bubble chart example for cpu backend

this example also demonstrates transparency and multiple plot rendering

examples/cpu/bubblechart.cpp

@@ -0,0 +1,126 @@
+/*******************************************************
+ * Copyright (c) 2015-2019, ArrayFire
+ * All rights reserved.
+ *
+ * This file is distributed under 3-clause BSD license.
+ * The complete license agreement can be obtained at:
+ * http://arrayfire.com/licenses/BSD-3-Clause
+ ********************************************************/
+
+#include <forge.h>
+#include <CPUCopy.hpp>
+#include <complex>
+#include <cmath>
+#include <vector>
+#include <iostream>
+#include <random>
+#include <algorithm>
+#include <functional>
+#include <iterator>
+
+const unsigned DIMX = 1000;
+const unsigned DIMY = 800;
+
+const float FRANGE_START = 0.f;
+const float FRANGE_END = 2.f * 3.1415926f;
+
+using namespace std;
+void map_range_to_vec_vbo(float range_start, float range_end, float dx,
+                          std::vector<float> &vec,
+                          float (*map) (float))
+{
+    if(range_start > range_end && dx > 0) return;
+    for(float i=range_start; i < range_end; i+=dx){
+        vec.push_back(i);
+        vec.push_back((*map)(i));
+    }
+}
+
+int main(void)
+{
+    std::vector<float> cosData;
+    std::vector<float> tanData;
+
+    map_range_to_vec_vbo(FRANGE_START, FRANGE_END, 0.1f, cosData, &cosf);
+    map_range_to_vec_vbo(FRANGE_START, FRANGE_END, 0.1f, tanData, &tanf);
+
+    std::random_device r;
+
+    std::default_random_engine e1(r());
+    std::mt19937_64 gen(r());
+
+    std::uniform_int_distribution<int> uDist(20, 80);
+    std::uniform_real_distribution<float> cDist(0.2, 0.6);
+    std::uniform_real_distribution<float> fDist(0.4, 0.6);
+
+    auto clr = std::bind(cDist, gen);
+    auto rnd = std::bind(uDist, e1);
+    auto alp = std::bind(fDist, gen);
+
+    std::vector<float> colors(3*tanData.size());
+    std::vector<float> alphas(tanData.size());
+    std::vector<float> radii(tanData.size());
+
+    std::generate(colors.begin(), colors.end(), clr);
+    std::generate(radii.begin(), radii.end(), rnd);
+    std::generate(alphas.begin(), alphas.end(), alp);
+
+    /*
+     * First Forge call should be a window creation call
+     * so that necessary OpenGL context is created for any
+     * other fg::* object to be created successfully
+     */
+    fg::Window wnd(DIMX, DIMY, "Plotting Demo");
+    wnd.makeCurrent();
+    /* create an font object and load necessary font
+     * and later pass it on to window object so that
+     * it can be used for rendering text */
+    fg::Font fnt;
+#ifdef OS_WIN
+    fnt.loadSystemFont("Calibri", 32);
+#else
+    fnt.loadSystemFont("Vera", 32);
+#endif
+    wnd.setFont(&fnt);
+
+    fg::Chart chart(fg::FG_2D);
+    chart.setAxesLimits(FRANGE_START, FRANGE_END, -1.1f, 1.1f);
+
+    /* Create several plot objects which creates the necessary
+     * vertex buffer objects to hold the different plot types
+     */
+    fg::Plot plt1 = chart.plot(cosData.size()/2, fg::f32,
+                               fg::FG_LINE, fg::FG_TRIANGLE); //or specify a specific plot type
+    fg::Plot plt2 = chart.plot(tanData.size()/2, fg::f32,
+                               fg::FG_LINE, fg::FG_CIRCLE); //last parameter specifies marker shape
+
+    /* Set plot colors */
+    plt1.setColor(fg::FG_RED);
+    plt2.setColor(fg::FG_GREEN);            //use a forge predefined color
+    /* Set plot legends */
+    plt1.setLegend("Cosine");
+    plt2.setLegend("Tangent");
+    /* set plot global marker size */
+    plt1.setMarkerSize(20);
+    /* copy your data into the opengl buffer object exposed by
+     * fg::Plot class and then proceed to rendering.
+     * To help the users with copying the data from compute
+     * memory to display memory, Forge provides copy headers
+     * along with the library to help with this task
+     */
+    fg::copy(plt1.vertices(), plt1.verticesSize(), cosData.data());
+    fg::copy(plt2.vertices(), plt2.verticesSize(), tanData.data());
+
+    /* update color value for tan graph */
+    fg::copy(plt2.colors(), plt2.colorsSize(), colors.data());
+    /* update alpha values for tan graph */
+    fg::copy(plt2.alphas(), plt2.alphasSize(), alphas.data());
+    /* update marker sizes for tan graph markers */
+    fg::copy(plt2.markers(), plt2.markersSize(), radii.data());
+
+    do {
+        wnd.draw(chart);
+    } while(!wnd.close());
+
+    return 0;
+}