--- /dev/null
+/*
+ * taper.c
+ *
+ * FUNCTION:
+ * Draws a tapered screw shape.
+ *
+ * HISTORY:
+ * -- created by Linas Vepstas October 1991
+ * -- heavily modified to draw more texas shapes, Feb 1993, Linas
+ * -- converted to use GLUT -- December 1995, Linas
+ *
+ */
+
+/* required include files */
+#include <math.h>
+#include <stdlib.h>
+#include <GL/gl.h>
+#include <GL/glut.h>
+#include <GL/tube.h>
+
+#ifndef NULL
+#define NULL ((void *) 0x0)
+#endif /* NULL */
+
+/* Some <math.h> files do not define M_PI... */
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+/* =========================================================== */
+
+#define SCALE 3.33333
+#define CONTOUR(x,y) { \
+ double ax, ay, alen; \
+ contour[i][0] = SCALE * (x); \
+ contour[i][1] = SCALE * (y); \
+ if (i!=0) { \
+ ax = contour[i][0] - contour[i-1][0]; \
+ ay = contour[i][1] - contour[i-1][1]; \
+ alen = 1.0 / sqrt (ax*ax + ay*ay); \
+ ax *= alen; ay *= alen; \
+ norms [i-1][0] = ay; \
+ norms [i-1][1] = -ax; \
+ } \
+ i++; \
+}
+
+#define NUM_PTS (25)
+
+double contour [NUM_PTS][2];
+double norms [NUM_PTS][2];
+
+static void init_contour (void)
+{
+ int i;
+
+ /* outline of extrusion */
+ i=0;
+ CONTOUR (1.0, 1.0);
+ CONTOUR (1.0, 2.9);
+ CONTOUR (0.9, 3.0);
+ CONTOUR (-0.9, 3.0);
+ CONTOUR (-1.0, 2.9);
+
+ CONTOUR (-1.0, 1.0);
+ CONTOUR (-2.9, 1.0);
+ CONTOUR (-3.0, 0.9);
+ CONTOUR (-3.0, -0.9);
+ CONTOUR (-2.9, -1.0);
+
+ CONTOUR (-1.0, -1.0);
+ CONTOUR (-1.0, -2.9);
+ CONTOUR (-0.9, -3.0);
+ CONTOUR (0.9, -3.0);
+ CONTOUR (1.0, -2.9);
+
+ CONTOUR (1.0, -1.0);
+ CONTOUR (2.9, -1.0);
+ CONTOUR (3.0, -0.9);
+ CONTOUR (3.0, 0.9);
+ CONTOUR (2.9, 1.0);
+
+ CONTOUR (1.0, 1.0); /* repeat so that last normal is computed */
+}
+
+/* =========================================================== */
+
+#define PSIZE 40
+double path[PSIZE][3];
+double twist[PSIZE];
+double taper[PSIZE];
+
+void init_taper (void) {
+ int j;
+ double z, deltaz;
+ double ang, dang;
+
+ z = -10.0;
+ deltaz = 0.5;
+
+ ang = 0.0;
+ dang = 20.0;
+ for (j=0; j<40; j++) {
+ path[j][0] = 0x0;
+ path[j][1] = 0x0;
+ path[j][2] = z;
+
+ twist[j] = ang;
+ ang += dang;
+
+ taper[j] = 0.1 * sqrt (9.51*9.51 - z*z);
+
+ z += deltaz;
+ }
+
+ taper[0] = taper[1];
+ taper[39] = taper[38];
+
+}
+
+/* =========================================================== */
+
+extern float lastx;
+extern float lasty;
+extern float rot_x;
+extern float rot_y;
+extern float rot_z;
+
+void InitStuff_taper (void)
+{
+ int style;
+
+ /* configure the pipeline */
+ style = TUBE_JN_CAP;
+ style |= TUBE_CONTOUR_CLOSED;
+ style |= TUBE_NORM_FACET;
+ style |= TUBE_JN_ANGLE;
+ gleSetJoinStyle (style);
+
+ init_contour();
+ init_taper();
+}
+
+/* =========================================================== */
+
+void gleTaper (int ncp,
+ gleDouble contour[][2],
+ gleDouble cont_normal[][2],
+ gleDouble up[3],
+ int npoints,
+ gleDouble point_array[][3],
+ float color_array[][3],
+ gleDouble taper[],
+ gleDouble twist[])
+{
+ int j;
+ gleAffine *xforms;
+ double co, si, angle;
+
+ /* malloc the extrusion array and the twist array */
+ xforms = (gleAffine *) malloc (npoints * sizeof(gleAffine));
+
+ for (j=0; j<npoints; j++) {
+ angle = (M_PI/180.0) * twist[j];
+ si = sin (angle);
+ co = cos (angle);
+ xforms[j][0][0] = taper[j] * co;
+ xforms[j][0][1] = - taper[j] * si;
+ xforms[j][0][2] = 0.0;
+ xforms[j][1][0] = taper[j] * si;
+ xforms[j][1][1] = taper[j] * co;
+ xforms[j][1][2] = 0.0;
+ }
+
+ gleSuperExtrusion (ncp, /* number of contour points */
+ contour, /* 2D contour */
+ cont_normal, /* 2D contour normals */
+ up, /* up vector for contour */
+ npoints, /* numpoints in poly-line */
+ point_array, /* polyline */
+ color_array, /* color of polyline */
+ xforms);
+
+ free (xforms);
+}
+
+/* =========================================================== */
+
+void DrawStuff_taper (void) {
+ int j;
+ double ang, dang;
+ double z, deltaz;
+ double ponent;
+ z=-1.0;
+ deltaz = 1.999/38;
+ ang = 0.0;
+ dang = lasty/40.0;
+ ponent = fabs (lastx/540.0);
+ for (j=1; j<39; j++) {
+ twist[j] = ang;
+ ang += dang;
+
+ taper[j] = pow ((1.0 - pow (fabs(z), 1.0/ponent)), ponent);
+ z += deltaz;
+ }
+
+ glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+ glColor3f (0.5, 0.6, 0.6);
+
+ /* set up some matrices so that the object spins with the mouse */
+ glPushMatrix ();
+ glTranslatef (0.0, 0.0, -80.0);
+ glRotatef(rot_x, 1, 0, 0);
+ glRotatef(rot_y, 0, 1, 0);
+ glRotatef(rot_z, 0, 0, 1);
+
+/* glRotatef (130.0, 0.0, 1.0, 0.0); */
+/* glRotatef (65.0, 1.0, 0.0, 0.0); */
+
+ /* draw the brand and the handle */
+ gleTaper (20, contour, norms, NULL, 40, path, NULL, taper, twist);
+
+ glPopMatrix ();
+}
+
+/* ===================== END OF FILE ================== */
projects / xscreensaver / blobdiff