Differences

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--- 0.8.3:volumerendering [2021/03/03 15:21] – [Slicing] admin
+++ 0.8.3:volumerendering [2022/04/08 10:06] (current) – [Gamut Mapping] admin
@@ Line 17: / Line 17: @@
   * Different render shapes: cube, sphere, cylinder
   * Changable ray front and back limit
+  * Managable ray step detail
   * Clipping plane support for optimal slicing
   * RAW file support
@@ Line 103: / Line 104: @@
 |TGorillaVolumetricMeshShape.vmsCylinder |Will set up a static cylinder mesh.|
-==== Upload Data ====
+==== Details ====
+TGorillaVolumetricMesh provides a "Details" property, which allows users to control raymarching algorithm.
+The details value increases or decreases ray steps when marching through the 3D volume data.
+This will have direct effect on the number of rendered slices and also on the produced color.
+Sometimes its necessary to have more performance, so lower detail may be a solution.
+==== RayLimits ====
+Besides "[[#Slicing|Slicing]]" technique users can also manipulate ray cast offsets.
+By reducing or increasing the so called "RayLimits".
+This is an optimization to reduce marching algorithm in shader and can improve efficiency.
+__NOTICE:__ But carefully, if setting limits to low or to high it may cause slicing in view direction.
+===== Upload Data =====
 TGorillaVolumetricMesh provides two file formats.
@@ Line 110: / Line 129: @@
   * NRRD File
-=== RAW File ===
+==== RAW File ====
 When uploading 3D data to the volumetric mesh, you can use the direct RAW data upload method.
@@ Line 126: / Line 145: @@
 </file>
-=== NRRD File ===
+==== NRRD File ====
 When uploading 3D from a NRRD file, you don't need further parameters. The method will automatically
@@ Line 135: / Line 154: @@
 </file>
+You can setup a NRRD header yourself in case you have only a RAW file.
+Just add some similar code at the beginning of your file:
+<code>
+NRRD0001
+content: "My NRRD File"
+type: unsigned char
+dimension: 3
+sizes: 256 256 256
+spacings: 1 1 1
+encoding: raw
+[... RAW DATA ...]
+</code>
+__NOTICE:__ **LF** and **CRLF** are supported as line endings.
+==== Procedural Data ====
+You can of course fill the 3D data array also manually.
+Pushing data to the 3D-texture by UpdateBuffer() expects to fill data correctly. Otherwise exception may occur.
+You have to take care of the 3D-texture size by the "Sizes" property of the component and the configured "DataType".
+In the following a simple code snippet showing a procedure to fill a 512 x 512 x 512 with 4-Byte float values.
+<file pascal>
+uses Gorilla.Material.Types, Gorilla.Context.Texturing;
+TMyVolumetricMesh = class(TGorillaVolumetricMesh)
+  procedure RandomFill();
+end;
+{...}
+procedure TMyVolumetricMesh.RandomFill();
+var LTex    : TGorillaTextureBitmap;
+    LData   : TBytes;
+    LDPtr   : PSingle; // vmdtFloat !!!
+    LValue  : Byte;
+    LOfs,
+    w, h, d : Integer;
+    LSizeF  : TPoint3D;
+    LSizeI  : record
+                X : Integer;
+                Y : Integer;
+                Z : Integer;
+              end;
+    LFSize,
+    LDSize  : Integer;
+begin
+  Self.Sizes := TGorillaVolumetricMeshSize.vms512x512x512;
+  Self.DataType := vmdtFloat; /// !!!
+  // get size in fragments
+  LSizeF := Self.GetSizeAsVector();
+  LSizeI.X := Round(LSizeF.X);
+  LSizeI.Y := Round(LSizeF.Y);
+  LSizeI.Z := Round(LSizeF.Z);
+  LFSize := GORILLA_VOLUMETRIC_MESH_DATASIZE[Self.DataType];
+  // create data array
+  LDSize := LSizeI.X * LSizeI.Y * LSizeI.Z * LFSize;
+  System.SetLength(LData, LDSize);
+  try
+    LDPtr := @LData[0];
+    // fill data with perlin noise
+    for w := 0 to (LSizeI.X - 1) do
+    begin
+      for h := 0 to (LSizeI.Y - 1) do
+      begin
+        for d := 0 to (LSizeI.Z - 1) do
+        begin
+          // NOTICE: MAYBE THE VALUE NEED TO BE IN REVERSED BYTE ORDER!
+          LDPtr^ := Single(RandomRange(0, 10000) / 10000);
+          Inc(LDPtr);
+      end;
+    end;
+    // push data to 3D texture
+    LTex := TGorillaVolumetricMeshMaterialSource(FMaterial).Texture as TGorillaTextureBitmap;
+    LTex.UpdateBuffer(LData, LDSize);
+  finally
+    System.SetLength(LData, 0);
+  end;
+end;
+</file>
 ===== Scene Setup =====
@@ Line 230: / Line 338: @@
 </file>
+===== Gamut Mapping =====
+Gamut is a colored texture to define how 3D values will be colored.
+Since 0.8.3.2265 this feature is available.
+Here an example of a simple gradient gamut texture:
+{{:0.8.3:gamut.jpg?nolink|}}
+TGorillaVolumetricMesh allows to configure the coloring method by some properties:
+^Property^Description^
+|Gamut|Texture used for mapping the 3D value during Raytracing|
+|GamutMode|Defines when and how the value-color mapping happens. Here different modes are available: GamutNone, GamutByValue, GamutByValueMultiply, GamutBySum, GamutBySumMultiply|
+|GamutFactor|A factor applied to the absolute 3D value before mapping onto the gamut texture (default value is 1.0)|
+=== Modes ===
+The available gamut modes allow to control the output of color mapping.
+^Mode^Description^
+|GamutNone|Gamut mapping is disabled|
+|GamutByValue|Gamut mapping will be applied to each 3D value on the casted ray.|
+|GamutByValueMultiply|Gamut mapping will be applied to each 3D value on the casted ray and afterwards multiplied with the previously computed color value.|
+|GamutBySum|Gamut mapping will be applied to the final casted ray value.|
+|GamutBySumMultiply|Gamut mapping will be applied to the final casted ray value and afterwards multiplied with the previously computed color value.|
+Next step: [[particles|Particles]]