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Backends: SDL_Renderer: Added renderer backend for SDL 2.0.17+ (#3926)

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Sylvain
2021-09-21 17:12:30 +02:00
committed by ocornut
parent d7260104b1
commit 62b17f928e
13 changed files with 777 additions and 1 deletions
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backends/imgui_impl_sdlrenderer.cpp Normal file
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// dear imgui: Renderer Backend for SDL_Renderer, with Platform Backend SDL
// (Requires: SDL 2.0.17+)
// Implemented features:
// You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs
// CHANGELOG
// 2021-16-03: Creation
#include "imgui.h"
#include "imgui_impl_sdlrenderer.h"
#if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier
#include <stddef.h> // intptr_t
#else
#include <stdint.h> // intptr_t
#endif
#include "SDL.h"
#if SDL_MAJOR_VERSION < 2 || SDL_MINOR_VERSION < 0 || SDL_PATCHLEVEL < 17
# error Requires: SDL 2.0.17+ because of SDL_RenderGeometry function
#endif
struct ImGui_ImplSDLRenderer_Data
{
SDL_Renderer *SDLRenderer;
SDL_Texture *FontTexture;
ImGui_ImplSDLRenderer_Data() { memset(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_ImplSDLRenderer_Data* ImGui_ImplSDLRenderer_GetBackendData()
{
return ImGui::GetCurrentContext() ? (ImGui_ImplSDLRenderer_Data*)ImGui::GetIO().BackendRendererUserData : NULL;
}
// Functions
bool ImGui_ImplSDLRenderer_Init(SDL_Renderer *renderer)
{
ImGuiIO& io = ImGui::GetIO();
IM_ASSERT(io.BackendRendererUserData == NULL && "Already initialized a renderer backend!");
IM_ASSERT(renderer != NULL && "SDL_Renderer not initialized!");
// Setup backend capabilities flags
ImGui_ImplSDLRenderer_Data* bd = IM_NEW(ImGui_ImplSDLRenderer_Data)();
io.BackendRendererUserData = (void*)bd;
io.BackendRendererName = "imgui_impl_SDLRenderer";
bd->SDLRenderer = renderer;
return true;
}
void ImGui_ImplSDLRenderer_Shutdown()
{
ImGuiIO& io = ImGui::GetIO();
ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
ImGui_ImplSDLRenderer_DestroyDeviceObjects();
io.BackendRendererName = NULL;
io.BackendRendererUserData = NULL;
IM_DELETE(bd);
}
static void ImGui_ImplSDLRenderer_SetupRenderState()
{
ImGui_ImplSDLRenderer_Data *bd = ImGui_ImplSDLRenderer_GetBackendData();
// Clear out any viewports and cliprects set by the user
SDL_RenderSetViewport(bd->SDLRenderer, NULL);
SDL_RenderSetClipRect(bd->SDLRenderer, NULL);
}
void ImGui_ImplSDLRenderer_NewFrame()
{
ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
IM_ASSERT(bd != NULL && "Did you call ImGui_ImplSDLRenderer_Init()?");
if (!bd->FontTexture) {
ImGui_ImplSDLRenderer_CreateDeviceObjects();
}
}
void ImGui_ImplSDLRenderer_RenderDrawData(ImDrawData* draw_data)
{
ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
// If there's a scale factor set by the user, use that instead
float rsX = 1.0f;
float rsY = 1.0f;
SDL_RenderGetScale(bd->SDLRenderer, &rsX, &rsY);
ImVec2 renderScale;
// 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.
renderScale.x = (rsX == 1.0f) ? draw_data->FramebufferScale.x : 1.0f;
renderScale.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 * renderScale.x);
int fb_height = (int)(draw_data->DisplaySize.y * renderScale.y);
if (fb_width == 0 || fb_height == 0)
return;
// Will project scissor/clipping rectangles into framebuffer space
ImVec2 clip_off = draw_data->DisplayPos; // (0,0) unless using multi-viewports
ImVec2 clip_scale = renderScale;
ImGui_ImplSDLRenderer_SetupRenderState();
for (int n = 0; n < draw_data->CmdListsCount; n++) {
const ImDrawList* cmd_list = draw_data->CmdLists[n];
const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;
const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;
for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
{
const ImDrawCmd* pcmd = &cmd_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_ImplSDLRenderer_SetupRenderState();
} else {
pcmd->UserCallback(cmd_list, pcmd);
}
}
else
{
// Project scissor/clipping rectangles into framebuffer space
ImVec4 clip_rect;
clip_rect.x = (pcmd->ClipRect.x - clip_off.x) * clip_scale.x;
clip_rect.y = (pcmd->ClipRect.y - clip_off.y) * clip_scale.y;
clip_rect.z = (pcmd->ClipRect.z - clip_off.x) * clip_scale.x;
clip_rect.w = (pcmd->ClipRect.w - clip_off.y) * clip_scale.y;
if (clip_rect.x < fb_width && clip_rect.y < fb_height && clip_rect.z >= 0.0f && clip_rect.w >= 0.0f)
{
SDL_Rect r;
r.x = clip_rect.x;
r.y = clip_rect.y;
r.w = clip_rect.z - clip_rect.x;
r.h = clip_rect.w - clip_rect.y;
SDL_RenderSetClipRect(bd->SDLRenderer, &r);
int xy_stride = sizeof(ImDrawVert);
float *xy = (float *)((char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, pos));
int uv_stride = sizeof(ImDrawVert);
float *uv = (float*)((char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, uv));
int col_stride = sizeof(ImDrawVert);
int *color = (int*)((char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, col));
SDL_Texture *tex = (SDL_Texture*)pcmd->TextureId;
SDL_RenderGeometryRaw(bd->SDLRenderer, tex,
xy, xy_stride, color,
col_stride,
uv, uv_stride,
cmd_list->VtxBuffer.Size,
idx_buffer, pcmd->ElemCount, sizeof (ImDrawIdx));
}
}
idx_buffer += pcmd->ElemCount;
}
}
}
// Called by Init/NewFrame/Shutdown
bool ImGui_ImplSDLRenderer_CreateFontsTexture()
{
// Build texture atlas
ImGuiIO& io = ImGui::GetIO();
ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
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.
bd->FontTexture = SDL_CreateTexture(bd->SDLRenderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STATIC, width, height);
if (bd->FontTexture == NULL) {
SDL_Log("error creating texture");
return false;
}
SDL_UpdateTexture(bd->FontTexture, NULL, pixels, 4 * width);
SDL_SetTextureBlendMode(bd->FontTexture, SDL_BLENDMODE_BLEND);
// Store our identifier
io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);
return true;
}
void ImGui_ImplSDLRenderer_DestroyFontsTexture()
{
ImGuiIO& io = ImGui::GetIO();
ImGui_ImplSDLRenderer_Data* bd = ImGui_ImplSDLRenderer_GetBackendData();
if (bd->FontTexture) {
io.Fonts->SetTexID(0);
SDL_DestroyTexture(bd->FontTexture);
bd->FontTexture = NULL;
}
}
bool ImGui_ImplSDLRenderer_CreateDeviceObjects()
{
return ImGui_ImplSDLRenderer_CreateFontsTexture();
}
void ImGui_ImplSDLRenderer_DestroyDeviceObjects()
{
ImGui_ImplSDLRenderer_DestroyFontsTexture();
}