63 lines
2.0 KiB
HLSL
63 lines
2.0 KiB
HLSL
/* Copyright (c) 2024, Sascha Willems
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 the "License";
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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struct VSOutput
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{
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float4 Pos : SV_POSITION;
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[[vk::location(0)]] float3 nearPoint : VECTOR0;
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[[vk::location(1)]] float3 farPoint : VECTOR1;
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[[vk::location(2)]] float4x4 view : MATRIX0;
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[[vk::location(6)]] float4x4 projection : MATRIX1;
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};
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float4 grid(float3 pos) {
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float2 coord = pos.xz;
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float2 derivative = fwidth(coord);
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float2 grid = abs(frac(coord - 0.5) - 0.5) / derivative;
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float _line = min(grid.x, grid.y);
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float minimumz = min(derivative.y, 1);
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float minimumx = min(derivative.x, 1);
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float4 color = float4(0.5, 0.5, 0.5, 1.0 - min(_line, 1.0));
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if(abs(pos.x) < minimumx)
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color.y = 1;
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if(abs(pos.z) < minimumz)
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color.x = 1;
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return color;
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}
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float fadeFactor(float3 pos, VSOutput input) {
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float z = mul(input.projection, mul(input.view, float4(pos.xyz, 1.0))).z;
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// Empirical values are used to determine when to cut off the grid before moire patterns become visible.
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return z * 6 - 0.5;
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}
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float4 main(VSOutput input) : SV_TARGET0
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{
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float t = -input.nearPoint.y / (input.farPoint.y - input.nearPoint.y);
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float3 pos = input.nearPoint + t * (input.farPoint - input.nearPoint);
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// Display only the lower plane
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if(t < 1.0) {
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float4 gridColor = grid(pos);
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return float4(gridColor.xyz, gridColor.w * fadeFactor(pos, input));
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}
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else {
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return float4(0.0, 0.0, 0.0, 0.0);
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}
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}
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