backends/imgui_impl_sdlrenderer3.cpp - third_party/imgui - Git at Google

 // dear imgui: Renderer Backend for SDL_Renderer for SDL3
 // (Requires: SDL 3.0.0+)

 // (**IMPORTANT: SDL 3.0.0 is NOT YET RELEASED AND CURRENTLY HAS A FAST CHANGING API. THIS CODE BREAKS OFTEN AS SDL3 CHANGES.**)

 // Note how SDL_Renderer is an _optional_ component of SDL3.
 // For a multi-platform app consider using e.g. SDL+DirectX on Windows and SDL+OpenGL on Linux/OSX.
 // If your application will want to render any non trivial amount of graphics other than UI,
 // please be aware that SDL_Renderer currently offers a limited graphic API to the end-user and
 // it might be difficult to step out of those boundaries.

 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
 // Missing features:
 //  [ ] Renderer: Multi-viewport support (multiple windows).

 // You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
 // Learn about Dear ImGui:
 // - FAQ                  https://dearimgui.com/faq
 // - Getting Started      https://dearimgui.com/getting-started
 // - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
 // - Introduction, links and more at the top of imgui.cpp

 // CHANGELOG
 //  2024-10-09: Expose selected render state in ImGui_ImplSDLRenderer3_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
 //  2024-07-01: Update for SDL3 api changes: SDL_RenderGeometryRaw() uint32 version was removed (SDL#9009).
 //  2024-05-14: *BREAKING CHANGE* ImGui_ImplSDLRenderer3_RenderDrawData() requires SDL_Renderer* passed as parameter.
 //  2024-02-12: Amend to query SDL_RenderViewportSet() and restore viewport accordingly.
 //  2023-05-30: Initial version.

 #include "imgui.h"
 #ifndef IMGUI_DISABLE
 #include "imgui_impl_sdlrenderer3.h"
 #include <stdint.h>     // intptr_t

 // Clang warnings with -Weverything
 #if defined(__clang__)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wsign-conversion"    // warning: implicit conversion changes signedness
 #endif

 // SDL
 #include <SDL3/SDL.h>
 #if !SDL_VERSION_ATLEAST(3,0,0)
 #error This backend requires SDL 3.0.0+
 #endif

 // SDL_Renderer data
 struct ImGui_ImplSDLRenderer3_Data
 {
     SDL_Renderer*           Renderer;       // Main viewport's renderer
     SDL_Texture*            FontTexture;
     ImVector<SDL_FColor>    ColorBuffer;

     ImGui_ImplSDLRenderer3_Data()   { memset((void*)this, 0, sizeof(*this)); }
 };

 // Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
 // It is STRONGLY preferred that you use docking branch with multi-viewports (== single Dear ImGui context + multiple windows) instead of multiple Dear ImGui contexts.
 static ImGui_ImplSDLRenderer3_Data* ImGui_ImplSDLRenderer3_GetBackendData()
 {
     return ImGui::GetCurrentContext() ? (ImGui_ImplSDLRenderer3_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }

 // Functions
 bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
 {
     ImGuiIO& io = ImGui::GetIO();
     IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
     IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");

     // Setup backend capabilities flags
     ImGui_ImplSDLRenderer3_Data* bd = IM_NEW(ImGui_ImplSDLRenderer3_Data)();
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_sdlrenderer3";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.

     bd->Renderer = renderer;

     return true;
 }

 void ImGui_ImplSDLRenderer3_Shutdown()
 {
     ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();

     ImGui_ImplSDLRenderer3_DestroyDeviceObjects();

