLE__)
240 glsl_version = "#version 150";
241 #else
242 glsl_version = "#version 130";
243 #endif
244 }
245 IM_ASSERT((int)strlen(glsl_version) + 2 < IM_ARRAYSIZE(bd->GlslVersionString));
246 strcpy(bd->GlslVersionString, glsl_version);
247 strcat(bd->GlslVersionString, "\n");
248
249 // Make an arbitrary GL call (we don't actually need the result)
250 // IF YOU GET A CRASH HERE: it probably means the OpenGL function loader didn't do its job. Let us know!
251 GLint current_texture;
252 glGetIntegerv(GL_TEXTURE_BINDING_2D, ¤t_texture);
253
254 // Detect extensions we support
255 bd->HasClipOrigin = (bd->GlVersion >= 450);
256 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_EXTENSIONS
257 GLint num_extensions = 0;
258 glGetIntegerv(GL_NUM_EXTENSIONS, &num_extensions);
259 for (GLint i = 0; i < num_extensions; i++)
260 {
261 const char* extension = (const char*)glGetStringi(GL_EXTENSIONS, i);
262 if (extension != NULL && strcmp(extension, "GL_ARB_clip_control") == 0)
263 bd->HasClipOrigin = true;
264 }
265 #endif
266
267 return true;
268 }
269
ImGui_ImplOpenGL3_Shutdown()270 void ImGui_ImplOpenGL3_Shutdown()
271 {
272 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
273 IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
274 ImGuiIO& io = ImGui::GetIO();
275
276 ImGui_ImplOpenGL3_DestroyDeviceObjects();
277 io.BackendRendererName = NULL;
278 io.BackendRendererUserData = NULL;
279 IM_DELETE(bd);
280 }
281
ImGui_ImplOpenGL3_NewFrame()282 void ImGui_ImplOpenGL3_NewFrame()
283 {
284 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
285 IM_ASSERT(bd != NULL && "Did you call ImGui_ImplOpenGL3_Init()?");
286
287 if (!bd->ShaderHandle)
288 ImGui_ImplOpenGL3_CreateDeviceObjects();
289 }
290
ImGui_ImplOpenGL3_SetupRenderState(ImDrawData * draw_data,int fb_width,int fb_height,GLuint vertex_array_object)291 static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height, GLuint vertex_array_object)
292 {
293 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
294
295 // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
296 glEnable(GL_BLEND);
297 glBlendEquation(GL_FUNC_ADD);
298 glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
299 glDisable(GL_CULL_FACE);
300 glDisable(GL_DEPTH_TEST);
301 glDisable(GL_STENCIL_TEST);
302 glEnable(GL_SCISSOR_TEST);
303 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
304 if (bd->GlVersion >= 310)
305 glDisable(GL_PRIMITIVE_RESTART);
306 #endif
307 #ifdef IMGUI_IMPL_HAS_POLYGON_MODE
308 glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
309 #endif
310
311 // Support for GL 4.5 rarely used glClipControl(GL_UPPER_LEFT)
312 #if defined(GL_CLIP_ORIGIN)
313 bool clip_origin_lower_left = true;
314 if (bd->HasClipOrigin)
315 {
316 GLenum current_clip_origin = 0; glGetIntegerv(GL_CLIP_ORIGIN, (GLint*)¤t_clip_origin);
317 if (current_clip_origin == GL_UPPER_LEFT)
318 clip_origin_lower_left = false;
319 }
320 #endif
321
322 // Setup viewport, orthographic projection matrix
323 // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single viewport apps.
