65 lines
2.3 KiB
Metal
65 lines
2.3 KiB
Metal
//
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// TerrainAlgorithms.metal
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// Terrain2
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//
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// Created by Eryn Wells on 11/4/18.
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// Copyright © 2018 Eryn Wells. All rights reserved.
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//
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#include <metal_stdlib>
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#include <metal_types>
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#include "ShaderTypes.h"
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#include "Random.hh"
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using namespace metal;
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kernel void updateGeometryHeights(texture2d<float> texture [[texture(GeneratorTextureIndexIn)]],
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constant float2 *texCoords [[buffer(GeneratorBufferIndexTexCoords)]],
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constant Uniforms &uniforms [[buffer(GeneratorBufferIndexUniforms)]],
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device packed_float3 *vertexes [[buffer(GeneratorBufferIndexMeshPositions)]],
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uint2 tid [[thread_position_in_grid]])
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{
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constexpr sampler s(coord::normalized, address::clamp_to_zero, filter::linear);
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const uint vIdx = tid.y * uniforms.terrainSegments.x + tid.x;
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// Get the height from the texture.
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float2 texCoord = texCoords[vIdx];
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float4 height = texture.sample(s, texCoord);
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// Update the vertex data.
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vertexes[vIdx].y = height.r;
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}
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kernel void updateGeometryNormals(constant packed_float3 *meshPositions [[buffer(GeneratorBufferIndexMeshPositions)]],
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constant packed_ushort3 *indexes [[buffer(GeneratorBufferIndexIndexes)]],
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device packed_float3 *faceNormals [[buffer(GeneratorBufferIndexFaceNormals)]],
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device packed_float3 *faceMidpoints [[buffer(GeneratorBufferIndexFaceMidpoints)]],
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uint tid [[thread_position_in_grid]])
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{
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const ushort3 triangleIndex = indexes[tid];
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const float3 v1 = meshPositions[triangleIndex.x];
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const float3 v2 = meshPositions[triangleIndex.y];
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const float3 v3 = meshPositions[triangleIndex.z];
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float3 side1 = v1 - v2;
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float3 side2 = v1 - v3;
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float3 normal = normalize(cross(side1, side2));
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faceNormals[tid] = normal;
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faceMidpoints[tid] = (1.0 / 3.0) * (v1 + v2 + v3);
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}
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kernel void updateGeometryVertexNormals()
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{
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}
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#pragma mark - ZeroGenerator
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kernel void zeroKernel(texture2d<float, access::write> outTexture [[texture(GeneratorTextureIndexOut)]],
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uint2 tid [[thread_position_in_grid]])
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{
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outTexture.write(0, tid);
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}
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