// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "PixelProgram.hpp"

#include "SamplerCore.hpp"
#include "Device/Primitive.hpp"
#include "Device/Renderer.hpp"

namespace sw
{
	void PixelProgram::setBuiltins(Int &x, Int &y, Float4(&z)[4], Float4 &w)
	{
		routine.setImmutableInputBuiltins(spirvShader);

		routine.setInputBuiltin(spirvShader, spv::BuiltInViewIndex, [&](const SpirvShader::BuiltinMapping& builtin, Array<SIMD::Float>& value)
		{
			assert(builtin.SizeInComponents == 1);
			value[builtin.FirstComponent] = As<Float4>(Int4((*Pointer<Int>(data + OFFSET(DrawData, viewID)))));
		});

		routine.setInputBuiltin(spirvShader, spv::BuiltInFragCoord, [&](const SpirvShader::BuiltinMapping& builtin, Array<SIMD::Float>& value)
		{
			assert(builtin.SizeInComponents == 4);
			value[builtin.FirstComponent+0] = SIMD::Float(Float(x)) + SIMD::Float(0.5f, 1.5f, 0.5f, 1.5f);
			value[builtin.FirstComponent+1] = SIMD::Float(Float(y)) + SIMD::Float(0.5f, 0.5f, 1.5f, 1.5f);
			value[builtin.FirstComponent+2] = z[0];	// sample 0
			value[builtin.FirstComponent+3] = w;
		});

		routine.setInputBuiltin(spirvShader, spv::BuiltInPointCoord, [&](const SpirvShader::BuiltinMapping& builtin, Array<SIMD::Float>& value)
		{
			assert(builtin.SizeInComponents == 2);
			value[builtin.FirstComponent+0] = SIMD::Float(0.5f) +
				SIMD::Float(Float(x) - (*Pointer<Float>(primitive + OFFSET(Primitive, pointCoordX))));
			value[builtin.FirstComponent+1] = SIMD::Float(0.5f) +
				SIMD::Float(Float(y) - (*Pointer<Float>(primitive + OFFSET(Primitive, pointCoordY))));
		});

		routine.setInputBuiltin(spirvShader, spv::BuiltInSubgroupSize, [&](const SpirvShader::BuiltinMapping& builtin, Array<SIMD::Float>& value)
		{
			assert(builtin.SizeInComponents == 1);
			value[builtin.FirstComponent] = As<SIMD::Float>(SIMD::Int(SIMD::Width));
		});

		routine.windowSpacePosition[0] = x + SIMD::Int(0,1,0,1);
		routine.windowSpacePosition[1] = y + SIMD::Int(0,0,1,1);
		routine.viewID = *Pointer<Int>(data + OFFSET(DrawData, viewID));
	}

	void PixelProgram::applyShader(Int cMask[4])
	{
		routine.descriptorSets = data + OFFSET(DrawData, descriptorSets);
		routine.descriptorDynamicOffsets = data + OFFSET(DrawData, descriptorDynamicOffsets);
		routine.pushConstants = data + OFFSET(DrawData, pushConstants);
		routine.constants = *Pointer<Pointer<Byte>>(data + OFFSET(DrawData, constants));

		auto it = spirvShader->inputBuiltins.find(spv::BuiltInFrontFacing);
		if (it != spirvShader->inputBuiltins.end())
		{
			ASSERT(it->second.SizeInComponents == 1);
			auto frontFacing = Int4(*Pointer<Int>(primitive + OFFSET(Primitive, clockwiseMask)));
			routine.getVariable(it->second.Id)[it->second.FirstComponent] = As<Float4>(frontFacing);
		}

		it = spirvShader->inputBuiltins.find(spv::BuiltInSampleMask);
		if (it != spirvShader->inputBuiltins.end())
		{
			static_assert(SIMD::Width == 4, "Expects SIMD width to be 4");
			Int4 laneBits = Int4(1, 2, 4, 8);