324 glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
325 float L = draw_data->DisplayPos.x;
326 float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
327 float T = draw_data->DisplayPos.y;
328 float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
329 #if defined(GL_CLIP_ORIGIN)
330 if (!clip_origin_lower_left) { float tmp = T; T = B; B = tmp; } // Swap top and bottom if origin is upper left
331 #endif
332 const float ortho_projection[4][4] =
333 {
334 { 2.0f/(R-L), 0.0f, 0.0f, 0.0f },
335 { 0.0f, 2.0f/(T-B), 0.0f, 0.0f },
336 { 0.0f, 0.0f, -1.0f, 0.0f },
337 { (R+L)/(L-R), (T+B)/(B-T), 0.0f, 1.0f },
338 };
339 glUseProgram(bd->ShaderHandle);
340 glUniform1i(bd->AttribLocationTex, 0);
341 glUniformMatrix4fv(bd->AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
342
343 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
344 if (bd->GlVersion >= 330)
345 glBindSampler(0, 0); // We use combined texture/sampler state. Applications using GL 3.3 may set that otherwise.
346 #endif
347
348 (void)vertex_array_object;
349 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
350 glBindVertexArray(vertex_array_object);
351 #endif
352
353 // Bind vertex/index buffers and setup attributes for ImDrawVert
354 glBindBuffer(GL_ARRAY_BUFFER, bd->VboHandle);
355 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, bd->ElementsHandle);
356 glEnableVertexAttribArray(bd->AttribLocationVtxPos);
357 glEnableVertexAttribArray(bd->AttribLocationVtxUV);
358 glEnableVertexAttribArray(bd->AttribLocationVtxColor);
359 glVertexAttribPointer(bd->AttribLocationVtxPos, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
360 glVertexAttribPointer(bd->AttribLocationVtxUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
361 glVertexAttribPointer(bd->AttribLocationVtxColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
362 }
363
364 // OpenGL3 Render function.
365 // Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly.
366 // This is in order to be able to run within an OpenGL engine that doesn't do so.
ImGui_ImplOpenGL3_RenderDrawData(ImDrawData * draw_data)367 void ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
368 {
369 // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
370 int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
371 int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
372 if (fb_width <= 0 || fb_height <= 0)
373 return;
374
375 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
376
377 // Backup GL state
378 GLenum last_active_texture; glGetIntegerv(GL_ACTIVE_TEXTURE, (GLint*)&last_active_texture);
379 glActiveTexture(GL_TEXTURE0);
380 GLuint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, (GLint*)&last_program);
381 GLuint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, (GLint*)&last_texture);
382 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
383 GLuint last_sampler; if (bd->GlVersion >= 330) { glGetIntegerv(GL_SAMPLER_BINDING, (GLint*)&last_sampler); } else { last_sampler = 0; }
384 #endif
385 GLuint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, (GLint*)&last_array_buffer);
386 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
387 GLuint last_vertex_array_object; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, (GLint*)&last_vertex_array_object);
388 #endif
389 #ifdef IMGUI_IMPL_HAS_POLYGON_MODE
390 GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
391 #endif
392 GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
393 GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
394 GLenum last_blend_src_rgb; glGetIntegerv(GL_BLEND_SRC_RGB, (GLint*)&last_blend_src_rgb);
395 GLenum last_blend_dst_rgb; glGetIntegerv(GL_BLEND_DST_RGB, (GLint*)&last_blend_dst_rgb);
396 GLenum last_blend_src_alpha; glGetIntegerv(GL_BLEND_SRC_ALPHA, (GLint*)&last_blend_src_alpha);
397 GLenum last_blend_dst_alpha; glGetIntegerv(GL_BLEND_DST_ALPHA, (GLint*)&last_blend_dst_alpha);
398 GLenum last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, (GLint*)&last_blend_equation_rgb);
399 GLenum last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, (GLint*)&last_blend_equation_alpha);
400 GLboolean last_enable_blend = glIsEnabled(GL_BLEND);
401 GLboolean last_enable_cull_face = glIsEnabled(GL_CULL_FACE);
402 GLboolean last_enable_depth_test = glIsEnabled(GL_DEPTH_TEST);
403 GLboolean last_enable_stencil_test = glIsEnabled(GL_STENCIL_TEST);
404 GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
405 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
406 GLboolean last_enable_primitive_restart = (bd->GlVersion >= 310) ? glIsEnabled(GL_PRIMITIVE_RESTART) : GL_FALSE;
407 #endif
408
409 // Setup desired GL state
410 // Recreate the VAO every time (this is to easily allow multiple GL contexts to be rendered to. VAO are not shared among GL contexts)
411 // The renderer would actually work without any VAO bound, but then our VertexAttrib calls would overwrite the default one currently bound.
