Fixed imgui_impl_opengl3 broken in previous few commits. (#2591, #2593, #2594)

examples/imgui_impl_opengl3.cpp

@@ -106,9 +106,9 @@
 
 // Desktop GL has glDrawElementsBaseVertex() which GL ES and WebGL don't have.
 #if defined(IMGUI_IMPL_OPENGL_ES2) || defined(IMGUI_IMPL_OPENGL_ES3)
-#define IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX     1
-#else
 #define IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX     0
+#else
+#define IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX     1
 #endif
 
 // OpenGL Data
@@ -312,9 +312,9 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
                     // Bind texture, Draw
                     glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
 #if IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX
-                    glDrawElementsBaseVertex(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)pcmd->IdxOffset, (GLint)pcmd->VtxOffset);
+                    glDrawElementsBaseVertex(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)), (GLint)pcmd->VtxOffset);
 #else
-                    glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)pcmd->IdxOffset);
+                    glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)));
 #endif
                 }
             }