			Int4 inputSampleMask = Int4(1) & CmpNEQ(Int4(cMask[0]) & laneBits, Int4(0));
			for (auto i = 1u; i < state.multiSample; i++)
			{
				inputSampleMask |= Int4(1 << i) & CmpNEQ(Int4(cMask[i]) & laneBits, Int4(0));
			}

			routine.getVariable(it->second.Id)[it->second.FirstComponent] = As<Float4>(inputSampleMask);
			// Sample mask input is an array, as the spec contemplates MSAA levels higher than 32.
			// Fill any non-zero indices with 0.
			for (auto i = 1u; i < it->second.SizeInComponents; i++)
				routine.getVariable(it->second.Id)[it->second.FirstComponent + i] = Float4(0);
		}

		// Note: all lanes initially active to facilitate derivatives etc. Actual coverage is
		// handled separately, through the cMask.
		auto activeLaneMask = SIMD::Int(0xFFFFFFFF);
		routine.killMask = 0;

		spirvShader->emit(&routine, activeLaneMask, descriptorSets);
		spirvShader->emitEpilog(&routine);

		for(int i = 0; i < RENDERTARGETS; i++)
		{
			c[i].x = routine.outputs[i * 4];
			c[i].y = routine.outputs[i * 4 + 1];
			c[i].z = routine.outputs[i * 4 + 2];
			c[i].w = routine.outputs[i * 4 + 3];
		}

		clampColor(c);

		if(spirvShader->getModes().ContainsKill)
		{
			for (auto i = 0u; i < state.multiSample; i++)
			{
				cMask[i] &= ~routine.killMask;
			}
		}

		it = spirvShader->outputBuiltins.find(spv::BuiltInSampleMask);
		if (it != spirvShader->outputBuiltins.end())
		{
			auto outputSampleMask = As<SIMD::Int>(routine.getVariable(it->second.Id)[it->second.FirstComponent]);

			for (auto i = 0u; i < state.multiSample; i++)
			{
				cMask[i] &= SignMask(CmpNEQ(outputSampleMask & SIMD::Int(1<<i), SIMD::Int(0)));
			}
		}

		it = spirvShader->outputBuiltins.find(spv::BuiltInFragDepth);
		if (it != spirvShader->outputBuiltins.end())
		{
			oDepth = Min(Max(routine.getVariable(it->second.Id)[it->second.FirstComponent], Float4(0.0f)), Float4(1.0f));
		}
	}

	Bool PixelProgram::alphaTest(Int cMask[4])
	{
		if(!state.alphaToCoverage)
		{
			return true;
		}

		alphaToCoverage(cMask, c[0].w);

		Int pass = cMask[0];

		for(unsigned int q = 1; q < state.multiSample; q++)
		{
			pass = pass | cMask[q];
		}

		return pass != 0x0;
	}

	void PixelProgram::rasterOperation(Pointer<Byte> cBuffer[4], Int &x, Int sMask[4], Int zMask[4], Int cMask[4])
	{
		for(int index = 0; index < RENDERTARGETS; index++)
		{
			if(!state.colorWriteActive(index))
			{
				continue;
			}

			auto format = state.targetFormat[index];
			switch(format)
			{
			case VK_FORMAT_A1R5G5B5_UNORM_PACK16:
			case VK_FORMAT_R5G6B5_UNORM_PACK16:
			case VK_FORMAT_B8G8R8A8_UNORM:
			case VK_FORMAT_B8G8R8A8_SRGB:
			case VK_FORMAT_R8G8B8A8_UNORM:
			case VK_FORMAT_R8G8B8A8_SRGB:
			case VK_FORMAT_R8G8_UNORM:
			case VK_FORMAT_R8_UNORM:
			case VK_FORMAT_R16G16_UNORM:
			case VK_FORMAT_R16G16B16A16_UNORM:
			case VK_FORMAT_A8B8G8R8_UNORM_PACK32:
			case VK_FORMAT_A8B8G8R8_SRGB_PACK32:
			case VK_FORMAT_A2B10G10R10_UNORM_PACK32:
				for(unsigned int q = 0; q < state.multiSample; q++)
				{
					Pointer<Byte> buffer = cBuffer[index] + q * *Pointer<Int>(data + OFFSET(DrawData, colorSliceB[index]));
					Vector4s color;

