Backends: using range-for to iterate draw_data->CmdLists[].

backends/imgui_impl_allegro5.cpp

@@ -160,10 +160,8 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplAllegro5_SetupRenderState(draw_data);
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
-
         ImVector<ImDrawVertAllegro>& vertices = bd->BufVertices;
 #if ALLEGRO_HAS_DRAW_INDEXED_PRIM
         vertices.resize(draw_list->VtxBuffer.Size);

backends/imgui_impl_dx10.cpp

@@ -200,9 +200,8 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     ImDrawIdx* idx_dst = nullptr;
     bd->pVB->Map(D3D10_MAP_WRITE_DISCARD, 0, (void**)&vtx_dst);
     bd->pIB->Map(D3D10_MAP_WRITE_DISCARD, 0, (void**)&idx_dst);
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
@@ -268,9 +267,8 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     int global_idx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
     ImVec2 clip_scale = draw_data->FramebufferScale;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];

backends/imgui_impl_dx11.cpp

@@ -208,9 +208,8 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
         return;
     ImDrawVert* vtx_dst = (ImDrawVert*)vtx_resource.pData;
     ImDrawIdx* idx_dst = (ImDrawIdx*)idx_resource.pData;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
@@ -282,9 +281,8 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     int global_vtx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
     ImVec2 clip_scale = draw_data->FramebufferScale;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];

backends/imgui_impl_dx12.cpp

@@ -262,9 +262,8 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
         return;
     ImDrawVert* vtx_dst = (ImDrawVert*)vtx_resource;
     ImDrawIdx* idx_dst = (ImDrawIdx*)idx_resource;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
@@ -295,9 +294,8 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
     int global_idx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
     ImVec2 clip_scale = draw_data->FramebufferScale;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];

backends/imgui_impl_dx9.cpp

@@ -228,9 +228,8 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
     // FIXME-OPT: This is a minor waste of resource, the ideal is to use imconfig.h and
     //  1) to avoid repacking colors:   #define IMGUI_USE_BGRA_PACKED_COLOR
     //  2) to avoid repacking vertices: #define IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT struct ImDrawVert { ImVec2 pos; float z; ImU32 col; ImVec2 uv; }
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_src = draw_list->VtxBuffer.Data;
         for (int i = 0; i < draw_list->VtxBuffer.Size; i++)
         {
@@ -260,9 +259,8 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
     int global_vtx_offset = 0;
     int global_idx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];

backends/imgui_impl_metal.mm

@@ -223,7 +223,7 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, id<MTLCommandBuffer>
     // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
     int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
     int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
-    if (fb_width <= 0 || fb_height <= 0 || draw_data->CmdListsCount == 0)
+    if (fb_width <= 0 || fb_height <= 0 || draw_data->CmdLists.Size == 0)
         return;
 
     // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
@@ -259,10 +259,8 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, id<MTLCommandBuffer>
     // Render command lists
     size_t vertexBufferOffset = 0;
     size_t indexBufferOffset = 0;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
-
         memcpy((char*)vertexBuffer.buffer.contents + vertexBufferOffset, draw_list->VtxBuffer.Data, (size_t)draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy((char*)indexBuffer.buffer.contents + indexBufferOffset, draw_list->IdxBuffer.Data, (size_t)draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
 

backends/imgui_impl_opengl2.cpp

@@ -208,9 +208,8 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
     ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_buffer = draw_list->VtxBuffer.Data;
         const ImDrawIdx* idx_buffer = draw_list->IdxBuffer.Data;
         glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + offsetof(ImDrawVert, pos)));

backends/imgui_impl_opengl3.cpp

@@ -584,10 +584,8 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
-
         // Upload vertex/index buffers
         // - OpenGL drivers are in a very sorry state nowadays....
         //   During 2021 we attempted to switch from glBufferData() to orphaning+glBufferSubData() following reports

backends/imgui_impl_sdlgpu3.cpp

@@ -180,9 +180,8 @@ void ImGui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuff
 
     ImDrawVert* vtx_dst = (ImDrawVert*)SDL_MapGPUTransferBuffer(v->Device, fd->VertexTransferBuffer, true);
     ImDrawIdx* idx_dst = (ImDrawIdx*)SDL_MapGPUTransferBuffer(v->Device, fd->IndexTransferBuffer, true);
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
@@ -238,9 +237,8 @@ void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffe
     // (Because we merged all buffers into a single one, we maintain our own offset into them)
     int global_vtx_offset = 0;
     int global_idx_offset = 0;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];

backends/imgui_impl_sdlrenderer2.cpp

@@ -169,9 +169,8 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     ImVec2 clip_scale = render_scale;
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_buffer = draw_list->VtxBuffer.Data;
         const ImDrawIdx* idx_buffer = draw_list->IdxBuffer.Data;
 

