opencl/histogram.cpp
/*******************************************************
* 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 "cl_helpers.h"
#include <cmath>
#include <ctime>
#include <vector>
#include <sstream>
#include <iostream>
#include <iterator>
#include <algorithm>
using namespace cl;
using namespace std;
const unsigned IMGW = 256;
const unsigned IMGH = 256;
const unsigned DIMX = 1000;
const unsigned DIMY = 800;
const unsigned IMG_SIZE = IMGW * IMGH * 4;
const unsigned NBINS = 256;
const float PERSISTENCE = 0.5f;
#define USE_FORGE_OPENCL_COPY_HELPERS
#include <ComputeCopy.h>
static const std::string perlinKernels =
R"EOK(
float rand(int x)
{
x = (x << 13) ^ x;
return ( 1.0 - ( (x * (x * x * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0);
}
float interp(float x0, float x1, float t)
{
return x0 + (x1 - x0) * t;
}
kernel
void init(global float* base, global float* perlin, int IMGW, int IMGH, int randSeed)
{
int x = get_global_id(0);
int y = get_global_id(1);
if (x<IMGW && y<IMGH) {
int i = x + y * IMGW;
base[i] = (1+rand(randSeed * i))/2.0f;
perlin[i] = 0.0f;
}
}
kernel
void compute(global float* perlin, global float* base,
unsigned IMGW, unsigned IMGH, float amp, int period)
{
int x = get_global_id(0);
int y = get_global_id(1);
if (x<IMGW && y<IMGH) {
int index = y*IMGW + x;
float freq = 1.0f / period;
int si0 = (x/period) * period;
int si1 = (si0 + period) % IMGW;
float hblend = (x - si0) * freq;
int sj0 = (y/period) * period;
int sj1 = (sj0 + period) % IMGH;
float vblend = (y - sj0) * freq;
float top = interp(base[si0+IMGW*sj0], base[si1+IMGW*sj0], hblend);
float bot = interp(base[si0+IMGW*sj1], base[si1+IMGW*sj1], hblend);
perlin[index] += (amp * interp(top, bot, vblend));
}
}
kernel
void normalizeNoise(global float* perlin, unsigned IMGW, unsigned IMGH, float tamp)
{
int x = get_global_id(0);
int y = get_global_id(1);
if (x<IMGW && y<IMGH) {
int index = y*IMGW + x;
perlin[index] = perlin[index]/tamp;
}
}
kernel
void fillImage(global unsigned char* ptr, unsigned width, unsigned height,
global float* perlin, unsigned IMGW, unsigned IMGH)
{
int x = get_global_id(0);
int y = get_global_id(1);
if (x<width && y<height) {
int offset = x + y * width;
unsigned u = (unsigned)(IMGW*x/(float)(width));
unsigned v = (unsigned)(IMGH*y/(float)(height));
int idx = u + v*IMGW;
unsigned char val = 255 * perlin[idx];
ptr[offset*4 + 0] = val;
ptr[offset*4 + 1] = val;
ptr[offset*4 + 2] = val;
ptr[offset*4 + 3] = 255;
}
}
kernel
void memSet(global int* out, unsigned len)
{
if (get_global_id(0)<len)
out[get_global_id(0)] = 0;
}
kernel
void histogram(const global unsigned char* perlinNoise, global int* histOut,
const unsigned w, const unsigned h, const unsigned nbins)
{
int x = get_global_id(0);
int y = get_global_id(1);
if (x<w && y<h) {
int offset = y * w + x;
unsigned char noiseVal = perlinNoise[offset*4 + 0];
offset = (int)(nbins * (noiseVal/255.f));
atomic_add(histOut + offset , 1);
}
}
kernel
void setColors(global float* out, unsigned rseed, unsigned gseed, unsigned bseed)
{
int i = get_global_id(0);
out[3*i+0] = (1+rand(rseed * i))/2.0f;
out[3*i+1] = (1+rand(gseed * i))/2.0f;
out[3*i+2] = (1+rand(bseed * i))/2.0f;
};
)EOK";
inline
int divup(int a, int b)
{
return (a+b-1)/b;
}
void kernel(cl::Buffer& image, cl::Buffer& base, cl::Buffer& perlin,
cl::Buffer& histOut, cl::Buffer& colors,
cl::CommandQueue& queue, cl::Device& device)
{
static bool compileFlag = true;
static cl::Program prog;
static cl::Kernel initKernel, computeKernel, normKernel, fillKernel;
static cl::Kernel memSetKernel, genHistogram, genHistColors;
