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365 lines
14 KiB
C++
365 lines
14 KiB
C++
// ImGui GLFW binding with OpenGL3 + shaders
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// https://github.com/ocornut/imgui
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#include <imgui.h>
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#include "imgui_impl_glfw_gl3.h"
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// GL3W/GLFW
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#include <GL/gl3w.h>
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#include <GLFW/glfw3.h>
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#ifdef _WIN32
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#undef APIENTRY
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#define GLFW_EXPOSE_NATIVE_WIN32
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#define GLFW_EXPOSE_NATIVE_WGL
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#include <GLFW/glfw3native.h>
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#endif
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// Data
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static GLFWwindow* g_Window = NULL;
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static double g_Time = 0.0f;
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static bool g_MousePressed[3] = { false, false, false };
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static float g_MouseWheel = 0.0f;
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static GLuint g_FontTexture = 0;
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static int g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
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static int g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;
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static int g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_AttribLocationColor = 0;
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static unsigned int g_VboHandle = 0, g_VaoHandle = 0, g_ElementsHandle = 0;
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// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
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// If text or lines are blurry when integrating ImGui in your engine:
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// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
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void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawData* draw_data)
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{
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// Backup GL state
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GLint last_program, last_texture, last_array_buffer, last_element_array_buffer, last_vertex_array;
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glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
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glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
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glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
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glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &last_element_array_buffer);
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glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
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// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled
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glEnable(GL_BLEND);
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glBlendEquation(GL_FUNC_ADD);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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glDisable(GL_CULL_FACE);
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glDisable(GL_DEPTH_TEST);
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glEnable(GL_SCISSOR_TEST);
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glActiveTexture(GL_TEXTURE0);
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// Handle cases of screen coordinates != from framebuffer coordinates (e.g. retina displays)
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ImGuiIO& io = ImGui::GetIO();
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float fb_height = io.DisplaySize.y * io.DisplayFramebufferScale.y;
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draw_data->ScaleClipRects(io.DisplayFramebufferScale);
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// Setup orthographic projection matrix
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const float ortho_projection[4][4] =
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{
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{ 2.0f/io.DisplaySize.x, 0.0f, 0.0f, 0.0f },
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{ 0.0f, 2.0f/-io.DisplaySize.y, 0.0f, 0.0f },
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{ 0.0f, 0.0f, -1.0f, 0.0f },
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{-1.0f, 1.0f, 0.0f, 1.0f },
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};
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glUseProgram(g_ShaderHandle);
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glUniform1i(g_AttribLocationTex, 0);
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glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
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glBindVertexArray(g_VaoHandle);
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for (int n = 0; n < draw_data->CmdListsCount; n++)
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{
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const ImDrawList* cmd_list = draw_data->CmdLists[n];
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const ImDrawIdx* idx_buffer_offset = 0;
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glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
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glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)cmd_list->VtxBuffer.size() * sizeof(ImDrawVert), (GLvoid*)&cmd_list->VtxBuffer.front(), GL_STREAM_DRAW);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
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glBufferData(GL_ELEMENT_ARRAY_BUFFER, (GLsizeiptr)cmd_list->IdxBuffer.size() * sizeof(ImDrawIdx), (GLvoid*)&cmd_list->IdxBuffer.front(), GL_STREAM_DRAW);
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for (const ImDrawCmd* pcmd = cmd_list->CmdBuffer.begin(); pcmd != cmd_list->CmdBuffer.end(); pcmd++)
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{
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if (pcmd->UserCallback)
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{
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pcmd->UserCallback(cmd_list, pcmd);
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}
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else
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{
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glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
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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));
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glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, GL_UNSIGNED_SHORT, idx_buffer_offset);
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}
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idx_buffer_offset += pcmd->ElemCount;
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}
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}
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// Restore modified GL state
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glUseProgram(last_program);
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glBindTexture(GL_TEXTURE_2D, last_texture);
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glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, last_element_array_buffer);
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glBindVertexArray(last_vertex_array);
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glDisable(GL_SCISSOR_TEST);
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}
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static const char* ImGui_ImplGlfwGL3_GetClipboardText()
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{
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return glfwGetClipboardString(g_Window);
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}
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static void ImGui_ImplGlfwGL3_SetClipboardText(const char* text)
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{
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glfwSetClipboardString(g_Window, text);
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}
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void ImGui_ImplGlfwGL3_MouseButtonCallback(GLFWwindow*, int button, int action, int /*mods*/)
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{
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if (action == GLFW_PRESS && button >= 0 && button < 3)
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g_MousePressed[button] = true;
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}
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void ImGui_ImplGlfwGL3_ScrollCallback(GLFWwindow*, double /*xoffset*/, double yoffset)
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{
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g_MouseWheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines.
