Demos (master): geartrain: fixed gear geometry, use flat shading
Brian Paul
brianp at kemper.freedesktop.org
Mon Aug 9 14:30:28 UTC 2010
Module: Demos
Branch: master
Commit: 514d7998f44f1c283a33e0245a59e5de4deb42b5
URL: http://cgit.freedesktop.org/mesa/demos/commit/?id=514d7998f44f1c283a33e0245a59e5de4deb42b5
Author: Christian Authmann <christian at authmann.de>
Date: Mon Aug 9 08:28:51 2010 -0600
geartrain: fixed gear geometry, use flat shading
Signed-off-by: Brian Paul <brianp at vmware.com>
---
src/demos/geartrain.c | 104 ++++++++++++++-----------------------------------
1 files changed, 30 insertions(+), 74 deletions(-)
diff --git a/src/demos/geartrain.c b/src/demos/geartrain.c
index 5d5e5e2..55bdc21 100644
--- a/src/demos/geartrain.c
+++ b/src/demos/geartrain.c
@@ -332,29 +332,27 @@ gear (GLint j, char type[], GLfloat radius, GLfloat width,
GLint teeth, GLfloat tooth_depth)
{
GLint i;
- GLfloat r1, r2;
+ GLfloat r1, r2_front, r2_back;
GLfloat angle, da;
GLfloat u, v, len, fraction = 0.5;
GLfloat n = 1.0;
r1 = radius - tooth_depth;
- r2 = radius;
+ r2_front = r2_back = radius;
+
+ fraction = 0.5;
+ n = 1.0;
da = 2.0 * M_PI / teeth / 4.0;
- if (!g[j].face)
- {
- fraction = -0.5;
- n = -1.0;
- }
- if (!(strcmp (type, "NORMAL")))
+ if (!(strcmp (type, "BEVEL")))
{
- fraction = 0.5;
- n = 1.0;
+ if (g[j].face)
+ r2_front = radius - width;
+ else
+ r2_back = radius - width;
}
/* draw front face */
- if (!(strcmp (type, "NORMAL")))
- {
glNormal3f (0.0, 0.0, 1.0 * n);
glBegin (GL_QUAD_STRIP);
for (i = 0; i <= teeth; i++)
@@ -366,25 +364,8 @@ gear (GLint j, char type[], GLfloat radius, GLfloat width,
glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), width * fraction);
}
glEnd ();
- }
- else
- {
- glNormal3f (0.0, 0.0, 1.0 * n);
- glBegin (GL_QUAD_STRIP);
- for (i = 0; i <= teeth; i++)
- {
- angle = i * 2.0 * M_PI / teeth;
- glVertex3f (0.0, 0.0, width * fraction);
- glVertex3f ((r2 - width) * cos (angle), (r2 - width) * sin (angle), width * fraction);
- glVertex3f (0.0, 0.0, width * fraction);
- glVertex3f ((r2 - width) * cos (angle + 3 * da), (r2 - width) * sin (angle + 3 * da), width * fraction);
- }
- glEnd ();
- }
/* draw front sides of teeth */
- if (!(strcmp (type, "NORMAL")))
- {
glNormal3f (0.0, 0.0, 1.0 * n);
glBegin (GL_QUADS);
da = 2.0 * M_PI / teeth / 4.0;
@@ -392,16 +373,14 @@ gear (GLint j, char type[], GLfloat radius, GLfloat width,
{
angle = i * 2.0 * M_PI / teeth;
glVertex3f (r1 * cos (angle), r1 * sin (angle), width * fraction);
- glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), width * fraction);
- glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), width * fraction);
+ glVertex3f (r2_front * cos (angle + da), r2_front * sin (angle + da), width * fraction);
+ glVertex3f (r2_front * cos (angle + 2 * da), r2_front * sin (angle + 2 * da), width * fraction);
glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), width * fraction);
}
glEnd ();
- }
-
- glNormal3f (0.0, 0.0, -1.0 * n);
/* draw back face */
+ glNormal3f (0.0, 0.0, -1.0 * n);
glBegin (GL_QUAD_STRIP);
for (i = 0; i <= teeth; i++)
{
@@ -421,70 +400,45 @@ gear (GLint j, char type[], GLfloat radius, GLfloat width,
{
angle = i * 2.0 * M_PI / teeth;
glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), -width * fraction);
- glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), -width * fraction);
- glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), -width * fraction);
+ glVertex3f (r2_back * cos (angle + 2 * da), r2_back * sin (angle + 2 * da), -width * fraction);
+ glVertex3f (r2_back * cos (angle + da), r2_back * sin (angle + da), -width * fraction);
glVertex3f (r1 * cos (angle), r1 * sin (angle), -width * fraction);
}
glEnd ();
/* draw outward faces of teeth */
