/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2013 Blender Foundation.
 * All rights reserved.
 *
 * Contributor(s): Sergey Sharybin.
 *                 Brecht van Lommel
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include "opensubdiv_capi.h"

#ifdef _MSC_VER
#  include "iso646.h"
#endif

#include <stdlib.h>
#include <GL/glew.h>

#include <opensubdiv/osd/glMesh.h>

/* CPU Backend */
#include <opensubdiv/osd/cpuGLVertexBuffer.h>
#include <opensubdiv/osd/cpuEvaluator.h>

#ifdef OPENSUBDIV_HAS_OPENMP
#  include <opensubdiv/osd/ompEvaluator.h>
#endif  /* OPENSUBDIV_HAS_OPENMP */

#ifdef OPENSUBDIV_HAS_OPENCL
#  include <opensubdiv/osd/clGLVertexBuffer.h>
#  include <opensubdiv/osd/clEvaluator.h>
#  include "opensubdiv_device_context_opencl.h"
#endif  /* OPENSUBDIV_HAS_OPENCL */

#ifdef OPENSUBDIV_HAS_CUDA
#  include <opensubdiv/osd/cudaGLVertexBuffer.h>
#  include <opensubdiv/osd/cudaEvaluator.h>
#  include "opensubdiv_device_context_cuda.h"
#endif  /* OPENSUBDIV_HAS_CUDA */

#ifdef OPENSUBDIV_HAS_GLSL_TRANSFORM_FEEDBACK
#  include <opensubdiv/osd/glXFBEvaluator.h>
#  include <opensubdiv/osd/glVertexBuffer.h>
#endif  /* OPENSUBDIV_HAS_GLSL_TRANSFORM_FEEDBACK */

#ifdef OPENSUBDIV_HAS_GLSL_COMPUTE
#  include <opensubdiv/osd/glComputeEvaluator.h>
#  include <opensubdiv/osd/glVertexBuffer.h>
#endif  /* OPENSUBDIV_HAS_GLSL_COMPUTE */

#include <opensubdiv/osd/glPatchTable.h>
#include <opensubdiv/far/stencilTable.h>

#include "opensubdiv_intern.h"

#include "MEM_guardedalloc.h"

/* **************** Types declaration **************** */

using OpenSubdiv::Osd::GLMeshInterface;
using OpenSubdiv::Osd::Mesh;
using OpenSubdiv::Osd::MeshBitset;
using OpenSubdiv::Far::StencilTable;
using OpenSubdiv::Osd::GLPatchTable;

using OpenSubdiv::Osd::Mesh;

/* CPU backend */
using OpenSubdiv::Osd::CpuGLVertexBuffer;
using OpenSubdiv::Osd::CpuEvaluator;
typedef Mesh<CpuGLVertexBuffer,
             StencilTable,
             CpuEvaluator,
             GLPatchTable> OsdCpuMesh;

#ifdef OPENSUBDIV_HAS_OPENMP
using OpenSubdiv::Osd::OmpEvaluator;
typedef Mesh<CpuGLVertexBuffer,
             StencilTable,
             OmpEvaluator,
             GLPatchTable> OsdOmpMesh;
#endif  /* OPENSUBDIV_HAS_OPENMP */

#ifdef OPENSUBDIV_HAS_OPENCL
using OpenSubdiv::Osd::CLEvaluator;
using OpenSubdiv::Osd::CLGLVertexBuffer;
using OpenSubdiv::Osd::CLStencilTable;
/* TODO(sergey): Use CLDeviceCOntext similar to OSD examples? */
typedef Mesh<CLGLVertexBuffer,
             CLStencilTable,
             CLEvaluator,
             GLPatchTable,
             CLDeviceContext> OsdCLMesh;
static CLDeviceContext g_clDeviceContext;
#endif  /* OPENSUBDIV_HAS_OPENCL */

#ifdef OPENSUBDIV_HAS_CUDA
using OpenSubdiv::Osd::CudaEvaluator;
using OpenSubdiv::Osd::CudaGLVertexBuffer;
using OpenSubdiv::Osd::CudaStencilTable;
typedef Mesh<CudaGLVertexBuffer,
             CudaStencilTable,
             CudaEvaluator,
             GLPatchTable> OsdCudaMesh;
static CudaDeviceContext g_cudaDeviceContext;
#endif  /* OPENSUBDIV_HAS_CUDA */