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}
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void ImGui_ImplGlfwGL3_KeyCallback(GLFWwindow*, int key, int, int action, int mods)
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{
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ImGuiIO& io = ImGui::GetIO();
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if (action == GLFW_PRESS)
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io.KeysDown[key] = true;
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if (action == GLFW_RELEASE)
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io.KeysDown[key] = false;
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(void)mods; // Modifiers are not reliable across systems
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io.KeyCtrl = io.KeysDown[GLFW_KEY_LEFT_CONTROL] || io.KeysDown[GLFW_KEY_RIGHT_CONTROL];
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io.KeyShift = io.KeysDown[GLFW_KEY_LEFT_SHIFT] || io.KeysDown[GLFW_KEY_RIGHT_SHIFT];
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io.KeyAlt = io.KeysDown[GLFW_KEY_LEFT_ALT] || io.KeysDown[GLFW_KEY_RIGHT_ALT];
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}
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void ImGui_ImplGlfwGL3_CharCallback(GLFWwindow*, unsigned int c)
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{
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ImGuiIO& io = ImGui::GetIO();
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if (c > 0 && c < 0x10000)
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io.AddInputCharacter((unsigned short)c);
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}
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void ImGui_ImplGlfwGL3_CreateFontsTexture()
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{
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ImGuiIO& io = ImGui::GetIO();
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// Build texture atlas
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unsigned char* pixels;
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int width, height;
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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.
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// Create OpenGL texture
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glGenTextures(1, &g_FontTexture);
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glBindTexture(GL_TEXTURE_2D, g_FontTexture);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
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// Store our identifier
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io.Fonts->TexID = (void *)(intptr_t)g_FontTexture;
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// Cleanup (don't clear the input data if you want to append new fonts later)
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io.Fonts->ClearInputData();
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io.Fonts->ClearTexData();
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}
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bool ImGui_ImplGlfwGL3_CreateDeviceObjects()
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{
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// Backup GL state
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GLint last_texture, last_array_buffer, last_vertex_array;
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glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
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glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
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glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
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const GLchar *vertex_shader =
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"#version 330\n"
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"uniform mat4 ProjMtx;\n"
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"in vec2 Position;\n"
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"in vec2 UV;\n"
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"in vec4 Color;\n"
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"out vec2 Frag_UV;\n"
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"out vec4 Frag_Color;\n"
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"void main()\n"
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"{\n"
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" Frag_UV = UV;\n"
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" Frag_Color = Color;\n"
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" gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
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"}\n";
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const GLchar* fragment_shader =
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"#version 330\n"
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"uniform sampler2D Texture;\n"
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"in vec2 Frag_UV;\n"
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"in vec4 Frag_Color;\n"
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"out vec4 Out_Color;\n"
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"void main()\n"
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"{\n"
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" Out_Color = Frag_Color * texture( Texture, Frag_UV.st);\n"
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"}\n";
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g_ShaderHandle = glCreateProgram();
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g_VertHandle = glCreateShader(GL_VERTEX_SHADER);
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g_FragHandle = glCreateShader(GL_FRAGMENT_SHADER);
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glShaderSource(g_VertHandle, 1, &vertex_shader, 0);
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glShaderSource(g_FragHandle, 1, &fragment_shader, 0);
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glCompileShader(g_VertHandle);
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glCompileShader(g_FragHandle);
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glAttachShader(g_ShaderHandle, g_VertHandle);
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glAttachShader(g_ShaderHandle, g_FragHandle);
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glLinkProgram(g_ShaderHandle);
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g_AttribLocationTex = glGetUniformLocation(g_ShaderHandle, "Texture");
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g_AttribLocationProjMtx = glGetUniformLocation(g_ShaderHandle, "ProjMtx");
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g_AttribLocationPosition = glGetAttribLocation(g_ShaderHandle, "Position");
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g_AttribLocationUV = glGetAttribLocation(g_ShaderHandle, "UV");
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g_AttribLocationColor = glGetAttribLocation(g_ShaderHandle, "Color");
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glGenBuffers(1, &g_VboHandle);
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glGenBuffers(1, &g_ElementsHandle);
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glGenVertexArrays(1, &g_VaoHandle);
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glBindVertexArray(g_VaoHandle);
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glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
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glEnableVertexAttribArray(g_AttribLocationPosition);
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glEnableVertexAttribArray(g_AttribLocationUV);
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glEnableVertexAttribArray(g_AttribLocationColor);
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#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT))
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glVertexAttribPointer(g_AttribLocationPosition, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, pos));
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glVertexAttribPointer(g_AttribLocationUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, uv));
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glVertexAttribPointer(g_AttribLocationColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, col));
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#undef OFFSETOF
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ImGui_ImplGlfwGL3_CreateFontsTexture();
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// Restore modified GL state
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glBindTexture(GL_TEXTURE_2D, last_texture);
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glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
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glBindVertexArray(last_vertex_array);
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return true;
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}
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bool ImGui_ImplGlfwGL3_Init(GLFWwindow* window, bool install_callbacks)
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{
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g_Window = window;
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ImGuiIO& io = ImGui::GetIO();
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io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
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io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
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io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
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io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
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io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
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io.KeyMap[ImGuiKey_PageUp] = GLFW_KEY_PAGE_UP;
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io.KeyMap[ImGuiKey_PageDown] = GLFW_KEY_PAGE_DOWN;
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io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
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io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
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io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
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io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
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io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
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io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
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io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
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io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
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io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
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io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
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io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
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io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;
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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.
