OpenCL OpenGL interop test

CMakeLists.txt

cmake_minimum_required (VERSION 2.6)
project (ogltest)

set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_SOURCE_DIR})

find_package(PkgConfig REQUIRED)
pkg_search_module(GLFW REQUIRED glfw3)

find_package(OpenGL REQUIRED)
if(NOT OPENGL_FOUND)
    message("ERROR: OpenGL not found")
endif(NOT OPENGL_FOUND)
set(GL_LIBRARY GL GLU X11)

find_package(OpenCL REQUIRED)
if(NOT OPENCL_FOUND)
    message("ERROR: OpenCL not found")
endif(NOT OPENCL_FOUND)
 
add_executable(gltest gltest.c)

include_directories(${GLFW_INCLUDE_DIRS} ${OPENCL_INCLUDE_DIRS})
 
target_link_libraries(gltest ${GLFW_LIBRARIES} ${GL_LIBRARY} ${OPENCL_LIBRARIES})

FindOpenCL.cmake

# - Try to find OpenCL
# This module tries to find an OpenCL implementation on your system. It supports
# AMD / ATI, Apple and NVIDIA implementations, but should work, too.
#
# To set manually the paths, define these environment variables:
# OpenCL_INCPATH    - Include path (e.g. OpenCL_INCPATH=/opt/cuda/4.0/cuda/include)
# OpenCL_LIBPATH    - Library path (e.h. OpenCL_LIBPATH=/usr/lib64/nvidia)
#
# Once done this will define
#  OPENCL_FOUND        - system has OpenCL
#  OPENCL_INCLUDE_DIRS  - the OpenCL include directory
#  OPENCL_LIBRARIES    - link these to use OpenCL
#
# WIN32 should work, but is untested

FIND_PACKAGE(PackageHandleStandardArgs)

SET (OPENCL_VERSION_STRING "0.1.0")
SET (OPENCL_VERSION_MAJOR 0)
SET (OPENCL_VERSION_MINOR 1)
SET (OPENCL_VERSION_PATCH 0)

IF (APPLE)

	FIND_LIBRARY(OPENCL_LIBRARIES OpenCL DOC "OpenCL lib for OSX")
	FIND_PATH(OPENCL_INCLUDE_DIRS OpenCL/cl.h DOC "Include for OpenCL on OSX")
	FIND_PATH(_OPENCL_CPP_INCLUDE_DIRS OpenCL/cl.hpp DOC "Include for OpenCL CPP bindings on OSX")

ELSE (APPLE)

	IF (WIN32)

		FIND_PATH(OPENCL_INCLUDE_DIRS CL/cl.h)
		FIND_PATH(_OPENCL_CPP_INCLUDE_DIRS CL/cl.hpp)

		# The AMD SDK currently installs both x86 and x86_64 libraries
		# This is only a hack to find out architecture
		IF( ${CMAKE_SYSTEM_PROCESSOR} STREQUAL "AMD64" )
			SET(OPENCL_LIB_DIR "$ENV{ATISTREAMSDKROOT}/lib/x86_64")
		ELSE (${CMAKE_SYSTEM_PROCESSOR} STREQUAL "AMD64")
			SET(OPENCL_LIB_DIR "$ENV{ATISTREAMSDKROOT}/lib/x86")
		ENDIF( ${CMAKE_SYSTEM_PROCESSOR} STREQUAL "AMD64" )
		FIND_LIBRARY(OPENCL_LIBRARIES OpenCL.lib PATHS ${OPENCL_LIB_DIR} ENV OpenCL_LIBPATH)

		GET_FILENAME_COMPONENT(_OPENCL_INC_CAND ${OPENCL_LIB_DIR}/../../include ABSOLUTE)

		# On Win32 search relative to the library
		FIND_PATH(OPENCL_INCLUDE_DIRS CL/cl.h PATHS "${_OPENCL_INC_CAND}" ENV OpenCL_INCPATH)
		FIND_PATH(_OPENCL_CPP_INCLUDE_DIRS CL/cl.hpp PATHS "${_OPENCL_INC_CAND}" ENV OpenCL_INCPATH)

	ELSE (WIN32)

		# Unix style platforms
		FIND_LIBRARY(OPENCL_LIBRARIES OpenCL
			PATHS ENV LD_LIBRARY_PATH ENV OpenCL_LIBPATH
		)

		GET_FILENAME_COMPONENT(OPENCL_LIB_DIR ${OPENCL_LIBRARIES} PATH)
		GET_FILENAME_COMPONENT(_OPENCL_INC_CAND ${OPENCL_LIB_DIR}/../../include ABSOLUTE)

		# The AMD SDK currently does not place its headers
		# in /usr/include, therefore also search relative
		# to the library
		FIND_PATH(OPENCL_INCLUDE_DIRS CL/cl.h PATHS ${_OPENCL_INC_CAND} "/usr/local/cuda/include" "/opt/AMDAPP/include" ENV OpenCL_INCPATH)
		FIND_PATH(_OPENCL_CPP_INCLUDE_DIRS CL/cl.hpp PATHS ${_OPENCL_INC_CAND} "/usr/local/cuda/include" "/opt/AMDAPP/include" ENV OpenCL_INCPATH)

	ENDIF (WIN32)

ENDIF (APPLE)

