example.hpp

// License: Apache 2.0. See LICENSE file in root directory.
// Copyright(c) 2015 Intel Corporation. All Rights Reserved.

#pragma once

#define GLFW_INCLUDE_GLU
#include <GLFW/glfw3.h>

#include <string>
#include <sstream>
#include <iostream>

//////////////////////////////
// Basic Data Types         //
//////////////////////////////

struct float3 { float x, y, z; };
struct float2 { float x, y; };

struct rect
{
    float x, y;
    float w, h;

    // Create new rect within original boundaries with give aspect ration
    rect adjust_ratio(float2 size) const
    {
        auto H = static_cast<float>(h), W = static_cast<float>(h) * size.x / size.y;
        if (W > w)
        {
            auto scale = w / W;
            W *= scale;
            H *= scale;
        }

        return{ x + (w - W) / 2, y + (h - H) / 2, W, H };
    }
};

//////////////////////////////
// Simple font loading code //
//////////////////////////////

#include "../third-party/stb_easy_font.h"

inline void draw_text(int x, int y, const char * text)
{
    char buffer[60000]; // ~300 chars
    glEnableClientState(GL_VERTEX_ARRAY);
    glVertexPointer(2, GL_FLOAT, 16, buffer);
    glDrawArrays(GL_QUADS, 0, 4 * stb_easy_font_print((float)x, (float)(y - 7), (char *)text, nullptr, buffer, sizeof(buffer)));
    glDisableClientState(GL_VERTEX_ARRAY);
}

////////////////////////
// Image display code //
////////////////////////

class texture
{
public:
    void render(const rs2::video_frame& frame, const rect& r)
    {
        upload(frame);
        show(r.adjust_ratio({ float(width), float(height) }));
    }

    void upload(const rs2::video_frame& frame)
    {
        if (!frame) return;

        if (!gl_handle)
            glGenTextures(1, &gl_handle);
        GLenum err = glGetError();

        auto format = frame.get_profile().format();
        width = frame.get_width();
        height = frame.get_height();
        stream = frame.get_profile().stream_type();

        glBindTexture(GL_TEXTURE_2D, gl_handle);

        switch (format)
        {
        case RS2_FORMAT_RGB8:
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, frame.get_data());
            break;
        case RS2_FORMAT_Y8:
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, frame.get_data());
            break;
        default:
            throw std::runtime_error("The requested format is not supported by this demo!");
        }

        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
        glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
        glBindTexture(GL_TEXTURE_2D, 0);
    }

    GLuint get_gl_handle() { return gl_handle; }

    void show(const rect& r) const
    {
        if (!gl_handle)
            return;

        glBindTexture(GL_TEXTURE_2D, gl_handle);
        glEnable(GL_TEXTURE_2D);
        glBegin(GL_QUAD_STRIP);
        glTexCoord2f(0.f, 1.f); glVertex2f(r.x, r.y + r.h);
        glTexCoord2f(0.f, 0.f); glVertex2f(r.x, r.y);
        glTexCoord2f(1.f, 1.f); glVertex2f(r.x + r.w, r.y + r.h);
        glTexCoord2f(1.f, 0.f); glVertex2f(r.x + r.w, r.y);
        glEnd();
        glDisable(GL_TEXTURE_2D);
        glBindTexture(GL_TEXTURE_2D, 0);

        draw_text((int)r.x + 15, (int)r.y + 20, rs2_stream_to_string(stream));
    }
private:
    GLuint gl_handle = 0;
    int width = 0;
    int height = 0;
    rs2_stream stream = RS2_STREAM_ANY;
};

class window
{
public:
    std::function<void(bool)>           on_left_mouse   = [](bool) {};
    std::function<void(double, double)> on_mouse_scroll = [](double, double) {};
    std::function<void(double, double)> on_mouse_move   = [](double, double) {};
    std::function<void(int)>            on_key_release  = [](int) {};

    window(int width, int height, const char* title)
        : _width(width), _height(height)
    {
        glfwInit();
        win = glfwCreateWindow(width, height, title, nullptr, nullptr);
        glfwMakeContextCurrent(win);

        glfwSetWindowUserPointer(win, this);
        glfwSetMouseButtonCallback(win, [](GLFWwindow * win, int button, int action, int mods)
        {
            auto s = (window*)glfwGetWindowUserPointer(win);
            if (button == 0) s->on_left_mouse(action == GLFW_PRESS);
        });

        glfwSetScrollCallback(win, [](GLFWwindow * win, double xoffset, double yoffset)
        {
            auto s = (window*)glfwGetWindowUserPointer(win);
            s->on_mouse_scroll(xoffset, yoffset);
        });

        glfwSetCursorPosCallback(win, [](GLFWwindow * win, double x, double y)
        {
            auto s = (window*)glfwGetWindowUserPointer(win);
            s->on_mouse_move(x, y);
        });

        glfwSetKeyCallback(win, [](GLFWwindow * win, int key, int scancode, int action, int mods)
        {
            auto s = (window*)glfwGetWindowUserPointer(win);
            if (0 == action) // on key release
            {
                s->on_key_release(key);
            }
        });
    }

    float width() const { return float(_width); }
    float height() const { return float(_height); }

    operator bool()
    {
        glPopMatrix();
        glfwSwapBuffers(win);

        auto res = !glfwWindowShouldClose(win);

        glfwPollEvents();
        glfwGetFramebufferSize(win, &_width, &_height);

        // Clear the framebuffer
        glClear(GL_COLOR_BUFFER_BIT);
        glViewport(0, 0, _width, _height);

        // Draw the images
        glPushMatrix();
        glfwGetWindowSize(win, &_width, &_height);
        glOrtho(0, _width, _height, 0, -1, +1);

        return res;
    }

    ~window()
    {
        glfwDestroyWindow(win);
        glfwTerminate();
    }

    operator GLFWwindow*() { return win; }

private:
    GLFWwindow* win;
    int _width, _height;
};