यूनिटी इंजन में ग्रास शैडर बनाना

आवश्यकताओं

काम पर लगना

1. जियोमेट्रिक शेड्स

 // Add inside the CGINCLUDE block. struct geometryOutput { float4 pos : SV_POSITION; }; [maxvertexcount(3)] void geo(triangle float4 IN[3] : SV_POSITION, inout TriangleStream<geometryOutput> triStream) { } … // Add inside the SubShader Pass, just below the #pragma fragment frag line. #pragma geometry geo 

 void geo(point vertexOutput IN[1], inout TriangleStream<geometryOutput> triStream) 

 geometryOutput o; o.pos = float4(0.5, 0, 0, 1); triStream.Append(o); o.pos = float4(-0.5, 0, 0, 1); triStream.Append(o); o.pos = float4(0, 1, 0, 1); triStream.Append(o); 

 // Update the return call in the vertex shader. //return UnityObjectToClipPos(vertex); return vertex; … // Update each assignment of o.pos in the geometry shader. o.pos = UnityObjectToClipPos(float4(0.5, 0, 0, 1)); … o.pos = UnityObjectToClipPos(float4(-0.5, 0, 0, 1)); … o.pos = UnityObjectToClipPos(float4(0, 1, 0, 1)); 

 // Add to the top of the geometry shader. float3 pos = IN[0]; … // Update each assignment of o.pos. o.pos = UnityObjectToClipPos(pos + float3(0.5, 0, 0)); … o.pos = UnityObjectToClipPos(pos + float3(-0.5, 0, 0)); … o.pos = UnityObjectToClipPos(pos + float3(0, 1, 0)); 

कुछ कोने त्रिकोण क्यों नहीं बनाते हैं?

यद्यपि हमने यह निर्धारित किया है कि आने वाली आदिम एक त्रिकोण होगी, त्रिकोण के एक बिंदु से केवल घास का एक ब्लेड प्रेषित होता है, अन्य दो को त्याग देता है। बेशक, हम आने वाले तीन बिंदुओं से घास के एक ब्लेड को स्थानांतरित कर सकते हैं, लेकिन यह इस तथ्य को जन्म देगा कि पड़ोसी त्रिकोण एक दूसरे के ऊपर घास के ब्लेड को अत्यधिक बनाते हैं।

या आप इस समस्या को ज्योमेट्रिक शेडर के इनकमिंग मेश के रूप में टोपोलॉजी पॉइंट्स के प्रकार होने से हल कर सकते हैं।

2. स्पर्शरेखा स्थान

 // Add to the CGINCLUDE block. struct vertexInput { float4 vertex : POSITION; float3 normal : NORMAL; float4 tangent : TANGENT; }; struct vertexOutput { float4 vertex : SV_POSITION; float3 normal : NORMAL; float4 tangent : TANGENT; }; … // Modify the vertex shader. vertexOutput vert(vertexInput v) { vertexOutput o; o.vertex = v.vertex; o.normal = v.normal; o.tangent = v.tangent; return o; } … // Modify the input for the geometry shader. Note that the SV_POSITION semantic is removed. void geo(triangle vertexOutput IN[3], inout TriangleStream<geometryOutput> triStream) … // Modify the existing line declaring pos. float3 pos = IN[0].vertex; 

 // Place in the geometry shader, below the line declaring float3 pos. float3 vNormal = IN[0].normal; float4 vTangent = IN[0].tangent; float3 vBinormal = cross(vNormal, vTangent) * vTangent.w; 

 // Add below the lines declaring the three vectors. float3x3 tangentToLocal = float3x3( vTangent.x, vBinormal.x, vNormal.x, vTangent.y, vBinormal.y, vNormal.y, vTangent.z, vBinormal.z, vNormal.z ); 

 // Add to the CGINCLUDE block. geometryOutput VertexOutput(float3 pos) { geometryOutput o; o.pos = UnityObjectToClipPos(pos); return o; } … // Remove the following from the geometry shader. //geometryOutput o; //o.pos = UnityObjectToClipPos(pos + float3(0.5, 0, 0)); //triStream.Append(o); //o.pos = UnityObjectToClipPos(pos + float3(-0.5, 0, 0)); //triStream.Append(o); //o.pos = UnityObjectToClipPos(pos + float3(0, 1, 0)); //triStream.Append(o); // ...and replace it with the code below. triStream.Append(VertexOutput(pos + float3(0.5, 0, 0))); triStream.Append(VertexOutput(pos + float3(-0.5, 0, 0))); triStream.Append(VertexOutput(pos + float3(0, 1, 0))); 

 triStream.Append(VertexOutput(pos + mul(tangentToLocal, float3(0.5, 0, 0)))); triStream.Append(VertexOutput(pos + mul(tangentToLocal, float3(-0.5, 0, 0)))); triStream.Append(VertexOutput(pos + mul(tangentToLocal, float3(0, 1, 0)))); 