FIND_PACKAGE_HANDLE_STANDARD_ARGS(OpenCL DEFAULT_MSG OPENCL_LIBRARIES OPENCL_INCLUDE_DIRS)

IF(_OPENCL_CPP_INCLUDE_DIRS)
	SET( OPENCL_HAS_CPP_BINDINGS TRUE )
	LIST( APPEND OPENCL_INCLUDE_DIRS ${_OPENCL_CPP_INCLUDE_DIRS} )
	# This is often the same, so clean up
	LIST( REMOVE_DUPLICATES OPENCL_INCLUDE_DIRS )
ENDIF(_OPENCL_CPP_INCLUDE_DIRS)

MARK_AS_ADVANCED(
  OPENCL_INCLUDE_DIRS
)

gltest.c

#include <GLFW/glfw3.h>
#include <stdlib.h>
#include <stdio.h>

#include <CL/cl.h>
#include <CL/cl_gl.h>

static void error_callback(int error, const char* description)
{
	fputs(description, stderr);
}
static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
	if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
		glfwSetWindowShouldClose(window, GL_TRUE);
}
int main(void)
{
	GLFWwindow* window;
	glfwSetErrorCallback(error_callback);
	if (!glfwInit())
		exit(EXIT_FAILURE);
	window = glfwCreateWindow(512, 512, "Simple example", NULL, NULL);
	if (!window)
	{
		glfwTerminate();
		exit(EXIT_FAILURE);
	}
	glfwMakeContextCurrent(window);
	glfwSetKeyCallback(window, key_callback);

	int width, height;
	glfwGetFramebufferSize(window, &width, &height);

	glEnable(GL_TEXTURE_2D);
	int texture[1];

	glGenTextures(1, &texture[0]);
    glBindTexture(GL_TEXTURE_2D, texture[0]);   // 2d texture (x and y size)

    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); // scale linearly when image bigger than texture
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); // scale linearly when image smalled than texture

    // 2d texture, level of detail 0 (normal), 3 components (red, green, blue), x size from image, y size from image, 
    // border 0 (normal), rgb color data, unsigned byte data, and finally the data itself.
    glTexImage2D(GL_TEXTURE_2D, 0, 3, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);

    // Init OpenCL
    cl_platform_id platform_id = NULL;
    cl_device_id device_id = NULL;   
    cl_uint ret_num_devices;
    cl_uint ret_num_platforms;
    cl_int ret = clGetPlatformIDs(1, &platform_id, &ret_num_platforms);
    ret = clGetDeviceIDs( platform_id, CL_DEVICE_TYPE_DEFAULT, 1, 
            &device_id, &ret_num_devices);

    cl_context_properties properties[] = {
		CL_CONTEXT_PLATFORM, (cl_context_properties)platform_id,
		CL_GL_CONTEXT_KHR, (cl_context_properties)glXGetCurrentContext(),
		CL_GLX_DISPLAY_KHR, (cl_context_properties)glXGetCurrentDisplay(),
	0
	};

    cl_context ctx = clCreateContext(properties, 1, &device_id, NULL, NULL, &ret);
    if(ret != 0)
		printf("Context creation => OpenCL error: %d\n", ret); 
 
    // Create a command queue
    cl_command_queue queue = clCreateCommandQueue(ctx, device_id, 0, &ret);

    //Create Image
	cl_mem image = clCreateFromGLTexture2D(ctx, CL_MEM_READ_WRITE, GL_TEXTURE_2D, 0, texture[0], &ret);
	if(ret != 0)
		printf("Texture creation =>  OpenCL error: %d\n", ret); 

	// Create Buffer RGB * width * height
    cl_mem buffer = clCreateBuffer(ctx, CL_MEM_WRITE_ONLY, 3 * width * height, NULL, &ret);
	if(ret != 0)
		printf("Buffer creation =>  OpenCL error: %d\n", ret); 

	while (!glfwWindowShouldClose(window))
	{
		float ratio;
		ratio = width / (float) height;
		glViewport(0, 0, width, height);
		glClear(GL_COLOR_BUFFER_BIT);
		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		glOrtho(-ratio, ratio, -1.f, 1.f, 1.f, -1.f);
		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();
		glRotatef(0.f, 0.f, 0.f, 1.f);
		glBindTexture(GL_TEXTURE_2D, texture[0]);
		glBegin(GL_QUADS);
			glColor3f(1.f, 0.f, 0.f);
			glVertex3f(-1.f, -1.f, 0.f);
			glColor3f(0.f, 1.f, 0.f);
			glVertex3f(-1.f, 1.f, 0.f);
			glColor3f(0.f, 0.f, 1.f);
			glVertex3f(1.f, 1.f, 0.f);
			glColor3f(0.f, 0.f, 1.f);
			glVertex3f(1.f, -1.f, 0.f);
		glEnd();
		glfwSwapBuffers(window);
		glfwPollEvents();
	}

	ret = clFlush(queue);
    ret = clFinish(queue);
    ret = clReleaseMemObject(image);
    ret = clReleaseMemObject(buffer);
    ret = clReleaseCommandQueue(queue);
    ret = clReleaseContext(ctx);

	glfwDestroyWindow(window);
	glfwTerminate();
	exit(EXIT_SUCCESS);
}