mirror of
https://github.com/ocornut/imgui.git
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389 lines
15 KiB
C++
389 lines
15 KiB
C++
// 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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#include "../../imgui.h"
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#define STB_IMAGE_IMPLEMENTATION
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#include "../shared/stb_image.h" // stb_image.h for PNG loading
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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, ortho_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(ortho_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 ortho;\n"
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"in vec2 Position;\n"
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"in vec2 UV;\n"
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"in vec4 Colour;\n"
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"out vec2 Frag_UV;\n"
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"out vec4 Frag_Colour;\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_Colour = Colour;\n"
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" gl_Position = ortho*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_Colour;\n"
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"out vec4 FragColor;\n"
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"void main()\n"
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"{\n"
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" FragColor = Frag_Colour * texture( Texture, Frag_UV.st);\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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ortho_location = glGetUniformLocation(shader_handle, "ortho");
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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, "Colour");
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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 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_NEAREST);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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const void* png_data;
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unsigned int png_size;
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ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
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int tex_x, tex_y, tex_comp;
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void* tex_data = stbi_load_from_memory((const unsigned char*)png_data, (int)png_size, &tex_x, &tex_y, &tex_comp, 0);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex_x, tex_y, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_data);
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stbi_image_free(tex_data);
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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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