412 GLuint vertex_array_object = 0;
413 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
414 glGenVertexArrays(1, &vertex_array_object);
415 #endif
416 ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
417
418 // Will project scissor/clipping rectangles into framebuffer space
419 ImVec2 clip_off = draw_data->DisplayPos; // (0,0) unless using multi-viewports
420 ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
421
422 // Render command lists
423 for (int n = 0; n < draw_data->CmdListsCount; n++)
424 {
425 const ImDrawList* cmd_list = draw_data->CmdLists[n];
426
427 // Upload vertex/index buffers
428 glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)cmd_list->VtxBuffer.Size * (int)sizeof(ImDrawVert), (const GLvoid*)cmd_list->VtxBuffer.Data, GL_STREAM_DRAW);
429 glBufferData(GL_ELEMENT_ARRAY_BUFFER, (GLsizeiptr)cmd_list->IdxBuffer.Size * (int)sizeof(ImDrawIdx), (const GLvoid*)cmd_list->IdxBuffer.Data, GL_STREAM_DRAW);
430
431 for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
432 {
433 const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
434 if (pcmd->UserCallback != NULL)
435 {
436 // User callback, registered via ImDrawList::AddCallback()
437 // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
438 if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
439 ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
440 else
441 pcmd->UserCallback(cmd_list, pcmd);
442 }
443 else
444 {
445 // Project scissor/clipping rectangles into framebuffer space
446 ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
447 ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
448 if (clip_max.x < clip_min.x || clip_max.y < clip_min.y)
449 continue;
450
451 // Apply scissor/clipping rectangle (Y is inverted in OpenGL)
452 glScissor((int)clip_min.x, (int)(fb_height - clip_max.y), (int)(clip_max.x - clip_min.x), (int)(clip_max.y - clip_min.y));
453
454 // Bind texture, Draw
455 glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->GetTexID());
456 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
457 if (bd->GlVersion >= 320)
458 glDrawElementsBaseVertex(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)), (GLint)pcmd->VtxOffset);
459 else
460 #endif
461 glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)));
462 }
463 }
464 }
465
466 // Destroy the temporary VAO
467 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
468 glDeleteVertexArrays(1, &vertex_array_object);
469 #endif
470
471 // Restore modified GL state
472 glUseProgram(last_program);
473 glBindTexture(GL_TEXTURE_2D, last_texture);
474 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
475 if (bd->GlVersion >= 330)
476 glBindSampler(0, last_sampler);
477 #endif
478 glActiveTexture(last_active_texture);
479 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
480 glBindVertexArray(last_vertex_array_object);
481 #endif
482 glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
483 glBlendEquationSeparate(last_blend_equation_rgb, last_blend_equation_alpha);
484 glBlendFuncSeparate(last_blend_src_rgb, last_blend_dst_rgb, last_blend_src_alpha, last_blend_dst_alpha);
485 if (last_enable_blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
486 if (last_enable_cull_face) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
487 if (last_enable_depth_test) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
488 if (last_enable_stencil_test) glEnable(GL_STENCIL_TEST); else glDisable(GL_STENCIL_TEST);
489 if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
490 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
491 if (bd->GlVersion >= 310) { if (last_enable_primitive_restart) glEnable(GL_PRIMITIVE_RESTART); else glDisable(GL_PRIMITIVE_RESTART); }
492 #endif
493
494 #ifdef IMGUI_IMPL_HAS_POLYGON_MODE
495 glPolygonMode(GL_FRONT_AND_BACK, (GLenum)last_polygon_mode[0]);
496 #endif
497 glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
498 glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
499 (void)bd; // Not all compilation paths use this
500 }
501
ImGui_ImplOpenGL3_CreateFontsTexture()502 bool ImGui_ImplOpenGL3_CreateFontsTexture()
503 {
504 ImGuiIO& io = ImGui::GetIO();
505 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
506
507 // Build texture atlas
508 unsigned char* pixels;
509 int width, height;
510 io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); // Load as RGBA 32-bit (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.