     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
     io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
     IM_DELETE(bd);
 }

 static void ImGui_ImplSDLRenderer3_SetupRenderState(SDL_Renderer* renderer)
 {
 	// Clear out any viewports and cliprect set by the user
     // FIXME: Technically speaking there are lots of other things we could backup/setup/restore during our render process.
 	SDL_SetRenderViewport(renderer, nullptr);
 	SDL_SetRenderClipRect(renderer, nullptr);
 }

 void ImGui_ImplSDLRenderer3_NewFrame()
 {
     ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplSDLRenderer3_Init()?");

     if (!bd->FontTexture)
         ImGui_ImplSDLRenderer3_CreateDeviceObjects();
 }

 // https://github.com/libsdl-org/SDL/issues/9009
 static int SDL_RenderGeometryRaw8BitColor(SDL_Renderer* renderer, ImVector<SDL_FColor>& colors_out, SDL_Texture* texture, const float* xy, int xy_stride, const SDL_Color* color, int color_stride, const float* uv, int uv_stride, int num_vertices, const void* indices, int num_indices, int size_indices)
 {
     const Uint8* color2 = (const Uint8*)color;
     colors_out.resize(num_vertices);
     SDL_FColor* color3 = colors_out.Data;
     for (int i = 0; i < num_vertices; i++)
     {
         color3[i].r = color->r / 255.0f;
         color3[i].g = color->g / 255.0f;
         color3[i].b = color->b / 255.0f;
         color3[i].a = color->a / 255.0f;
         color2 += color_stride;
         color = (const SDL_Color*)color2;
     }
     return SDL_RenderGeometryRaw(renderer, texture, xy, xy_stride, color3, sizeof(*color3), uv, uv_stride, num_vertices, indices, num_indices, size_indices);
 }

 void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer)
 {
     ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();

 	// If there's a scale factor set by the user, use that instead
     // If the user has specified a scale factor to SDL_Renderer already via SDL_RenderSetScale(), SDL will scale whatever we pass
     // to SDL_RenderGeometryRaw() by that scale factor. In that case we don't want to be also scaling it ourselves here.
     float rsx = 1.0f;
 	float rsy = 1.0f;
 	SDL_GetRenderScale(renderer, &rsx, &rsy);
     ImVec2 render_scale;
 	render_scale.x = (rsx == 1.0f) ? draw_data->FramebufferScale.x : 1.0f;
 	render_scale.y = (rsy == 1.0f) ? draw_data->FramebufferScale.y : 1.0f;

 	// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
 	int fb_width = (int)(draw_data->DisplaySize.x * render_scale.x);
 	int fb_height = (int)(draw_data->DisplaySize.y * render_scale.y);
 	if (fb_width == 0 || fb_height == 0)
 		return;

     // Backup SDL_Renderer state that will be modified to restore it afterwards
     struct BackupSDLRendererState
     {
         SDL_Rect    Viewport;
         bool        ViewportEnabled;
         bool        ClipEnabled;
         SDL_Rect    ClipRect;
     };
     BackupSDLRendererState old = {};
     old.ViewportEnabled = SDL_RenderViewportSet(renderer);
     old.ClipEnabled = SDL_RenderClipEnabled(renderer);
     SDL_GetRenderViewport(renderer, &old.Viewport);
     SDL_GetRenderClipRect(renderer, &old.ClipRect);

     // Setup desired state
     ImGui_ImplSDLRenderer3_SetupRenderState(renderer);

     // Setup render state structure (for callbacks and custom texture bindings)
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     ImGui_ImplSDLRenderer3_RenderState render_state;
     render_state.Renderer = renderer;
     platform_io.Renderer_RenderState = &render_state;

 	// Will project scissor/clipping rectangles into framebuffer space
 	ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
 	ImVec2 clip_scale = render_scale;

     // Render command lists
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* draw_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_buffer = draw_list->VtxBuffer.Data;
         const ImDrawIdx* idx_buffer = draw_list->IdxBuffer.Data;

