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imgui/examples/opengl_sdl_example/imgui_impl_sdl.cpp

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#ifdef _MSC_VER
#include <Windows.h>
#include <gl/GL.h>
#include <gl/GLU.h>
#endif
#ifdef MACOSX
#include <OpenGL/gl.h>
#endif
#include <SDL.h>
#include <SDL_syswm.h>
#include <imgui.h>
#include "imgui_impl_sdl.h"
// Data
static double g_Time = 0.0f;
static bool g_MousePressed[3] = { false, false, false };
static float g_MouseWheel = 0.0f;
static GLuint g_FontTexture = 0;
// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
// If text or lines are blurry when integrating ImGui in your engine:
// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
static void ImGui_ImplSdl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
{
// We are using the OpenGL fixed pipeline to make the example code simpler to read!
// A probable faster way to render would be to collate all vertices from all cmd_lists into a single vertex buffer.
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers.
glPushAttrib(GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT | GL_TRANSFORM_BIT);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_SCISSOR_TEST);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glEnable(GL_TEXTURE_2D);
//glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context
// Setup orthographic projection matrix
const float width = ImGui::GetIO().DisplaySize.x;
const float height = ImGui::GetIO().DisplaySize.y;
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glOrtho(0.0f, width, height, 0.0f, -1.0f, +1.0f);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
// Render command lists
#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT))
for (int n = 0; n < cmd_lists_count; n++)
{
const ImDrawList* cmd_list = cmd_lists[n];
const unsigned char* vtx_buffer = (const unsigned char*)&cmd_list->vtx_buffer.front();
glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer + OFFSETOF(ImDrawVert, pos)));
glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer + OFFSETOF(ImDrawVert, uv)));
glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (void*)(vtx_buffer + OFFSETOF(ImDrawVert, col)));
int vtx_offset = 0;
for (size_t cmd_i = 0; cmd_i < cmd_list->commands.size(); cmd_i++)
{
const ImDrawCmd* pcmd = &cmd_list->commands[cmd_i];
if (pcmd->user_callback)
{
pcmd->user_callback(cmd_list, pcmd);
}
else
{
glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->texture_id);
glScissor((int)pcmd->clip_rect.x, (int)(height - pcmd->clip_rect.w), (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y));
glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
}
vtx_offset += pcmd->vtx_count;
}
}
#undef OFFSETOF
// Restore modified state
glDisableClientState(GL_COLOR_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
glBindTexture(GL_TEXTURE_2D, 0);
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glPopAttrib();
}
static const char* ImGui_ImplSdl_GetClipboardText()
{
return SDL_GetClipboardText();
}
static void ImGui_ImplSdl_SetClipboardText(const char* text)
{
SDL_SetClipboardText(text);
}
void ImGui_ImplSdl_KeyCallback(int key, bool down)
{
ImGuiIO& io = ImGui::GetIO();
if (down)
io.KeysDown[key] = true;
else
io.KeysDown[key] = false;
io.KeyShift = ((SDL_GetModState() & KMOD_SHIFT) != 0);
io.KeyCtrl = ((SDL_GetModState() & KMOD_CTRL) != 0);
io.KeyAlt = ((SDL_GetModState() & KMOD_ALT) != 0);
}
void ImGui_ImplSdl_CharCallback(unsigned int c)
{
ImGuiIO& io = ImGui::GetIO();
if (c > 0 && c < 0x10000)
io.AddInputCharacter((unsigned short)c);
}
bool ImGui_ImplSdl_CreateDeviceObjects()
{
ImGuiIO& io = ImGui::GetIO();
// Build texture
unsigned char* pixels;
int width, height;
io.Fonts->GetTexDataAsAlpha8(&pixels, &width, &height);
// Create texture
glGenTextures(1, &g_FontTexture);
glBindTexture(GL_TEXTURE_2D, g_FontTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, pixels);
// Store our identifier
io.Fonts->TexID = (void *)(intptr_t)g_FontTexture;
io.Fonts->ClearInputData();
io.Fonts->ClearTexData();
return true;
}
void ImGui_ImplSdl_InvalidateDeviceObjects()
{
if (g_FontTexture)
{
glDeleteTextures(1, &g_FontTexture);
ImGui::GetIO().Fonts->TexID = 0;