511
512 // Upload texture to graphics system
513 GLint last_texture;
514 glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
515 glGenTextures(1, &bd->FontTexture);
516 glBindTexture(GL_TEXTURE_2D, bd->FontTexture);
517 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
518 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
519 #ifdef GL_UNPACK_ROW_LENGTH // Not on WebGL/ES
520 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
521 #endif
522 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
523
524 // Store our identifier
525 io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);
526
527 // Restore state
528 glBindTexture(GL_TEXTURE_2D, last_texture);
529
530 return true;
531 }
532
ImGui_ImplOpenGL3_DestroyFontsTexture()533 void ImGui_ImplOpenGL3_DestroyFontsTexture()
534 {
535 ImGuiIO& io = ImGui::GetIO();
536 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
537 if (bd->FontTexture)
538 {
539 glDeleteTextures(1, &bd->FontTexture);
540 io.Fonts->SetTexID(0);
541 bd->FontTexture = 0;
542 }
543 }
544
545 // If you get an error please report on github. You may try different GL context version or GLSL version. See GL<>GLSL version table at the top of this file.
CheckShader(GLuint handle,const char * desc)546 static bool CheckShader(GLuint handle, const char* desc)
547 {
548 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
549 GLint status = 0, log_length = 0;
550 glGetShaderiv(handle, GL_COMPILE_STATUS, &status);
551 glGetShaderiv(handle, GL_INFO_LOG_LENGTH, &log_length);
552 if ((GLboolean)status == GL_FALSE)
553 fprintf(stderr, "ERROR: ImGui_ImplOpenGL3_CreateDeviceObjects: failed to compile %s! With GLSL: %s\n", desc, bd->GlslVersionString);
554 if (log_length > 1)
555 {
556 ImVector<char> buf;
557 buf.resize((int)(log_length + 1));
558 glGetShaderInfoLog(handle, log_length, NULL, (GLchar*)buf.begin());
559 fprintf(stderr, "%s\n", buf.begin());
560 }
561 return (GLboolean)status == GL_TRUE;
562 }
563
564 // 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)565 static bool CheckProgram(GLuint handle, const char* desc)
566 {
567 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
568 GLint status = 0, log_length = 0;
569 glGetProgramiv(handle, GL_LINK_STATUS, &status);
570 glGetProgramiv(handle, GL_INFO_LOG_LENGTH, &log_length);
571 if ((GLboolean)status == GL_FALSE)
572 fprintf(stderr, "ERROR: ImGui_ImplOpenGL3_CreateDeviceObjects: failed to link %s! With GLSL %s\n", desc, bd->GlslVersionString);
573 if (log_length > 1)
574 {
575 ImVector<char> buf;
576 buf.resize((int)(log_length + 1));
577 glGetProgramInfoLog(handle, log_length, NULL, (GLchar*)buf.begin());
578 fprintf(stderr, "%s\n", buf.begin());
579 }
580 return (GLboolean)status == GL_TRUE;
581 }
582
ImGui_ImplOpenGL3_CreateDeviceObjects()583 bool ImGui_ImplOpenGL3_CreateDeviceObjects()
584 {
585 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
586
587 // Backup GL state
588 GLint last_texture, last_array_buffer;
589 glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
590 glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