 // Modify the position of the third vertex being emitted. triStream.Append(VertexOutput(pos + mul(tangentToLocal, float3(0, 0, 1)))); 

3. घास का दिखना

3.1 रंग ढाल

 // Add to the geometryOutput struct. float2 uv : TEXCOORD0; … // Modify the VertexOutput function signature. geometryOutput VertexOutput(float3 pos, float2 uv) … // Add to VertexOutput, just below the line assigning o.pos. o.uv = uv; … // Modify the existing lines in the geometry shader. triStream.Append(VertexOutput(pos + mul(tangentToLocal, float3(0.5, 0, 0)), float2(0, 0))); triStream.Append(VertexOutput(pos + mul(tangentToLocal, float3(-0.5, 0, 0)), float2(1, 0))); triStream.Append(VertexOutput(pos + mul(tangentToLocal, float3(0, 0, 1)), float2(0.5, 1))); 

 // Modify the function signature of the fragment shader. float4 frag (geometryOutput i, fixed facing : VFACE) : SV_Target … // Replace the existing return call. return float4(1, 1, 1, 1); return lerp(_BottomColor, _TopColor, i.uv.y); 

3.2 रैंडम ब्लेड दिशा

 // Add below the line declaring the tangentToLocal matrix. float3x3 facingRotationMatrix = AngleAxis3x3(rand(pos) * UNITY_TWO_PI, float3(0, 0, 1)); 

 // Add below the line declaring facingRotationMatrix. float3x3 transformationMatrix = mul(tangentToLocal, facingRotationMatrix); … // Replace the multiplication matrix operand with our new transformationMatrix. triStream.Append(VertexOutput(pos + mul(transformationMatrix, float3(0.5, 0, 0)), float2(0, 0))); triStream.Append(VertexOutput(pos + mul(transformationMatrix, float3(-0.5, 0, 0)), float2(1, 0))); triStream.Append(VertexOutput(pos + mul(transformationMatrix, float3(0, 0, 1)), float2(0.5, 1))); 

3.3 बेतरतीब आगे झुकना

 // Add as a new property. _BendRotationRandom("Bend Rotation Random", Range(0, 1)) = 0.2 … // Add to the CGINCLUDE block. float _BendRotationRandom; … // Add to the geometry shader, below the line declaring facingRotationMatrix. float3x3 bendRotationMatrix = AngleAxis3x3(rand(pos.zzx) * _BendRotationRandom * UNITY_PI * 0.5, float3(-1, 0, 0)); 

 // Modify the existing line. float3x3 transformationMatrix = mul(mul(tangentToLocal, facingRotationMatrix), bendRotationMatrix); 

३.४ चौड़ाई और ऊँचाई

 // Add as new properties. _BladeWidth("Blade Width", Float) = 0.05 _BladeWidthRandom("Blade Width Random", Float) = 0.02 _BladeHeight("Blade Height", Float) = 0.5 _BladeHeightRandom("Blade Height Random", Float) = 0.3 … // Add to the CGINCLUDE block. float _BladeHeight; float _BladeHeightRandom; float _BladeWidth; float _BladeWidthRandom; … // Add to the geometry shader, above the triStream.Append calls. float height = (rand(pos.zyx) * 2 - 1) * _BladeHeightRandom + _BladeHeight; float width = (rand(pos.xzy) * 2 - 1) * _BladeWidthRandom + _BladeWidth; … // Modify the existing positions with our new height and width. triStream.Append(VertexOutput(pos + mul(transformationMatrix, float3(width, 0, 0)), float2(0, 0))); triStream.Append(VertexOutput(pos + mul(transformationMatrix, float3(-width, 0, 0)), float2(1, 0))); triStream.Append(VertexOutput(pos + mul(transformationMatrix, float3(0, 0, height)), float2(0.5, 1))); 

4. टेशन

 // Add inside the CGINCLUDE block, below the other #include statements. #include "Shaders/CustomTessellation.cginc" 

