From 6dbc33dc2a1ea681a098716682746cb3a8f81fbf Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Sun, 9 Jul 2023 03:29:32 -0500
Subject: [PATCH] renderGL: fix unusable when font tex fails to load

---
 .../backends/imgui_impl_opengl3.cpp           | 25 +++++++++++--------
 .../backends/imgui_impl_opengl3.h             |  2 +-
 src/gui/render/renderGL.cpp                   |  3 +--
 3 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/extern/imgui_patched/backends/imgui_impl_opengl3.cpp b/extern/imgui_patched/backends/imgui_impl_opengl3.cpp
index 2ff3e262..c9bd8e17 100644
--- a/extern/imgui_patched/backends/imgui_impl_opengl3.cpp
+++ b/extern/imgui_patched/backends/imgui_impl_opengl3.cpp
@@ -208,6 +208,8 @@
 #define GL_CALL(_CALL)      _CALL   // Call without error check
 #endif
 
+#define GL_CALL_FALSE(_CALL)  _CALL; { GLenum gl_err = glGetError(); if (gl_err != 0) return false; }
+
 // OpenGL Data
 struct ImGui_ImplOpenGL3_Data
 {
@@ -389,13 +391,14 @@ void    ImGui_ImplOpenGL3_Shutdown()
     IM_DELETE(bd);
 }
 
-void    ImGui_ImplOpenGL3_NewFrame()
+bool    ImGui_ImplOpenGL3_NewFrame()
 {
     ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
     IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplOpenGL3_Init()?");
 
     if (!bd->ShaderHandle)
-        ImGui_ImplOpenGL3_CreateDeviceObjects();
+        return ImGui_ImplOpenGL3_CreateDeviceObjects();
+    return true;
 }
 
 static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height, GLuint vertex_array_object)
@@ -674,14 +677,14 @@ bool ImGui_ImplOpenGL3_CreateFontsTexture()
     // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
     GLint last_texture;
     GL_CALL(glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture));
-    GL_CALL(glGenTextures(1, &bd->FontTexture));
-    GL_CALL(glBindTexture(GL_TEXTURE_2D, bd->FontTexture));
-    GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
-    GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
+    GL_CALL_FALSE(glGenTextures(1, &bd->FontTexture));
+    GL_CALL_FALSE(glBindTexture(GL_TEXTURE_2D, bd->FontTexture));
+    GL_CALL_FALSE(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
+    GL_CALL_FALSE(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
 #ifdef GL_UNPACK_ROW_LENGTH // Not on WebGL/ES
-    GL_CALL(glPixelStorei(GL_UNPACK_ROW_LENGTH, 0));
+    GL_CALL_FALSE(glPixelStorei(GL_UNPACK_ROW_LENGTH, 0));
 #endif
-    GL_CALL(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels));
+    GL_CALL_FALSE(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels));
 
     // Store our identifier
     io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);
@@ -918,7 +921,9 @@ bool    ImGui_ImplOpenGL3_CreateDeviceObjects()
     glGenBuffers(1, &bd->VboHandle);
     glGenBuffers(1, &bd->ElementsHandle);
 
-    ImGui_ImplOpenGL3_CreateFontsTexture();
+    bool whatReturn=true;
+
+    if (!ImGui_ImplOpenGL3_CreateFontsTexture()) whatReturn=false;
 
     // Restore modified GL state
     glBindTexture(GL_TEXTURE_2D, last_texture);
@@ -927,7 +932,7 @@ bool    ImGui_ImplOpenGL3_CreateDeviceObjects()
     glBindVertexArray(last_vertex_array);
 #endif
 
-    return true;
+    return whatReturn;
 }
 
 void    ImGui_ImplOpenGL3_DestroyDeviceObjects()
diff --git a/extern/imgui_patched/backends/imgui_impl_opengl3.h b/extern/imgui_patched/backends/imgui_impl_opengl3.h
index 1c7666c8..328a145d 100644
--- a/extern/imgui_patched/backends/imgui_impl_opengl3.h
+++ b/extern/imgui_patched/backends/imgui_impl_opengl3.h
@@ -29,7 +29,7 @@
 // Backend API
 IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_Init(const char* glsl_version = nullptr);
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_Shutdown();
-IMGUI_IMPL_API void     ImGui_ImplOpenGL3_NewFrame();
+IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_NewFrame();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data);
 
 // (Optional) Called by Init/NewFrame/Shutdown
diff --git a/src/gui/render/renderGL.cpp b/src/gui/render/renderGL.cpp
index b16f0497..38fa4966 100644
--- a/src/gui/render/renderGL.cpp
+++ b/src/gui/render/renderGL.cpp
@@ -233,8 +233,7 @@ void FurnaceGUIRenderGL::clear(ImVec4 color) {
 }
 
 bool FurnaceGUIRenderGL::newFrame() {
-  ImGui_ImplOpenGL3_NewFrame();
-  return true;
+  return ImGui_ImplOpenGL3_NewFrame();
 }
 
 void FurnaceGUIRenderGL::createFontsTexture() {