lighting optimization

panda/src/tinydisplay/tinyGraphicsStateGuardian.I

@@ -12,3 +12,23 @@
 //
 ////////////////////////////////////////////////////////////////////
 
+
+////////////////////////////////////////////////////////////////////
+//     Function: TinyGraphicsStateGuardian::clear_light_state
+//       Access: Private
+//  Description: Removes the current list of active lights from the
+//               current state context.
+////////////////////////////////////////////////////////////////////
+INLINE void TinyGraphicsStateGuardian::
+clear_light_state() {
+  _c->lighting_enabled = false;
+#ifndef NDEBUG
+  GLLight *gl_light = _c->first_light;
+  while (gl_light != (GLLight *)NULL) {
+    GLLight *next = gl_light->next;
+    gl_light->next = NULL;
+    gl_light = next;
+  }
+#endif  // NDEBUG
+  _c->first_light = NULL;
+}

panda/src/tinydisplay/tinyGraphicsStateGuardian.cxx

@@ -438,6 +438,13 @@ end_scene() {
     }
     _c->zb = _current_frame_buffer;
   }
+
+  // Clear the lighting state.
+  clear_light_state();
+  _plights.clear();
+  _dlights.clear();
+  _slights.clear();
+
   GraphicsStateGuardian::end_scene();
 }
 
@@ -1571,15 +1578,7 @@ do_issue_light() {
   }
 
   // First, release all of the previously-assigned lights.
-  _c->lighting_enabled = false;
-
-  GLLight *gl_light = _c->first_light;
-  while (gl_light != (GLLight *)NULL) {
-    GLLight *next = gl_light->next;
-    gl_light->next = NULL;
-    gl_light = next;
-  }
-  _c->first_light = NULL;
+  clear_light_state();
 
   // Now, assign new lights.
   if (_target._light != (LightAttrib *)NULL) {
@@ -1604,21 +1603,18 @@ do_issue_light() {
 
       } else {
         // Other kinds of lights each get their own GLLight object.
-        nassertv(num_enabled < MAX_LIGHTS);
-        GLLight *gl_light = &_c->lights[num_enabled];
-        memset(gl_light, 0, sizeof(GLLight));
-
-        gl_light->next = _c->first_light;
-        _c->first_light = gl_light;
+        light_obj->bind(this, light, num_enabled);
+        num_enabled++;
 
+        // Handle the diffuse color here, since all lights have this
+        // property.
+        GLLight *gl_light = _c->first_light;
+        nassertv(gl_light != NULL);
         const Colorf &diffuse = light_obj->get_color();
         gl_light->diffuse.v[0] = diffuse[0];
         gl_light->diffuse.v[1] = diffuse[1];
         gl_light->diffuse.v[2] = diffuse[2];
         gl_light->diffuse.v[3] = diffuse[3];
-
-        light_obj->bind(this, light, num_enabled);
-        num_enabled++;
       }
     }
   }
@@ -1643,8 +1639,11 @@ do_issue_light() {
 ////////////////////////////////////////////////////////////////////
 void TinyGraphicsStateGuardian::
 bind_light(PointLight *light_obj, const NodePath &light, int light_id) {
-  GLLight *gl_light = _c->first_light;
-  nassertv(gl_light != (GLLight *)NULL);
+  pair<Lights::iterator, bool> lookup = _plights.insert(Lights::value_type(light, GLLight()));
+  GLLight *gl_light = &(*lookup.first).second;
+  if (lookup.second) {
+    // It's a brand new light.  Define it.
+    memset(gl_light, 0, sizeof(GLLight));
 
     const Colorf &specular = light_obj->get_specular_color();
     gl_light->specular.v[0] = specular[0];
@@ -1676,6 +1675,13 @@ bind_light(PointLight *light_obj, const NodePath &light, int light_id) {
     gl_light->attenuation[0] = att[0];
     gl_light->attenuation[1] = att[1];
     gl_light->attenuation[2] = att[2];
+  }
+
+  nassertv(gl_light->next == NULL);
+
+  // Add it to the linked list of active lights.
+  gl_light->next = _c->first_light;
+  _c->first_light = gl_light;
 }
 