 /*struct vertexInput { float4 vertex : POSITION; float3 normal : NORMAL; float4 tangent : TANGENT; }; struct vertexOutput { float4 vertex : SV_POSITION; float3 normal : NORMAL; float4 tangent : TANGENT; }; vertexOutput vert(vertexInput v) { vertexOutput o; o.vertex = v.vertex; o.normal = v.normal; o.tangent = v.tangent; return o; }*/ 

 // Add as a new property. _TessellationUniform("Tessellation Uniform", Range(1, 64)) = 1 … // Add below the other #pragma statements in the SubShader Pass. #pragma hull hull #pragma domain domain 

5. हवा

 // Add as new properties. _WindDistortionMap("Wind Distortion Map", 2D) = "white" {} _WindFrequency("Wind Frequency", Vector) = (0.05, 0.05, 0, 0) … // Add to the CGINCLUDE block. sampler2D _WindDistortionMap; float4 _WindDistortionMap_ST; float2 _WindFrequency; … // Add to the geometry shader, just above the line declaring the transformationMatrix. float2 uv = pos.xz * _WindDistortionMap_ST.xy + _WindDistortionMap_ST.zw + _WindFrequency * _Time.y; 

 // Add as a new property. _WindStrength("Wind Strength", Float) = 1 … // Add to the CGINCLUDE block. float _WindStrength; … // Add below the line declaring float2 uv. float2 windSample = (tex2Dlod(_WindDistortionMap, float4(uv, 0, 0)).xy * 2 - 1) * _WindStrength; 

 // Add below the line declaring float2 windSample. float3 wind = normalize(float3(windSample.x, windSample.y, 0)); 

 // Add below the line declaring float3 wind. float3x3 windRotation = AngleAxis3x3(UNITY_PI * windSample, wind); … // Modify the existing line. float3x3 transformationMatrix = mul(mul(mul(tangentToLocal, windRotation), facingRotationMatrix), bendRotationMatrix); 

 // Add below the line declaring float3x3 transformationMatrix. float3x3 transformationMatrixFacing = mul(tangentToLocal, facingRotationMatrix); … // Modify the existing lines outputting the base vertex positions. triStream.Append(VertexOutput(pos + mul(transformationMatrixFacing, float3(width, 0, 0)), float2(0, 0))); triStream.Append(VertexOutput(pos + mul(transformationMatrixFacing, float3(-width, 0, 0)), float2(1, 0))); 

6. घास के ब्लेड की वक्रता

 // Add to the CGINCLUDE block. #define BLADE_SEGMENTS 3 … // Modify the existing line defining the maxvertexcount. [maxvertexcount(BLADE_SEGMENTS * 2 + 1)] 

 geometryOutput GenerateGrassVertex(float3 vertexPosition, float width, float height, float2 uv, float3x3 transformMatrix) { float3 tangentPoint = float3(width, 0, height); float3 localPosition = vertexPosition + mul(transformMatrix, tangentPoint); return VertexOutput(localPosition, uv); } 

 // Update the existing code outputting the vertices. triStream.Append(GenerateGrassVertex(pos, width, 0, float2(0, 0), transformationMatrixFacing)); triStream.Append(GenerateGrassVertex(pos, -width, 0, float2(1, 0), transformationMatrixFacing)); triStream.Append(GenerateGrassVertex(pos, 0, height, float2(0.5, 1), transformationMatrix)); 

 for (int i = 0; i < BLADE_SEGMENTS; i++) { float t = i / (float)BLADE_SEGMENTS; } 

 // Add below the line declaring float t. float segmentHeight = height * t; float segmentWidth = width * (1 - t); 

 // Add below the line declaring float segmentWidth. float3x3 transformMatrix = i == 0 ? transformationMatrixFacing : transformationMatrix; triStream.Append(GenerateGrassVertex(pos, segmentWidth, segmentHeight, float2(0, t), transformMatrix)); triStream.Append(GenerateGrassVertex(pos, -segmentWidth, segmentHeight, float2(1, t), transformMatrix)); … // Add just below the loop to insert the vertex at the tip of the blade. triStream.Append(GenerateGrassVertex(pos, 0, height, float2(0.5, 1), transformationMatrix)); … // Remove the existing calls to triStream.Append. //triStream.Append(GenerateGrassVertex(pos, width, 0, float2(0, 0), transformationMatrixFacing)); //triStream.Append(GenerateGrassVertex(pos, -width, 0, float2(1, 0), transformationMatrixFacing)); //triStream.Append(GenerateGrassVertex(pos, 0, height, float2(0.5, 1), transformationMatrix)); 

