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393 lines
15 KiB
393 lines
15 KiB
// ImGui - standalone example application for OpenGL 3, using programmable pipeline |
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#ifdef _MSC_VER |
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#pragma warning (disable: 4996) // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen |
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#endif |
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#ifdef __clang__ |
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#pragma clang diagnostic ignored "-Wunused-function" // warning: unused function |
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#endif |
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#include "../../imgui.h" |
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#include <stdio.h> |
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// Glfw/Glew |
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#define GLEW_STATIC |
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#include <GL/glew.h> |
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#include <GLFW/glfw3.h> |
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#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT)) |
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static GLFWwindow* window; |
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static GLuint fontTex; |
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static bool mousePressed[2] = { false, false }; |
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// Shader variables |
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static int shader_handle, vert_handle, frag_handle; |
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static int texture_location, proj_mtx_location; |
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static int position_location, uv_location, colour_location; |
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static size_t vbo_max_size = 20000; |
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static unsigned int vbo_handle, vao_handle; |
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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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// - try adjusting ImGui::GetIO().PixelCenterOffset to 0.0f or 0.5f |
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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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static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count) |
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{ |
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if (cmd_lists_count == 0) |
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return; |
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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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// Setup texture |
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glActiveTexture(GL_TEXTURE0); |
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glBindTexture(GL_TEXTURE_2D, fontTex); |
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// Setup orthographic projection matrix |
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const float width = ImGui::GetIO().DisplaySize.x; |
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const float height = ImGui::GetIO().DisplaySize.y; |
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const float ortho_projection[4][4] = |
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{ |
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{ 2.0f/width, 0.0f, 0.0f, 0.0f }, |
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{ 0.0f, 2.0f/-height, 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(shader_handle); |
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glUniform1i(texture_location, 0); |
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glUniformMatrix4fv(proj_mtx_location, 1, GL_FALSE, &ortho_projection[0][0]); |
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// Grow our buffer according to what we need |
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size_t total_vtx_count = 0; |
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for (int n = 0; n < cmd_lists_count; n++) |
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total_vtx_count += cmd_lists[n]->vtx_buffer.size(); |
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glBindBuffer(GL_ARRAY_BUFFER, vbo_handle); |
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size_t neededBufferSize = total_vtx_count * sizeof(ImDrawVert); |
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if (neededBufferSize > vbo_max_size) |
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{ |
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vbo_max_size = neededBufferSize + 5000; // Grow buffer |
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glBufferData(GL_ARRAY_BUFFER, vbo_max_size, NULL, GL_STREAM_DRAW); |
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} |
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// Copy and convert all vertices into a single contiguous buffer |
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unsigned char* buffer_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY); |
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if (!buffer_data) |
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return; |
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for (int n = 0; n < cmd_lists_count; n++) |
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{ |
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const ImDrawList* cmd_list = cmd_lists[n]; |
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memcpy(buffer_data, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert)); |
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buffer_data += cmd_list->vtx_buffer.size() * sizeof(ImDrawVert); |
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} |
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glUnmapBuffer(GL_ARRAY_BUFFER); |
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glBindBuffer(GL_ARRAY_BUFFER, 0); |
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glBindVertexArray(vao_handle); |
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int cmd_offset = 0; |
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for (int n = 0; n < cmd_lists_count; n++) |
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{ |
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const ImDrawList* cmd_list = cmd_lists[n]; |
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int vtx_offset = cmd_offset; |
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const ImDrawCmd* pcmd_end = cmd_list->commands.end(); |
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for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++) |
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{ |
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glScissor((int)pcmd->clip_rect.x, (int)(height - pcmd->clip_rect.w), (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y)); |
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glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count); |
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vtx_offset += pcmd->vtx_count; |
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} |
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cmd_offset = vtx_offset; |
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} |
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// Restore modified state |
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glBindVertexArray(0); |
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glUseProgram(0); |
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glDisable(GL_SCISSOR_TEST); |
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glBindTexture(GL_TEXTURE_2D, 0); |
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} |
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static const char* ImImpl_GetClipboardTextFn() |
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{ |
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return glfwGetClipboardString(window); |
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} |
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static void ImImpl_SetClipboardTextFn(const char* text) |
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{ |
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glfwSetClipboardString(window, text); |
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} |
