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| Shader "MathematicalVisualizationArt/MyLearning09"
{
Properties
{
}
SubShader
{
Tags{"RenderType" = "Transparent" "RenderPipeline" = "UniversalRenderPipeline" "IgnoreProjector" = "True"}
LOD 300
Pass
{
Name "DefaultPass"
HLSLPROGRAM
struct Attributes
{
float4 positionOS : POSITION;
float2 uv : TEXCOORD0;
};
struct Varyings
{
float2 uv : TEXCOORD0;
float4 positionCS : SV_POSITION;
float4 screenPos : TEXCOORD1;
};
Varyings vert (Attributes input)
{
Varyings output = (Varyings)0;
VertexPositionInputs vertexInput = GetVertexPositionInputs(input.positionOS.xyz);
output.uv = input.uv;
output.positionCS = vertexInput.positionCS;
output.screenPos = ComputeScreenPos(vertexInput.positionCS);
return output;
}
// 一、定义数据
// 二、定义三维几何体sdf
// 球体sdf
float sdSphere( float3 p, float r )
{
return length(p)-r;
}
// 平面sdf
float sdPlane( float3 p, float3 n, float h )
{
// n must be normalized
n = normalize(n);
return dot(p,n) + h;
}
// 圆环sdf
float sdTorus( float3 p, float2 t )
{
float2 q = float2(length(p.xz)-t.x,p.y);
return length(q)-t.y;
}
// 圆锥sdf
float sdCone( float3 p, float2 c, float h )
{
// c is the sin/cos of the angle, h is height
// Alternatively pass q instead of (c,h),
// which is the point at the base in 2D
float2 q = h*float2(c.x/c.y,-1.0);
float2 w = float2( length(p.xz), p.y );
float2 a = w - q*clamp( dot(w,q)/dot(q,q), 0.0, 1.0 );
float2 b = w - q*float2( clamp( w.x/q.x, 0.0, 1.0 ), 1.0 );
float k = sign( q.y );
float d = min(dot( a, a ),dot(b, b));
float s = max( k*(w.x*q.y-w.y*q.x),k*(w.y-q.y) );
return sqrt(d)*sign(s);
}
// 圆角盒sdf
float sdRoundBox( float3 p, float3 b, float r )
{
float3 q = abs(p) - b;
return length(max(q,0.0)) + min(max(q.x,max(q.y,q.z)),0.0) - r;
}
// scene sdf
// 用于计算CSG几何运算后的场景结果
float sdScene(float3 p)
{
//定义球体
float3 spherePos = float3(1.5, 1.0, 0.0);
float sphereRadius = 1.0;
float3 sphereNormal = normalize( p - spherePos );
//定义圆角盒
float3 boxPos = float3(-1.5, 0.5, 0.0);
float3 boxSize = float3(1.0, 0.5, 0.5);
float boxRadius = 0.1;
//定义圆环
float3 torusPos = float3(5.0, 1.0, 0.0);
float2 torusRadius = float2(0.8, 0.3);
//定义圆锥
float3 conePos = float3(-5.0, 2.0, 0.0);
float2 coneRadius = float2(0.1, 0.3);
float coneHeight = 2.0;
//定义平面
float3 planePos = float3(0.0, 0.0, 0.0);
float3 planeNormal = float3(0.0, 1.0, 0.0);
//求交集
float sphereDist = sdSphere(p - spherePos, sphereRadius);
float torusDist = sdTorus(p - torusPos, torusRadius);
float coneDist = sdCone(p - conePos, coneRadius, coneHeight);
float planeDist = sdPlane(p - planePos, planeNormal, 0.0);
float boxDist = sdRoundBox(p - boxPos, boxSize, boxRadius);
return min(min(min(min(sphereDist, boxDist),coneDist),torusDist),planeDist);
}
// RayMarch, 用于计算光线与物体的交点
// 输入分别是摄像机位置与光线方向
float RayMarch(float3 ro, float3 rd)
{
float depth = 0.0;
for(int i = 0; i < MAX_MARCHING_STEPS; i++)
{
float3 p = ro + rd*depth;
float dist = sdScene(p);
depth+=dist;
if(depth > MAX_DIST || dist < MIN_DIST)
break;
}
return depth;
}
half3 PixelColor(float2 uv)
{
half3 c = half3(0, 0, 0);
//
float uvSizeScale = 1;
//四象限转一象限
uv.y = 1.0- uv.y;
//全象限 (-5, 5)
uv = (uv*2.0 -1.0)*uvSizeScale;
//消除屏幕拉伸影响
half co = width/height;
uv = float2(uv.x*co, uv.y);
// 根据摄像机位置与uv坐标计算出光线方向
//定义摄像机
float3 camPos = float3(0.0, 1.0, -5.0);
float3 lightDir = normalize(float3(uv, 1.0));
float dist = RayMarch(camPos, lightDir); // 步进距离总和（深度）
c = half3(dist/(20-time), dist/(20-time), dist/(20-time));
return c;
}
half4 frag(Varyings input) : SV_Target
{
float2 screenUV = GetNormalizedScreenSpaceUV(input.positionCS);
screenUV = screenUV * float2(1.0, -1.0) + float2(0.0, 1.0);
half3 col = Gamma22ToLinear(PixelColor(screenUV));
return half4(col, 1);
}
ENDHLSL
}
}
}
|