         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
                 // User callback, registered via ImDrawList::AddCallback()
                 // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
                 if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                     ImGui_ImplSDLRenderer3_SetupRenderState(renderer);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
             }
             else
             {
                 // Project scissor/clipping rectangles into framebuffer space
                 ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
                 ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
                 if (clip_min.x < 0.0f) { clip_min.x = 0.0f; }
                 if (clip_min.y < 0.0f) { clip_min.y = 0.0f; }
                 if (clip_max.x > (float)fb_width) { clip_max.x = (float)fb_width; }
                 if (clip_max.y > (float)fb_height) { clip_max.y = (float)fb_height; }
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;

                 SDL_Rect r = { (int)(clip_min.x), (int)(clip_min.y), (int)(clip_max.x - clip_min.x), (int)(clip_max.y - clip_min.y) };
                 SDL_SetRenderClipRect(renderer, &r);

                 const float* xy = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, pos));
                 const float* uv = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, uv));
                 const SDL_Color* color = (const SDL_Color*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, col)); // SDL 2.0.19+

                 // Bind texture, Draw
 				SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID();
                 SDL_RenderGeometryRaw8BitColor(renderer, bd->ColorBuffer, tex,
                     xy, (int)sizeof(ImDrawVert),
                     color, (int)sizeof(ImDrawVert),
                     uv, (int)sizeof(ImDrawVert),
                     draw_list->VtxBuffer.Size - pcmd->VtxOffset,
                     idx_buffer + pcmd->IdxOffset, pcmd->ElemCount, sizeof(ImDrawIdx));
             }
         }
     }
     platform_io.Renderer_RenderState = NULL;

     // Restore modified SDL_Renderer state
     SDL_SetRenderViewport(renderer, old.ViewportEnabled ? &old.Viewport : nullptr);
     SDL_SetRenderClipRect(renderer, old.ClipEnabled ? &old.ClipRect : nullptr);
 }

 // Called by Init/NewFrame/Shutdown
 bool ImGui_ImplSDLRenderer3_CreateFontsTexture()
 {
     ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();

     // Build texture atlas
     unsigned char* pixels;
     int width, height;
     io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bit (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.

     // Upload texture to graphics system
     // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
     bd->FontTexture = SDL_CreateTexture(bd->Renderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height);
     if (bd->FontTexture == nullptr)
     {
         SDL_Log("error creating texture");
         return false;
     }
     SDL_UpdateTexture(bd->FontTexture, nullptr, pixels, 4 * width);
     SDL_SetTextureBlendMode(bd->FontTexture, SDL_BLENDMODE_BLEND);
     SDL_SetTextureScaleMode(bd->FontTexture, SDL_SCALEMODE_LINEAR);

     // Store our identifier
     io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);

     return true;
 }

 void ImGui_ImplSDLRenderer3_DestroyFontsTexture()
 {
     ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
     if (bd->FontTexture)
     {
         io.Fonts->SetTexID(0);
         SDL_DestroyTexture(bd->FontTexture);
         bd->FontTexture = nullptr;
     }
 }

 bool ImGui_ImplSDLRenderer3_CreateDeviceObjects()
 {
     return ImGui_ImplSDLRenderer3_CreateFontsTexture();
 }

 void ImGui_ImplSDLRenderer3_DestroyDeviceObjects()
 {
     ImGui_ImplSDLRenderer3_DestroyFontsTexture();
 }

 //-----------------------------------------------------------------------------

 #if defined(__clang__)
 #pragma clang diagnostic pop
 #endif

 #endif // #ifndef IMGUI_DISABLE
	// dear imgui: Renderer Backend for SDL_Renderer for SDL3
	// (Requires: SDL 3.0.0+)

	// (IMPORTANT: SDL 3.0.0 is NOT YET RELEASED AND CURRENTLY HAS A FAST CHANGING API. THIS CODE BREAKS OFTEN AS SDL3 CHANGES.)

	// Note how SDL_Renderer is an _optional_ component of SDL3.
	// For a multi-platform app consider using e.g. SDL+DirectX on Windows and SDL+OpenGL on Linux/OSX.
	// If your application will want to render any non trivial amount of graphics other than UI,
	// please be aware that SDL_Renderer currently offers a limited graphic API to the end-user and
	// it might be difficult to step out of those boundaries.