					if(format == VK_FORMAT_A1R5G5B5_UNORM_PACK16)
					{
						color.x = UShort4(c[index].x * Float4(0xFBFF), false);
						color.y = UShort4(c[index].y * Float4(0xFBFF), false);
						color.z = UShort4(c[index].z * Float4(0xFBFF), false);
						color.w = UShort4(c[index].w * Float4(0xFFFF), false);
					}
					else if(format == VK_FORMAT_R5G6B5_UNORM_PACK16)
					{
						color.x = UShort4(c[index].x * Float4(0xFBFF), false);
						color.y = UShort4(c[index].y * Float4(0xFDFF), false);
						color.z = UShort4(c[index].z * Float4(0xFBFF), false);
						color.w = UShort4(c[index].w * Float4(0xFFFF), false);
					}
					else
					{
						color.x = convertFixed16(c[index].x, false);
						color.y = convertFixed16(c[index].y, false);
						color.z = convertFixed16(c[index].z, false);
						color.w = convertFixed16(c[index].w, false);
					}

					if(state.multiSampleMask & (1 << q))
					{
						alphaBlend(index, buffer, color, x);
						writeColor(index, buffer, x, color, sMask[q], zMask[q], cMask[q]);
					}
				}
				break;
			case VK_FORMAT_R16_SFLOAT:
			case VK_FORMAT_R16G16_SFLOAT:
			case VK_FORMAT_R16G16B16A16_SFLOAT:
			case VK_FORMAT_R32_SFLOAT:
			case VK_FORMAT_R32G32_SFLOAT:
			case VK_FORMAT_R32G32B32A32_SFLOAT:
			case VK_FORMAT_R32_SINT:
			case VK_FORMAT_R32G32_SINT:
			case VK_FORMAT_R32G32B32A32_SINT:
			case VK_FORMAT_R32_UINT:
			case VK_FORMAT_R32G32_UINT:
			case VK_FORMAT_R32G32B32A32_UINT:
			case VK_FORMAT_R16_SINT:
			case VK_FORMAT_R16G16_SINT:
			case VK_FORMAT_R16G16B16A16_SINT:
			case VK_FORMAT_R16_UINT:
			case VK_FORMAT_R16G16_UINT:
			case VK_FORMAT_R16G16B16A16_UINT:
			case VK_FORMAT_R8_SINT:
			case VK_FORMAT_R8G8_SINT:
			case VK_FORMAT_R8G8B8A8_SINT:
			case VK_FORMAT_R8_UINT:
			case VK_FORMAT_R8G8_UINT:
			case VK_FORMAT_R8G8B8A8_UINT:
			case VK_FORMAT_A8B8G8R8_UINT_PACK32:
			case VK_FORMAT_A8B8G8R8_SINT_PACK32:
			case VK_FORMAT_A2B10G10R10_UINT_PACK32:
				for(unsigned int q = 0; q < state.multiSample; q++)
				{
					Pointer<Byte> buffer = cBuffer[index] + q * *Pointer<Int>(data + OFFSET(DrawData, colorSliceB[index]));
					Vector4f color = c[index];

					if(state.multiSampleMask & (1 << q))
					{
						alphaBlend(index, buffer, color, x);
						writeColor(index, buffer, x, color, sMask[q], zMask[q], cMask[q]);
					}
				}
				break;
			default:
				UNIMPLEMENTED("VkFormat: %d", int(format));
			}
		}
	}

