// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)
// Upgrade NOTE: excluded shader from OpenGL ES 2.0 because it uses non-square matrices
#pragma exclude_renderers gles

#ifndef UNITY_STANDARD_PARTICLE_INSTANCING_INCLUDED
#define UNITY_STANDARD_PARTICLE_INSTANCING_INCLUDED

#if defined(UNITY_PROCEDURAL_INSTANCING_ENABLED) && !defined(SHADER_TARGET_SURFACE_ANALYSIS)
#define UNITY_PARTICLE_INSTANCING_ENABLED
#endif

#if defined(UNITY_PARTICLE_INSTANCING_ENABLED)

#ifndef UNITY_PARTICLE_INSTANCE_DATA
#define UNITY_PARTICLE_INSTANCE_DATA DefaultParticleInstanceData
#endif

struct DefaultParticleInstanceData
{
    float3x4 transform;
    uint color;
    float animFrame;
};

StructuredBuffer<UNITY_PARTICLE_INSTANCE_DATA> unity_ParticleInstanceData;
float4 unity_ParticleUVShiftData;
float unity_ParticleUseMeshColors;

void vertInstancingMatrices(out float4x4 objectToWorld, out float4x4 worldToObject)
{
    UNITY_PARTICLE_INSTANCE_DATA data = unity_ParticleInstanceData[unity_InstanceID];

    // transform matrix
    objectToWorld._11_21_31_41 = float4(data.transform._11_21_31, 0.0f);
    objectToWorld._12_22_32_42 = float4(data.transform._12_22_32, 0.0f);
    objectToWorld._13_23_33_43 = float4(data.transform._13_23_33, 0.0f);
    objectToWorld._14_24_34_44 = float4(data.transform._14_24_34, 1.0f);

    // inverse transform matrix
    float3x3 w2oRotation;
    w2oRotation[0] = objectToWorld[1].yzx * objectToWorld[2].zxy - objectToWorld[1].zxy * objectToWorld[2].yzx;
    w2oRotation[1] = objectToWorld[0].zxy * objectToWorld[2].yzx - objectToWorld[0].yzx * objectToWorld[2].zxy;
    w2oRotation[2] = objectToWorld[0].yzx * objectToWorld[1].zxy - objectToWorld[0].zxy * objectToWorld[1].yzx;

    float det = dot(objectToWorld[0].xyz, w2oRotation[0]);

    w2oRotation = transpose(w2oRotation);

    w2oRotation *= rcp(det);

    float3 w2oPosition = mul(w2oRotation, -objectToWorld._14_24_34);

    worldToObject._11_21_31_41 = float4(w2oRotation._11_21_31, 0.0f);
    worldToObject._12_22_32_42 = float4(w2oRotation._12_22_32, 0.0f);
    worldToObject._13_23_33_43 = float4(w2oRotation._13_23_33, 0.0f);
    worldToObject._14_24_34_44 = float4(w2oPosition, 1.0f);
}

void vertInstancingSetup()
{
    vertInstancingMatrices(unity_ObjectToWorld, unity_WorldToObject);
}

void vertInstancingColor(inout fixed4 color)
{
#ifndef UNITY_PARTICLE_INSTANCE_DATA_NO_COLOR
    UNITY_PARTICLE_INSTANCE_DATA data = unity_ParticleInstanceData[unity_InstanceID];
    color = lerp(fixed4(1.0f, 1.0f, 1.0f, 1.0f), color, unity_ParticleUseMeshColors);
    color *= float4(data.color & 255, (data.color >> 8) & 255, (data.color >> 16) & 255, (data.color >> 24) & 255) * (1.0f / 255);
#endif
}

void vertInstancingUVs(in float2 uv, out float2 texcoord, out float3 texcoord2AndBlend)
{
    if (unity_ParticleUVShiftData.x != 0.0f)
    {
        UNITY_PARTICLE_INSTANCE_DATA data = unity_ParticleInstanceData[unity_InstanceID];

        float numTilesX = unity_ParticleUVShiftData.y;
        float2 animScale = unity_ParticleUVShiftData.zw;
#ifdef UNITY_PARTICLE_INSTANCE_DATA_NO_ANIM_FRAME
        float sheetIndex = 0.0f;
#else
        float sheetIndex = data.animFrame;
#endif

        float index0 = floor(sheetIndex);
        float vIdx0 = floor(index0 / numTilesX);
        float uIdx0 = floor(index0 - vIdx0 * numTilesX);
        float2 offset0 = float2(uIdx0 * animScale.x, (1.0f - animScale.y) - vIdx0 * animScale.y);

        texcoord = uv * animScale.xy + offset0.xy;

#ifdef _FLIPBOOK_BLENDING
        float index1 = floor(sheetIndex + 1.0f);
        float vIdx1 = floor(index1 / numTilesX);
        float uIdx1 = floor(index1 - vIdx1 * numTilesX);
        float2 offset1 = float2(uIdx1 * animScale.x, (1.0f - animScale.y) - vIdx1 * animScale.y);

        texcoord2AndBlend.xy = uv * animScale.xy + offset1.xy;
        texcoord2AndBlend.z = frac(sheetIndex);
#else
        texcoord2AndBlend.xy = texcoord;
        texcoord2AndBlend.z = 0.0f;
#endif
    }
    else
    {
        texcoord = uv;
        texcoord2AndBlend.xy = uv;
        texcoord2AndBlend.z = 0.0f;
    }
}

void vertInstancingUVs(in float2 uv, out float2 texcoord)
{
    float3 texcoord2AndBlend = 0.0f;
    vertInstancingUVs(uv, texcoord, texcoord2AndBlend);
}

#else

void vertInstancingSetup() {}
void vertInstancingColor(inout fixed4 color) {}
void vertInstancingUVs(in float2 uv, out float2 texcoord, out float3 texcoord2AndBlend) { texcoord = 0.0f; texcoord2AndBlend = 0.0f; }
void vertInstancingUVs(in float2 uv, out float2 texcoord) { texcoord = 0.0f; }

#endif

#endif // UNITY_STANDARD_PARTICLE_INSTANCING_INCLUDED