std::srand(std::time(0));
if (compileFlag) {
try {
prog = cl::Program(queue.getInfo<CL_QUEUE_CONTEXT>(), perlinKernels, false);
std::vector<cl::Device> devs;
devs.push_back(device);
prog.build(devs);
initKernel = cl::Kernel(prog, "init");
computeKernel = cl::Kernel(prog, "compute");
normKernel = cl::Kernel(prog, "normalizeNoise");
fillKernel = cl::Kernel(prog, "fillImage");
memSetKernel = cl::Kernel(prog, "memSet");
genHistogram = cl::Kernel(prog, "histogram");
genHistColors = cl::Kernel(prog, "setColors");
} catch (cl::Error err) {
std::cout << "Compile Errors: " << std::endl;
std::cout << err.what() << err.err() << std::endl;
std::cout << prog.getBuildInfo<CL_PROGRAM_BUILD_LOG>(device) << std::endl;
exit(255);
}
std::cout<< "Kernels compiled successfully" << std::endl;
compileFlag = false;
}
static const NDRange local(16, 16);
NDRange global(local[0] * divup(IMGW, local[0]),
local[1] * divup(IMGH, local[1]));
float persistence = 0.5f;
float amp = 1.0f;
float tamp = 0.0f;
initKernel.setArg(0, base);
initKernel.setArg(1, perlin);
initKernel.setArg(2, IMGW);
initKernel.setArg(3, IMGH);
initKernel.setArg(4, std::rand());
queue.enqueueNDRangeKernel(initKernel, cl::NullRange, global, local);
for (int octave=6; octave>=0; --octave) {
int period = 1 << octave;
computeKernel.setArg(0, perlin);
computeKernel.setArg(1, base);
computeKernel.setArg(2, IMGW);
computeKernel.setArg(3, IMGH);
computeKernel.setArg(4, amp);
computeKernel.setArg(5, period);
queue.enqueueNDRangeKernel(computeKernel, cl::NullRange, global, local);
tamp += amp;
amp *= persistence;
}
normKernel.setArg(0, perlin);
normKernel.setArg(1, IMGW);
normKernel.setArg(2, IMGH);
normKernel.setArg(3, tamp);
queue.enqueueNDRangeKernel(normKernel, cl::NullRange, global, local);
fillKernel.setArg(0, image);
fillKernel.setArg(1, IMGW);
fillKernel.setArg(2, IMGH);
fillKernel.setArg(3, perlin);
fillKernel.setArg(4, IMGW);
fillKernel.setArg(5, IMGH);
queue.enqueueNDRangeKernel(fillKernel, cl::NullRange, global, local);
static const NDRange global_hist(NBINS);
memSetKernel.setArg(0, histOut);
memSetKernel.setArg(1, NBINS);
queue.enqueueNDRangeKernel(memSetKernel, cl::NullRange, global_hist);
genHistogram.setArg(0, image);
genHistogram.setArg(1, histOut);
genHistogram.setArg(2, IMGW);
genHistogram.setArg(3, IMGH);
genHistogram.setArg(4, NBINS);
queue.enqueueNDRangeKernel(genHistogram, cl::NullRange, global, local);
genHistColors.setArg(0, colors);
genHistColors.setArg(1, std::rand());
genHistColors.setArg(2, std::rand());
genHistColors.setArg(3, std::rand());
queue.enqueueNDRangeKernel(genHistColors, cl::NullRange, global_hist);
}
int main(void)
{
try {
/*
* First Forge call should be a window creation call
* so that necessary OpenGL context is created for any
* other forge::* object to be created successfully
*/
forge::Window wnd(DIMX, DIMY, "Histogram Demo");
wnd.makeCurrent();
forge::Image img(IMGW, IMGH, FG_RGBA, forge::u8);
forge::Chart chart(FG_CHART_2D);
chart.setAxesLabelFormat("%3.1f", "%.2e");
/* set x axis limits to maximum and minimum values of data
* and y axis limits to range [0, number of pixels ideally]
* but practically total number of pixels as y range will skew
* the histogram graph vertically. Therefore setting it to
* 25% of total number of pixels */
chart.setAxesLimits(0, 1, 0, IMGW*IMGH/(float)(NBINS/4.0));
/*
* Create histogram object specifying number of bins
*/
forge::Histogram hist = chart.histogram(NBINS, forge::s32);
/*
* Set histogram colors
*/
hist.setColor(FG_YELLOW);
/*
* Helper function to create a CLGL interop context.
