wined3d: Properly handle WINED3DSIH_DP2 in the GLSL shader backend.

dlls/wined3d/glsl_shader.c

@@ -2665,13 +2665,13 @@ static void shader_glsl_dot(const struct wined3d_shader_instruction *ins)
     dst_write_mask = shader_glsl_append_dst(buffer, ins);
     dst_size = shader_glsl_get_write_mask_size(dst_write_mask);
 
-    /* dp3 works on vec3, dp4 on vec4 */
+    /* dp4 works on vec4, dp3 on vec3, etc. */
     if (ins->handler_idx == WINED3DSIH_DP4)
-    {
         src_write_mask = WINED3DSP_WRITEMASK_ALL;
-    } else {
+    else if (ins->handler_idx == WINED3DSIH_DP3)
         src_write_mask = WINED3DSP_WRITEMASK_0 | WINED3DSP_WRITEMASK_1 | WINED3DSP_WRITEMASK_2;
-    }
+    else
+        src_write_mask = WINED3DSP_WRITEMASK_0 | WINED3DSP_WRITEMASK_1;
 
     shader_glsl_add_src_param(ins, &ins->src[0], src_write_mask, &src0_param);
     shader_glsl_add_src_param(ins, &ins->src[1], src_write_mask, &src1_param);