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asteroidgen/vendor/imgui_impl_glfw_gl3.cpp

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// ImGui GLFW binding with OpenGL3 + shaders
// In this binding, ImTextureID is used to store an OpenGL 'GLuint' texture identifier. Read the FAQ about ImTextureID in imgui.cpp.
// 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
#include <imgui.h>
#include "imgui_impl_glfw_gl3.h"
// GL3W/GLFW
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#ifdef _WIN32
#undef APIENTRY
#define GLFW_EXPOSE_NATIVE_WIN32
#define GLFW_EXPOSE_NATIVE_WGL
#include <GLFW/glfw3native.h>
#endif
// Data
static GLFWwindow* g_Window = NULL;
static double g_Time = 0.0f;
static bool g_MouseJustPressed[3] = { false, false, false };
static float g_MouseWheel = 0.0f;
static GLuint g_FontTexture = 0;
static int g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
static int g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;
static int g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_AttribLocationColor = 0;
static unsigned int g_VboHandle = 0, g_VaoHandle = 0, g_ElementsHandle = 0;
// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
// 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.
// 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_ImplGlfwGL3_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);
// Backup GL state
GLenum last_active_texture; glGetIntegerv(GL_ACTIVE_TEXTURE, (GLint*)&last_active_texture);
glActiveTexture(GL_TEXTURE0);
GLint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
GLint last_sampler; glGetIntegerv(GL_SAMPLER_BINDING, &last_sampler);
GLint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
GLint last_element_array_buffer; glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &last_element_array_buffer);
GLint last_vertex_array; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
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);
GLenum last_blend_src_rgb; glGetIntegerv(GL_BLEND_SRC_RGB, (GLint*)&last_blend_src_rgb);
GLenum last_blend_dst_rgb; glGetIntegerv(GL_BLEND_DST_RGB, (GLint*)&last_blend_dst_rgb);
GLenum last_blend_src_alpha; glGetIntegerv(GL_BLEND_SRC_ALPHA, (GLint*)&last_blend_src_alpha);
GLenum last_blend_dst_alpha; glGetIntegerv(GL_BLEND_DST_ALPHA, (GLint*)&last_blend_dst_alpha);
GLenum last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, (GLint*)&last_blend_equation_rgb);
GLenum last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, (GLint*)&last_blend_equation_alpha);
GLboolean last_enable_blend = glIsEnabled(GL_BLEND);
GLboolean last_enable_cull_face = glIsEnabled(GL_CULL_FACE);
GLboolean last_enable_depth_test = glIsEnabled(GL_DEPTH_TEST);
GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
glEnable(GL_BLEND);
glBlendEquation(GL_FUNC_ADD);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_SCISSOR_TEST);
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
// Setup viewport, orthographic projection matrix
glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
const float ortho_projection[4][4] =
{
{ 2.0f/io.DisplaySize.x, 0.0f, 0.0f, 0.0f },
{ 0.0f, 2.0f/-io.DisplaySize.y, 0.0f, 0.0f },
{ 0.0f, 0.0f, -1.0f, 0.0f },
{-1.0f, 1.0f, 0.0f, 1.0f },
};
glUseProgram(g_ShaderHandle);
glUniform1i(g_AttribLocationTex, 0);
glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
glBindVertexArray(g_VaoHandle);
glBindSampler(0, 0); // Rely on combined texture/sampler state.
