Differences

This shows you the differences between two versions of the page.

--- 1.1.0:water [2023/10/25 08:08] – [Water] admin
+++ 1.1.0:water [2024/01/23 08:23] (current) – [Example] admin
@@ Line 20: / Line 20: @@
 The plane is a simple and opaque instance of TGorillaPlane or TPlane. It will be used as basis mesh to render water onto.
+Using a none planar object is not recommended, because reflection and refraction computation is based on plane models.
 ==== Refraction ====
@@ Line 32: / Line 34: @@
 FRefraction.IgnoreControl(FWaterPlane);
 </file>
 The water surface would be black, because it's image information will be computed in main render pass first.
+Because the refraction pass should render from a certain position, we have to adjust the surface position to the current water plane position everytime it changes:
+<file pascal>
+  // set the current position of the water plane as surface plane
+  // this needs to be updated, if water plane moves
+  FRefraction.SurfacePosition.Point := TPoint3D(FWaterPlane.AbsolutePosition);
+</file>
 ==== Reflection ====
@@ Line 52: / Line 62: @@
   // set the current position of the water plane as mirror plane
   // this needs to be updated, if water plane moves
-  FReflection.MirrorPosition := TPoint3D(FWaterPlane.AbsolutePosition);
+  FReflection.MirrorPosition.Point := TPoint3D(FWaterPlane.AbsolutePosition);
 </file>
 In case plane size or position changes, you have to update those values in reflection pass.
+==== Displacement ====
+Our water shader supports displacement mapping to render waves. This manipulates vertex position in the vertex shader.
+To use displacement mapping, apply a tetxure to the "DisplacementMap" property and configure the intensity of waves by
+the "DisplIntensity" property of your material source.
+When working with displacement mapping, vertices getting shifted. This leads to offsets in refraction and reflection, because
+in those render passes we rendered with different information.
+Therefor you have to adjust the reflection mirror position and refraction surface position by the "DisplIntensity" value:
+<file pascal>
+  FReflection.MirrorPosition.Point := TPoint3D(FWaterPlane.AbsolutePosition) +
+    Point3D(0, -FWaterMaterial.DisplIntensity, 0);
+  FRefraction.SurfacePosition.Point := TPoint3D(FWaterPlane.AbsolutePosition) +
+    Point3D(0, -FWaterMaterial.DisplIntensity, 0);
+</file>
 ==== Water Material ====
@@ Line 138: / Line 166: @@
 end;
 </file>
+Ripple computation in the vertex shader is embedded inside our water shader program.
+In case you'll need additional handling in the fragment shader, you could a code snippet like that.
+<file Pascal>
+var LStr := TStringList.Create();
+try
+  LStr.Text :=
+	'''
+	  void SurfaceShader(inout TLocals DATA){
+		float l_TotalRippleEffect = 0.0;
+		float l_Time = abs(_TimeInfo.w);
+		vec3 l_TransfVertexPos = DATA.TransfVertPos.xyz;
+		for(int i = 0; i < int(_RippleCount); i++){
+		  float l_RippleDist = distance(l_TransfVertexPos.xz, _Ripples[i].xz);
+		  float l_RippleTime = abs((_TimeInfo.x + l_Time) - _Ripples[i].w);
+		  float l_TimeLimit = clamp(1.0 / (l_RippleTime / (_RippleProximity * _RippleDecay)), 0.0, 1.0);
+		  float l_RippleEffect = (-_RippleAmplification * exp(_RippleDecay * - l_RippleDist));
+		  l_RippleEffect *= cos(_RippleProximity * (l_RippleDist - l_RippleTime));
+		  l_RippleEffect *= l_TimeLimit;
+		  l_TotalRippleEffect += exp(-l_RippleDist) * sin(0.5 * l_RippleDist) * l_RippleEffect;
+		}
+		if(l_TotalRippleEffect > 0.01){
+		  vec4 l_BoatTrail = tex2D(_WaterShore, DATA.TexCoord0.xy);
+		  DATA.BaseColor.rgb += vec3(l_BoatTrail.rgb * l_TotalRippleEffect);
+		  DATA.SumColor.rgb += vec3(l_BoatTrail.rgb * l_TotalRippleEffect);
+		}
+	  }
+	''';
+  FWaterMat.SurfaceShader := LStr;
+finally
+  LStr.Free;
+end;
+</file>
+This snippet will render the water shore texture onto the ripples if they have a minimum size of 0.01.
+===== Tutorial =====
+{{youtube>bIXeUcTrd58}}
 ===== Example =====