/******************************************************************************
 * The MIT License (MIT)
 * 
 * Copyright (c) 2014 Crytek
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 ******************************************************************************/

// compute shaders that figure out the min/max values or histogram in a texture heirarchically
// note that we have to conditionally compile this shader for float/uint/sint as doing that
// dynamically produces a shader with too many temp registers unfortunately.

RWBuffer<float4> MinMaxDestFloat : register(u0);
RWBuffer<uint4> MinMaxDestUInt : register(u1);
RWBuffer<int4> MinMaxDestInt : register(u2);

[numthreads(HGRAM_TILES_PER_BLOCK, HGRAM_TILES_PER_BLOCK, 1)]
void RENDERDOC_TileMinMaxCS(uint3 tid : SV_GroupThreadID, uint3 gid : SV_GroupID)
{
	uint texType = SHADER_RESTYPE;

	uint3 texDim = uint3(HistogramTextureResolution);

	uint blocksX = (int)ceil(float(texDim.x)/float(HGRAM_PIXELS_PER_TILE*HGRAM_TILES_PER_BLOCK));

	uint2 topleft = (gid.xy*HGRAM_TILES_PER_BLOCK + tid.xy)*HGRAM_PIXELS_PER_TILE;

	uint outIdx = (tid.y*HGRAM_TILES_PER_BLOCK + tid.x) + (gid.y*blocksX + gid.x)*(HGRAM_TILES_PER_BLOCK*HGRAM_TILES_PER_BLOCK);

	int i=0;

#if UINT_TEX
	{
		uint4 minval = 0;
		uint4 maxval = 0;

		for(uint y=topleft.y; y < min(texDim.y, topleft.y + HGRAM_PIXELS_PER_TILE); y++)
		{
			for(uint x=topleft.x; x < min(texDim.x, topleft.x + HGRAM_PIXELS_PER_TILE); x++)
			{
				uint4 data = SampleTextureUInt4(texType, float2(x, y)/float2(texDim.xy),
												HistogramSlice, HistogramMip, HistogramSample, texDim);

				if(i == 0)
				{
					minval = maxval = data;
				}
				else
				{
					minval = min(minval, data);
					maxval = max(maxval, data);
				}

				i++;
			}
		}

		MinMaxDestUInt[outIdx*2+0] = minval;
		MinMaxDestUInt[outIdx*2+1] = maxval;
		return;
	}
#elif SINT_TEX
	{
		int4 minval = 0;
		int4 maxval = 0;

		for(uint y=topleft.y; y < min(texDim.y, topleft.y + HGRAM_PIXELS_PER_TILE); y++)
		{
			for(uint x=topleft.x; x < min(texDim.x, topleft.x + HGRAM_PIXELS_PER_TILE); x++)
			{
				int4 data = SampleTextureInt4(texType, float2(x, y)/float2(texDim.xy),
												HistogramSlice, HistogramMip, HistogramSample, texDim);

				if(i == 0)
				{
					minval = maxval = data;
				}
				else
				{
					minval = min(minval, data);
					maxval = max(maxval, data);
				}

				i++;
			}
		}

		MinMaxDestInt[outIdx*2+0] = minval;
		MinMaxDestInt[outIdx*2+1] = maxval;
		return;
	}
#else
	{
		float4 minval = 0;
		float4 maxval = 0;

		for(uint y=topleft.y; y < min(texDim.y, topleft.y + HGRAM_PIXELS_PER_TILE); y++)
		{
			for(uint x=topleft.x; x < min(texDim.x, topleft.x + HGRAM_PIXELS_PER_TILE); x++)
			{
				float4 data = SampleTextureFloat4(texType, false, float2(x, y)/float2(texDim.xy),
													HistogramSlice, HistogramMip, HistogramSample, texDim);

				if(i == 0)
				{
					minval = maxval = data;
				}
				else
				{
					minval = min(minval, data);
					maxval = max(maxval, data);
				}

				i++;
			}
		}

		MinMaxDestFloat[outIdx*2+0] = minval;
		MinMaxDestFloat[outIdx*2+1] = maxval;
		return;
	}
#endif
}