for (int n = 0; n < draw_data->CmdListsCount; n++)
{
const ImDrawList* cmd_list = draw_data->CmdLists[n];
const ImDrawIdx* idx_buffer_offset = 0;
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)cmd_list->VtxBuffer.Size * sizeof(ImDrawVert), (const GLvoid*)cmd_list->VtxBuffer.Data, GL_STREAM_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, (GLsizeiptr)cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx), (const GLvoid*)cmd_list->IdxBuffer.Data, GL_STREAM_DRAW);
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_offset);
}
idx_buffer_offset += pcmd->ElemCount;
}
}
// Restore modified GL state
glUseProgram(last_program);
glBindTexture(GL_TEXTURE_2D, last_texture);
glBindSampler(0, last_sampler);
glActiveTexture(last_active_texture);
glBindVertexArray(last_vertex_array);
glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, last_element_array_buffer);
glBlendEquationSeparate(last_blend_equation_rgb, last_blend_equation_alpha);
glBlendFuncSeparate(last_blend_src_rgb, last_blend_dst_rgb, last_blend_src_alpha, last_blend_dst_alpha);
if (last_enable_blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
if (last_enable_cull_face) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
if (last_enable_depth_test) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
glPolygonMode(GL_FRONT_AND_BACK, last_polygon_mode[0]);
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_ImplGlfwGL3_GetClipboardText(void* user_data)
{
return glfwGetClipboardString((GLFWwindow*)user_data);
}
static void ImGui_ImplGlfwGL3_SetClipboardText(void* user_data, const char* text)
{
glfwSetClipboardString((GLFWwindow*)user_data, text);
}
void ImGui_ImplGlfwGL3_MouseButtonCallback(GLFWwindow*, int button, int action, int /*mods*/)
{
if (action == GLFW_PRESS && button >= 0 && button < 3)
g_MouseJustPressed[button] = true;
}
void ImGui_ImplGlfwGL3_ScrollCallback(GLFWwindow*, double /*xoffset*/, double yoffset)
{
g_MouseWheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines.
}
void ImGui_ImplGlfwGL3_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_ImplGlfwGL3_CharCallback(GLFWwindow*, unsigned int c)
{
ImGuiIO& io = ImGui::GetIO();
if (c > 0 && c < 0x10000)
io.AddInputCharacter((unsigned short)c);
}
bool ImGui_ImplGlfwGL3_CreateFontsTexture()
{
// 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);
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;
}
bool ImGui_ImplGlfwGL3_CreateDeviceObjects()
{
// Backup GL state
GLint last_texture, last_array_buffer, last_vertex_array;
glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
const GLchar *vertex_shader =
"#version 330\n"
"uniform mat4 ProjMtx;\n"
"in vec2 Position;\n"
"in vec2 UV;\n"
"in vec4 Color;\n"
"out vec2 Frag_UV;\n"
"out vec4 Frag_Color;\n"
"void main()\n"
"{\n"
" Frag_UV = UV;\n"
" Frag_Color = Color;\n"
" gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
"}\n";
const GLchar* fragment_shader =
"#version 330\n"
"uniform sampler2D Texture;\n"
"in vec2 Frag_UV;\n"
"in vec4 Frag_Color;\n"
"out vec4 Out_Color;\n"
"void main()\n"
"{\n"
" Out_Color = Frag_Color * texture( Texture, Frag_UV.st);\n"
"}\n";
g_ShaderHandle = glCreateProgram();
g_VertHandle = glCreateShader(GL_VERTEX_SHADER);
g_FragHandle = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(g_VertHandle, 1, &vertex_shader, 0);
glShaderSource(g_FragHandle, 1, &fragment_shader, 0);
glCompileShader(g_VertHandle);
glCompileShader(g_FragHandle);
glAttachShader(g_ShaderHandle, g_VertHandle);
glAttachShader(g_ShaderHandle, g_FragHandle);
glLinkProgram(g_ShaderHandle);
g_AttribLocationTex = glGetUniformLocation(g_ShaderHandle, "Texture");
g_AttribLocationProjMtx = glGetUniformLocation(g_ShaderHandle, "ProjMtx");
g_AttribLocationPosition = glGetAttribLocation(g_ShaderHandle, "Position");
g_AttribLocationUV = glGetAttribLocation(g_ShaderHandle, "UV");
g_AttribLocationColor = glGetAttribLocation(g_ShaderHandle, "Color");
