// Copyright 2021 Michael Fabian Dirks <info@xaymar.com>
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
//    this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holder nor the names of its contributors
//    may be used to endorse or promote products derived from this software
//    without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

//------------------------------------------------------------------------------
// Defines
//------------------------------------------------------------------------------
// Kernel size as sequential float4's.
#define KERNEL_SIZE 32

//------------------------------------------------------------------------------
// Uniforms
//------------------------------------------------------------------------------
uniform float4x4 ViewProj;
uniform texture2d pImage;
uniform float2 pImageSize;
uniform float2 pImageTexel;
uniform float pSize;
uniform float pSizeInverseMul;
uniform float pAngle;
uniform float2 pCenter;
uniform float2 pStepScale;
uniform float4 pKernel[KERNEL_SIZE];

//------------------------------------------------------------------------------
// Structures
//------------------------------------------------------------------------------
struct VertexInformation {
	float4 pos : POSITION;
	float2 uv  : TEXCOORD0;
};

sampler_state LinearClampSampler {
	Filter = Linear;
	AddressU = Clamp;
	AddressV = Clamp;
	MinLOD = 0;
	MaxLOD = 0;
};

//------------------------------------------------------------------------------
// Functions
//------------------------------------------------------------------------------

VertexInformation VSDefault(VertexInformation vtx) {
	vtx.pos = mul(float4(vtx.pos.xyz, 1.0), ViewProj);
	return vtx;
}

float2 rotate(float2 pt, float angle) {
	float cp = cos(angle);
	float sp = sin(angle);
	float sn = -sp;
	return float2((pt.x * cp) + (pt.y * sn), (pt.x * sp) + (pt.y * cp));
}

float2 rotateAround(float2 pt, float2 cpt, float angle) {
	return rotate(pt - cpt, angle) + cpt;
}

float kernelAt(uint i) {
	return pKernel[i/4u][i%4u];
}