 ////////////////////////////////////////////////////////////////////
@@ -1688,8 +1694,11 @@ bind_light(PointLight *light_obj, const NodePath &light, int light_id) {
 ////////////////////////////////////////////////////////////////////
 void TinyGraphicsStateGuardian::
 bind_light(DirectionalLight *light_obj, const NodePath &light, int light_id) {
-  GLLight *gl_light = _c->first_light;
-  nassertv(gl_light != (GLLight *)NULL);
+  pair<Lights::iterator, bool> lookup = _dlights.insert(Lights::value_type(light, GLLight()));
+  GLLight *gl_light = &(*lookup.first).second;
+  if (lookup.second) {
+    // It's a brand new light.  Define it.
+    memset(gl_light, 0, sizeof(GLLight));
 
     const Colorf &specular = light_obj->get_specular_color();
     gl_light->specular.v[0] = specular[0];
@@ -1728,6 +1737,13 @@ bind_light(DirectionalLight *light_obj, const NodePath &light, int light_id) {
     gl_light->attenuation[0] = 1.0f;
     gl_light->attenuation[1] = 0.0f;
     gl_light->attenuation[2] = 0.0f;
+  }
+
+  nassertv(gl_light->next == NULL);
+
+  // Add it to the linked list of active lights.
+  gl_light->next = _c->first_light;
+  _c->first_light = gl_light;
 }
 
 ////////////////////////////////////////////////////////////////////
@@ -1740,8 +1756,11 @@ bind_light(DirectionalLight *light_obj, const NodePath &light, int light_id) {
 ////////////////////////////////////////////////////////////////////
 void TinyGraphicsStateGuardian::
 bind_light(Spotlight *light_obj, const NodePath &light, int light_id) {
-  GLLight *gl_light = _c->first_light;
-  nassertv(gl_light != (GLLight *)NULL);
+  pair<Lights::iterator, bool> lookup = _plights.insert(Lights::value_type(light, GLLight()));
+  GLLight *gl_light = &(*lookup.first).second;
+  if (lookup.second) {
+    // It's a brand new light.  Define it.
+    memset(gl_light, 0, sizeof(GLLight));
 
     const Colorf &specular = light_obj->get_specular_color();
     gl_light->specular.v[0] = specular[0];
@@ -1786,6 +1805,13 @@ bind_light(Spotlight *light_obj, const NodePath &light, int light_id) {
     gl_light->attenuation[0] = att[0];
     gl_light->attenuation[1] = att[1];
     gl_light->attenuation[2] = att[2];
+  }
+
+  nassertv(gl_light->next == NULL);
+
+  // Add it to the linked list of active lights.
+  gl_light->next = _c->first_light;
+  _c->first_light = gl_light;
 }
 
 ////////////////////////////////////////////////////////////////////

panda/src/tinydisplay/tinyGraphicsStateGuardian.h

@@ -22,12 +22,9 @@
 #include "simpleLru.h"
 #include "zmath.h"
 #include "zbuffer.h"
+#include "zgl.h"
 
 class TinyTextureContext;
-struct GLContext;
-struct GLVertex;
-struct GLMaterial;
-struct GLTexture;
 
 ////////////////////////////////////////////////////////////////////
 //       Class : TinyGraphicsStateGuardian
@@ -126,6 +123,8 @@ private:
   static int get_color_blend_op(ColorBlendAttrib::Operand operand);
   static ZB_lookupTextureFunc get_tex_filter_func(Texture::FilterType filter);
 
+  INLINE void clear_light_state();
+
 public:
   // Filled in by the Tiny*GraphicsWindow at begin_frame().
   ZBuffer *_current_frame_buffer;
@@ -150,6 +149,12 @@ private:
 
   CPT(TransformState) _scissor_mat;
 
+  // Cache the data necessary to bind each particular light each
+  // frame, so if we bind a given light multiple times, we only have
+  // to compute its data once.
+  typedef pmap<NodePath, GLLight> Lights;
+  Lights _plights, _dlights, _slights;
+
   // Used during being_draw_primitives() .. end_draw_primitives().
   int _min_vertex;
   int _max_vertex;