1 files changed, 395 insertions, 0 deletions

diff --git a/src/imgui_impl_sdl_gl3.cpp b/src/imgui_impl_sdl_gl3.cpp
new file mode 100644
index 0000000..63d7033
--- /dev/null
+++ b/src/imgui_impl_sdl_gl3.cpp
@@ -0,0 +1,395 @@
+// ImGui SDL2 binding with OpenGL3
+// 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_sdl_gl3.h"
+
+// SDL,GL3W
+#include <SDL.h>
+#include <SDL_syswm.h>
+#include <GL/glew.h>    // This example is using gl3w to access OpenGL functions (because it is small). You may use glew/glad/glLoadGen/etc. whatever already works for you.
+
+// 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;
+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)
+// 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_ImplSdlGL3_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_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_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
+    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);
+
+    // 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);
+
+    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);
+    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);
+    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_ImplSdlGL3_GetClipboardText(void*)
+{
+    return SDL_GetClipboardText();
+}
+
+static void ImGui_ImplSdlGL3_SetClipboardText(void*, const char* text)
+{
+    SDL_SetClipboardText(text);
+}
+
+bool ImGui_ImplSdlGL3_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;
+}
+
+void ImGui_ImplSdlGL3_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 for OpenGL3 demo because it is more likely to be compatible with user's existing shader.
+
+    // 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);
+}
+
+bool ImGui_ImplSdlGL3_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_ImplSdlGL3_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_ImplSdlGL3_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_ImplSdlGL3_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_ImplSdlGL3_RenderDrawLists;   // Alternatively you can set this to NULL and call ImGui::GetDrawData() after ImGui::Render() to get the same ImDrawData pointer.
+    io.SetClipboardTextFn = ImGui_ImplSdlGL3_SetClipboardText;
+    io.GetClipboardTextFn = ImGui_ImplSdlGL3_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_ImplSdlGL3_Shutdown()
+{
+    ImGui_ImplSdlGL3_InvalidateDeviceObjects();
+    ImGui::Shutdown();
+}
+
+void ImGui_ImplSdlGL3_NewFrame(SDL_Window* window)
+{
+    if (!g_FontTexture)
+        ImGui_ImplSdlGL3_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(-FLT_MAX, -FLT_MAX);
+
+    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();
+}