591 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
592 GLint last_vertex_array;
593 glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
594 #endif
595
596 // Parse GLSL version string
597 int glsl_version = 130;
598 sscanf(bd->GlslVersionString, "#version %d", &glsl_version);
599
600 const GLchar* vertex_shader_glsl_120 =
601 "uniform mat4 ProjMtx;\n"
602 "attribute vec2 Position;\n"
603 "attribute vec2 UV;\n"
604 "attribute vec4 Color;\n"
605 "varying vec2 Frag_UV;\n"
606 "varying vec4 Frag_Color;\n"
607 "void main()\n"
608 "{\n"
609 " Frag_UV = UV;\n"
610 " Frag_Color = Color;\n"
611 " gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
612 "}\n";
613
614 const GLchar* vertex_shader_glsl_130 =
615 "uniform mat4 ProjMtx;\n"
616 "in vec2 Position;\n"
617 "in vec2 UV;\n"
618 "in vec4 Color;\n"
619 "out vec2 Frag_UV;\n"
620 "out vec4 Frag_Color;\n"
621 "void main()\n"
622 "{\n"
623 " Frag_UV = UV;\n"
624 " Frag_Color = Color;\n"
625 " gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
626 "}\n";
627
628 const GLchar* vertex_shader_glsl_300_es =
629 "precision highp float;\n"
630 "layout (location = 0) in vec2 Position;\n"
631 "layout (location = 1) in vec2 UV;\n"
632 "layout (location = 2) in vec4 Color;\n"
633 "uniform mat4 ProjMtx;\n"
634 "out vec2 Frag_UV;\n"
635 "out vec4 Frag_Color;\n"
636 "void main()\n"
637 "{\n"
638 " Frag_UV = UV;\n"
639 " Frag_Color = Color;\n"
640 " gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
641 "}\n";
642
643 const GLchar* vertex_shader_glsl_410_core =
644 "layout (location = 0) in vec2 Position;\n"
645 "layout (location = 1) in vec2 UV;\n"
646 "layout (location = 2) in vec4 Color;\n"
647 "uniform mat4 ProjMtx;\n"
648 "out vec2 Frag_UV;\n"
649 "out vec4 Frag_Color;\n"
650 "void main()\n"
651 "{\n"
652 " Frag_UV = UV;\n"
653 " Frag_Color = Color;\n"
654 " gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
655 "}\n";
656
657 const GLchar* fragment_shader_glsl_120 =
658 "#ifdef GL_ES\n"
659 " precision mediump float;\n"
660 "#endif\n"
661 "uniform sampler2D Texture;\n"
662 "varying vec2 Frag_UV;\n"
663 "varying vec4 Frag_Color;\n"
664 "void main()\n"
665 "{\n"
666 " gl_FragColor = Frag_Color * texture2D(Texture, Frag_UV.st);\n"
667 "}\n";
668
669 const GLchar* fragment_shader_glsl_130 =
670 "uniform sampler2D Texture;\n"
671 "in vec2 Frag_UV;\n"
672 "in vec4 Frag_Color;\n"
673 "out vec4 Out_Color;\n"
674 "void main()\n"
675 "{\n"
676 " Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
677 "}\n";
678
679 const GLchar* fragment_shader_glsl_300_es =
680 "precision mediump float;\n"
681 "uniform sampler2D Texture;\n"
682 "in vec2 Frag_UV;\n"
683 "in vec4 Frag_Color;\n"
684 "layout (location = 0) out vec4 Out_Color;\n"
685 "void main()\n"
686 "{\n"
687 " Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
688 "}\n";
689
690 const GLchar* fragment_shader_glsl_410_core =
691 "in vec2 Frag_UV;\n"
692 "in vec4 Frag_Color;\n"
693 "uniform sampler2D Texture;\n"
694 "layout (location = 0) out vec4 Out_Color;\n"
695 "void main()\n"
696 "{\n"
697 " Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
