depth offset

panda/src/tinydisplay/clip.cxx

@@ -22,6 +22,8 @@ void gl_transform_to_viewport(GLContext *c,GLVertex *v)
                    + c->viewport.trans.v[1] );
   v->zp.z= (int) ( v->pc.v[2] * winv * c->viewport.scale.v[2] 
                    + c->viewport.trans.v[2] );
+  v->zp.z += (c->zbias << (ZB_Z_BITS - 8));
+
   /* color */
   v->zp.r=(int)(v->color.v[0] * (ZB_POINT_RED_MAX - ZB_POINT_RED_MIN) 
                 + ZB_POINT_RED_MIN);

panda/src/tinydisplay/init.cxx

@@ -56,6 +56,7 @@ void glInit(GLContext *c, ZBuffer *zbuffer)
 
   /* depth test */
   c->depth_test = 0;
+  c->zbias = 0;
 }
 
 void glClose(GLContext *c)

panda/src/tinydisplay/tinyGraphicsStateGuardian.cxx

@@ -23,6 +23,7 @@
 #include "directionalLight.h"
 #include "spotlight.h"
 #include "depthWriteAttrib.h"
+#include "depthOffsetAttrib.h"
 #include "colorWriteAttrib.h"
 #include "alphaTestAttrib.h"
 #include "depthTestAttrib.h"
@@ -98,8 +99,9 @@ reset() {
   _inv_state_mask.clear_bit(ColorAttrib::get_class_slot());
   _inv_state_mask.clear_bit(ColorScaleAttrib::get_class_slot());
   _inv_state_mask.clear_bit(CullFaceAttrib::get_class_slot());
-  _inv_state_mask.clear_bit(RescaleNormalAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(DepthOffsetAttrib::get_class_slot());
   _inv_state_mask.clear_bit(RenderModeAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(RescaleNormalAttrib::get_class_slot());
   _inv_state_mask.clear_bit(TextureAttrib::get_class_slot());
   _inv_state_mask.clear_bit(MaterialAttrib::get_class_slot());
   _inv_state_mask.clear_bit(LightAttrib::get_class_slot());
@@ -1464,6 +1466,14 @@ set_state_and_transform(const RenderState *target,
     _state_mask.set_bit(cull_face_slot);
   }
 
+  int depth_offset_slot = DepthOffsetAttrib::get_class_slot();
+  if (_target_rs->get_attrib(depth_offset_slot) != _state_rs->get_attrib(depth_offset_slot) ||
+      !_state_mask.get_bit(depth_offset_slot)) {
+    //PStatTimer timer(_draw_set_state_depth_offset_pcollector);
+    do_issue_depth_offset();
+    _state_mask.set_bit(depth_offset_slot);
+  }
+
   int rescale_normal_slot = RescaleNormalAttrib::get_class_slot();
   if (_target_rs->get_attrib(rescale_normal_slot) != _state_rs->get_attrib(rescale_normal_slot) ||
       !_state_mask.get_bit(rescale_normal_slot)) {
@@ -2008,6 +2018,18 @@ do_issue_rescale_normal() {
   }
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: TinyGraphicsStateGuardian::do_issue_depth_offset
+//       Access: Protected
+//  Description:
+////////////////////////////////////////////////////////////////////
+void TinyGraphicsStateGuardian::
+do_issue_depth_offset() {
+  const DepthOffsetAttrib *target_depth_offset = DCAST(DepthOffsetAttrib, _target_rs->get_attrib_def(DepthOffsetAttrib::get_class_slot()));
+  int offset = target_depth_offset->get_offset();
+  _c->zbias = offset;
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: TinyGraphicsStateGuardian::do_issue_cull_face
 //       Access: Protected

panda/src/tinydisplay/tinyGraphicsStateGuardian.h

@@ -99,6 +99,7 @@ private:
   void do_issue_render_mode();
   void do_issue_cull_face();
   void do_issue_rescale_normal();
+  void do_issue_depth_offset();
   void do_issue_material();
   void do_issue_texture();
   void do_issue_scissor();

panda/src/tinydisplay/vertex.cxx

@@ -9,7 +9,7 @@ void gl_eval_viewport(GLContext * c) {
   float xmin = v->xmin + v->xsize * s->left;
   float ysize = v->ysize * (s->top - s->bottom);
   float ymin = v->ymin + v->ysize * (1.0f - s->top);
-  float zsize = (1 << (ZB_Z_BITS + ZB_POINT_Z_FRAC_BITS));
+  float zsize = (float)(1 << (ZB_Z_BITS + ZB_POINT_Z_FRAC_BITS));
 
   v->trans.v[0] = ((xsize - 0.5f) / 2.0f) + xmin;
   v->trans.v[1] = ((ysize - 0.5f) / 2.0f) + ymin;

panda/src/tinydisplay/zbuffer.h

@@ -8,9 +8,9 @@
 #include "zfeatures.h"
 #include "pbitops.h"
 
-typedef unsigned short ZPOINT;
-#define ZB_Z_BITS 16
-#define ZB_POINT_Z_FRAC_BITS 14
+typedef unsigned int ZPOINT;
+#define ZB_Z_BITS 20
+#define ZB_POINT_Z_FRAC_BITS 10  // These must add to < 32.
 
 /* The number of fractional bits below the S and T texture coords.
    The more we have, the more precise the texel calculation will be

panda/src/tinydisplay/zgl.h

@@ -183,6 +183,7 @@ typedef struct GLContext {
 
   /* depth test */
   int depth_test;
+  int zbias;
   
   /* specular buffer. could probably be shared between contexts, 
     but that wouldn't be 100% thread safe */