#ifdef OPENSUBDIV_HAS_GLSL_TRANSFORM_FEEDBACK
using OpenSubdiv::Osd::GLXFBEvaluator;
using OpenSubdiv::Osd::GLStencilTableTBO;
using OpenSubdiv::Osd::GLVertexBuffer;
typedef Mesh<GLVertexBuffer,
             GLStencilTableTBO,
             GLXFBEvaluator,
             GLPatchTable> OsdGLSLTransformFeedbackMesh;
#endif  /* OPENSUBDIV_HAS_GLSL_TRANSFORM_FEEDBACK */

#ifdef OPENSUBDIV_HAS_GLSL_COMPUTE
using OpenSubdiv::Osd::GLComputeEvaluator;
using OpenSubdiv::Osd::GLStencilTableSSBO;
using OpenSubdiv::Osd::GLVertexBuffer;
typedef Mesh<GLVertexBuffer,
             GLStencilTableSSBO,
             GLComputeEvaluator,
             GLPatchTable> OsdGLSLComputeMesh;
#endif

struct OpenSubdiv_GLMesh *openSubdiv_createOsdGLMeshFromTopologyRefiner(
        OpenSubdiv_TopologyRefinerDescr *topology_refiner,
        int evaluator_type,
        int level,
        int /*subdivide_uvs*/)
{
	using OpenSubdiv::Far::TopologyRefiner;

	MeshBitset bits;
	/* TODO(sergey): Adaptive subdivisions are not currently
	 * possible because of the lack of tessellation shader.
	 */
	bits.set(OpenSubdiv::Osd::MeshAdaptive, 0);
	bits.set(OpenSubdiv::Osd::MeshUseSingleCreasePatch, 0);
	bits.set(OpenSubdiv::Osd::MeshInterleaveVarying, 1);
	bits.set(OpenSubdiv::Osd::MeshFVarData, 1);
	bits.set(OpenSubdiv::Osd::MeshEndCapBSplineBasis, 1);

	const int num_vertex_elements = 3;
	const int num_varying_elements = 3;

	GLMeshInterface *mesh = NULL;
	TopologyRefiner *refiner = (TopologyRefiner*)topology_refiner;

	switch(evaluator_type) {
#define CHECK_EVALUATOR_TYPE(type, class) \
		case OPENSUBDIV_EVALUATOR_ ## type: \
			mesh = new class(refiner, \
			                 num_vertex_elements, \
			                 num_varying_elements, \
			                 level, \
			                 bits); \
			break;

		CHECK_EVALUATOR_TYPE(CPU, OsdCpuMesh)

#ifdef OPENSUBDIV_HAS_OPENMP
		CHECK_EVALUATOR_TYPE(OPENMP, OsdOmpMesh)
#endif

#ifdef OPENSUBDIV_HAS_OPENCL
		CHECK_EVALUATOR_TYPE(OPENCL, OsdCLMesh)
#endif

#ifdef OPENSUBDIV_HAS_CUDA
		CHECK_EVALUATOR_TYPE(CUDA, OsdCudaMesh)
#endif

#ifdef OPENSUBDIV_HAS_GLSL_TRANSFORM_FEEDBACK
		CHECK_EVALUATOR_TYPE(GLSL_TRANSFORM_FEEDBACK,
		                     OsdGLSLTransformFeedbackMesh)
#endif

#ifdef OPENSUBDIV_HAS_GLSL_COMPUTE
		CHECK_EVALUATOR_TYPE(GLSL_COMPUTE, OsdGLSLComputeMesh)
#endif

#undef CHECK_EVALUATOR_TYPE
	}

	if (mesh == NULL) {
		return NULL;
	}

	OpenSubdiv_GLMesh *gl_mesh =
		(OpenSubdiv_GLMesh *) OBJECT_GUARDED_NEW(OpenSubdiv_GLMesh);
	gl_mesh->evaluator_type = evaluator_type;
	gl_mesh->descriptor = (OpenSubdiv_GLMeshDescr *) mesh;
	gl_mesh->topology_refiner = (OpenSubdiv_TopologyRefinerDescr*)refiner;

	return gl_mesh;
}

void openSubdiv_deleteOsdGLMesh(struct OpenSubdiv_GLMesh *gl_mesh)
{
	switch (gl_mesh->evaluator_type) {
#define CHECK_EVALUATOR_TYPE(type, class) \
		case OPENSUBDIV_EVALUATOR_ ## type: \
			delete (class *) gl_mesh->descriptor; \
			break;

