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imgui/examples/opengl2_example/imgui_impl_glfw_gl2.cpp
2018-04-14 10:28:10 +02:00

365 lines
16 KiB
C++

// ImGui GLFW binding with OpenGL (legacy, fixed pipeline)
// (GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.)
// Implemented features:
// [X] User texture binding. Cast 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
// **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
// **Prefer using the code in the opengl3_example/ folder**
// This code is mostly provided as a reference to learn how ImGui integration works, because it is shorter to read.
// If your code is using GL3+ context or any semi modern OpenGL calls, using this is likely to make everything more
// complicated, will require your code to reset every single OpenGL attributes to their initial state, and might
// confuse your GPU driver.
// The GL2 code is unable to reset attributes or even call e.g. "glUseProgram(0)" because they don't exist in that API.
// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
// If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown().
// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
// https://github.com/ocornut/imgui
// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
// 2018-03-20: Misc: Setup io.BackendFlags ImGuiBackendFlags_HasMouseCursors and ImGuiBackendFlags_HasSetMousePos flags + honor ImGuiConfigFlags_NoMouseCursorChange flag.
// 2018-02-20: Inputs: Added support for mouse cursors (ImGui::GetMouseCursor() value, passed to glfwSetCursor()).
// 2018-02-20: Inputs: Renamed GLFW callbacks exposed in .h to not include GL2 in their name.
// 2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplGlfwGL2_RenderDrawData() in the .h file so you can call it yourself.
// 2018-02-06: Misc: Removed call to ImGui::Shutdown() which is not available from 1.60 WIP, user needs to call CreateContext/DestroyContext themselves.
// 2018-02-06: Inputs: Added mapping for ImGuiKey_Space.
// 2018-02-06: Inputs: Honoring the io.WantSetMousePos flag by repositioning the mouse (ImGuiConfigFlags_NavEnableSetMousePos is set).
// 2018-01-20: Inputs: Added Horizontal Mouse Wheel support.
// 2018-01-18: Inputs: Added mapping for ImGuiKey_Insert.
// 2018-01-09: Misc: Renamed imgui_impl_glfw.* to imgui_impl_glfw_gl2.*.
// 2017-09-01: OpenGL: Save and restore current polygon mode.
// 2017-08-25: Inputs: MousePos set to -FLT_MAX,-FLT_MAX when mouse is unavailable/missing (instead of -1,-1).
// 2016-10-15: Misc: Added a void* user_data parameter to Clipboard function handlers.
// 2016-09-10: OpenGL: Uploading font texture as RGBA32 to increase compatibility with users shaders (not ideal).
// 2016-09-05: OpenGL: Fixed save and restore of current scissor rectangle.
#include "imgui.h"
#include "imgui_impl_glfw_gl2.h"
// GLFW
#include <GLFW/glfw3.h>
#ifdef _WIN32
#undef APIENTRY
#define GLFW_EXPOSE_NATIVE_WIN32
#define GLFW_EXPOSE_NATIVE_WGL
#include <GLFW/glfw3native.h>
#endif
// GLFW data
static GLFWwindow* g_Window = NULL;
static double g_Time = 0.0f;
static bool g_MouseJustPressed[3] = { false, false, false };
static GLFWcursor* g_MouseCursors[ImGuiMouseCursor_COUNT] = { 0 };
// OpenGL data
static GLuint g_FontTexture = 0;
// OpenGL2 Render function.
// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
void ImGui_ImplGlfwGL2_RenderDrawData(ImDrawData* draw_data)
{
// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
ImGuiIO& io = ImGui::GetIO();
int fb_width = (int)(io.DisplaySize.x * io.DisplayFramebufferScale.x);
int fb_height = (int)(io.DisplaySize.y * io.DisplayFramebufferScale.y);
if (fb_width == 0 || fb_height == 0)
return;
draw_data->ScaleClipRects(io.DisplayFramebufferScale);
// We are using the OpenGL fixed pipeline to make the example code simpler to read!
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers, polygon fill.
GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
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);
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
//glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound
// Setup viewport, orthographic projection matrix
glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glOrtho(0.0f, io.DisplaySize.x, io.DisplaySize.y, 0.0f, -1.0f, +1.0f);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
// Render command lists
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;
glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, pos)));
glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, uv)));
glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, col)));
for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
{
const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
if (pcmd->UserCallback)
{
pcmd->UserCallback(cmd_list, pcmd);
}
else
{
glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
glScissor((int)pcmd->ClipRect.x, (int)(fb_height - pcmd->ClipRect.w), (int)(pcmd->ClipRect.z - pcmd->ClipRect.x), (int)(pcmd->ClipRect.w - pcmd->ClipRect.y));
glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer);
}
idx_buffer += pcmd->ElemCount;
}
}
// Restore modified state
glDisableClientState(GL_COLOR_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
glBindTexture(GL_TEXTURE_2D, (GLuint)last_texture);
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glPopAttrib();
glPolygonMode(GL_FRONT, (GLenum)last_polygon_mode[0]); glPolygonMode(GL_BACK, (GLenum)last_polygon_mode[1]);
glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
}
static const char* ImGui_ImplGlfwGL2_GetClipboardText(void* user_data)
{
return glfwGetClipboardString((GLFWwindow*)user_data);
}
static void ImGui_ImplGlfwGL2_SetClipboardText(void* user_data, const char* text)
{
glfwSetClipboardString((GLFWwindow*)user_data, text);
}
void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow*, int button, int action, int /*mods*/)
{
if (action == GLFW_PRESS && button >= 0 && button < 3)
g_MouseJustPressed[button] = true;
}
void ImGui_ImplGlfw_ScrollCallback(GLFWwindow*, double xoffset, double yoffset)
{
ImGuiIO& io = ImGui::GetIO();
io.MouseWheelH += (float)xoffset;
io.MouseWheel += (float)yoffset;
}
void ImGui_ImplGlfw_KeyCallback(GLFWwindow*, int key, int, int action, int mods)
{
ImGuiIO& io = ImGui::GetIO();
if (action == GLFW_PRESS)
io.KeysDown[key] = true;
if (action == GLFW_RELEASE)
io.KeysDown[key] = false;
(void)mods; // Modifiers are not reliable across systems
io.KeyCtrl = io.KeysDown[GLFW_KEY_LEFT_CONTROL] || io.KeysDown[GLFW_KEY_RIGHT_CONTROL];
io.KeyShift = io.KeysDown[GLFW_KEY_LEFT_SHIFT] || io.KeysDown[GLFW_KEY_RIGHT_SHIFT];
io.KeyAlt = io.KeysDown[GLFW_KEY_LEFT_ALT] || io.KeysDown[GLFW_KEY_RIGHT_ALT];
io.KeySuper = io.KeysDown[GLFW_KEY_LEFT_SUPER] || io.KeysDown[GLFW_KEY_RIGHT_SUPER];
}
void ImGui_ImplGlfw_CharCallback(GLFWwindow*, unsigned int c)
{
ImGuiIO& io = ImGui::GetIO();
if (c > 0 && c < 0x10000)
io.AddInputCharacter((unsigned short)c);
}
bool ImGui_ImplGlfwGL2_CreateDeviceObjects()
{
// Build texture atlas
ImGuiIO& io = ImGui::GetIO();
unsigned char* pixels;
int width, height;
io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); // Load as RGBA 32-bits (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
GLint last_texture;
glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_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);
glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
// Store our identifier
io.Fonts->TexID = (void *)(intptr_t)g_FontTexture;
// Restore state
glBindTexture(GL_TEXTURE_2D, last_texture);
return true;
}
void ImGui_ImplGlfwGL2_InvalidateDeviceObjects()
{
if (g_FontTexture)
{
glDeleteTextures(1, &g_FontTexture);
ImGui::GetIO().Fonts->TexID = 0;
g_FontTexture = 0;
}
}
static void ImGui_ImplGlfw_InstallCallbacks(GLFWwindow* window)
{
glfwSetMouseButtonCallback(window, ImGui_ImplGlfw_MouseButtonCallback);
glfwSetScrollCallback(window, ImGui_ImplGlfw_ScrollCallback);
glfwSetKeyCallback(window, ImGui_ImplGlfw_KeyCallback);
glfwSetCharCallback(window, ImGui_ImplGlfw_CharCallback);
}
bool ImGui_ImplGlfwGL2_Init(GLFWwindow* window, bool install_callbacks)
{
g_Window = window;
// Setup back-end capabilities flags
ImGuiIO& io = ImGui::GetIO();
io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors; // We can honor GetMouseCursor() values (optional)
io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos; // We can honor io.WantSetMousePos requests (optional, rarely used)
// Keyboard mapping. ImGui will use those indices to peek into the io.KeysDown[] array.