	// Implemented features:
	// [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
	// [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
	// [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
	// Missing features:
	// [ ] Renderer: Multi-viewport support (multiple windows).

	// You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
	// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
	// Learn about Dear ImGui:
	// - FAQ https://dearimgui.com/faq
	// - Getting Started https://dearimgui.com/getting-started
	// - Documentation https://dearimgui.com/docs (same as your local docs/ folder).
	// - Introduction, links and more at the top of imgui.cpp

	// CHANGELOG
	// 2024-10-09: Expose selected render state in ImGui_ImplSDLRenderer3_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
	// 2024-07-01: Update for SDL3 api changes: SDL_RenderGeometryRaw() uint32 version was removed (SDL#9009).
	// 2024-05-14: BREAKING CHANGE ImGui_ImplSDLRenderer3_RenderDrawData() requires SDL_Renderer* passed as parameter.
	// 2024-02-12: Amend to query SDL_RenderViewportSet() and restore viewport accordingly.
	// 2023-05-30: Initial version.

	#include "imgui.h"
	#ifndef IMGUI_DISABLE
	#include "imgui_impl_sdlrenderer3.h"
	#include <stdint.h> // intptr_t

	// Clang warnings with -Weverything
	#if defined(__clang__)
	#pragma clang diagnostic push
	#pragma clang diagnostic ignored "-Wsign-conversion" // warning: implicit conversion changes signedness
	#endif

	// SDL
	#include <SDL3/SDL.h>
	#if !SDL_VERSION_ATLEAST(3,0,0)
	#error This backend requires SDL 3.0.0+
	#endif

	// SDL_Renderer data
	struct ImGui_ImplSDLRenderer3_Data
	{
	SDL_Renderer* Renderer; // Main viewport's renderer
	SDL_Texture* FontTexture;
	ImVector<SDL_FColor> ColorBuffer;

	ImGui_ImplSDLRenderer3_Data() { memset((void)this, 0, sizeof(this)); }
	};

	// Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
	// It is STRONGLY preferred that you use docking branch with multi-viewports (== single Dear ImGui context + multiple windows) instead of multiple Dear ImGui contexts.
	static ImGui_ImplSDLRenderer3_Data* ImGui_ImplSDLRenderer3_GetBackendData()
	{
	return ImGui::GetCurrentContext() ? (ImGui_ImplSDLRenderer3_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
	}

	// Functions
	bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
	{
	ImGuiIO& io = ImGui::GetIO();
	IMGUI_CHECKVERSION();
	IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
	IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");

	// Setup backend capabilities flags
	ImGui_ImplSDLRenderer3_Data* bd = IM_NEW(ImGui_ImplSDLRenderer3_Data)();
	io.BackendRendererUserData = (void*)bd;
	io.BackendRendererName = "imgui_impl_sdlrenderer3";
	io.BackendFlags \|= ImGuiBackendFlags_RendererHasVtxOffset; // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.

	bd->Renderer = renderer;

	return true;
	}

	void ImGui_ImplSDLRenderer3_Shutdown()
	{
	ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
	IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
	ImGuiIO& io = ImGui::GetIO();

	ImGui_ImplSDLRenderer3_DestroyDeviceObjects();

	io.BackendRendererName = nullptr;
	io.BackendRendererUserData = nullptr;
	io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
	IM_DELETE(bd);
	}

	static void ImGui_ImplSDLRenderer3_SetupRenderState(SDL_Renderer* renderer)
	{
	// Clear out any viewports and cliprect set by the user
	// FIXME: Technically speaking there are lots of other things we could backup/setup/restore during our render process.
	SDL_SetRenderViewport(renderer, nullptr);
	SDL_SetRenderClipRect(renderer, nullptr);
	}

