i965: Move select_clip_planes to brw_vs.c

Reviewed-by: Matt Turner <mattst88@gmail.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_vs.c b/src/mesa/drivers/dri/i965/brw_vs.c
index 3f11a76506e..a9c474ac06a 100644
--- a/src/mesa/drivers/dri/i965/brw_vs.c
+++ b/src/mesa/drivers/dri/i965/brw_vs.c
@@ -43,6 +43,32 @@
 
 #include "util/ralloc.h"
 
+/**
+ * Decide which set of clip planes should be used when clipping via
+ * gl_Position or gl_ClipVertex.
+ */
+gl_clip_plane *
+brw_select_clip_planes(struct gl_context *ctx)
+{
+   if (ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX]) {
+      /* There is currently a GLSL vertex shader, so clip according to GLSL
+       * rules, which means compare gl_ClipVertex (or gl_Position, if
+       * gl_ClipVertex wasn't assigned) against the eye-coordinate clip planes
+       * that were stored in EyeUserPlane at the time the clip planes were
+       * specified.
+       */
+      return ctx->Transform.EyeUserPlane;
+   } else {
+      /* Either we are using fixed function or an ARB vertex program.  In
+       * either case the clip planes are going to be compared against
+       * gl_Position (which is in clip coordinates) so we have to clip using
+       * _ClipUserPlane, which was transformed into clip coordinates by Mesa
+       * core.
+       */
+      return ctx->Transform._ClipUserPlane;
+   }
+}
+
 GLbitfield64
 brw_vs_outputs_written(struct brw_context *brw, struct brw_vs_prog_key *key,
                        GLbitfield64 user_varyings)