From 137d531ca5128563f2c1a167684cb1035a34a6bc Mon Sep 17 00:00:00 2001
From: ouv <ouv@opencascade.com>
Date: Mon, 10 Oct 2005 16:24:51 +0000
Subject: [PATCH] Hue parameter computing.

---
 src/PIPELINE/VISU_OpenGLPointSpriteMapper.cxx | 68 +++++++++++++++----
 1 file changed, 54 insertions(+), 14 deletions(-)

diff --git a/src/PIPELINE/VISU_OpenGLPointSpriteMapper.cxx b/src/PIPELINE/VISU_OpenGLPointSpriteMapper.cxx
index 0d20a0e9..91f7c70d 100755
--- a/src/PIPELINE/VISU_OpenGLPointSpriteMapper.cxx
+++ b/src/PIPELINE/VISU_OpenGLPointSpriteMapper.cxx
@@ -104,8 +104,9 @@ PFNGLVERTEXATTRIB1FARBPROC           glVertexAttrib1fARB          = NULL;
 
 struct TVertex
 {
-  GLfloat r, g, b;
+  GLfloat r, g, b, hue;
   GLfloat vx, vy, vz;
+  //GLfloat hue;
 };
 
 //-----------------------------------------------------------------------------
@@ -270,7 +271,6 @@ GLhandleARB VISU_OpenGLPointSpriteMapper::InitShader()
 
   glLinkProgramARB( VertexProgram );
   //this->PrintInfoLog( VertexProgram );
-
   /*
   cout << "Shader from " << fileName << endl;
   for( int i = 0; i < strlen( shader ); i++ )
@@ -415,13 +415,9 @@ void VISU_OpenGLPointSpriteMapper::InitExtensions()
     //  (PFNGLUSEPROGRAMOBJECTARBPROC)dlsym( this->OpenGLLibrary, "glUseProgramObjectARB" );
     //glUseProgramObjectARB( VISU_OpenGLPointSpriteMapper::VertexProgram );
     /*
-    this->SetShaderVariable( "attrib1",       1.0 );
-    this->SetShaderVariable( "attrib2",       1.0 );
-    this->SetShaderVariable( "attrib3",       1.0 );
     this->SetShaderVariable( "results",       this->PointSpriteResults );
     this->SetShaderVariable( "clamp",         this->PointSpriteClamp );
     this->SetShaderVariable( "geomSize",      this->PointSpriteSize );
-    this->SetShaderVariable( "attrib4",       1.0 );
     this->SetShaderVariable( "minSize",       this->PointSpriteMinSize );
     this->SetShaderVariable( "maxSize",       this->PointSpriteMaxSize );
     this->SetShaderVariable( "magnification", this->PointSpriteMagnification );
@@ -719,6 +715,52 @@ void VISU_OpenGLPointSpriteMapper::InitTextures()
   glBindTexture( GL_TEXTURE_2D, this->PointSpriteTexture );
 }
 
+//-----------------------------------------------------------------------------
+int ComputeHue( int r, int g, int b )
+{
+  int h = 0;
+
+  int max = r;
+  int whatmax = 0;
+  if( g > max ) {
+    max = g;
+    whatmax = 1;
+  }
+  if( b > max ) {
+    max = b;
+    whatmax = 2;
+  }
+
+  int min = r;
+  if ( g < min ) min = g;
+  if ( b < min ) min = b;
+  int delta = max-min;
+
+  if( delta == 0 )
+    h = 0;
+  else if( whatmax == 0 ) {
+    if ( g >= b )
+      h = (120*(g-b)+delta)/(2*delta);
+    else
+      h = (120*(g-b+delta)+delta)/(2*delta) + 300;
+  }
+  else if( whatmax == 1 ) {
+    if ( b > r )
+      h = 120 + (120*(b-r)+delta)/(2*delta);
+    else
+      h = 60 + (120*(b-r+delta)+delta)/(2*delta);
+  }
+  else {
+    if ( r > g )
+      h = 240 + (120*(r-g)+delta)/(2*delta);
+    else
+      h = 180 + (120*(r-g+delta)+delta)/(2*delta);
+  }
+
+  //cout << h << endl;
+  return h + 1;
+}
+
 //-----------------------------------------------------------------------------
 void VISU_OpenGLPointSpriteMapper::DrawPoints(int idx,
 					      vtkPoints *p,
@@ -748,13 +790,9 @@ void VISU_OpenGLPointSpriteMapper::DrawPoints(int idx,
 
   glUseProgramObjectARB( myVertexProgram );
 
-  this->SetShaderVariable( "attrib1",       0.0 );
-  this->SetShaderVariable( "attrib2",       0.0 );
-  this->SetShaderVariable( "attrib3",       0.0 );
   this->SetShaderVariable( "results",       this->PointSpriteResults );
   this->SetShaderVariable( "clamp",         this->PointSpriteClamp );
   this->SetShaderVariable( "geomSize",      this->PointSpriteSize );
-  this->SetShaderVariable( "attrib4",       0.0 );
   this->SetShaderVariable( "minSize",       this->PointSpriteMinSize );
   this->SetShaderVariable( "maxSize",       this->PointSpriteMaxSize );
   this->SetShaderVariable( "magnification", this->PointSpriteMagnification );
@@ -789,6 +827,10 @@ void VISU_OpenGLPointSpriteMapper::DrawPoints(int idx,
       aVertex[i].g = aPropertyColorGreen;
       aVertex[i].b = aPropertyColorBlue;
     }
+
+    aVertex[i].hue = ComputeHue( ( int )( aVertex[i].r * 255 ),
+				 ( int )( aVertex[i].g * 255 ),
+				 ( int )( aVertex[i].b * 255 ) );
   }
 
   GLuint aBufferObjectID = 0;
@@ -803,10 +845,8 @@ void VISU_OpenGLPointSpriteMapper::DrawPoints(int idx,
   glBindBufferARB( GL_ARRAY_BUFFER_ARB, 0 );
   glBindBufferARB( GL_ARRAY_BUFFER_ARB, aBufferObjectID );
 
-  static int aDisplacement = 3*sizeof(GLfloat);
-  
-  glColorPointer( 3, GL_FLOAT, sizeof(TVertex), (void*)0 );
-  glVertexPointer( 3, GL_FLOAT, sizeof(TVertex), (void*)aDisplacement );
+  glColorPointer( 4, GL_FLOAT, sizeof(TVertex), (void*)0 );
+  glVertexPointer( 3, GL_FLOAT, sizeof(TVertex), (void*)(4*sizeof(GLfloat)) );
 
   glEnableClientState(GL_VERTEX_ARRAY);
   glEnableClientState(GL_COLOR_ARRAY);
-- 
2.39.2