i965: limit on LOD Bias, fix#11987

diff --git a/src/mesa/drivers/dri/i965/brw_wm_sampler_state.c b/src/mesa/drivers/dri/i965/brw_wm_sampler_state.c
index 81fc9ef2f0ca109f0f9549bb91b16cd70090434a..8afefdd4353111741569e53f6d8bd9b0e46ed413 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_wm_sampler_state.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_sampler_state.c
@@ -178,7 +178,7 @@ static void brw_update_sampler_state( struct gl_texture_unit *texUnit,
 
    /* Set LOD bias: 
     */
-   sampler->ss0.lod_bias = S_FIXED(texUnit->LodBias + texObj->LodBias, 6);
+   sampler->ss0.lod_bias = S_FIXED(CLAMP(texUnit->LodBias + texObj->LodBias, -16, 15), 6);
 
    sampler->ss0.lod_preclamp = 1; /* OpenGL mode */
    sampler->ss0.default_color_mode = 0; /* OpenGL/DX10 mode */