1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
/**
* @file llrendersphere.cpp
* @brief implementation of the LLRenderSphere class.
*
* $LicenseInfo:firstyear=2001&license=viewergpl$
*
* Copyright (c) 2001-2008, Linden Research, Inc.
*
* Second Life Viewer Source Code
* The source code in this file ("Source Code") is provided by Linden Lab
* to you under the terms of the GNU General Public License, version 2.0
* ("GPL"), unless you have obtained a separate licensing agreement
* ("Other License"), formally executed by you and Linden Lab. Terms of
* the GPL can be found in doc/GPL-license.txt in this distribution, or
* online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
*
* There are special exceptions to the terms and conditions of the GPL as
* it is applied to this Source Code. View the full text of the exception
* in the file doc/FLOSS-exception.txt in this software distribution, or
* online at http://secondlifegrid.net/programs/open_source/licensing/flossexception
*
* By copying, modifying or distributing this software, you acknowledge
* that you have read and understood your obligations described above,
* and agree to abide by those obligations.
*
* ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
* WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
* COMPLETENESS OR PERFORMANCE.
* $/LicenseInfo$
*/
// Sphere creates a set of display lists that can then be called to create
// a lit sphere at different LOD levels. You only need one instance of sphere
// per viewer - then call the appropriate list.
#include "linden_common.h"
#include "llrendersphere.h"
#include "llerror.h"
#include "llglheaders.h"
GLUquadricObj *gQuadObj2 = NULL;
LLRenderSphere gSphere;
void drawSolidSphere(GLdouble radius, GLint slices, GLint stacks);
void drawSolidSphere(GLdouble radius, GLint slices, GLint stacks)
{
if (!gQuadObj2)
{
gQuadObj2 = gluNewQuadric();
if (!gQuadObj2)
{
llwarns << "drawSolidSphere couldn't allocate quadric" << llendl;
return;
}
}
gluQuadricDrawStyle(gQuadObj2, GLU_FILL);
gluQuadricNormals(gQuadObj2, GLU_SMOOTH);
// If we ever changed/used the texture or orientation state
// of quadObj, we'd need to change it to the defaults here
// with gluQuadricTexture and/or gluQuadricOrientation.
gluQuadricTexture(gQuadObj2, GL_TRUE);
gluSphere(gQuadObj2, radius, slices, stacks);
}
// lat = 0 is Z-axis
// lon = 0, lat = 90 at X-axis
void lat2xyz(LLVector3 * result, F32 lat, F32 lon)
{
// Convert a latitude and longitude to x,y,z on a normal sphere and return it in result
F32 r;
result->mV[VX] = (F32) (cos(lon * DEG_TO_RAD) * sin(lat * DEG_TO_RAD));
result->mV[VY] = (F32) (sin(lon * DEG_TO_RAD) * sin(lat * DEG_TO_RAD));
r = (F32) pow(result->mV[VX] * result->mV[VX] + result->mV[VY] * result->mV[VY], 0.5f);
if (r == 1.0f)
{
result->mV[VZ] = 0.0f;
}
else
{
result->mV[VZ] = (F32) pow(1 - r*r, 0.5f);
if (lat > 90.01)
{
result->mV[VZ] *= -1.0;
}
}
}
void lat2xyz_rad(LLVector3 * result, F32 lat, F32 lon)
{
// Convert a latitude and longitude to x,y,z on a normal sphere and return it in result
F32 r;
result->mV[VX] = (F32) (cos(lon) * sin(lat));
result->mV[VY] = (F32) (sin(lon) * sin(lat));
r = (F32) pow(result->mV[VX] * result->mV[VX] + result->mV[VY] * result->mV[VY], 0.5f);
if (r == 1.0f)
result->mV[VZ] = 0.0f;
else
{
result->mV[VZ] = (F32) pow(1 - r*r, 0.5f);
if (lat > F_PI_BY_TWO) result->mV[VZ] *= -1.0;
}
}
// A couple thoughts on sphere drawing:
// 1) You need more slices than stacks, but little less than 2:1
// 2) At low LOD, setting stacks to an odd number avoids a "band" around the equator, making things look smoother
void LLRenderSphere::prerender()
{
// Create a series of display lists for different LODs
mDList[0] = glGenLists(1);
glNewList(mDList[0], GL_COMPILE);
drawSolidSphere(1.0, 30, 20);
glEndList();
mDList[1] = glGenLists(1);
glNewList(mDList[1], GL_COMPILE);
drawSolidSphere(1.0, 20, 15);
glEndList();
mDList[2] = glGenLists(1);
glNewList(mDList[2], GL_COMPILE);
drawSolidSphere(1.0, 12, 8);
glEndList();
mDList[3] = glGenLists(1);
glNewList(mDList[3], GL_COMPILE);
drawSolidSphere(1.0, 8, 5);
glEndList();
}
void LLRenderSphere::cleanupGL()
{
for (S32 detail = 0; detail < 4; detail++)
{
glDeleteLists(mDList[detail], 1);
mDList[detail] = 0;
}
if (gQuadObj2)
{
gluDeleteQuadric(gQuadObj2);
gQuadObj2 = NULL;
}
}
// Constants here are empirically derived from my eyeballs, JNC
//
// The toughest adjustment is the cutoff for the lowest LOD
// Maybe we should have more LODs at the low end?
void LLRenderSphere::render(F32 pixel_area)
{
S32 level_of_detail;
if (pixel_area > 10000.f)
{
level_of_detail = 0;
}
else if (pixel_area > 800.f)
{
level_of_detail = 1;
}
else if (pixel_area > 100.f)
{
level_of_detail = 2;
}
else
{
level_of_detail = 3;
}
glCallList(mDList[level_of_detail]);
}
void LLRenderSphere::render()
{
glCallList(mDList[0]);
}
|