glGenBuffers(1, &g_VboHandle);
glGenBuffers(1, &g_ElementsHandle);
glGenVertexArrays(1, &g_VaoHandle);
glBindVertexArray(g_VaoHandle);
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
glEnableVertexAttribArray(g_AttribLocationPosition);
glEnableVertexAttribArray(g_AttribLocationUV);
glEnableVertexAttribArray(g_AttribLocationColor);
#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT))
glVertexAttribPointer(g_AttribLocationPosition, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, pos));
glVertexAttribPointer(g_AttribLocationUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, uv));
glVertexAttribPointer(g_AttribLocationColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, col));
#undef OFFSETOF
ImGui_ImplGlfwGL3_CreateFontsTexture();
// Restore modified GL state
glBindTexture(GL_TEXTURE_2D, last_texture);
glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
glBindVertexArray(last_vertex_array);
return true;
}
void ImGui_ImplGlfwGL3_InvalidateDeviceObjects()
{
if (g_VaoHandle) glDeleteVertexArrays(1, &g_VaoHandle);
if (g_VboHandle) glDeleteBuffers(1, &g_VboHandle);
if (g_ElementsHandle) glDeleteBuffers(1, &g_ElementsHandle);
g_VaoHandle = g_VboHandle = g_ElementsHandle = 0;
if (g_ShaderHandle && g_VertHandle) glDetachShader(g_ShaderHandle, g_VertHandle);
if (g_VertHandle) glDeleteShader(g_VertHandle);
g_VertHandle = 0;
if (g_ShaderHandle && g_FragHandle) glDetachShader(g_ShaderHandle, g_FragHandle);
if (g_FragHandle) glDeleteShader(g_FragHandle);
g_FragHandle = 0;
if (g_ShaderHandle) glDeleteProgram(g_ShaderHandle);
g_ShaderHandle = 0;
if (g_FontTexture)
{
glDeleteTextures(1, &g_FontTexture);
ImGui::GetIO().Fonts->TexID = 0;
g_FontTexture = 0;
}
}
bool ImGui_ImplGlfwGL3_Init(GLFWwindow* window, bool install_callbacks)
{
g_Window = window;
ImGuiIO& io = ImGui::GetIO();
io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
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_Delete] = GLFW_KEY_DELETE;
io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
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.RenderDrawListsFn = ImGui_ImplGlfwGL3_RenderDrawLists; // Alternatively you can set this to NULL and call ImGui::GetDrawData() after ImGui::Render() to get the same ImDrawData pointer.
io.SetClipboardTextFn = ImGui_ImplGlfwGL3_SetClipboardText;
io.GetClipboardTextFn = ImGui_ImplGlfwGL3_GetClipboardText;
io.ClipboardUserData = g_Window;
#ifdef _WIN32
io.ImeWindowHandle = glfwGetWin32Window(g_Window);
#endif
if (install_callbacks)
{
glfwSetMouseButtonCallback(window, ImGui_ImplGlfwGL3_MouseButtonCallback);
glfwSetScrollCallback(window, ImGui_ImplGlfwGL3_ScrollCallback);
glfwSetKeyCallback(window, ImGui_ImplGlfwGL3_KeyCallback);
glfwSetCharCallback(window, ImGui_ImplGlfwGL3_CharCallback);
}
return true;
}
void ImGui_ImplGlfwGL3_Shutdown()
{
ImGui_ImplGlfwGL3_InvalidateDeviceObjects();
ImGui::Shutdown();
}
void ImGui_ImplGlfwGL3_NewFrame()
{
if (!g_FontTexture)
ImGui_ImplGlfwGL3_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))
{
if (io.WantMoveMouse)
{
glfwSetCursorPos(g_Window, (double)io.MousePos.x, (double)io.MousePos.y); // Set mouse position if requested by io.WantMoveMouse flag (used when io.NavMovesTrue is enabled by user and using directional navigation)
}
else
{
double mouse_x, mouse_y;
glfwGetCursorPos(g_Window, &mouse_x, &mouse_y);
io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); // Get mouse position in screen coordinates (set to -1,-1 if no mouse / on another screen, etc.)
}
}
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;
}
io.MouseWheel = g_MouseWheel;
g_MouseWheel = 0.0f;
// Hide OS mouse cursor if ImGui is drawing it
glfwSetInputMode(g_Window, GLFW_CURSOR, io.MouseDrawCursor ? GLFW_CURSOR_HIDDEN : GLFW_CURSOR_NORMAL);
// Start the frame
ImGui::NewFrame();
}
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