	void PixelProgram::clampColor(Vector4f oC[RENDERTARGETS])
	{
		for(int index = 0; index < RENDERTARGETS; index++)
		{
			if(!state.colorWriteActive(index) && !(index == 0 && state.alphaToCoverage))
			{
				continue;
			}

			switch(state.targetFormat[index])
			{
			case VK_FORMAT_UNDEFINED:
				break;
			case VK_FORMAT_A1R5G5B5_UNORM_PACK16:
			case VK_FORMAT_R5G6B5_UNORM_PACK16:
			case VK_FORMAT_B8G8R8A8_UNORM:
			case VK_FORMAT_B8G8R8A8_SRGB:
			case VK_FORMAT_R8G8B8A8_UNORM:
			case VK_FORMAT_R8G8B8A8_SRGB:
			case VK_FORMAT_R8G8_UNORM:
			case VK_FORMAT_R8_UNORM:
			case VK_FORMAT_R16G16_UNORM:
			case VK_FORMAT_R16G16B16A16_UNORM:
			case VK_FORMAT_A8B8G8R8_UNORM_PACK32:
			case VK_FORMAT_A8B8G8R8_SRGB_PACK32:
			case VK_FORMAT_A2B10G10R10_UNORM_PACK32:
				oC[index].x = Max(oC[index].x, Float4(0.0f)); oC[index].x = Min(oC[index].x, Float4(1.0f));
				oC[index].y = Max(oC[index].y, Float4(0.0f)); oC[index].y = Min(oC[index].y, Float4(1.0f));
				oC[index].z = Max(oC[index].z, Float4(0.0f)); oC[index].z = Min(oC[index].z, Float4(1.0f));
				oC[index].w = Max(oC[index].w, Float4(0.0f)); oC[index].w = Min(oC[index].w, Float4(1.0f));
				break;
			case VK_FORMAT_R32_SFLOAT:
			case VK_FORMAT_R32G32_SFLOAT:
			case VK_FORMAT_R32G32B32A32_SFLOAT:
			case VK_FORMAT_R32_SINT:
			case VK_FORMAT_R32G32_SINT:
			case VK_FORMAT_R32G32B32A32_SINT:
			case VK_FORMAT_R32_UINT:
			case VK_FORMAT_R32G32_UINT:
			case VK_FORMAT_R32G32B32A32_UINT:
			case VK_FORMAT_R16_SFLOAT:
			case VK_FORMAT_R16G16_SFLOAT:
			case VK_FORMAT_R16G16B16A16_SFLOAT:
			case VK_FORMAT_R16_SINT:
			case VK_FORMAT_R16G16_SINT:
			case VK_FORMAT_R16G16B16A16_SINT:
			case VK_FORMAT_R16_UINT:
			case VK_FORMAT_R16G16_UINT:
			case VK_FORMAT_R16G16B16A16_UINT:
			case VK_FORMAT_R8_SINT:
			case VK_FORMAT_R8G8_SINT:
			case VK_FORMAT_R8G8B8A8_SINT:
			case VK_FORMAT_R8_UINT:
			case VK_FORMAT_R8G8_UINT:
			case VK_FORMAT_R8G8B8A8_UINT:
			case VK_FORMAT_A8B8G8R8_UINT_PACK32:
			case VK_FORMAT_A8B8G8R8_SINT_PACK32:
			case VK_FORMAT_A2B10G10R10_UINT_PACK32:
				break;
			default:
				UNIMPLEMENTED("VkFormat: %d", int(state.targetFormat[index]));
			}
		}
	}

	Float4 PixelProgram::linearToSRGB(const Float4 &x)   // Approximates x^(1.0/2.2)
	{
		Float4 sqrtx = Rcp_pp(RcpSqrt_pp(x));
		Float4 sRGB = sqrtx * Float4(1.14f) - x * Float4(0.14f);

		return Min(Max(sRGB, Float4(0.0f)), Float4(1.0f));
	}
}