		CHECK_EVALUATOR_TYPE(CPU, OsdCpuMesh)

#ifdef OPENSUBDIV_HAS_OPENMP
		CHECK_EVALUATOR_TYPE(OPENMP, OsdOmpMesh)
#endif

#ifdef OPENSUBDIV_HAS_OPENCL
		CHECK_EVALUATOR_TYPE(OPENCL, OsdCLMesh)
#endif

#ifdef OPENSUBDIV_HAS_CUDA
		CHECK_EVALUATOR_TYPE(CUDA, OsdCudaMesh)
#endif

#ifdef OPENSUBDIV_HAS_GLSL_TRANSFORM_FEEDBACK
		CHECK_EVALUATOR_TYPE(GLSL_TRANSFORM_FEEDBACK,
		                     OsdGLSLTransformFeedbackMesh)
#endif

#ifdef OPENSUBDIV_HAS_GLSL_COMPUTE
		CHECK_EVALUATOR_TYPE(GLSL_COMPUTE, OsdGLSLComputeMesh)
#endif

#undef CHECK_EVALUATOR_TYPE
	}

	OBJECT_GUARDED_DELETE(gl_mesh, OpenSubdiv_GLMesh);
}

unsigned int openSubdiv_getOsdGLMeshPatchIndexBuffer(struct OpenSubdiv_GLMesh *gl_mesh)
{
	return ((GLMeshInterface *)gl_mesh->descriptor)->GetPatchTable()->GetPatchIndexBuffer();
}

unsigned int openSubdiv_getOsdGLMeshVertexBuffer(struct OpenSubdiv_GLMesh *gl_mesh)
{
	return ((GLMeshInterface *)gl_mesh->descriptor)->BindVertexBuffer();
}

void openSubdiv_osdGLMeshUpdateVertexBuffer(struct OpenSubdiv_GLMesh *gl_mesh,
                                            const float *vertex_data,
                                            int start_vertex,
                                            int num_verts)
{
	((GLMeshInterface *)gl_mesh->descriptor)->UpdateVertexBuffer(vertex_data,
	                                                             start_vertex,
	                                                             num_verts);
}

void openSubdiv_osdGLMeshRefine(struct OpenSubdiv_GLMesh *gl_mesh)
{
	((GLMeshInterface *)gl_mesh->descriptor)->Refine();
}

void openSubdiv_osdGLMeshSynchronize(struct OpenSubdiv_GLMesh *gl_mesh)
{
	((GLMeshInterface *)gl_mesh->descriptor)->Synchronize();
}

void openSubdiv_osdGLMeshBindVertexBuffer(OpenSubdiv_GLMesh *gl_mesh)
{
	((GLMeshInterface *)gl_mesh->descriptor)->BindVertexBuffer();
}

const struct OpenSubdiv_TopologyRefinerDescr *openSubdiv_getGLMeshTopologyRefiner(
        OpenSubdiv_GLMesh *gl_mesh)
{
	return gl_mesh->topology_refiner;
}

int openSubdiv_supportGPUDisplay(void)
{
	{
		/* Currently Intel GPUs has hard time working on Windows.
		 *
		 * For until we've got access to a hardware which demonstrates
		 * the issue we disable OpenSubdiv on Intel GPUs.
		 */
		static bool vendor_checked = false;
		static bool is_intel = false;
		if (!vendor_checked) {
			vendor_checked = true;
			const char *vendor = (const char *)glGetString(GL_VENDOR);
			if (vendor != NULL && strstr(vendor, "Intel")) {
				if(getenv("OPENSUBDIV_ALLOW_INTEL") == NULL) {
					is_intel = true;
				}
			}
		}
		if (is_intel) {
			return false;
		}
	}

	return GLEW_EXT_geometry_shader4 &&
	       GLEW_ARB_gpu_shader5 &&
	       GLEW_ARB_uniform_buffer_object;
}