backends/imgui_impl_sdlrenderer3.cpp

@@ -189,9 +189,8 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     ImVec2 clip_scale = render_scale;
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_buffer = draw_list->VtxBuffer.Data;
         const ImDrawIdx* idx_buffer = draw_list->IdxBuffer.Data;
 

backends/imgui_impl_vulkan.cpp

@@ -550,9 +550,8 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
         check_vk_result(err);
         err = vkMapMemory(v->Device, rb->IndexBufferMemory, 0, index_size, 0, (void**)&idx_dst);
         check_vk_result(err);
-        for (int n = 0; n < draw_data->CmdListsCount; n++)
+        for (const ImDrawList* draw_list : draw_data->CmdLists)
         {
-            const ImDrawList* draw_list = draw_data->CmdLists[n];
             memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
             memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
             vtx_dst += draw_list->VtxBuffer.Size;
@@ -590,9 +589,8 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
     // (Because we merged all buffers into a single one, we maintain our own offset into them)
     int global_vtx_offset = 0;
     int global_idx_offset = 0;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];

backends/imgui_impl_wgpu.cpp

@@ -367,7 +367,7 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
     // Avoid rendering when minimized
     int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
     int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
-    if (fb_width <= 0 || fb_height <= 0 || draw_data->CmdListsCount == 0)
+    if (fb_width <= 0 || fb_height <= 0 || draw_data->CmdLists.Size == 0)
         return;
 
     // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
@@ -442,9 +442,8 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
     // Upload vertex/index data into a single contiguous GPU buffer
     ImDrawVert* vtx_dst = (ImDrawVert*)fr->VertexBufferHost;
     ImDrawIdx* idx_dst = (ImDrawIdx*)fr->IndexBufferHost;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
@@ -471,9 +470,8 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
     int global_idx_offset = 0;
     ImVec2 clip_scale = draw_data->FramebufferScale;
     ImVec2 clip_off = draw_data->DisplayPos;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];

docs/BACKENDS.md

@@ -245,9 +245,8 @@ void MyImGuiBackend_RenderDrawData(ImDrawData* draw_data)
     // Render command lists
     ImVec2 clip_off = draw_data->DisplayPos;
     ImVec2 clip_scale = draw_data->FramebufferScale;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* cmd_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;  // vertex buffer generated by Dear ImGui
         const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;   // index buffer generated by Dear ImGui
         for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)

imgui.h

@@ -3361,7 +3361,7 @@ struct ImDrawList
 struct ImDrawData
 {
     bool                Valid;              // Only valid after Render() is called and before the next NewFrame() is called.
-    int                 CmdListsCount;      // Number of ImDrawList* to render. (== CmdLists.Size). Exists for legacy reason.
+    int                 CmdListsCount;      // == CmdLists.Size. (OBSOLETE: exists for legacy reasons). Number of ImDrawList* to render.
     int                 TotalIdxCount;      // For convenience, sum of all ImDrawList's IdxBuffer.Size
     int                 TotalVtxCount;      // For convenience, sum of all ImDrawList's VtxBuffer.Size
     ImVector<ImDrawList*> CmdLists;         // Array of ImDrawList* to render. The ImDrawLists are owned by ImGuiContext and only pointed to from here.

imgui_draw.cpp

@@ -2312,17 +2312,16 @@ void ImDrawData::DeIndexAllBuffers()
 {
     ImVector<ImDrawVert> new_vtx_buffer;
     TotalVtxCount = TotalIdxCount = 0;
-    for (int i = 0; i < CmdListsCount; i++)
+    for (ImDrawList* draw_list : CmdLists)
     {
-        ImDrawList* cmd_list = CmdLists[i];
-        if (cmd_list->IdxBuffer.empty())
+        if (draw_list->IdxBuffer.empty())
             continue;
-        new_vtx_buffer.resize(cmd_list->IdxBuffer.Size);
-        for (int j = 0; j < cmd_list->IdxBuffer.Size; j++)
-            new_vtx_buffer[j] = cmd_list->VtxBuffer[cmd_list->IdxBuffer[j]];
-        cmd_list->VtxBuffer.swap(new_vtx_buffer);
-        cmd_list->IdxBuffer.resize(0);
-        TotalVtxCount += cmd_list->VtxBuffer.Size;
+        new_vtx_buffer.resize(draw_list->IdxBuffer.Size);
+        for (int j = 0; j < draw_list->IdxBuffer.Size; j++)
+            new_vtx_buffer[j] = draw_list->VtxBuffer[draw_list->IdxBuffer[j]];
+        draw_list->VtxBuffer.swap(new_vtx_buffer);
+        draw_list->IdxBuffer.resize(0);
+        TotalVtxCount += draw_list->VtxBuffer.Size;
     }
 }