Buffer<float4> MinMaxResultSourceFloat : register(t0);
Buffer<uint4> MinMaxResultSourceUInt : register(t1);
Buffer<int4> MinMaxResultSourceInt : register(t2);

RWBuffer<float4> MinMaxResultDestFloat : register(u0);
RWBuffer<uint4> MinMaxResultDestUInt : register(u1);
RWBuffer<int4> MinMaxResultDestInt : register(u2);

[numthreads(1,1,1)]
void RENDERDOC_ResultMinMaxCS()
{
	uint3 texDim = uint3(HistogramTextureResolution);

	uint blocksX = (int)ceil(float(texDim.x)/float(HGRAM_PIXELS_PER_TILE*HGRAM_TILES_PER_BLOCK));
	uint blocksY = (int)ceil(float(texDim.y)/float(HGRAM_PIXELS_PER_TILE*HGRAM_TILES_PER_BLOCK));

#if UINT_TEX
	uint4 minvalU = MinMaxResultSourceUInt[0];
	uint4 maxvalU = MinMaxResultSourceUInt[1];
#elif SINT_TEX
	int4 minvalI = MinMaxResultSourceInt[0];
	int4 maxvalI = MinMaxResultSourceInt[1];
#else
	float4 minvalF = MinMaxResultSourceFloat[0];
	float4 maxvalF = MinMaxResultSourceFloat[1];
#endif
	
	// i is the tile we're looking at
	for(uint i=1; i < blocksX*blocksY*HGRAM_TILES_PER_BLOCK*HGRAM_TILES_PER_BLOCK; i++)
	{
		uint blockIdx = i/(HGRAM_TILES_PER_BLOCK*HGRAM_TILES_PER_BLOCK);
		uint tileIdx = i%(HGRAM_TILES_PER_BLOCK*HGRAM_TILES_PER_BLOCK);

		// which block and tile is this in
		uint2 blockXY = uint2(blockIdx % blocksX, blockIdx / blocksX);
		uint2 tileXY = uint2(tileIdx % HGRAM_TILES_PER_BLOCK, tileIdx / HGRAM_TILES_PER_BLOCK);

		// if this is at least partially within the texture, include it.
		if(blockXY.x*(HGRAM_TILES_PER_BLOCK*HGRAM_TILES_PER_BLOCK) + tileXY.x*HGRAM_PIXELS_PER_TILE < texDim.x &&
		   blockXY.y*(HGRAM_TILES_PER_BLOCK*HGRAM_TILES_PER_BLOCK) + tileXY.y*HGRAM_PIXELS_PER_TILE < texDim.y)
		{
#if UINT_TEX
			minvalU = min(minvalU, MinMaxResultSourceUInt[i*2 + 0]);
			maxvalU = max(maxvalU, MinMaxResultSourceUInt[i*2 + 1]);
#elif SINT_TEX
			minvalI = min(minvalI, MinMaxResultSourceInt[i*2 + 0]);
			maxvalI = max(maxvalI, MinMaxResultSourceInt[i*2 + 1]);
#else
			minvalF = min(minvalF, MinMaxResultSourceFloat[i*2 + 0]);
			maxvalF = max(maxvalF, MinMaxResultSourceFloat[i*2 + 1]);
#endif
		}
	}
	
#if UINT_TEX
	MinMaxResultDestUInt[0] = minvalU;
	MinMaxResultDestUInt[1] = maxvalU;
#elif SINT_TEX
	MinMaxResultDestInt[0] = minvalI;
	MinMaxResultDestInt[1] = maxvalI;
#else
	MinMaxResultDestFloat[0] = minvalF;
	MinMaxResultDestFloat[1] = maxvalF;
#endif
}

RWBuffer<uint> HistogramDest : register(u0);

