From 5d00e131d8a264498b8d050c3eded093ee5c42f2 Mon Sep 17 00:00:00 2001
From: Michel Dänzer <michel@daenzer.net>
Date: Fri, 23 Jan 2004 03:19:47 +0000
Subject: Fix attenuation hardware state handling, inspired by the R200 DDK
 reference driver (our r200 driver basically didn't do this at all, maybe got
 lost along the way?)

---
 src/mesa/drivers/dri/r200/r200_state.c | 39 ++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

(limited to 'src/mesa/drivers/dri/r200/r200_state.c')

diff --git a/src/mesa/drivers/dri/r200/r200_state.c b/src/mesa/drivers/dri/r200/r200_state.c
index 37da564986..7ea45f3d78 100644
--- a/src/mesa/drivers/dri/r200/r200_state.c
+++ b/src/mesa/drivers/dri/r200/r200_state.c
@@ -1104,6 +1104,10 @@ static void r200Lightfv( GLcontext *ctx, GLenum light,
    case GL_CONSTANT_ATTENUATION:
       R200_STATECHANGE(rmesa, lit[p]);
       fcmd[LIT_ATTEN_CONST] = params[0];
+      if ( params[0] == 0.0 )
+	 fcmd[LIT_ATTEN_CONST_INV] = FLT_MAX;
+      else
+	 fcmd[LIT_ATTEN_CONST_INV] = 1.0 / params[0];
       break;
    case GL_LINEAR_ATTENUATION:
       R200_STATECHANGE(rmesa, lit[p]);
@@ -1117,6 +1121,41 @@ static void r200Lightfv( GLcontext *ctx, GLenum light,
       return;
    }
 
+   /* Set RANGE_ATTEN only when needed */
+   switch (pname) {
+   case GL_POSITION:
+   case GL_CONSTANT_ATTENUATION:
+   case GL_LINEAR_ATTENUATION:
+   case GL_QUADRATIC_ATTENUATION: {
+      GLuint *icmd = (GLuint *)R200_DB_STATE( tcl );
+      GLuint idx = TCL_PER_LIGHT_CTL_0 + p/2;
+      GLuint atten_flag = ( p&1 ) ? R200_LIGHT_1_ENABLE_RANGE_ATTEN
+				  : R200_LIGHT_0_ENABLE_RANGE_ATTEN;
+      GLuint atten_const_flag = ( p&1 ) ? R200_LIGHT_1_CONSTANT_RANGE_ATTEN
+				  : R200_LIGHT_0_CONSTANT_RANGE_ATTEN;
+
+      if ( l->EyePosition[3] == 0.0F ||
+	   ( ( fcmd[LIT_ATTEN_CONST] == 0.0 || fcmd[LIT_ATTEN_CONST] == 1.0 ) &&
+	     fcmd[LIT_ATTEN_QUADRATIC] == 0.0 && fcmd[LIT_ATTEN_LINEAR] == 0.0 ) ) {
+	 /* Disable attenuation */
+	 icmd[idx] &= ~atten_flag;
+      } else {
+	 if ( fcmd[LIT_ATTEN_QUADRATIC] == 0.0 && fcmd[LIT_ATTEN_LINEAR] == 0.0 ) {
+	    /* Enable only constant portion of attenuation calculation */
+	    icmd[idx] |= ( atten_flag | atten_const_flag );
+	 } else {
+	    /* Enable full attenuation calculation */
+	    icmd[idx] &= ~atten_const_flag;
+	    icmd[idx] |= atten_flag;
+	 }
+      }
+
+      R200_DB_STATECHANGE( rmesa, &rmesa->hw.tcl );
+      break;
+   }
+   default:
+     break;
+   }
 }
 
 		  
-- 
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