From 839b2116df12523446f3a257f471ae6d1eb29c70 Mon Sep 17 00:00:00 2001
From: milek7 <me@milek7.pl>
Date: Fri, 22 Jan 2021 02:36:49 +0100
Subject: [PATCH] fixes in imgui gl2 interaction with renderers

---
 application.cpp              |  8 ++++++++
 imgui/imgui_impl_opengl2.cpp |  2 --
 opengl33renderer.cpp         | 11 ++++++++++-
 openglrenderer.cpp           |  3 +++
 4 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/application.cpp b/application.cpp
index d1b87e2b..35b57fc0 100644
--- a/application.cpp
+++ b/application.cpp
@@ -782,6 +782,10 @@ eu07_application::init_glfw() {
             glfwWindowHint( GLFW_CONTEXT_VERSION_MINOR, 3 );
         }
         else {
+#ifdef EU07_USEIMGUIIMPLOPENGL2
+            ErrorLog("gles not supported in imgui gl2 build");
+            return -1;
+#endif
 #ifdef GLFW_CONTEXT_CREATION_API
             if (m_glfwversion >= 30200)
                 glfwWindowHint( GLFW_CONTEXT_CREATION_API, GLFW_EGL_CONTEXT_API );
@@ -791,6 +795,10 @@ eu07_application::init_glfw() {
             glfwWindowHint( GLFW_CONTEXT_VERSION_MINOR, 0 );
         }
     } else {
+        if (Global.gfx_usegles) {
+            ErrorLog("legacy renderer not supported in gles mode");
+            return -1;
+        }
         Global.gfx_shadergamma = false;
         glfwWindowHint( GLFW_OPENGL_PROFILE, GLFW_OPENGL_ANY_PROFILE );
         glfwWindowHint( GLFW_CONTEXT_VERSION_MINOR, 0 );
diff --git a/imgui/imgui_impl_opengl2.cpp b/imgui/imgui_impl_opengl2.cpp
index 90521b1b..8bb303ac 100644
--- a/imgui/imgui_impl_opengl2.cpp
+++ b/imgui/imgui_impl_opengl2.cpp
@@ -124,8 +124,6 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
         const ImDrawList* cmd_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;
         const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;
-        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
-        glBindBuffer(GL_ARRAY_BUFFER, 0);
         glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, pos)));
         glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, uv)));
         glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, col)));
diff --git a/opengl33renderer.cpp b/opengl33renderer.cpp
index fa0bd5fc..91b78b90 100644
--- a/opengl33renderer.cpp
+++ b/opengl33renderer.cpp
@@ -670,8 +670,13 @@ void opengl33_renderer::Render_pass(viewport_config &vp, rendermode const Mode)
 			gl::framebuffer::unbind();
             glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
 			glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-			if (vp.main)
+            if (vp.main) {
+                // clear state for ui
+                gl::vao::unbind();
+                gl::buffer::unbind();
+                gl::program::unbind();
 				Application.render_ui();
+            }
 			break;
 		}
 
@@ -938,6 +943,10 @@ void opengl33_renderer::Render_pass(viewport_config &vp, rendermode const Mode)
 		Timer::subsystem.gfx_gui.start();
 
         if (vp.main) {
+            // clear state for ui
+            gl::vao::unbind();
+            gl::buffer::unbind();
+            gl::program::unbind();
 			draw_debug_ui();
 			Application.render_ui();
 		}
diff --git a/openglrenderer.cpp b/openglrenderer.cpp
index 1b8859ad..a6acb243 100644
--- a/openglrenderer.cpp
+++ b/openglrenderer.cpp
@@ -339,6 +339,9 @@ opengl_renderer::Render() {
     setup_units( true, false, false );
     ::glPushClientAttrib( GL_CLIENT_VERTEX_ARRAY_BIT );
     ::glClientActiveTexture( GL_TEXTURE0 + m_diffusetextureunit );
+
+    // clear state for ui
+    ::glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, 0 );
     ::glBindBuffer( GL_ARRAY_BUFFER, 0 );
     Application.render_ui();
     ::glPopClientAttrib();