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// GLFW callbacks to get events |
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static void glfw_error_callback(int error, const char* description) |
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{ |
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fputs(description, stderr); |
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} |
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static void glfw_mouse_button_callback(GLFWwindow* window, int button, int action, int mods) |
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{ |
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if (action == GLFW_PRESS && button >= 0 && button < 2) |
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mousePressed[button] = true; |
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} |
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static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset) |
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{ |
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ImGuiIO& io = ImGui::GetIO(); |
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io.MouseWheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines. |
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} |
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static void glfw_key_callback(GLFWwindow* window, int key, int scancode, 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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io.KeyCtrl = (mods & GLFW_MOD_CONTROL) != 0; |
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io.KeyShift = (mods & GLFW_MOD_SHIFT) != 0; |
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} |
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static void glfw_char_callback(GLFWwindow* window, unsigned int c) |
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{ |
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if (c > 0 && c < 0x10000) |
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ImGui::GetIO().AddInputCharacter((unsigned short)c); |
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} |
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// OpenGL code based on http://open.gl tutorials |
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void InitGL() |
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{ |
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glfwSetErrorCallback(glfw_error_callback); |
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if (!glfwInit()) |
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exit(1); |
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glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); |
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glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); |
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glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); |
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window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL); |
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glfwMakeContextCurrent(window); |
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glfwSetKeyCallback(window, glfw_key_callback); |
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glfwSetMouseButtonCallback(window, glfw_mouse_button_callback); |
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glfwSetScrollCallback(window, glfw_scroll_callback); |
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glfwSetCharCallback(window, glfw_char_callback); |
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glewExperimental = GL_TRUE; |
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GLenum err = glewInit(); |
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if (GLEW_OK != err) |
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fprintf(stderr, "Error: %s\n", glewGetErrorString(err)); |
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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;\n" |
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" Out_Color.w *= texture( Texture, Frag_UV.st).x;\n" |
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"}\n"; |
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shader_handle = glCreateProgram(); |
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vert_handle = glCreateShader(GL_VERTEX_SHADER); |
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frag_handle = glCreateShader(GL_FRAGMENT_SHADER); |
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glShaderSource(vert_handle, 1, &vertex_shader, 0); |
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glShaderSource(frag_handle, 1, &fragment_shader, 0); |
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glCompileShader(vert_handle); |
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glCompileShader(frag_handle); |
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glAttachShader(shader_handle, vert_handle); |
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glAttachShader(shader_handle, frag_handle); |
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glLinkProgram(shader_handle); |
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texture_location = glGetUniformLocation(shader_handle, "Texture"); |
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proj_mtx_location = glGetUniformLocation(shader_handle, "ProjMtx"); |
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position_location = glGetAttribLocation(shader_handle, "Position"); |
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uv_location = glGetAttribLocation(shader_handle, "UV"); |
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colour_location = glGetAttribLocation(shader_handle, "Color"); |
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glGenBuffers(1, &vbo_handle); |
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glBindBuffer(GL_ARRAY_BUFFER, vbo_handle); |
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glBufferData(GL_ARRAY_BUFFER, vbo_max_size, NULL, GL_DYNAMIC_DRAW); |
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glGenVertexArrays(1, &vao_handle); |
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glBindVertexArray(vao_handle); |
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glBindBuffer(GL_ARRAY_BUFFER, vbo_handle); |
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glEnableVertexAttribArray(position_location); |
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glEnableVertexAttribArray(uv_location); |
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glEnableVertexAttribArray(colour_location); |
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glVertexAttribPointer(position_location, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, pos)); |
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glVertexAttribPointer(uv_location, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, uv)); |
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glVertexAttribPointer(colour_location, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, col)); |
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glBindVertexArray(0); |
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glBindBuffer(GL_ARRAY_BUFFER, 0); |
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} |
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void InitImGui() |
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{ |
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ImGuiIO& io = ImGui::GetIO(); |
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io.DeltaTime = 1.0f / 60.0f; // Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable) |
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io.PixelCenterOffset = 0.5f; // Align OpenGL texels |
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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_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 = ImImpl_RenderDrawLists; |
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io.SetClipboardTextFn = ImImpl_SetClipboardTextFn; |
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io.GetClipboardTextFn = ImImpl_GetClipboardTextFn; |
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// Load font |
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io.Font = new ImFont(); |
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io.Font->LoadDefault(); |
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//io.Font->LoadFromFileTTF("myfont.ttf", font_size_px, ImFont::GetGlyphRangesDefault()); |
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//io.Font->DisplayOffset.y += 0.0f; |