* This function checks for if the extension is available
* and creates the context on the appropriate device.
* Note: context and queue are defined in cl_helpers.h
*/
context = createCLGLContext(wnd);
Device device = context.getInfo<CL_CONTEXT_DEVICES>()[0];
queue = CommandQueue(context, device);
cl::Buffer image(context, CL_MEM_READ_WRITE, IMG_SIZE);
cl::Buffer baseNoise(context, CL_MEM_READ_WRITE, IMG_SIZE);
cl::Buffer perlinNoise(context, CL_MEM_READ_WRITE, IMG_SIZE);
cl::Buffer histOut(context, CL_MEM_READ_WRITE, NBINS * sizeof(int));
cl::Buffer colors(context, CL_MEM_READ_WRITE, 3 * NBINS * sizeof(float));
GfxHandle* handles[3];
createGLBuffer(&handles[0], img.pixels(), FORGE_IMAGE_BUFFER);
createGLBuffer(&handles[1], hist.vertices(), FORGE_VERTEX_BUFFER);
createGLBuffer(&handles[2], hist.colors(), FORGE_VERTEX_BUFFER);
unsigned frame = 0;
do {
if (frame%8==0) {
kernel(image, baseNoise, perlinNoise, histOut, colors, queue, device);
copyToGLBuffer(handles[0], (ComputeResourceHandle)image(), img.size());
copyToGLBuffer(handles[1], (ComputeResourceHandle)histOut(), hist.verticesSize());
copyToGLBuffer(handles[2], (ComputeResourceHandle)colors(), hist.colorsSize());
frame = 0;
}
/*
* Split the window into grid regions
*/
wnd.draw(1, 2, 0, img, "Dynamic Perlin Noise" );
wnd.draw(1, 2, 1, chart, "Histogram of Noisy Image");
wnd.swapBuffers();
frame++;
} while(!wnd.close());
releaseGLBuffer(handles[0]);
releaseGLBuffer(handles[1]);
releaseGLBuffer(handles[2]);
}catch (forge::Error err) {
std::cout << err.what() << "(" << err.err() << ")" << std::endl;
} catch (cl::Error err) {
std::cout << err.what() << "(" << err.err() << ")" << std::endl;
}
return 0;
}
ComputeCopy.h
ComputeResourceHandle
void * ComputeResourceHandle
A backend-agnostic handle to a compute memory resource originating from an OpenGL resource.
Definition ComputeCopy.h:73
FORGE_VERTEX_BUFFER
@ FORGE_VERTEX_BUFFER
OpenGL Vertex Buffer Object.
Definition ComputeCopy.h:77
FORGE_IMAGE_BUFFER
@ FORGE_IMAGE_BUFFER
OpenGL Pixel Buffer Object.
Definition ComputeCopy.h:76
forge::Chart
Chart is base canvas where other plottable objects are rendered.
Definition chart.h:316
forge::Error
Definition exception.h:22
forge::Error::err
ErrorCode err() const
Definition exception.h:31
forge::Error::what
virtual const char * what() const
Definition exception.h:46
forge::Histogram
Histogram is a bar graph to display data frequencey.
Definition histogram.h:163
forge::Histogram::vertices
FGAPI unsigned vertices() const
Get the buffer identifier for vertices.
forge::Histogram::setColor
FGAPI void setColor(const Color pColor)
Set the color of bar in the bar graph(histogram).
forge::Histogram::verticesSize
FGAPI unsigned verticesSize() const
Get the vertex buffer size in bytes.
forge::Histogram::colorsSize
FGAPI unsigned colorsSize() const
Get the colors buffer size in bytes.
forge::Histogram::colors
FGAPI unsigned colors() const
Get the buffer identifier for color values per vertex.
forge::Image
Image is plain rendering of an image over the window or sub-region of it.
Definition image.h:174
forge::Window
Window is where other objects such as Images, Plots etc.
Definition window.h:300
FG_RGBA
@ FG_RGBA
Four(Red, Green, Blue & Alpha) channels.
Definition defines.h:113
FG_YELLOW
@ FG_YELLOW
Definition defines.h:143
FG_CHART_2D
@ FG_CHART_2D
Two dimensional charts.
Definition defines.h:118
forge.h
forge::s32
@ s32
Definition defines.h:191
forge::u8
@ u8
Definition defines.h:190
GfxHandle
Definition ComputeCopy.h:80