Textures: Added ImTextureData::UsedRect.

# Conflicts:
#	imgui_internal.h

imgui.cpp

@@ -15724,10 +15724,13 @@ void ImGui::DebugNodeTexture(ImTextureData* tex)
     ImGuiContext& g = *GImGui;
     if (TreeNode(tex, "Texture #%03d (%dx%d pixels)", tex->UniqueID, tex->Width, tex->Height))
     {
+        ImGuiMetricsConfig* cfg = &g.DebugMetricsConfig;
+        Checkbox("Show used rect", &cfg->ShowTextureUsedRect);
         PushStyleVar(ImGuiStyleVar_ImageBorderSize, ImMax(1.0f, g.Style.ImageBorderSize));
-        ImTextureRef tex_id;
-        tex_id._TexData = tex; // Don't use tex->TexID directly so first frame works.
-        ImageWithBg(tex_id, ImVec2((float)tex->Width, (float)tex->Height), ImVec2(0.0f, 0.0f), ImVec2(1.0f, 1.0f), ImVec4(0.0f, 0.0f, 0.0f, 1.0f));
+        ImVec2 p = GetCursorScreenPos();
+        ImageWithBg(tex->GetTexRef(), ImVec2((float)tex->Width, (float)tex->Height), ImVec2(0.0f, 0.0f), ImVec2(1.0f, 1.0f), ImVec4(0.0f, 0.0f, 0.0f, 1.0f));
+        if (cfg->ShowTextureUsedRect)
+            GetWindowDrawList()->AddRect(ImVec2(p.x + tex->UsedRect.x, p.y + tex->UsedRect.y), ImVec2(p.x + tex->UsedRect.x + tex->UsedRect.w, p.y + tex->UsedRect.y + tex->UsedRect.h), IM_COL32(255, 0, 255, 255));
         PopStyleVar();
 
         char texid_desc[20];

imgui.h

@@ -3389,7 +3389,8 @@ struct IMGUI_API ImTextureData
     unsigned char*      Pixels;                 // Pointer to buffer holding 'Width*Height' pixels and 'Width*Height*BytesPerPixels' bytes.
     ImTextureID         TexID;                  // Always use SetTexID() to modify! Identifier stored in ImDrawCmd::GetTexID() and passed to backend RenderDrawData loop.
     void*               BackendUserData;        // Convenience storage for backend. Some backends may have enough with TexID.
-    ImTextureRect       UpdateRect;             // Bounding box encompassing all individual updates.
+    ImTextureRect       UsedRect;               // Bounding box encompassing all past and queued Updates[].
+    ImTextureRect       UpdateRect;             // Bounding box encompassing all queued Updates[].
     ImVector<ImTextureRect> Updates;            // Array of individual updates.
     int                 UnusedFrames;           // In order to facilitate handling Status==WantDestroy in some backend: this is a count successive frames where the texture was not used. Always >0 when Status==WantDestroy.
     unsigned short      RefCount;               // Number of contexts using this texture.

imgui_draw.cpp

@@ -2439,6 +2439,7 @@ void ImTextureData::Create(ImTextureFormat format, int w, int h)
     Pixels = (unsigned char*)IM_ALLOC(Width * Height * BytesPerPixel);
     IM_ASSERT(Pixels != NULL);
     memset(Pixels, 0, Width * Height * BytesPerPixel);
+    UsedRect.x = UsedRect.y = UsedRect.w = UsedRect.h = 0;
     UpdateRect.x = UpdateRect.y = (unsigned short)~0;
     UpdateRect.w = UpdateRect.h = 0;
 }
@@ -2918,6 +2919,10 @@ void ImFontAtlasTextureBlockQueueUpload(ImFontAtlas* atlas, ImTextureData* tex,
     tex->UpdateRect.y = ImMin(tex->UpdateRect.y, req.y);
     tex->UpdateRect.w = (unsigned short)(new_x1 - tex->UpdateRect.x);
     tex->UpdateRect.h = (unsigned short)(new_y1 - tex->UpdateRect.y);
+    tex->UsedRect.x = ImMin(tex->UsedRect.x, req.x);
+    tex->UsedRect.y = ImMin(tex->UsedRect.y, req.y);
+    tex->UsedRect.w = (unsigned short)(ImMax(tex->UsedRect.x + tex->UsedRect.w, req.x + req.w) - tex->UsedRect.x);
+    tex->UsedRect.h = (unsigned short)(ImMax(tex->UsedRect.y + tex->UsedRect.h, req.y + req.h) - tex->UsedRect.y);
     atlas->TexIsBuilt = false;
 
     // No need to queue if status is _WantCreate
@@ -3957,7 +3962,7 @@ void ImFontAtlasBuildGrowTexture(ImFontAtlas* atlas, int old_tex_w, int old_tex_
         old_tex_h = atlas->TexData->Height;
 
     // FIXME-NEWATLAS-V2: What to do when reaching limits exposed by backend?
-    // FIXME-NEWATLAS-V2: Does ImFontAtlasFlags_NoPowerOfTwoHeight makes sense now? Allow 'lock' and 'compact' operations? Could we expose e.g. tex->UsedRect.
+    // FIXME-NEWATLAS-V2: Does ImFontAtlasFlags_NoPowerOfTwoHeight makes sense now? Allow 'lock' and 'compact' operations?
     IM_ASSERT(ImIsPowerOfTwo(old_tex_w) && ImIsPowerOfTwo(old_tex_h));
     IM_ASSERT(ImIsPowerOfTwo(atlas->TexMinWidth) && ImIsPowerOfTwo(atlas->TexMaxWidth) && ImIsPowerOfTwo(atlas->TexMinHeight) && ImIsPowerOfTwo(atlas->TexMaxHeight));
 

imgui_internal.h

@@ -2075,6 +2075,7 @@ struct ImGuiMetricsConfig
     bool        ShowDrawCmdMesh = true;
     bool        ShowDrawCmdBoundingBoxes = true;
     bool        ShowTextEncodingViewer = false;
+    bool        ShowTextureUsedRect = false;
     int         ShowWindowsRectsType = -1;
     int         ShowTablesRectsType = -1;
     int         HighlightMonitorIdx = -1;