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Backends: moved global to a data structure to facilitate support for …
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…multi-contexts. (#586, #1851, #2004, #3012, #3934, #4141)

This is NOT enable multi-contexts for any backends
- in order to make this commit as harmless as possible, while containing all the cruft/renaming
-
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@ocornut
ocornut committed Jun 29, 2021
1 parent 88f4c13 commit 70c6038
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Showing 12 changed files with 1,046 additions and 709 deletions.
122 changes: 74 additions & 48 deletions backends/imgui_impl_allegro5.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -9,13 +9,14 @@
// [ ] Renderer: The renderer is suboptimal as we need to unindex our buffers and convert vertices manually.
// [ ] Platform: Missing gamepad support.

// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
// You can 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.
// 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
// (minor and older changes stripped away, please see git history for details)
// 2021-06-29: Reorganized backend to pull data from a single structure to facilitate usage with multiple-contexts (all g_XXXX access changed to bd->XXXX).
// 2021-05-19: Renderer: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
// 2021-02-18: Change blending equation to preserve alpha in output buffer.
// 2020-08-10: Inputs: Fixed horizontal mouse wheel direction.
Expand Down Expand Up @@ -53,13 +54,24 @@
#pragma warning (disable: 4127) // condition expression is constant
#endif

// Data
static ALLEGRO_DISPLAY* g_Display = NULL;
static ALLEGRO_BITMAP* g_Texture = NULL;
static double g_Time = 0.0;
static ALLEGRO_MOUSE_CURSOR* g_MouseCursorInvisible = NULL;
static ALLEGRO_VERTEX_DECL* g_VertexDecl = NULL;
static char* g_ClipboardTextData = NULL;
// Allegro Data
struct ImGui_ImplAllegro5_Data
{
ALLEGRO_DISPLAY* Display;
ALLEGRO_BITMAP* Texture;
double Time;
ALLEGRO_MOUSE_CURSOR* MouseCursorInvisible;
ALLEGRO_VERTEX_DECL* VertexDecl;
char* ClipboardTextData;

ImGui_ImplAllegro5_Data() { memset(this, 0, sizeof(*this)); }
};

// Wrapping access to backend data (to facilitate multiple-contexts stored in io.BackendPlatformUserData)
static ImGui_ImplAllegro5_Data* g_Data;
static ImGui_ImplAllegro5_Data* ImGui_ImplAllegro5_CreateBackendData() { IM_ASSERT(g_Data == NULL); g_Data = IM_NEW(ImGui_ImplAllegro5_Data); return g_Data; }
static ImGui_ImplAllegro5_Data* ImGui_ImplAllegro5_GetBackendData() { return ImGui::GetCurrentContext() != NULL ? g_Data : NULL; }
static void ImGui_ImplAllegro5_DestroyBackendData() { IM_DELETE(g_Data); g_Data = NULL; }

struct ImDrawVertAllegro
{
Expand Down Expand Up @@ -96,6 +108,7 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
return;

// Backup Allegro state that will be modified
ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
ALLEGRO_TRANSFORM last_transform = *al_get_current_transform();
ALLEGRO_TRANSFORM last_projection_transform = *al_get_current_projection_transform();
int last_clip_x, last_clip_y, last_clip_w, last_clip_h;
Expand Down Expand Up @@ -161,7 +174,7 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
// Draw
ALLEGRO_BITMAP* texture = (ALLEGRO_BITMAP*)pcmd->GetTexID();
al_set_clipping_rectangle(pcmd->ClipRect.x - clip_off.x, pcmd->ClipRect.y - clip_off.y, pcmd->ClipRect.z - pcmd->ClipRect.x, pcmd->ClipRect.w - pcmd->ClipRect.y);
al_draw_prim(&vertices[0], g_VertexDecl, texture, idx_offset, idx_offset + pcmd->ElemCount, ALLEGRO_PRIM_TRIANGLE_LIST);
al_draw_prim(&vertices[0], bd->VertexDecl, texture, idx_offset, idx_offset + pcmd->ElemCount, ALLEGRO_PRIM_TRIANGLE_LIST);
}
idx_offset += pcmd->ElemCount;
}
Expand All @@ -177,6 +190,7 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
bool ImGui_ImplAllegro5_CreateDeviceObjects()
{
// Build texture atlas
ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
ImGuiIO& io = ImGui::GetIO();
unsigned char* pixels;
int width, height;
Expand Down Expand Up @@ -210,54 +224,61 @@ bool ImGui_ImplAllegro5_CreateDeviceObjects()

// Store our identifier
io.Fonts->SetTexID((void*)cloned_img);
g_Texture = cloned_img;
bd->Texture = cloned_img;

