I am trying to build a very simple SDL + OpenGL program, using linc, since I am starting work with binding dear imgui to Haxe, but I am having trouble compiling as I am coming across the following error:
c:\haxetoolkit\haxe\lib\linc_opengl\git\linc\../lib/glew/include/GL/glew.h(85): fatal error C1189: #error: gl.h included before glew.h
I have looked into this and many stack overflow answers are similar, in that they explain something else is using gl.h. In this case, it is likely SDL, but trying to get the Haxe compiler to generate code in the correct order does not seem possible (as far as I am concerned). It would mean going into each individual .h and .cpp file, and changing the order of #includes to prevent this error from occurring.
The culprit appears to lie in a cpp file I am attempting to bind with:
#include "cpp/imgui.h"
#include "hx/imgui_impl_sdl.h"
#include <SDL.h>
#include <SDL_syswm.h>
#include <SDL_opengl.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;
ImVec2 ImGui_GetDisplaySize()
{
ImVec2 size = ImGui::GetIO().DisplaySize;
return size;
}
// 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)
void ImGui_ImplSdl_RenderDrawLists(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.
GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
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);
//glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context
// 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
#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT))
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 + OFFSETOF(ImDrawVert, pos)));
glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + OFFSETOF(ImDrawVert, uv)));
glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + 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;
}
}
#undef OFFSETOF
// 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();
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_ImplSdl_GetClipboardText(void*)
{
return SDL_GetClipboardText();
}
static void ImGui_ImplSdl_SetClipboardText(void*, const char* text)
{
SDL_SetClipboardText(text);
}
bool ImGui_ImplSdl_ProcessEvent(SDL_Event* event)
{
ImGuiIO& io = ImGui::GetIO();
switch (event->type)
{
case SDL_MOUSEWHEEL:
{
if (event->wheel.y > 0)
g_MouseWheel = 1;
if (event->wheel.y < 0)
g_MouseWheel = -1;
return true;
}
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;
return true;
}
case SDL_TEXTINPUT:
{
io.AddInputCharactersUTF8(event->text.text);
return true;
}
case SDL_KEYDOWN:
case SDL_KEYUP:
{
int key = event->key.keysym.sym & ~SDLK_SCANCODE_MASK;
io.KeysDown[key] = (event->type == SDL_KEYDOWN);
io.KeyShift = ((SDL_GetModState() & KMOD_SHIFT) != 0);
io.KeyCtrl = ((SDL_GetModState() & KMOD_CTRL) != 0);
io.KeyAlt = ((SDL_GetModState() & KMOD_ALT) != 0);
io.KeySuper = ((SDL_GetModState() & KMOD_GUI) != 0);
return true;
}
}
return false;
}
bool ImGui_ImplSdl_CreateDeviceObjects()
{
// Build texture atlas
ImGuiIO& io = ImGui::GetIO();
unsigned char* pixels;
int width, height;
io.Fonts->GetTexDataAsAlpha8(&pixels, &width, &height);
// 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_ALPHA, width, height, 0, GL_ALPHA, 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_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_PageUp] = SDL_SCANCODE_PAGEUP;
io.KeyMap[ImGuiKey_PageDown] = SDL_SCANCODE_PAGEDOWN;
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; // Alternatively you can set this to NULL and call ImGui::GetDrawData() after ImGui::Render() to get the same ImDrawData pointer.
io.SetClipboardTextFn = ImGui_ImplSdl_SetClipboardText;
io.GetClipboardTextFn = ImGui_ImplSdl_GetClipboardText;
io.ClipboardUserData = NULL;
#ifdef _WIN32
SDL_SysWMinfo wmInfo;
SDL_VERSION(&wmInfo.version);
SDL_GetWindowWMInfo(window, &wmInfo);
io.ImeWindowHandle = wmInfo.info.win.window;
#else
(void)window;
#endif
return true;
}
void ImGui_ImplSdl_Shutdown()
{
ImGui_ImplSdl_InvalidateDeviceObjects();
ImGui::Shutdown();
}
void ImGui_ImplSdl_NewFrame(SDL_Window *window)
{
if (!g_FontTexture)
ImGui_ImplSdl_CreateDeviceObjects();
ImGuiIO& io = ImGui::GetIO();
// Setup display size (every frame to accommodate for window resizing)
int w, h;
int display_w, display_h;
SDL_GetWindowSize(window, &w, &h);
SDL_GL_GetDrawableSize(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
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;
// Setup inputs
// (we already got mouse wheel, keyboard keys & characters from SDL_PollEvent())
int mx, my;
Uint32 mouseMask = SDL_GetMouseState(&mx, &my);
if (SDL_GetWindowFlags(window) & SDL_WINDOW_MOUSE_FOCUS)
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);
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;
io.MouseWheel = g_MouseWheel;
g_MouseWheel = 0.0f;
// Hide OS mouse cursor if ImGui is drawing it
SDL_ShowCursor(io.MouseDrawCursor ? 0 : 1);
// Start the frame
ImGui::NewFrame();
}
I realise this is a lot of code, and I apologise for that, but I believe it will help you to identify the culprit. I think it may the order that files are being included, but I could be wrong. What do you think the best solution is, to get this binding working?
EDIT: Just so you know, I have tested with a bare bones example, without the binding, and compiles successfully, with a linc SDL window opening successfully with a black screen using OpenGL.
