1 files changed, 9 insertions, 3 deletions

diff --git a/src/imgui_impl_sdl_gl3.cpp b/src/imgui_impl_sdl_gl3.cpp
index 63d7033..9833b12 100644
--- a/src/imgui_impl_sdl_gl3.cpp
+++ b/src/imgui_impl_sdl_gl3.cpp
@@ -25,8 +25,8 @@ static int          g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_Attr
 static unsigned int g_VboHandle = 0, g_VaoHandle = 0, g_ElementsHandle = 0;
 
 // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
-// If text or lines are blurry when integrating ImGui in your engine:
-// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
+// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so. 
+// If text or lines are blurry when integrating ImGui in your engine: in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
 void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
 {
     // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
@@ -42,9 +42,11 @@ void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
     glActiveTexture(GL_TEXTURE0);
     GLint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
     GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
+    GLint last_sampler; glGetIntegerv(GL_SAMPLER_BINDING, &last_sampler);
     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_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
     GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
     GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
     GLenum last_blend_src_rgb; glGetIntegerv(GL_BLEND_SRC_RGB, (GLint*)&last_blend_src_rgb);
@@ -58,13 +60,14 @@ void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
     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
+    // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
     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);
+    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 
     // Setup viewport, orthographic projection matrix
     glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
@@ -79,6 +82,7 @@ void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
     glUniform1i(g_AttribLocationTex, 0);
     glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
     glBindVertexArray(g_VaoHandle);
+    glBindSampler(0, 0); // Rely on combined texture/sampler state.
 
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
@@ -111,6 +115,7 @@ void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
     // Restore modified GL state
     glUseProgram(last_program);
     glBindTexture(GL_TEXTURE_2D, last_texture);
+    glBindSampler(0, last_sampler);
     glActiveTexture(last_active_texture);
     glBindVertexArray(last_vertex_array);
     glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
@@ -121,6 +126,7 @@ void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
     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);
+    glPolygonMode(GL_FRONT_AND_BACK, last_polygon_mode[0]);
     glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
     glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
 }