 // Update the function signature of GenerateGrassVertex. geometryOutput GenerateGrassVertex(float3 vertexPosition, float width, float height, float forward, float2 uv, float3x3 transformMatrix) … // Modify the Y coordinate assignment of tangentPoint. float3 tangentPoint = float3(width, forward, height); 

 // Add as new properties. _BladeForward("Blade Forward Amount", Float) = 0.38 _BladeCurve("Blade Curvature Amount", Range(1, 4)) = 2 … // Add to the CGINCLUDE block. float _BladeForward; float _BladeCurve; … // Add inside the geometry shader, below the line declaring float width. float forward = rand(pos.yyz) * _BladeForward; … // Add inside the loop, below the line declaring segmentWidth. float segmentForward = pow(t, _BladeCurve) * forward; … // Modify the GenerateGrassVertex calls inside the loop. triStream.Append(GenerateGrassVertex(pos, segmentWidth, segmentHeight, segmentForward, float2(0, t), transformMatrix)); triStream.Append(GenerateGrassVertex(pos, -segmentWidth, segmentHeight, segmentForward, float2(1, t), transformMatrix)); … // Modify the GenerateGrassVertex calls outside the loop. triStream.Append(GenerateGrassVertex(pos, 0, height, forward, float2(0.5, 1), transformationMatrix)); 

7. प्रकाश और छाया

7.1 कास्टिंग छाया

 // Add below the existing Pass. Pass { Tags { "LightMode" = "ShadowCaster" } CGPROGRAM #pragma vertex vert #pragma geometry geo #pragma fragment frag #pragma hull hull #pragma domain domain #pragma target 4.6 #pragma multi_compile_shadowcaster float4 frag(geometryOutput i) : SV_Target { SHADOW_CASTER_FRAGMENT(i) } ENDCG } 

7.2 छाया प्राप्त करना

 // Add to the geometryOutput struct. unityShadowCoord4 _ShadowCoord : TEXCOORD1; … // Add to the VertexOutput function, just above the return call. o._ShadowCoord = ComputeScreenPos(o.pos); 

 #define SHADOW_ATTENUATION(a) unitySampleShadow(a._ShadowCoord) 

 // Add to the ForwardBase pass's fragment shader, replacing the existing return call. return SHADOW_ATTENUATION(i); //return lerp(_BottomColor, _TopColor, i.uv.y); 

 // Add to the ForwardBase pass's preprocessor directives, below #pragma target 4.6. #pragma multi_compile_fwdbase 

 // Add at the end of the VertexOutput function, just above the return call. #if UNITY_PASS_SHADOWCASTER // Applying the bias prevents artifacts from appearing on the surface. o.pos = UnityApplyLinearShadowBias(o.pos); #endif 

घास के छायांकित ब्लेड के किनारों के साथ कलाकृतियां क्यों हैं?

(multisample anti-aliasing MSAA ) Unity , . , .

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Lighting.३ प्रकाश

 // Add to the GenerateGrassVertex function, belowing the line declaring tangentPoint. float3 tangentNormal = float3(0, -1, 0); float3 localNormal = mul(transformMatrix, tangentNormal); 

 // Modify the return call in GenerateGrassVertex. return VertexOutput(localPosition, uv, localNormal); … // Add to the geometryOutput struct. float3 normal : NORMAL; … // Modify the existing function signature. geometryOutput VertexOutput(float3 pos, float2 uv, float3 normal) … // Add to the VertexOutput function to pass the normal through to the fragment shader. o.normal = UnityObjectToWorldNormal(normal); 

 // Add to the ForwardBase fragment shader. float3 normal = facing > 0 ? i.normal : -i.normal; return float4(normal * 0.5 + 0.5, 1); // Remove the existing return call. //return SHADOW_ATTENUATION(i); 

 // Modify the existing line in GenerateGrassVertex. float3 tangentNormal = normalize(float3(0, -1, forward)); 

 // Add to the ForwardBase fragment shader, below the line declaring float3 normal. float shadow = SHADOW_ATTENUATION(i); float NdotL = saturate(saturate(dot(normal, _WorldSpaceLightPos0)) + _TranslucentGain) * shadow; float3 ambient = ShadeSH9(float4(normal, 1)); float4 lightIntensity = NdotL * _LightColor0 + float4(ambient, 1); float4 col = lerp(_BottomColor, _TopColor * lightIntensity, i.uv.y); return col; // Remove the existing return call. //return float4(normal * 0.5 + 0.5, 1); 

निष्कर्ष

जोड़: सहयोग