#include "./../../../GPUInstancer/Resources/Compute/Include/PlatformDefines.compute"

#pragma kernel CSCrowdAnimatorController

uniform RWStructuredBuffer<float4> gpuiAnimationData; // index: 0 x -> frameNo1, y -> frameNo2, z -> frameNo3, w -> frameNo4
                                                      // index: 1 x -> weight1, y -> weight2, z -> weight3, w -> weight4

uniform StructuredBuffer<float4> gpuiCrowdAnimatorController; // 0 to 4: x ->  minFrame, y -> maxFrame (negative if not looping), z -> speed, w -> startTime

uniform uint instanceCount;
uniform float currentTime;
uniform uint frameRate;

#define MIN_SPEED 0.000001f

[numthreads(GPUI_THREADS, 1, 1)]
void CSCrowdAnimatorController(uint3 id : SV_DispatchThreadID)
{
    if (id.x >= instanceCount)
        return;
    
    uint animationIndex = id.x * 2;
    uint crowdAnimatorIndex = id.x * 4;

    float4 animationData = gpuiAnimationData[animationIndex];
    
    float4 crowdAnimatorData = gpuiCrowdAnimatorController[crowdAnimatorIndex];
    // If loop is disabled max frame is negative (trick to conserve memory)
    int isLooping = sign(crowdAnimatorData.y);
    // absolute value
    crowdAnimatorData.y = crowdAnimatorData.y * isLooping;
    float clipTime = abs(currentTime - crowdAnimatorData.w) * crowdAnimatorData.z;
    float clipFrameCount = crowdAnimatorData.y - crowdAnimatorData.x;
    float length = clipFrameCount / frameRate;

    if (crowdAnimatorData.z > MIN_SPEED)
    {
        if (isLooping < 0 && clipTime > length)
            animationData.x = crowdAnimatorData.y;
        else
            animationData.x = frac(clipTime / length) * clipFrameCount + crowdAnimatorData.x;
    }

    if (animationData.y >= 0)
    {
        crowdAnimatorData = gpuiCrowdAnimatorController[crowdAnimatorIndex + 1];
        if (crowdAnimatorData.z > MIN_SPEED)
        {
            isLooping = sign(crowdAnimatorData.y);
            crowdAnimatorData.y = crowdAnimatorData.y * isLooping;
            clipTime = abs(currentTime - crowdAnimatorData.w) * crowdAnimatorData.z;
            clipFrameCount = crowdAnimatorData.y - crowdAnimatorData.x;
            length = clipFrameCount / frameRate;

            if (isLooping < 0 && clipTime > length)
                animationData.y = crowdAnimatorData.y;
            else
                animationData.y = frac(clipTime / length) * clipFrameCount + crowdAnimatorData.x;
        }
    }
    
    if (animationData.z >= 0)
    {
        crowdAnimatorData = gpuiCrowdAnimatorController[crowdAnimatorIndex + 2];
        if (crowdAnimatorData.z > MIN_SPEED)
        {
            isLooping = sign(crowdAnimatorData.y);
            crowdAnimatorData.y = crowdAnimatorData.y * isLooping;
            clipTime = abs(currentTime - crowdAnimatorData.w) * crowdAnimatorData.z;
            clipFrameCount = crowdAnimatorData.y - crowdAnimatorData.x;
            length = clipFrameCount / frameRate;

            if (isLooping < 0 && clipTime > length)
                animationData.z = crowdAnimatorData.y;
            else
                animationData.z = frac(clipTime / length) * clipFrameCount + crowdAnimatorData.x;
        }
    }
    
    if (animationData.w >= 0)
    {
        crowdAnimatorData = gpuiCrowdAnimatorController[crowdAnimatorIndex + 3];
        if (crowdAnimatorData.z > MIN_SPEED)
        {
            isLooping = sign(crowdAnimatorData.y);
            crowdAnimatorData.y = crowdAnimatorData.y * isLooping;
            clipTime = abs(currentTime - crowdAnimatorData.w) * crowdAnimatorData.z;
            clipFrameCount = crowdAnimatorData.y - crowdAnimatorData.x;
            length = clipFrameCount / frameRate;

            if (isLooping < 0 && clipTime > length)
                animationData.w = crowdAnimatorData.y;
            else
                animationData.w = frac(clipTime / length) * clipFrameCount + crowdAnimatorData.x;
        }
    }
    
    gpuiAnimationData[animationIndex] = animationData;
}