anki-3d-engine/AnKi/Shaders/DepthDownscaleRaster.ankiprog

// Copyright (C) 2009-2022, Panagiotis Christopoulos Charitos and contributors.
// All rights reserved.
// Code licensed under the BSD License.
// http://www.anki3d.org/LICENSE

#pragma anki mutator REDUCTION_SAMPLER 0 1

#pragma anki start vert
#include <AnKi/Shaders/QuadVert.glsl>
#pragma anki end

#pragma anki start frag
#include <AnKi/Shaders/Common.glsl>

layout(location = 0) in Vec2 in_uv;
layout(location = 0) out F32 out_depth;

layout(set = 0, binding = 0) uniform texture2D u_inputTex;
layout(set = 0, binding = 1) uniform sampler u_sampler;

layout(std430, set = 0, binding = 2) writeonly buffer b_cb
{
	F32 u_clientBuf[];
};

layout(push_constant, std140) uniform b_pc
{
	Vec3 u_padding;
	U32 u_lastMipWidth;
};

void main()
{
#if !REDUCTION_SAMPLER
	out_depth = textureLod(u_inputTex, u_sampler, in_uv, 0.0).x;
#else
	const Vec4 depths = textureGather(sampler2D(u_inputTex, u_sampler), in_uv, 0);
	out_depth = max(depths.x, max(depths.y, max(depths.z, depths.w)));
#endif

	if(u_lastMipWidth != 0u)
	{
		const UVec2 p = UVec2(gl_FragCoord.xy);
		const U32 idx = p.y * u_lastMipWidth + p.x;
		u_clientBuf[idx] = out_depth;
	}
}
#pragma anki end