// Create an invisible mouse cursor
// Because al_hide_mouse_cursor() seems to mess up with the actual inputs..
ALLEGRO_BITMAP* mouse_cursor = al_create_bitmap(8, 8);
g_MouseCursorInvisible = al_create_mouse_cursor(mouse_cursor, 0, 0);
bd->MouseCursorInvisible = al_create_mouse_cursor(mouse_cursor, 0, 0);
al_destroy_bitmap(mouse_cursor);

return true;
}

void ImGui_ImplAllegro5_InvalidateDeviceObjects()
{
if (g_Texture)
ImGuiIO& io = ImGui::GetIO();
ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
if (bd->Texture)
{
ImGuiIO& io = ImGui::GetIO();
io.Fonts->SetTexID(NULL);
al_destroy_bitmap(g_Texture);
g_Texture = NULL;
al_destroy_bitmap(bd->Texture);
bd->Texture = NULL;
}
if (g_MouseCursorInvisible)
if (bd->MouseCursorInvisible)
{
al_destroy_mouse_cursor(g_MouseCursorInvisible);
g_MouseCursorInvisible = NULL;
al_destroy_mouse_cursor(bd->MouseCursorInvisible);
bd->MouseCursorInvisible = NULL;
}
}

#if ALLEGRO_HAS_CLIPBOARD
static const char* ImGui_ImplAllegro5_GetClipboardText(void*)
{
if (g_ClipboardTextData)
al_free(g_ClipboardTextData);
g_ClipboardTextData = al_get_clipboard_text(g_Display);
return g_ClipboardTextData;
ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
if (bd->ClipboardTextData)
al_free(bd->ClipboardTextData);
bd->ClipboardTextData = al_get_clipboard_text(bd->Display);
return bd->ClipboardTextData;
}

static void ImGui_ImplAllegro5_SetClipboardText(void*, const char* text)
{
al_set_clipboard_text(g_Display, text);
ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
al_set_clipboard_text(bd->Display, text);
}
#endif

bool ImGui_ImplAllegro5_Init(ALLEGRO_DISPLAY* display)
{
g_Display = display;
ImGuiIO& io = ImGui::GetIO();
IM_ASSERT(io.BackendPlatformUserData == NULL && "Already initialized a platform backend!");

ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_CreateBackendData();
bd->Display = display;

// Setup backend capabilities flags
ImGuiIO& io = ImGui::GetIO();
io.BackendRendererUserData = (void*)bd;
io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors; // We can honor GetMouseCursor() values (optional)
io.BackendPlatformName = io.BackendRendererName = "imgui_impl_allegro5";

Expand All @@ -271,7 +292,7 @@ bool ImGui_ImplAllegro5_Init(ALLEGRO_DISPLAY* display)
{ ALLEGRO_PRIM_COLOR_ATTR, 0, IM_OFFSETOF(ImDrawVertAllegro, col) },
{ 0, 0, 0 }
};
g_VertexDecl = al_create_vertex_decl(elems, sizeof(ImDrawVertAllegro));
bd->VertexDecl = al_create_vertex_decl(elems, sizeof(ImDrawVertAllegro));

io.KeyMap[ImGuiKey_Tab] = ALLEGRO_KEY_TAB;
io.KeyMap[ImGuiKey_LeftArrow] = ALLEGRO_KEY_LEFT;
Expand Down Expand Up @@ -308,18 +329,20 @@ bool ImGui_ImplAllegro5_Init(ALLEGRO_DISPLAY* display)

void ImGui_ImplAllegro5_Shutdown()
{
ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
ImGui_ImplAllegro5_InvalidateDeviceObjects();

g_Display = NULL;
g_Time = 0.0;
bd->Display = NULL;
bd->Time = 0.0;

if (g_VertexDecl)
al_destroy_vertex_decl(g_VertexDecl);
g_VertexDecl = NULL;
if (bd->VertexDecl)
al_destroy_vertex_decl(bd->VertexDecl);
bd->VertexDecl = NULL;

if (g_ClipboardTextData)
al_free(g_ClipboardTextData);
g_ClipboardTextData = NULL;
if (bd->ClipboardTextData)
al_free(bd->ClipboardTextData);
bd->ClipboardTextData = NULL;
ImGui_ImplAllegro5_DestroyBackendData();
}

// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
Expand All @@ -329,11 +352,12 @@ void ImGui_ImplAllegro5_Shutdown()
bool ImGui_ImplAllegro5_ProcessEvent(ALLEGRO_EVENT* ev)
{
ImGuiIO& io = ImGui::GetIO();
ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();

switch (ev->type)
{
case ALLEGRO_EVENT_MOUSE_AXES:
if (ev->mouse.display == g_Display)
if (ev->mouse.display == bd->Display)
{
io.MouseWheel += ev->mouse.dz;
io.MouseWheelH -= ev->mouse.dw;
Expand All @@ -342,31 +366,31 @@ bool ImGui_ImplAllegro5_ProcessEvent(ALLEGRO_EVENT* ev)
return true;
case ALLEGRO_EVENT_MOUSE_BUTTON_DOWN:
case ALLEGRO_EVENT_MOUSE_BUTTON_UP:
if (ev->mouse.display == g_Display && ev->mouse.button <= 5)
if (ev->mouse.display == bd->Display && ev->mouse.button <= 5)
io.MouseDown[ev->mouse.button - 1] = (ev->type == ALLEGRO_EVENT_MOUSE_BUTTON_DOWN);
return true;
case ALLEGRO_EVENT_TOUCH_MOVE:
if (ev->touch.display == g_Display)
if (ev->touch.display == bd->Display)
io.MousePos = ImVec2(ev->touch.x, ev->touch.y);
return true;
case ALLEGRO_EVENT_TOUCH_BEGIN:
case ALLEGRO_EVENT_TOUCH_END:
case ALLEGRO_EVENT_TOUCH_CANCEL:
if (ev->touch.display == g_Display && ev->touch.primary)
if (ev->touch.display == bd->Display && ev->touch.primary)
io.MouseDown[0] = (ev->type == ALLEGRO_EVENT_TOUCH_BEGIN);
return true;
case ALLEGRO_EVENT_MOUSE_LEAVE_DISPLAY:
if (ev->mouse.display == g_Display)
if (ev->mouse.display == bd->Display)
io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
return true;
case ALLEGRO_EVENT_KEY_CHAR:
if (ev->keyboard.display == g_Display)
if (ev->keyboard.display == bd->Display)
if (ev->keyboard.unichar != 0)
io.AddInputCharacter((unsigned int)ev->keyboard.unichar);
return true;
case ALLEGRO_EVENT_KEY_DOWN:
case ALLEGRO_EVENT_KEY_UP:
if (ev->keyboard.display == g_Display)
if (ev->keyboard.display == bd->Display)
io.KeysDown[ev->keyboard.keycode] = (ev->type == ALLEGRO_EVENT_KEY_DOWN);
return true;
}
Expand All @@ -379,11 +403,12 @@ static void ImGui_ImplAllegro5_UpdateMouseCursor()
if (io.ConfigFlags & ImGuiConfigFlags_NoMouseCursorChange)
return;

ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
ImGuiMouseCursor imgui_cursor = ImGui::GetMouseCursor();
if (io.MouseDrawCursor || imgui_cursor == ImGuiMouseCursor_None)
{
// Hide OS mouse cursor if imgui is drawing it or if it wants no cursor
al_set_mouse_cursor(g_Display, g_MouseCursorInvisible);
al_set_mouse_cursor(bd->Display, bd->MouseCursorInvisible);
}
else
{
Expand All @@ -398,27 +423,28 @@ static void ImGui_ImplAllegro5_UpdateMouseCursor()
case ImGuiMouseCursor_ResizeNWSE: cursor_id = ALLEGRO_SYSTEM_MOUSE_CURSOR_RESIZE_NW; break;
case ImGuiMouseCursor_NotAllowed: cursor_id = ALLEGRO_SYSTEM_MOUSE_CURSOR_UNAVAILABLE; break;
}
al_set_system_mouse_cursor(g_Display, cursor_id);
al_set_system_mouse_cursor(bd->Display, cursor_id);
}
}

void ImGui_ImplAllegro5_NewFrame()
{
if (!g_Texture)
ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
if (!bd->Texture)
ImGui_ImplAllegro5_CreateDeviceObjects();

ImGuiIO& io = ImGui::GetIO();

// Setup display size (every frame to accommodate for window resizing)
int w, h;
w = al_get_display_width(g_Display);
h = al_get_display_height(g_Display);
w = al_get_display_width(bd->Display);
h = al_get_display_height(bd->Display);
io.DisplaySize = ImVec2((float)w, (float)h);

// Setup time step
double current_time = al_get_time();
io.DeltaTime = g_Time > 0.0 ? (float)(current_time - g_Time) : (float)(1.0f / 60.0f);
g_Time = current_time;
io.DeltaTime = bd->Time > 0.0 ? (float)(current_time - bd->Time) : (float)(1.0f / 60.0f);
bd->Time = current_time;

// Setup inputs
ALLEGRO_KEYBOARD_STATE keys;
Expand Down
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