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IM_ASSERT(io.Font->IsLoaded()); |
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// Copy font texture |
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glGenTextures(1, &fontTex); |
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glBindTexture(GL_TEXTURE_2D, fontTex); |
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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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IM_ASSERT(io.Font->IsLoaded()); |
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, io.Font->TexWidth, io.Font->TexHeight, 0, GL_RED, GL_UNSIGNED_BYTE, io.Font->TexPixels); |
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} |
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void UpdateImGui() |
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{ |
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ImGuiIO& io = ImGui::GetIO(); |
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// Setup resolution (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(window, &w, &h); |
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glfwGetFramebufferSize(window, &display_w, &display_h); |
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io.DisplaySize = ImVec2((float)display_w, (float)display_h); // Display size, in pixels. For clamping windows positions. |
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// Setup time step |
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static double time = 0.0f; |
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const double current_time = glfwGetTime(); |
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io.DeltaTime = (float)(current_time - time); |
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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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double mouse_x, mouse_y; |
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glfwGetCursorPos(window, &mouse_x, &mouse_y); |
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mouse_x *= (float)display_w / w; // Convert mouse coordinates to pixels |
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mouse_y *= (float)display_h / h; |
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io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.) |
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io.MouseDown[0] = mousePressed[0] || glfwGetMouseButton(window, GLFW_MOUSE_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. |
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io.MouseDown[1] = mousePressed[1] || glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0; |
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// Start the frame |
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ImGui::NewFrame(); |
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} |
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// Application code |
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int main(int argc, char** argv) |
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{ |
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InitGL(); |
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InitImGui(); |
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while (!glfwWindowShouldClose(window)) |
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{ |
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ImGuiIO& io = ImGui::GetIO(); |
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io.MouseWheel = 0; |
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mousePressed[0] = mousePressed[1] = false; |
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glfwPollEvents(); |
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UpdateImGui(); |
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static bool show_test_window = true; |
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static bool show_another_window = false; |
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// 1. Show a simple window |
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// Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug" |
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{ |
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static float f; |
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ImGui::Text("Hello, world!"); |
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ImGui::SliderFloat("float", &f, 0.0f, 1.0f); |
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show_test_window ^= ImGui::Button("Test Window"); |
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show_another_window ^= ImGui::Button("Another Window"); |
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// Calculate and show frame rate |
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static float ms_per_frame[120] = { 0 }; |
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static int ms_per_frame_idx = 0; |
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static float ms_per_frame_accum = 0.0f; |
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ms_per_frame_accum -= ms_per_frame[ms_per_frame_idx]; |
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ms_per_frame[ms_per_frame_idx] = ImGui::GetIO().DeltaTime * 1000.0f; |
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ms_per_frame_accum += ms_per_frame[ms_per_frame_idx]; |
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ms_per_frame_idx = (ms_per_frame_idx + 1) % 120; |
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const float ms_per_frame_avg = ms_per_frame_accum / 120; |
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ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", ms_per_frame_avg, 1000.0f / ms_per_frame_avg); |
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} |
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// 2. Show another simple window, this time using an explicit Begin/End pair |
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if (show_another_window) |
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{ |
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ImGui::Begin("Another Window", &show_another_window, ImVec2(200,100)); |
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ImGui::Text("Hello"); |
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ImGui::End(); |
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} |
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// 3. Show the ImGui test window. Most of the sample code is in ImGui::ShowTestWindow() |
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if (show_test_window) |
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{ |
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ImGui::SetNextWindowPos(ImVec2(650, 20), ImGuiSetCondition_FirstUseEver); |
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ImGui::ShowTestWindow(&show_test_window); |
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} |
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// Rendering |
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glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y); |
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glClearColor(0.8f, 0.6f, 0.6f, 1.0f); |
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glClear(GL_COLOR_BUFFER_BIT); |
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ImGui::Render(); |
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glfwSwapBuffers(window); |
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} |
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// Cleanup |
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if (vao_handle) glDeleteVertexArrays(1, &vao_handle); |
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if (vbo_handle) glDeleteBuffers(1, &vbo_handle); |
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glDetachShader(shader_handle, vert_handle); |
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glDetachShader(shader_handle, frag_handle); |
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glDeleteShader(vert_handle); |
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glDeleteShader(frag_handle); |
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glDeleteProgram(shader_handle); |
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ImGui::Shutdown(); |
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glfwTerminate(); |
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return 0; |
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}
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