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?)

3 files changed, 43 insertions, 3 deletions

diff --git a/src/mesa/drivers/dri/r200/r200_context.h b/src/mesa/drivers/dri/r200/r200_context.h
index 5de1cb6eedf..65ca9ef7622 100644
--- a/src/mesa/drivers/dri/r200/r200_context.h
+++ b/src/mesa/drivers/dri/r200/r200_context.h
@@ -399,9 +399,9 @@ struct r200_state_atom {
 #define LIT_DIRECTION_Y            18
 #define LIT_DIRECTION_Z            19
 #define LIT_DIRECTION_W            20
-#define LIT_ATTEN_CONST            21
+#define LIT_ATTEN_QUADRATIC        21
 #define LIT_ATTEN_LINEAR           22
-#define LIT_ATTEN_QUADRATIC        23
+#define LIT_ATTEN_CONST            23
 #define LIT_ATTEN_XXX              24
 #define LIT_CMD_1                  25
 #define LIT_SPOT_DCD               26
@@ -410,7 +410,7 @@ struct r200_state_atom {
 #define LIT_SPOT_CUTOFF            29
 #define LIT_SPECULAR_THRESH        30
 #define LIT_RANGE_CUTOFF           31 /* ? */
-#define LIT_RANGE_ATTEN            32 /* ? */
+#define LIT_ATTEN_CONST_INV        32
 #define LIT_STATE_SIZE             33
 
 /* Fog
diff --git a/src/mesa/drivers/dri/r200/r200_state.c b/src/mesa/drivers/dri/r200/r200_state.c
index 37da564986d..7ea45f3d788 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;
+   }
 }
 
 		  
diff --git a/src/mesa/drivers/dri/r200/r200_state_init.c b/src/mesa/drivers/dri/r200/r200_state_init.c
index 22ad4e376e7..b9fc724f569 100644
--- a/src/mesa/drivers/dri/r200/r200_state_init.c
+++ b/src/mesa/drivers/dri/r200/r200_state_init.c
@@ -683,6 +683,7 @@ void r200InitState( r200ContextPtr rmesa )
 			   &l->LinearAttenuation );
       ctx->Driver.Lightfv( ctx, p, GL_QUADRATIC_ATTENUATION, 
 			   &l->QuadraticAttenuation );
+      *(float *)&(rmesa->hw.lit[i].cmd[LIT_ATTEN_XXX]) = 0.0;
    }
 
    ctx->Driver.LightModelfv( ctx, GL_LIGHT_MODEL_AMBIENT,