io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB;
io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
io.KeyMap[ImGuiKey_PageUp] = GLFW_KEY_PAGE_UP;
io.KeyMap[ImGuiKey_PageDown] = GLFW_KEY_PAGE_DOWN;
io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
io.KeyMap[ImGuiKey_Insert] = GLFW_KEY_INSERT;
io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
io.KeyMap[ImGuiKey_Space] = GLFW_KEY_SPACE;
io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;
io.SetClipboardTextFn = ImGui_ImplGlfwGL2_SetClipboardText;
io.GetClipboardTextFn = ImGui_ImplGlfwGL2_GetClipboardText;
io.ClipboardUserData = g_Window;
#ifdef _WIN32
io.ImeWindowHandle = glfwGetWin32Window(g_Window);
#endif
// Load cursors
// FIXME: GLFW doesn't expose suitable cursors for ResizeAll, ResizeNESW, ResizeNWSE. We revert to arrow cursor for those.
g_MouseCursors[ImGuiMouseCursor_Arrow] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
g_MouseCursors[ImGuiMouseCursor_TextInput] = glfwCreateStandardCursor(GLFW_IBEAM_CURSOR);
g_MouseCursors[ImGuiMouseCursor_ResizeAll] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
g_MouseCursors[ImGuiMouseCursor_ResizeNS] = glfwCreateStandardCursor(GLFW_VRESIZE_CURSOR);
g_MouseCursors[ImGuiMouseCursor_ResizeEW] = glfwCreateStandardCursor(GLFW_HRESIZE_CURSOR);
g_MouseCursors[ImGuiMouseCursor_ResizeNESW] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
g_MouseCursors[ImGuiMouseCursor_ResizeNWSE] = glfwCreateStandardCursor(GLFW_ARROW_CURSOR);
if (install_callbacks)
ImGui_ImplGlfw_InstallCallbacks(window);
return true;
}
void ImGui_ImplGlfwGL2_Shutdown()
{
// Destroy GLFW mouse cursors
for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
glfwDestroyCursor(g_MouseCursors[cursor_n]);
memset(g_MouseCursors, 0, sizeof(g_MouseCursors));
// Destroy OpenGL objects
ImGui_ImplGlfwGL2_InvalidateDeviceObjects();
}
void ImGui_ImplGlfwGL2_NewFrame()
{
if (!g_FontTexture)
ImGui_ImplGlfwGL2_CreateDeviceObjects();
ImGuiIO& io = ImGui::GetIO();
// Setup display size (every frame to accommodate for window resizing)
int w, h;
int display_w, display_h;
glfwGetWindowSize(g_Window, &w, &h);
glfwGetFramebufferSize(g_Window, &display_w, &display_h);
io.DisplaySize = ImVec2((float)w, (float)h);
io.DisplayFramebufferScale = ImVec2(w > 0 ? ((float)display_w / w) : 0, h > 0 ? ((float)display_h / h) : 0);
// Setup time step
double current_time = glfwGetTime();
io.DeltaTime = g_Time > 0.0 ? (float)(current_time - g_Time) : (float)(1.0f/60.0f);
g_Time = current_time;
// Setup inputs
// (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
if (glfwGetWindowAttrib(g_Window, GLFW_FOCUSED))
{
// Set OS mouse position if requested (only used when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
if (io.WantSetMousePos)
{
glfwSetCursorPos(g_Window, (double)io.MousePos.x, (double)io.MousePos.y);
}
else
{
double mouse_x, mouse_y;
glfwGetCursorPos(g_Window, &mouse_x, &mouse_y);
io.MousePos = ImVec2((float)mouse_x, (float)mouse_y);
}
}
else
{
io.MousePos = ImVec2(-FLT_MAX,-FLT_MAX);
}
for (int i = 0; i < 3; i++)
{
// 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[i] = g_MouseJustPressed[i] || glfwGetMouseButton(g_Window, i) != 0;
g_MouseJustPressed[i] = false;
}
// Update OS/hardware mouse cursor if imgui isn't drawing a software cursor
if ((io.ConfigFlags & ImGuiConfigFlags_NoMouseCursorChange) == 0 && glfwGetInputMode(g_Window, GLFW_CURSOR) != GLFW_CURSOR_DISABLED)
{
ImGuiMouseCursor cursor = ImGui::GetMouseCursor();
if (io.MouseDrawCursor || cursor == ImGuiMouseCursor_None)
{
glfwSetInputMode(g_Window, GLFW_CURSOR, GLFW_CURSOR_HIDDEN);
}
else
{
glfwSetCursor(g_Window, g_MouseCursors[cursor] ? g_MouseCursors[cursor] : g_MouseCursors[ImGuiMouseCursor_Arrow]);
glfwSetInputMode(g_Window, GLFW_CURSOR, GLFW_CURSOR_NORMAL);
}
}
// Start the frame. This call will update the io.WantCaptureMouse, io.WantCaptureKeyboard flag that you can use to dispatch inputs (or not) to your application.
ImGui::NewFrame();
}