#include "OpenGLSupport.h"
#include "OpenGLVertexBufferObjectSupport.h"

#include "PolyVoxCore/IndexedSurfacePatch.h"

using namespace PolyVox;
using namespace std;

OpenGLSurfacePatch BuildOpenGLSurfacePatch(const IndexedSurfacePatch& isp)
{
	//Represents our filled in OpenGL vertex and index buffer objects.
	OpenGLSurfacePatch result;

	//Convienient access to the vertices and indices
	const vector<SurfaceVertex>& vecVertices = isp.getVertices();
	const vector<PolyVox::uint32_t>& vecIndices = isp.getIndices();

	//If we have any indices...
	if(!vecIndices.empty())
	{
		//Create an OpenGL index buffer
		glGenBuffers(1, &result.indexBuffer);
		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, result.indexBuffer);

		//Get a pointer to the first index
		GLvoid* pIndices = (GLvoid*)(&(vecIndices[0]));		

		//Fill the OpenGL index buffer with our data. 
		glBufferData(GL_ELEMENT_ARRAY_BUFFER, vecIndices.size() * sizeof(PolyVox::uint32_t), pIndices, GL_STATIC_DRAW);
	}

	result.noOfIndices = vecIndices.size();

	glGenBuffers(1, &result.vertexBuffer);
	glBindBuffer(GL_ARRAY_BUFFER, result.vertexBuffer);
	glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(GLfloat) * 9, 0, GL_STATIC_DRAW);
	GLfloat* ptr = (GLfloat*)glMapBuffer(GL_ARRAY_BUFFER, GL_READ_WRITE);

	for(vector<SurfaceVertex>::const_iterator iterVertex = vecVertices.begin(); iterVertex != vecVertices.end(); ++iterVertex)
	{
		const SurfaceVertex& vertex = *iterVertex;
		const Vector3DFloat& v3dVertexPos = vertex.getPosition();
		//const Vector3DFloat v3dRegionOffset(uRegionX * g_uRegionSideLength, uRegionY * g_uRegionSideLength, uRegionZ * g_uRegionSideLength);
		const Vector3DFloat v3dFinalVertexPos = v3dVertexPos + static_cast<Vector3DFloat>(isp.m_v3dRegionPosition);

		*ptr = v3dFinalVertexPos.getX();
		ptr++;
		*ptr = v3dFinalVertexPos.getY();
		ptr++;
		*ptr = v3dFinalVertexPos.getZ();
		ptr++;

		*ptr = vertex.getNormal().getX();
		ptr++;
		*ptr = vertex.getNormal().getY();
		ptr++;
		*ptr = vertex.getNormal().getZ();
		ptr++;

		PolyVox::uint8_t material = vertex.getMaterial() + 0.5;

		OpenGLColour colour = convertMaterialIDToColour(material);

		*ptr = colour.red;
		ptr++;
		*ptr = colour.green;
		ptr++;
		*ptr = colour.blue;
		ptr++;
	}

	glUnmapBuffer(GL_ARRAY_BUFFER);

	return result;
}

void renderRegionVertexBufferObject(const OpenGLSurfacePatch& openGLSurfacePatch)
{
	glBindBuffer(GL_ARRAY_BUFFER, openGLSurfacePatch.vertexBuffer);
	glVertexPointer(3, GL_FLOAT, 36, 0);
	glNormalPointer(GL_FLOAT, 36, (GLvoid*)12);
	glColorPointer(3, GL_FLOAT, 36, (GLvoid*)24);

	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, openGLSurfacePatch.indexBuffer);

	glEnableClientState(GL_VERTEX_ARRAY);
	glEnableClientState(GL_NORMAL_ARRAY);
	glEnableClientState(GL_COLOR_ARRAY);

	glDrawElements(GL_TRIANGLES, openGLSurfacePatch.noOfIndices, GL_UNSIGNED_INT, 0);

	glDisableClientState(GL_COLOR_ARRAY);
	glDisableClientState(GL_NORMAL_ARRAY);
	glDisableClientState(GL_VERTEX_ARRAY);
}