enable GL_EXT_fog_coord. Calculate fog factors and submit them instead of fog coords (it seems the chip cannot do fog factor computation when not using fragment depth as fog coord source). vtxfmt uses fallback for now (most code present but some magic would be needed if replaying vertices is necessary later on).

1 files changed, 96 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/r200/r200_tcl.c b/src/mesa/drivers/dri/r200/r200_tcl.c
index 78d16ed0f3..d2dfc5fda1 100644
--- a/src/mesa/drivers/dri/r200/r200_tcl.c
+++ b/src/mesa/drivers/dri/r200/r200_tcl.c
@@ -269,6 +269,90 @@ void r200TclPrimitive( GLcontext *ctx,
 
 
 /**********************************************************************/
+/*             Fog blend factor computation for hw tcl                */
+/*             same calculation used as in t_vb_fog.c                 */
+/**********************************************************************/
+
+#define FOG_EXP_TABLE_SIZE 256
+#define FOG_MAX (10.0)
+#define EXP_FOG_MAX .0006595
+#define FOG_INCR (FOG_MAX/FOG_EXP_TABLE_SIZE)
+static GLfloat exp_table[FOG_EXP_TABLE_SIZE];
+
+#if 1
+#define NEG_EXP( result, narg )						\
+do {									\
+   GLfloat f = (GLfloat) (narg * (1.0/FOG_INCR));			\
+   GLint k = (GLint) f;							\
+   if (k > FOG_EXP_TABLE_SIZE-2) 					\
+      result = (GLfloat) EXP_FOG_MAX;					\
+   else									\
+      result = exp_table[k] + (f-k)*(exp_table[k+1]-exp_table[k]);	\
+} while (0)
+#else
+#define NEG_EXP( result, narg )					\
+do {								\
+   result = exp(-narg);						\
+} while (0)
+#endif
+
+
+/**
+ * Initialize the exp_table[] lookup table for approximating exp().
+ */
+void
+r200InitStaticFogData( void )
+{
+   GLfloat f = 0.0F;
+   GLint i = 0;
+   for ( ; i < FOG_EXP_TABLE_SIZE ; i++, f += FOG_INCR) {
+      exp_table[i] = (GLfloat) exp(-f);
+   }
+}
+
+
+/**
+ * Compute per-vertex fog blend factors from fog coordinates by
+ * evaluating the GL_LINEAR, GL_EXP or GL_EXP2 fog function.
+ * Fog coordinates are distances from the eye (typically between the
+ * near and far clip plane distances).
+ * Note the fog (eye Z) coords may be negative so we use ABS(z) below.
+ * Fog blend factors are in the range [0,1].
+ */
+float
+r200ComputeFogBlendFactor( GLcontext *ctx, GLfloat fogcoord )
+{
+   GLfloat end  = ctx->Fog.End;
+   GLfloat d, temp;
+   const GLfloat z = FABSF(fogcoord);
+
+   switch (ctx->Fog.Mode) {
+   case GL_LINEAR:
+      if (ctx->Fog.Start == ctx->Fog.End)
+         d = 1.0F;
+      else
+         d = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
+      temp = (end - z) * d;
+      return CLAMP(temp, 0.0F, 1.0F);
+      break;
+   case GL_EXP:
+      d = ctx->Fog.Density;
+      NEG_EXP( temp, d * z );
+      return temp;
+      break;
+   case GL_EXP2:
+      d = ctx->Fog.Density*ctx->Fog.Density;
+      NEG_EXP( temp, d * z * z );
+      return temp;
+      break;
+   default:
+      _mesa_problem(ctx, "Bad fog mode in make_fog_coord");
+      return 0;
+   }
+}
+
+
+/**********************************************************************/
 /*                          Render pipeline stage                     */
 /**********************************************************************/
 
@@ -349,6 +433,10 @@ static void r200_check_tcl_render( GLcontext *ctx,
 	 }
       }
 
+      if ( ctx->Fog.FogCoordinateSource == GL_FOG_COORD ) {
+	 inputs |= VERT_BIT_FOG;
+      }
+
       for (unit = 0 ; unit < ctx->Const.MaxTextureUnits; unit++) {
 	 if (ctx->Texture.Unit[unit]._ReallyEnabled) {
 	    if (rmesa->TexGenNeedNormals[unit]) {
@@ -457,6 +545,14 @@ static void transition_to_hwtnl( GLcontext *ctx )
    rmesa->hw.vap.cmd[VAP_SE_VAP_CNTL] |= R200_VAP_TCL_ENABLE;
    rmesa->hw.vap.cmd[VAP_SE_VAP_CNTL] &= ~R200_VAP_FORCE_W_TO_ONE;
 
+   if ( ((rmesa->hw.ctx.cmd[CTX_PP_FOG_COLOR] & R200_FOG_USE_MASK)
+      == R200_FOG_USE_SPEC_ALPHA) &&
+      (ctx->Fog.FogCoordinateSource == GL_FOG_COORD )) {
+      R200_STATECHANGE( rmesa, ctx );
+      rmesa->hw.ctx.cmd[CTX_PP_FOG_COLOR] &= ~R200_FOG_USE_MASK;
+      rmesa->hw.ctx.cmd[CTX_PP_FOG_COLOR] |= R200_FOG_USE_VTX_FOG;
+   }
+   
    R200_STATECHANGE( rmesa, vte );
    rmesa->hw.vte.cmd[VTE_SE_VTE_CNTL] &= ~(R200_VTX_XY_FMT|R200_VTX_Z_FMT);