	void ImGui_ImplSDLRenderer3_NewFrame()
	{
	ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
	IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplSDLRenderer3_Init()?");

	if (!bd->FontTexture)
	ImGui_ImplSDLRenderer3_CreateDeviceObjects();
	}

	// https://github.com/libsdl-org/SDL/issues/9009
	static int SDL_RenderGeometryRaw8BitColor(SDL_Renderer* renderer, ImVector<SDL_FColor>& colors_out, SDL_Texture* texture, const float* xy, int xy_stride, const SDL_Color* color, int color_stride, const float* uv, int uv_stride, int num_vertices, const void* indices, int num_indices, int size_indices)
	{
	const Uint8* color2 = (const Uint8*)color;
	colors_out.resize(num_vertices);
	SDL_FColor* color3 = colors_out.Data;
	for (int i = 0; i < num_vertices; i++)
	{
	color3[i].r = color->r / 255.0f;
	color3[i].g = color->g / 255.0f;
	color3[i].b = color->b / 255.0f;
	color3[i].a = color->a / 255.0f;
	color2 += color_stride;
	color = (const SDL_Color*)color2;
	}
	return SDL_RenderGeometryRaw(renderer, texture, xy, xy_stride, color3, sizeof(*color3), uv, uv_stride, num_vertices, indices, num_indices, size_indices);
	}

	void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer)
	{
	ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();

	// If there's a scale factor set by the user, use that instead
	// If the user has specified a scale factor to SDL_Renderer already via SDL_RenderSetScale(), SDL will scale whatever we pass
	// to SDL_RenderGeometryRaw() by that scale factor. In that case we don't want to be also scaling it ourselves here.
	float rsx = 1.0f;
	float rsy = 1.0f;
	SDL_GetRenderScale(renderer, &rsx, &rsy);
	ImVec2 render_scale;
	render_scale.x = (rsx == 1.0f) ? draw_data->FramebufferScale.x : 1.0f;
	render_scale.y = (rsy == 1.0f) ? draw_data->FramebufferScale.y : 1.0f;

	// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
	int fb_width = (int)(draw_data->DisplaySize.x * render_scale.x);
	int fb_height = (int)(draw_data->DisplaySize.y * render_scale.y);
	if (fb_width == 0 \|\| fb_height == 0)
	return;

	// Backup SDL_Renderer state that will be modified to restore it afterwards
	struct BackupSDLRendererState
	{
	SDL_Rect Viewport;
	bool ViewportEnabled;
	bool ClipEnabled;
	SDL_Rect ClipRect;
	};
	BackupSDLRendererState old = {};
	old.ViewportEnabled = SDL_RenderViewportSet(renderer);
	old.ClipEnabled = SDL_RenderClipEnabled(renderer);
	SDL_GetRenderViewport(renderer, &old.Viewport);
	SDL_GetRenderClipRect(renderer, &old.ClipRect);

	// Setup desired state
	ImGui_ImplSDLRenderer3_SetupRenderState(renderer);

	// Setup render state structure (for callbacks and custom texture bindings)
	ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
	ImGui_ImplSDLRenderer3_RenderState render_state;
	render_state.Renderer = renderer;
	platform_io.Renderer_RenderState = &render_state;

	// Will project scissor/clipping rectangles into framebuffer space
	ImVec2 clip_off = draw_data->DisplayPos; // (0,0) unless using multi-viewports
	ImVec2 clip_scale = render_scale;