[numthreads(HGRAM_TILES_PER_BLOCK, HGRAM_TILES_PER_BLOCK, 1)]
void RENDERDOC_HistogramCS(uint3 tid : SV_GroupThreadID, uint3 gid : SV_GroupID)
{
	uint texType = SHADER_RESTYPE;

	uint3 texDim = uint3(HistogramTextureResolution);

	uint blocksX = (int)ceil(float(texDim.x)/float(HGRAM_PIXELS_PER_TILE*HGRAM_PIXELS_PER_TILE));

	uint2 topleft = (gid.xy*HGRAM_TILES_PER_BLOCK + tid.xy)*HGRAM_PIXELS_PER_TILE;

	int i=0;

	for(uint y=topleft.y; y < min(texDim.y, topleft.y + HGRAM_PIXELS_PER_TILE); y++)
	{
		for(uint x=topleft.x; x < min(texDim.x, topleft.x + HGRAM_PIXELS_PER_TILE); x++)
		{
			uint bucketIdx = HGRAM_NUM_BUCKETS+1;
			
#if UINT_TEX
			{
				uint4 data = SampleTextureUInt4(texType, float2(x, y)/float2(texDim.xy),
												HistogramSlice, HistogramMip, HistogramSample, texDim);

				float divisor = 0.0f;
				uint sum = 0;
				if(HistogramChannels & 0x1)
				{
					sum += data.x;
					divisor += 1.0f;
				}
				if(HistogramChannels & 0x2)
				{
					sum += data.y;
					divisor += 1.0f;
				}
				if(HistogramChannels & 0x4)
				{
					sum += data.z;
					divisor += 1.0f;
				}
				if(HistogramChannels & 0x8)
				{
					sum += data.w;
					divisor += 1.0f;
				}

				if(divisor > 0.0f)
				{
					float val = float(sum)/divisor;

					float normalisedVal = (val - HistogramMin)/(HistogramMax - HistogramMin);

					if(normalisedVal < 0.0f)
						normalisedVal = 2.0f;

					bucketIdx = (uint)floor(normalisedVal*HGRAM_NUM_BUCKETS);
				}
			}
#elif SINT_TEX
			{
				int4 data = SampleTextureInt4(texType, float2(x, y)/float2(texDim.xy),
												HistogramSlice, HistogramMip, HistogramSample, texDim);

				float divisor = 0.0f;
				int sum = 0;
				if(HistogramChannels & 0x1)
				{
					sum += data.x;
					divisor += 1.0f;
				}
				if(HistogramChannels & 0x2)
				{
					sum += data.y;
					divisor += 1.0f;
				}
				if(HistogramChannels & 0x4)
				{
					sum += data.z;
					divisor += 1.0f;
				}
				if(HistogramChannels & 0x8)
				{
					sum += data.w;
					divisor += 1.0f;
				}

				if(divisor > 0.0f)
				{
					float val = float(sum)/divisor;

					float normalisedVal = (val - HistogramMin)/(HistogramMax - HistogramMin);

					if(normalisedVal < 0.0f)
						normalisedVal = 2.0f;

					bucketIdx = (uint)floor(normalisedVal*HGRAM_NUM_BUCKETS);
				}
			}
#else
			{
				float4 data = SampleTextureFloat4(texType, false, float2(x, y)/float2(texDim.xy),
					HistogramSlice, HistogramMip, HistogramSample, texDim);

				float divisor = 0.0f;
				float sum = 0.0f;
				if(HistogramChannels & 0x1)
				{
					sum += data.x;
					divisor += 1.0f;
				}
				if(HistogramChannels & 0x2)
				{
					sum += data.y;
					divisor += 1.0f;
				}
				if(HistogramChannels & 0x4)
				{
					sum += data.z;
					divisor += 1.0f;
				}
				if(HistogramChannels & 0x8)
				{
					sum += data.w;
					divisor += 1.0f;
				}

				if(divisor > 0.0f)
				{
					float val = sum/divisor;

					float normalisedVal = (val - HistogramMin)/(HistogramMax - HistogramMin);

					if(normalisedVal < 0.0f)
						normalisedVal = 2.0f;

					bucketIdx = (uint)floor(normalisedVal*HGRAM_NUM_BUCKETS);
				}
			}
#endif

			if(bucketIdx >= 0 && bucketIdx < HGRAM_NUM_BUCKETS)
				InterlockedAdd(HistogramDest[bucketIdx], 1);
		}
	}
}

