#pragma require geometry
#pragma vertex vert
#pragma geometry geom

#define VFX_NON_UNIFORM_SCALE VFX_LOCAL_SPACE

uint vert(uint id : SV_VertexID) : TEXCOORD0
{
	return id;
}

#if VFX_PRIMITIVE_TRIANGLE
#define VERTEX_COUNT 3
#elif VFX_PRIMITIVE_QUAD
#define VERTEX_COUNT 4
#elif VFX_PRIMITIVE_OCTAGON
#define VERTEX_COUNT 8
#endif

[maxvertexcount(VERTEX_COUNT)]
void geom(point uint intStream[1] : TEXCOORD0,inout TriangleStream<VFX_VARYING_PS_INPUTS> outStream)
{
	uint index = intStream[0];
	
	${VFXLoadAttributesOrCull}
	${VFXProcessBlocks}
			
	if (!attributes.alive)
		return;
		
	${VFXLoadSize}
	
	const float4x4 elementToVFX = GetElementToVFXMatrix(
		attributes.axisX,
		attributes.axisY,
		attributes.axisZ,
		float3(attributes.angleX,attributes.angleY,attributes.angleZ),
		float3(attributes.pivotX,attributes.pivotY,attributes.pivotZ),
		size3,
		attributes.position);
	
	VFX_VARYING_PS_INPUTS o = (VFX_VARYING_PS_INPUTS)0;
	
#if VFX_NON_UNIFORM_SCALE
	float3x3 elementToVFX_N = GetElementToVFXMatrixNormal(
		attributes.axisX,
		attributes.axisY,
		attributes.axisZ,
		float3(attributes.angleX,attributes.angleY,attributes.angleZ),
		size3);
#else
	float3x3 elementToVFX_N = (float3x3)elementToVFX;
#endif
	
	#ifdef VFX_VARYING_NORMAL
	float normalFlip = (size3.x * size3.y * size3.z) < 0 ? -1 : 1;
	o.VFX_VARYING_NORMAL = normalFlip * normalize(TransformNormalVFXToWorld(normalize(-transpose(elementToVFX_N)[2].xyz)));
	#endif
	#ifdef VFX_VARYING_TANGENT
	o.VFX_VARYING_TANGENT = normalize(TransformDirectionVFXToWorld(normalize(transpose(elementToVFX)[0].xyz)));
	#endif
	
	[unroll]
	for (int id = 0; id < VERTEX_COUNT; ++id)
	{
		float2 varyingUV = (float2)0.0f;
		
#if VFX_PRIMITIVE_QUAD

	    varyingUV.x = float(id & 1);
	    varyingUV.y = (id & 2) * 0.5f;
	    const float2 vOffsets = varyingUV.xy - 0.5f;
	
#elif VFX_PRIMITIVE_TRIANGLE

	    const float2 kOffsets[] = {
		    float2(-0.5f, 	-0.288675129413604736328125f),
		    float2(0.0f, 	0.57735025882720947265625f),
		    float2(0.5f,	-0.288675129413604736328125f),
	    };
	
	    const float kUVScale = 0.866025388240814208984375f;
	
	    const float2 vOffsets = kOffsets[id % 3];
	    varyingUV.xy = (vOffsets * kUVScale) + 0.5f;
	
#elif VFX_PRIMITIVE_OCTAGON	
	    // TODO Not working at the moment. Order of strips has to be fixed
        // But need to fine a nice way to know whether a vertex needs displacement or not (cannot use & 1)
	    const float2 kUvs[8] = 
	    {
		    float2(-0.5f,	0.0f),
		    float2(-0.5f,	0.5f),
		    float2(0.0f,	0.5f),
		    float2(0.5f,	0.5f),
		    float2(0.5f,	0.0f),
		    float2(0.5f,	-0.5f),
		    float2(0.0f,	-0.5f),
		    float2(-0.5f,	-0.5f),
	    };
	
	    ${VFXLoadParameter:{cropFactor}}
	    cropFactor = id & 1 ? 1.0f - cropFactor : 1.0f;
	    const float2 vOffsets = kUvs[id & 7] * cropFactor;
	    varyingUV.xy = vOffsets + 0.5f;
	
#endif
						
		const float3 vPos = mul(elementToVFX,float4(vOffsets,0.0f,1.0f)).xyz;
		o.VFX_VARYING_POSCS = TransformPositionVFXToClip(vPos);
		
		#ifdef VFX_VARYING_UV
		o.VFX_VARYING_UV.xy = varyingUV;
		#endif
		
		#ifdef VFX_VARYING_BENTFACTORS
		${VFXLoadParameter:{normalBendingFactor}}
		o.VFX_VARYING_BENTFACTORS = vOffsets * normalBendingFactor;
		#endif

		${VFXVertexCommonProcess}
		
		${VFXVertexSetFlipbooksInterpolants}
		
		${VFXVertexAdditionalProcess}
		
		outStream.Append(o);
	}
}