- if (!(strcmp (type, "NORMAL")))
- {
glBegin (GL_QUAD_STRIP);
for (i = 0; i < teeth; i++)
{
angle = i * 2.0 * M_PI / teeth;
+ glNormal3f (cos (angle - 0.5*da), sin (angle - 0.5*da), 0.0);
glVertex3f (r1 * cos (angle), r1 * sin (angle), width * fraction);
glVertex3f (r1 * cos (angle), r1 * sin (angle), -width * fraction);
- u = r2 * cos (angle + da) - r1 * cos (angle);
- v = r2 * sin (angle + da) - r1 * sin (angle);
+ u = (r2_front+r2_back)/2.0 * cos (angle + da) - r1 * cos (angle);
+ v = (r2_front+r2_back)/2.0 * sin (angle + da) - r1 * sin (angle);
len = sqrt (u * u + v * v);
u /= len;
v /= len;
glNormal3f (v, -u, 0.0);
- glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), width * fraction);
- glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), -width * fraction);
- glNormal3f (cos (angle), sin (angle), 0.0);
- glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), width * fraction);
- glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), -width * fraction);
- u = r1 * cos (angle + 3 * da) - r2 * cos (angle + 2 * da);
- v = r1 * sin (angle + 3 * da) - r2 * sin (angle + 2 * da);
- glNormal3f (v, -u, 0.0);
- glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), width * fraction);
- glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), -width * fraction);
- glNormal3f (cos (angle), sin (angle), 0.0);
- }
- }
- else
- {
- glBegin (GL_QUAD_STRIP);
- for (i = 0; i < teeth; i++)
- {
- angle = i * 2.0 * M_PI / teeth;
- glVertex3f (r1 * cos (angle), r1 * sin (angle), width * fraction);
- glVertex3f (r1 * cos (angle), r1 * sin (angle), -width * fraction);
- u = r2 * cos (angle + da) - r1 * cos (angle);
- v = r2 * sin (angle + da) - r1 * sin (angle);
+ glVertex3f (r2_front * cos (angle + da), r2_front * sin (angle + da), width * fraction);
+ glVertex3f (r2_back * cos (angle + da), r2_back * sin (angle + da), -width * fraction);
+ glNormal3f (cos (angle + 1.5*da), sin (angle + 1.5*da), 0.0);
+ glVertex3f (r2_front * cos (angle + 2 * da), r2_front * sin (angle + 2 * da), width * fraction);
+ glVertex3f (r2_back * cos (angle + 2 * da), r2_back * sin (angle + 2 * da), -width * fraction);
+ u = r1 * cos (angle + 3 * da) - (r2_front+r2_back)/2.0 * cos (angle + 2 * da);
+ v = r1 * sin (angle + 3 * da) - (r2_front+r2_back)/2.0 * sin (angle + 2 * da);
len = sqrt (u * u + v * v);
u /= len;
v /= len;
glNormal3f (v, -u, 0.0);
- glVertex3f ((r2 - width) * cos (angle + da), (r2 - width) * sin (angle + da), width * fraction);
- glVertex3f (r2 * cos (angle + da), r2 * sin (angle + da), -width * fraction);
- glNormal3f (cos (angle), sin (angle), n);
- glVertex3f ((r2 - width) * cos (angle + 2 * da), (r2 - width) * sin (angle + 2 * da), width * fraction);
- glVertex3f (r2 * cos (angle + 2 * da), r2 * sin (angle + 2 * da), -width * fraction);
- u = r1 * cos (angle + 3 * da) - r2 * cos (angle + 2 * da);
- v = r1 * sin (angle + 3 * da) - r2 * sin (angle + 2 * da);
- glNormal3f (v, -u, 0.0);
glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), width * fraction);
glVertex3f (r1 * cos (angle + 3 * da), r1 * sin (angle + 3 * da), -width * fraction);
- glNormal3f (cos (angle), sin (angle), n);
+ glNormal3f (cos (angle + 3.5*da), sin (angle + 3.5*da), 0.0);
}
- }
+ glNormal3f (cos (-0.5*da), sin (-0.5*da), 0.0);
glVertex3f (r1 * cos (0), r1 * sin (0), width * fraction);
glVertex3f (r1 * cos (0), r1 * sin (0), -width * fraction);
glEnd ();
@@ -993,12 +947,14 @@ static void
init (void)
{
GLfloat matShine = 20.00F;
- GLfloat light0Pos[4] =
+ const GLfloat light0Pos[4] =
{
0.70F, 0.70F, 1.25F, 0.50F
};
int i;
+ glShadeModel(GL_FLAT);
+
glClearColor (background[0], background[1], background[2], 1.0F);
glClearIndex ((GLfloat) 0.0);
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