Я следил за учебником, сделанным Сэмом Вронски, также известным как. World of Zero (учебник World of Zero), где он кодирует геометрический шейдер. для генератора облака точек травы. Отличный учебник, но мне интересно (и я не нашел подходящего решения после нескольких дней исследований), как я могу реализовать тени для шейдера (отбрасывая и получая тени). Я пытаюсь углубиться в шейдеры, но это пока слишком высокий для меня уровень.
Мой вопрос: как я могу реализовать отбрасывание и получение теней для этого шейдера травы? Код, который существует и работает до сих пор, выглядит следующим образом:
Shader "Custom/GrassGeometryShader" {
// https://www.youtube.com/watch?v=HY6qFbmbij8 und http://www.battlemaze.com/?p=153
Properties {
// --> HDR allows High Dynamic Colors
[HDR]_BackgroundColor ("Background Color", Color) = (1,0,0,1) // default to red
[HDR]_ForegroundColor ("Foreground Color", Color) = (0,1,0,1) // default to green
_MainTex ("Albedo (RGB)", 2D) = "white" {}
_Glossiness ("Smoothness", Range(0,1)) = 0.5
_Metallic ("Metallic", Range(0,1)) = 0.0
_Cutoff("Alpha Cuttoff", Range (0,1)) = 0.15 // Wieviel abgeschnitten sien soll
_GrassHeight("GrasHeight", Float) = 0.25
_GrassWidt("GrasWidth", Float) = 0.25
_WindSpeed ("WindSpeed", Float) = 100
_WindStrength("WindStrength", Float) = 0.05
}
SubShader {
Tags { "RenderType"="Opaque" }
LOD 200
Pass
{
Cull OFF
CGPROGRAM
#include "UnityCG.cginc" // like: "using" in C#
// Vertex-Shader with vert-function
#pragma vertex vert
// Fragment-Shader with frag-function
#pragma fragment frag
// Geometry-Shader with geom-function
#pragma geometry geom
// Use shader model 3.0 target, to get nicer looking lighting
#pragma target 4.0 // needs to be 4.0 !
sampler2D _MainTex;
// vertex to graphics (v2g)
struct v2g
{
float4 pos : SV_POSITION;
float3 norm : NORMAL;
float2 uv : TEXCOORD0;
float3 color : TEXCOORD1;
};
//graphics to fragments (g2f)
struct g2f
{
float4 pos : SV_POSITION;
float3 norm : NORMAL;
float2 uv : TEXCOORD0;
float3 diffuseColor : TEXCOORD1;
//float3 specularColor : TEXCOORD2;
};
half _Glossiness;
half _Metallic;
fixed4 _BackgroundColor;
fixed4 _ForegroundColor;
half _GrassHeight;
half _GrassWidth;
half _Cutoff;
half _WindStrength;
half _WindSpeed;
// Vertex-Shader from Battlemaze.com
v2g vert(appdata_full v)
{
float3 v0 = mul(unity_ObjectToWorld, v.vertex).xyz;
v2g OUT;
OUT.pos = v.vertex;
OUT.norm = v.normal;
OUT.uv = v.texcoord;
OUT.color = tex2Dlod(_MainTex, v.texcoord).rgb;
return OUT;
}
void buldQuad(inout TriangleStream<g2f> triStream, float3 points[4], float3 color) {
g2f OUT;
float3 faceNormal = cross(points[1]-points[0], points[2]-points[0]);
for(int i; i < 4; ++i) {
OUT.pos = UnityObjectToClipPos(points[i]);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(i%2, (int)i/2);
triStream.Append(OUT);
}
triStream.RestartStrip();
}
// geom-Funktion
[maxvertexcount(24)]
void geom(point v2g IN[1], inout TriangleStream<g2f> triStream)
{
float3 lightPosition = _WorldSpaceLightPos0;
float3 perpendicularAngle = float3(0,0,1);
float3 faceNormal = cross(perpendicularAngle, IN[0].norm); // normal of gras
float3 v0 = IN[0].pos.xyz; // Tip of the gras
float3 v1 = IN[0].pos.xyz + IN[0].norm * _GrassHeight; // base of the gras
float3 v2 = IN[0].pos.xyz + IN[0].norm * _GrassHeight / 2; // middle part (?)
float3 wind = float3(sin(_Time.x * _WindSpeed + v0.x) + sin(_Time.x * _WindSpeed + v0.z * 2), 0, cos(_Time.x * _WindSpeed + v0.x * 2) + cos(_Time.x * _WindSpeed + v0.z)); // Anzahl oder Stärke der Manipulation an den Eckpunkten
// (_Time.x + v0.x + v0.z looks "random", because it's using time + coordinates)
v1 += wind * _WindStrength;
v2 += (wind * _WindStrength/2)/2;
float3 color = (IN[0].color); // color of the gras
float sin30 = 0.5;
float sin60 = 0.866f;
float cos30 = sin60;
float cos60 = sin30;
g2f OUT;
// Quad 1 - the following code could fit in one function (BUT!) it did not work on MacOSX, that's why it's still calculated the long way
OUT.pos = UnityObjectToClipPos(v0 + perpendicularAngle * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 + perpendicularAngle * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 - perpendicularAngle * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0 - perpendicularAngle * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
// Quad 2
OUT.pos = UnityObjectToClipPos(v0 + float3(sin60, 0, -cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 + float3(sin60, 0, -cos60)* 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0 - float3(sin60, 0, -cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 - float3(sin60, 0, -cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
// Quad 3 - Positive
OUT.pos = UnityObjectToClipPos(v0 + float3(sin60, 0, cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 + float3(sin60, 0, cos60)* 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0 - float3(sin60, 0, cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 - float3(sin60, 0, cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
}
// Fragment-Shader by Battlemaze.com --> gets input v2g and renders it on screen
half4 frag(g2f IN) : COLOR
{
fixed4 c = tex2D(_MainTex, IN.uv);
clip(c.a - _Cutoff);
return c;
//return float4 (IN.diffuseColor.rgb, 1.0);
}
ENDCG
}
}
}
Как я уже упоминал, я работаю с машиной под управлением MacOS, которая, к сожалению, не работает с вычислительными шейдерами.
Буду признателен за любую помощь в этом.
