Backends: OpenGL3: Enable OES_vertex_array_object extension for emscripten/wasm build (#4266, #4267)
diff --git a/backends/imgui_impl_opengl3.cpp b/backends/imgui_impl_opengl3.cpp
index 2048603..4b9b2e0 100644
--- a/backends/imgui_impl_opengl3.cpp
+++ b/backends/imgui_impl_opengl3.cpp
@@ -14,6 +14,7 @@
// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
+// 2021-06-25: OpenGL: Use OES_vertex_array extension on Emscripten + backup/restore current state.
// 2021-06-21: OpenGL: Destroy individual vertex/fragment shader objects right after they are linked into the main shader.
// 2021-05-24: OpenGL: Access GL_CLIP_ORIGIN when "GL_ARB_clip_control" extension is detected, inside of just OpenGL 4.5 version.
// 2021-05-19: OpenGL: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
@@ -94,6 +95,12 @@
// GL includes
#if defined(IMGUI_IMPL_OPENGL_ES2)
#include <GLES2/gl2.h>
+#if defined(__EMSCRIPTEN__)
+#ifndef GL_GLEXT_PROTOTYPES
+#define GL_GLEXT_PROTOTYPES
+#endif
+#include <GLES2/gl2ext.h>
+#endif
#elif defined(IMGUI_IMPL_OPENGL_ES3)
#if (defined(__APPLE__) && (TARGET_OS_IOS || TARGET_OS_TV))
#include <OpenGLES/ES3/gl.h> // Use GL ES 3
@@ -132,6 +139,17 @@
#endif
#endif
+// Vertex arrays are not supported on ES2/WebGL1 unless Emscripten which uses an extension
+#ifndef IMGUI_IMPL_OPENGL_ES2
+#define IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
+#elif defined(__EMSCRIPTEN__)
+#define IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
+#define glBindVertexArray glBindVertexArrayOES
+#define glGenVertexArrays glGenVertexArraysOES
+#define glDeleteVertexArrays glDeleteVertexArraysOES
+#define GL_VERTEX_ARRAY_BINDING GL_VERTEX_ARRAY_BINDING_OES
+#endif
+
// Desktop GL 3.2+ has glDrawElementsBaseVertex() which GL ES and WebGL don't have.
#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_2)
#define IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
@@ -323,7 +341,7 @@
#endif
(void)vertex_array_object;
-#ifndef IMGUI_IMPL_OPENGL_ES2
+#ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
glBindVertexArray(vertex_array_object);
#endif
@@ -358,7 +376,7 @@
GLuint last_sampler; if (g_GlVersion >= 330) { glGetIntegerv(GL_SAMPLER_BINDING, (GLint*)&last_sampler); } else { last_sampler = 0; }
#endif
GLuint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, (GLint*)&last_array_buffer);
-#ifndef IMGUI_IMPL_OPENGL_ES2
+#ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
GLuint last_vertex_array_object; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, (GLint*)&last_vertex_array_object);
#endif
#ifdef GL_POLYGON_MODE
@@ -385,7 +403,7 @@
// Recreate the VAO every time (this is to easily allow multiple GL contexts to be rendered to. VAO are not shared among GL contexts)
// The renderer would actually work without any VAO bound, but then our VertexAttrib calls would overwrite the default one currently bound.
GLuint vertex_array_object = 0;
-#ifndef IMGUI_IMPL_OPENGL_ES2
+#ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
glGenVertexArrays(1, &vertex_array_object);
#endif
ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
@@ -443,7 +461,7 @@
}
// Destroy the temporary VAO
-#ifndef IMGUI_IMPL_OPENGL_ES2
+#ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
glDeleteVertexArrays(1, &vertex_array_object);
#endif
@@ -455,7 +473,7 @@
glBindSampler(0, last_sampler);
#endif
glActiveTexture(last_active_texture);
-#ifndef IMGUI_IMPL_OPENGL_ES2
+#ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
glBindVertexArray(last_vertex_array_object);
#endif
glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
@@ -559,7 +577,7 @@
GLint last_texture, last_array_buffer;
glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
-#ifndef IMGUI_IMPL_OPENGL_ES2
+#ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
GLint last_vertex_array;
glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
#endif
@@ -732,7 +750,7 @@
// Restore modified GL state
glBindTexture(GL_TEXTURE_2D, last_texture);
glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
-#ifndef IMGUI_IMPL_OPENGL_ES2
+#ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
glBindVertexArray(last_vertex_array);
#endif
diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 0cd0424..3b18dc0 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -63,6 +63,7 @@
about building on 32-bit systems. (#4225) [@kingofthebongo2008]
- Backends: OpenGL3: Handle GL_CLIP_ORIGIN on <4.5 contexts if "GL_ARB_clip_control" extension is detected. (#4170, #3998)
- Backends: OpenGL3: Destroy vertex/fragment shader objects right after they are linked into main shader. (#4244) [@Crowbarous]
+- Backends: OpenGL3: Use OES_vertex_array extension on Emscripten + backup/restore current state. (#4266, #4267) [@harry75369]
- Backends: OSX: Added a fix for shortcuts using CTRL key instead of CMD key. (#4253) [@rokups]
- Examples: OSX+OpenGL2: Fix event forwarding (fix key remaining stuck when using shortcuts with Cmd/Super key).
Other OSX examples were not affected. (#4253, #1873) [@rokups]