698 "}\n";
699
700 // Select shaders matching our GLSL versions
701 const GLchar* vertex_shader = NULL;
702 const GLchar* fragment_shader = NULL;
703 if (glsl_version < 130)
704 {
705 vertex_shader = vertex_shader_glsl_120;
706 fragment_shader = fragment_shader_glsl_120;
707 }
708 else if (glsl_version >= 410)
709 {
710 vertex_shader = vertex_shader_glsl_410_core;
711 fragment_shader = fragment_shader_glsl_410_core;
712 }
713 else if (glsl_version == 300)
714 {
715 vertex_shader = vertex_shader_glsl_300_es;
716 fragment_shader = fragment_shader_glsl_300_es;
717 }
718 else
719 {
720 vertex_shader = vertex_shader_glsl_130;
721 fragment_shader = fragment_shader_glsl_130;
722 }
723
724 // Create shaders
725 const GLchar* vertex_shader_with_version[2] = { bd->GlslVersionString, vertex_shader };
726 GLuint vert_handle = glCreateShader(GL_VERTEX_SHADER);
727 glShaderSource(vert_handle, 2, vertex_shader_with_version, NULL);
728 glCompileShader(vert_handle);
729 CheckShader(vert_handle, "vertex shader");
730
731 const GLchar* fragment_shader_with_version[2] = { bd->GlslVersionString, fragment_shader };
732 GLuint frag_handle = glCreateShader(GL_FRAGMENT_SHADER);
733 glShaderSource(frag_handle, 2, fragment_shader_with_version, NULL);
734 glCompileShader(frag_handle);
735 CheckShader(frag_handle, "fragment shader");
736
737 // Link
738 bd->ShaderHandle = glCreateProgram();
739 glAttachShader(bd->ShaderHandle, vert_handle);
740 glAttachShader(bd->ShaderHandle, frag_handle);
741 glLinkProgram(bd->ShaderHandle);
742 CheckProgram(bd->ShaderHandle, "shader program");
743
744 glDetachShader(bd->ShaderHandle, vert_handle);
745 glDetachShader(bd->ShaderHandle, frag_handle);
746 glDeleteShader(vert_handle);
747 glDeleteShader(frag_handle);
748
749 bd->AttribLocationTex = glGetUniformLocation(bd->ShaderHandle, "Texture");
750 bd->AttribLocationProjMtx = glGetUniformLocation(bd->ShaderHandle, "ProjMtx");
751 bd->AttribLocationVtxPos = (GLuint)glGetAttribLocation(bd->ShaderHandle, "Position");
752 bd->AttribLocationVtxUV = (GLuint)glGetAttribLocation(bd->ShaderHandle, "UV");
753 bd->AttribLocationVtxColor = (GLuint)glGetAttribLocation(bd->ShaderHandle, "Color");
754
755 // Create buffers
756 glGenBuffers(1, &bd->VboHandle);
757 glGenBuffers(1, &bd->ElementsHandle);
758
759 ImGui_ImplOpenGL3_CreateFontsTexture();
760
761 // Restore modified GL state
762 glBindTexture(GL_TEXTURE_2D, last_texture);
763 glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
764 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
765 glBindVertexArray(last_vertex_array);
766 #endif
767
768 return true;
769 }
770
ImGui_ImplOpenGL3_DestroyDeviceObjects()771 void ImGui_ImplOpenGL3_DestroyDeviceObjects()
772 {
773 ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
774 if (bd->VboHandle) { glDeleteBuffers(1, &bd->VboHandle); bd->VboHandle = 0; }
775 if (bd->ElementsHandle) { glDeleteBuffers(1, &bd->ElementsHandle); bd->ElementsHandle = 0; }
776 if (bd->ShaderHandle) { glDeleteProgram(bd->ShaderHandle); bd->ShaderHandle = 0; }
777 ImGui_ImplOpenGL3_DestroyFontsTexture();
778 }
779