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io.SetClipboardTextFn = ImGui_ImplGlfwGL3_SetClipboardText;
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io.GetClipboardTextFn = ImGui_ImplGlfwGL3_GetClipboardText;
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#ifdef _WIN32
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io.ImeWindowHandle = glfwGetWin32Window(g_Window);
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#endif
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if (install_callbacks)
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{
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glfwSetMouseButtonCallback(window, ImGui_ImplGlfwGL3_MouseButtonCallback);
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glfwSetScrollCallback(window, ImGui_ImplGlfwGL3_ScrollCallback);
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glfwSetKeyCallback(window, ImGui_ImplGlfwGL3_KeyCallback);
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glfwSetCharCallback(window, ImGui_ImplGlfwGL3_CharCallback);
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}
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return true;
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}
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void ImGui_ImplGlfwGL3_Shutdown()
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{
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if (g_VaoHandle) glDeleteVertexArrays(1, &g_VaoHandle);
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if (g_VboHandle) glDeleteBuffers(1, &g_VboHandle);
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if (g_ElementsHandle) glDeleteBuffers(1, &g_ElementsHandle);
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g_VaoHandle = g_VboHandle = g_ElementsHandle = 0;
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glDetachShader(g_ShaderHandle, g_VertHandle);
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glDeleteShader(g_VertHandle);
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g_VertHandle = 0;
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glDetachShader(g_ShaderHandle, g_FragHandle);
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glDeleteShader(g_FragHandle);
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g_FragHandle = 0;
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glDeleteProgram(g_ShaderHandle);
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g_ShaderHandle = 0;
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if (g_FontTexture)
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{
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glDeleteTextures(1, &g_FontTexture);
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ImGui::GetIO().Fonts->TexID = 0;
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g_FontTexture = 0;
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}
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ImGui::Shutdown();
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}
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void ImGui_ImplGlfwGL3_NewFrame()
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{
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if (!g_FontTexture)
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ImGui_ImplGlfwGL3_CreateDeviceObjects();
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ImGuiIO& io = ImGui::GetIO();
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// Setup display size (every frame to accommodate for window resizing)
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int w, h;
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int display_w, display_h;
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glfwGetWindowSize(g_Window, &w, &h);
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glfwGetFramebufferSize(g_Window, &display_w, &display_h);
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io.DisplaySize = ImVec2((float)w, (float)h);
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io.DisplayFramebufferScale = ImVec2((float)display_w / w, (float)display_h / h);
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// Setup time step
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double current_time = glfwGetTime();
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io.DeltaTime = g_Time > 0.0 ? (float)(current_time - g_Time) : (float)(1.0f/60.0f);
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g_Time = current_time;
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// Setup inputs
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// (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
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if (glfwGetWindowAttrib(g_Window, GLFW_FOCUSED))
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{
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double mouse_x, mouse_y;
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glfwGetCursorPos(g_Window, &mouse_x, &mouse_y);
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io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); // Mouse position in screen coordinates (set to -1,-1 if no mouse / on another screen, etc.)
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}
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else
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{
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io.MousePos = ImVec2(-1,-1);
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}
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for (int i = 0; i < 3; i++)
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{
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io.MouseDown[i] = g_MousePressed[i] || glfwGetMouseButton(g_Window, i) != 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.
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g_MousePressed[i] = false;
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}
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io.MouseWheel = g_MouseWheel;
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g_MouseWheel = 0.0f;
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// Hide OS mouse cursor if ImGui is drawing it
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glfwSetInputMode(g_Window, GLFW_CURSOR, io.MouseDrawCursor ? GLFW_CURSOR_HIDDEN : GLFW_CURSOR_NORMAL);
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// Start the frame
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ImGui::NewFrame();
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}
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