Created a RenderState for ImGuiRenderPass

include/Engine/Rendering/ImGuiRenderPass.h

@@ -1,6 +1,7 @@
 #include <imgui/imgui.h>
 #include "../OpenGL.h"
 #include "IRenderer.h"
+#include "RenderState.h"
 #include "../Core/EventBroker.h"
 #include "../Core/EMousePress.h"
 #include "../Core/EMouseRelease.h"
@@ -10,6 +11,22 @@
 #include "../Core/EKeyUp.h"
 #include "../Core/EKeyboardChar.h"
 
+class ImGuiRenderState : public RenderState
+{
+public:
+    ImGuiRenderState()
+        : RenderState()
+    {
+        BindFramebuffer(0);
+        Enable(GL_BLEND);
+        BlendEquation(GL_FUNC_ADD);
+        BlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+        Disable(GL_CULL_FACE);
+        Disable(GL_DEPTH_TEST);
+        Enable(GL_SCISSOR_TEST);
+    }
+};
+
 class ImGuiRenderPass
 {
 public:

src/Engine/Rendering/ImGuiRenderPass.cpp

@@ -69,29 +69,8 @@ void ImGuiRenderPass::Draw()
 
     ImDrawData* draw_data = ImGui::GetDrawData();
 
-    // Backup GL state
+    // Set up render state
-    GLint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
+    ImGuiRenderState state;
-    GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
-    GLint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
-    GLint last_element_array_buffer; glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &last_element_array_buffer);
-    GLint last_vertex_array; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
-    GLint last_blend_src; glGetIntegerv(GL_BLEND_SRC, &last_blend_src);
-    GLint last_blend_dst; glGetIntegerv(GL_BLEND_DST, &last_blend_dst);
-    GLint last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, &last_blend_equation_rgb);
-    GLint last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, &last_blend_equation_alpha);
-    GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
-    GLboolean last_enable_blend = glIsEnabled(GL_BLEND);
-    GLboolean last_enable_cull_face = glIsEnabled(GL_CULL_FACE);
-    GLboolean last_enable_depth_test = glIsEnabled(GL_DEPTH_TEST);
-    GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
-
-    // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled
-    glEnable(GL_BLEND);
-    glBlendEquation(GL_FUNC_ADD);
-    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-    glDisable(GL_CULL_FACE);
-    glDisable(GL_DEPTH_TEST);
-    glEnable(GL_SCISSOR_TEST);
     glActiveTexture(GL_TEXTURE0);
 
     // Handle cases of screen coordinates != from framebuffer coordinates (e.g. retina displays)
@@ -134,20 +113,6 @@ void ImGuiRenderPass::Draw()
         }
     }
 
-    // Restore modified GL state
-    glUseProgram(last_program);
-    glBindTexture(GL_TEXTURE_2D, last_texture);
-    glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
-    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, last_element_array_buffer);
-    glBindVertexArray(last_vertex_array);
-    glBlendEquationSeparate(last_blend_equation_rgb, last_blend_equation_alpha);
-    glBlendFunc(last_blend_src, last_blend_dst);
-    if (last_enable_blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
-    if (last_enable_cull_face) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
-    if (last_enable_depth_test) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
-    if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
-    glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
-
     // Start next frame
     newFrame();
 }