g_FontTexture = 0;
}
}
bool ImGui_ImplSdl_Init(SDL_Window *window)
{
ImGuiIO& io = ImGui::GetIO();
io.KeyMap[ImGuiKey_Tab] = SDLK_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
io.KeyMap[ImGuiKey_LeftArrow] = SDL_SCANCODE_LEFT;
io.KeyMap[ImGuiKey_RightArrow] = SDL_SCANCODE_RIGHT;
io.KeyMap[ImGuiKey_UpArrow] = SDL_SCANCODE_UP;
io.KeyMap[ImGuiKey_DownArrow] = SDL_SCANCODE_DOWN;
io.KeyMap[ImGuiKey_Home] = SDL_SCANCODE_HOME;
io.KeyMap[ImGuiKey_End] = SDL_SCANCODE_END;
io.KeyMap[ImGuiKey_Delete] = SDLK_DELETE;
io.KeyMap[ImGuiKey_Backspace] = SDLK_BACKSPACE;
io.KeyMap[ImGuiKey_Enter] = SDLK_RETURN;
io.KeyMap[ImGuiKey_Escape] = SDLK_ESCAPE;
io.KeyMap[ImGuiKey_A] = SDLK_a;
io.KeyMap[ImGuiKey_C] = SDLK_c;
io.KeyMap[ImGuiKey_V] = SDLK_v;
io.KeyMap[ImGuiKey_X] = SDLK_x;
io.KeyMap[ImGuiKey_Y] = SDLK_y;
io.KeyMap[ImGuiKey_Z] = SDLK_z;
io.RenderDrawListsFn = ImGui_ImplSdl_RenderDrawLists;
io.SetClipboardTextFn = ImGui_ImplSdl_SetClipboardText;
io.GetClipboardTextFn = ImGui_ImplSdl_GetClipboardText;
#ifdef _MSC_VER
SDL_SysWMinfo wmInfo;
SDL_VERSION(&wmInfo.version);
SDL_GetWindowWMInfo(window, &wmInfo);
io.ImeWindowHandle = wmInfo.info.win.window;
#endif
return true;
}
void ImGui_ImplSdl_Shutdown()
{
ImGui_ImplSdl_InvalidateDeviceObjects();
ImGui::Shutdown();
}
bool ImGui_ImplSdl_NewFrame(SDL_Window *window)
{
if (!g_FontTexture)
ImGui_ImplSdl_CreateDeviceObjects();
ImGuiIO& io = ImGui::GetIO();
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bool done = false;
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SDL_Event event;
while (SDL_PollEvent(&event))
{
switch (event.type)
{
case SDL_QUIT:
done = true;
break;
case SDL_MOUSEWHEEL:
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if (event.wheel.y > 0)
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g_MouseWheel = 1;
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if (event.wheel.y < 0)
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g_MouseWheel = -1;
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break;
case SDL_MOUSEBUTTONDOWN:
if (event.button.button == SDL_BUTTON_LEFT) g_MousePressed[0] = true;
if (event.button.button == SDL_BUTTON_RIGHT) g_MousePressed[1] = true;
if (event.button.button == SDL_BUTTON_MIDDLE) g_MousePressed[2] = true;
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break;
case SDL_TEXTINPUT:
ImGui_ImplSdl_CharCallback(event.text.text[0]);
break;
case SDL_KEYUP:
ImGui_ImplSdl_KeyCallback(event.key.keysym.sym&~SDLK_SCANCODE_MASK, false);
break;
case SDL_KEYDOWN:
ImGui_ImplSdl_KeyCallback(event.key.keysym.sym&~SDLK_SCANCODE_MASK, true);
break;
default:
break;
}
}
// Setup display size (every frame to accommodate for window resizing)
int w, h;
SDL_GetWindowSize(window, &w, &h);
io.DisplaySize = ImVec2((float)w, (float)h);
// Time
Uint32 time = SDL_GetTicks();
double current_time = time / 1000.0;
io.DeltaTime = g_Time > 0.0 ? (float)(current_time - g_Time) : (float)(1.0f/60.0f);
g_Time = current_time;
int mx, my;
Uint32 mouseMask = SDL_GetMouseState(&mx, &my);
// Setup inputs
// (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
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if (SDL_GetWindowFlags(window) & SDL_WINDOW_MOUSE_FOCUS)
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io.MousePos = ImVec2((float)mx, (float)my); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
else
io.MousePos = ImVec2(-1,-1);
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io.MouseDown[0] = g_MousePressed[0] || (mouseMask & SDL_BUTTON(SDL_BUTTON_LEFT)) != 0; // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
io.MouseDown[1] = g_MousePressed[1] || (mouseMask & SDL_BUTTON(SDL_BUTTON_RIGHT)) != 0;
io.MouseDown[2] = g_MousePressed[2] || (mouseMask & SDL_BUTTON(SDL_BUTTON_MIDDLE)) != 0;
g_MousePressed[0] = g_MousePressed[1] = g_MousePressed[2] = false;
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io.MouseWheel = g_MouseWheel;
g_MouseWheel = 0.0f;
// Hide/show hardware mouse cursor
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SDL_ShowCursor(io.MouseDrawCursor ? 0 : 1);
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// Start the frame
ImGui::NewFrame();
return done;
}