	// Render command lists
	for (int n = 0; n < draw_data->CmdListsCount; n++)
	{
	const ImDrawList* draw_list = draw_data->CmdLists[n];
	const ImDrawVert* vtx_buffer = draw_list->VtxBuffer.Data;
	const ImDrawIdx* idx_buffer = draw_list->IdxBuffer.Data;

	for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
	{
	const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];
	if (pcmd->UserCallback)
	{
	// User callback, registered via ImDrawList::AddCallback()
	// (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
	if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
	ImGui_ImplSDLRenderer3_SetupRenderState(renderer);
	else
	pcmd->UserCallback(draw_list, pcmd);
	}
	else
	{
	// Project scissor/clipping rectangles into framebuffer space
	ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
	ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
	if (clip_min.x < 0.0f) { clip_min.x = 0.0f; }
	if (clip_min.y < 0.0f) { clip_min.y = 0.0f; }
	if (clip_max.x > (float)fb_width) { clip_max.x = (float)fb_width; }
	if (clip_max.y > (float)fb_height) { clip_max.y = (float)fb_height; }
	if (clip_max.x <= clip_min.x \|\| clip_max.y <= clip_min.y)
	continue;

	SDL_Rect r = { (int)(clip_min.x), (int)(clip_min.y), (int)(clip_max.x - clip_min.x), (int)(clip_max.y - clip_min.y) };
	SDL_SetRenderClipRect(renderer, &r);

	const float* xy = (const float)(const void)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, pos));
	const float* uv = (const float)(const void)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, uv));
	const SDL_Color* color = (const SDL_Color)(const void)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, col)); // SDL 2.0.19+

	// Bind texture, Draw
	SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID();
	SDL_RenderGeometryRaw8BitColor(renderer, bd->ColorBuffer, tex,
	xy, (int)sizeof(ImDrawVert),
	color, (int)sizeof(ImDrawVert),
	uv, (int)sizeof(ImDrawVert),
	draw_list->VtxBuffer.Size - pcmd->VtxOffset,
	idx_buffer + pcmd->IdxOffset, pcmd->ElemCount, sizeof(ImDrawIdx));
	}
	}
	}
	platform_io.Renderer_RenderState = NULL;

	// Restore modified SDL_Renderer state
	SDL_SetRenderViewport(renderer, old.ViewportEnabled ? &old.Viewport : nullptr);
	SDL_SetRenderClipRect(renderer, old.ClipEnabled ? &old.ClipRect : nullptr);
	}

	// Called by Init/NewFrame/Shutdown
	bool ImGui_ImplSDLRenderer3_CreateFontsTexture()
	{
	ImGuiIO& io = ImGui::GetIO();
	ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();

	// Build texture atlas
	unsigned char* pixels;
	int width, height;
	io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); // Load as RGBA 32-bit (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.

	// Upload texture to graphics system
	// (Bilinear sampling is required by default. Set 'io.Fonts->Flags \|= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
	bd->FontTexture = SDL_CreateTexture(bd->Renderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height);
	if (bd->FontTexture == nullptr)
	{
	SDL_Log("error creating texture");
	return false;
	}
	SDL_UpdateTexture(bd->FontTexture, nullptr, pixels, 4 * width);
	SDL_SetTextureBlendMode(bd->FontTexture, SDL_BLENDMODE_BLEND);
	SDL_SetTextureScaleMode(bd->FontTexture, SDL_SCALEMODE_LINEAR);

	// Store our identifier
	io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);

	return true;
	}

	void ImGui_ImplSDLRenderer3_DestroyFontsTexture()
	{
	ImGuiIO& io = ImGui::GetIO();
	ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
	if (bd->FontTexture)
	{
	io.Fonts->SetTexID(0);
	SDL_DestroyTexture(bd->FontTexture);
	bd->FontTexture = nullptr;
	}
	}

	bool ImGui_ImplSDLRenderer3_CreateDeviceObjects()
	{
	return ImGui_ImplSDLRenderer3_CreateFontsTexture();
	}

	void ImGui_ImplSDLRenderer3_DestroyDeviceObjects()
	{
	ImGui_ImplSDLRenderer3_DestroyFontsTexture();
	}

	//-----------------------------------------------------------------------------

	#if defined(__clang__)
	#pragma clang diagnostic pop
	#endif

	#endif // #ifndef IMGUI_DISABLE