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Enhanced to handle ccw and cw tri-stripe winding. This is a temporary

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admission of defeat.  I will eventually go back and get all the stripes
wound the same way (ccw).
This commit is contained in:
curt 1997-12-08 22:51:17 +00:00
parent 98ec9af098
commit 2425bbe6bd
2 changed files with 55 additions and 11 deletions
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55
Scenery/obj.c
View file

@ -47,13 +47,14 @@ float normals[MAXNODES][3];
/* Load a .obj file and generate the GL call list */ /* Load a .obj file and generate the GL call list */
GLint fgObjLoad(char *path) { GLint fgObjLoad(char *path) {
char line[256]; char line[256], winding[256];
static GLfloat color[4] = { 0.5, 0.5, 0.25, 1.0 }; static GLfloat color[4] = { 0.5, 0.5, 0.25, 1.0 };
double v1[3], v2[3], approx_normal[3], dot_prod, temp; double v1[3], v2[3], approx_normal[3], dot_prod, temp;
struct fgCartesianPoint ref; struct fgCartesianPoint ref;
GLint area; GLint area;
FILE *f; FILE *f;
int first, ncount, vncount, n1, n2, n3, n4; int first, ncount, vncount, n1, n2, n3, n4;
int i;
if ( (f = fopen(path, "r")) == NULL ) { if ( (f = fopen(path, "r")) == NULL ) {
printf("Cannot open file: %s\n", path); printf("Cannot open file: %s\n", path);
@ -103,6 +104,19 @@ GLint fgObjLoad(char *path) {
printf("Read too many vertex normals ... dying :-(\n"); printf("Read too many vertex normals ... dying :-(\n");
exit(-1); exit(-1);
} }
} else if ( strncmp(line, "winding ", 8) == 0 ) {
sscanf(line+8, "%s", winding);
printf("WINDING = %s\n", winding);
/* can't call glFrontFace() between glBegin() & glEnd() */
glEnd();
first = 1;
if ( strcmp(winding, "cw") == 0 ) {
glFrontFace( GL_CW );
} else {
glFrontFace ( GL_CCW );
}
} else if ( line[0] == 't' ) { } else if ( line[0] == 't' ) {
/* start a new triangle strip */ /* start a new triangle strip */
@ -115,8 +129,6 @@ GLint fgObjLoad(char *path) {
first = 0; first = 0;
} }
glBegin(GL_TRIANGLE_STRIP);
/* printf("new tri strip = %s", line); */ /* printf("new tri strip = %s", line); */
sscanf(line, "t %d %d %d %d\n", &n1, &n2, &n3, &n4); sscanf(line, "t %d %d %d %d\n", &n1, &n2, &n3, &n4);
@ -125,7 +137,7 @@ GLint fgObjLoad(char *path) {
/* try to get the proper rotation by calculating an /* try to get the proper rotation by calculating an
* approximate normal and seeing if it is close to the * approximate normal and seeing if it is close to the
* precalculated normal */ * precalculated normal */
v1[0] = nodes[n2][0] - nodes[n1][0]; /*v1[0] = nodes[n2][0] - nodes[n1][0];
v1[1] = nodes[n2][1] - nodes[n1][1]; v1[1] = nodes[n2][1] - nodes[n1][1];
v1[2] = nodes[n2][2] - nodes[n1][2]; v1[2] = nodes[n2][2] - nodes[n1][2];
v2[0] = nodes[n3][0] - nodes[n1][0]; v2[0] = nodes[n3][0] - nodes[n1][0];
@ -136,10 +148,18 @@ GLint fgObjLoad(char *path) {
printf("Approx normal = %.2f %.2f %.2f\n", approx_normal[0], printf("Approx normal = %.2f %.2f %.2f\n", approx_normal[0],
approx_normal[1], approx_normal[2]); approx_normal[1], approx_normal[2]);
dot_prod = MAT3_DOT_PRODUCT(normals[n1], approx_normal); dot_prod = MAT3_DOT_PRODUCT(normals[n1], approx_normal);
printf("Dot product = %.4f\n", dot_prod); printf("Dot product = %.4f\n", dot_prod); */
/* angle = acos(dot_prod); */ /* angle = acos(dot_prod); */
/* printf("Normal ANGLE = %.3f rads.\n", angle); */ /* printf("Normal ANGLE = %.3f rads.\n", angle); */
/* if ( dot_prod < -0.5 ) {
glFrontFace( GL_CW );
} else {
glFrontFace( GL_CCW );
} */
glBegin(GL_TRIANGLE_STRIP);
glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]); glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y, glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
nodes[n1][2] - ref.z); nodes[n1][2] - ref.z);
@ -207,6 +227,20 @@ GLint fgObjLoad(char *path) {
} }
glEnd(); glEnd();
/* Draw normal vectors (for visually verifying normals)*/
/* glBegin(GL_LINES); */
/* glColor3f(0.0, 0.0, 0.0); */
/* for ( i = 0; i < ncount; i++ ) { */
/* glVertex3d(nodes[i][0] - ref.x, */
/* nodes[i][1] - ref.y, */
/* nodes[i][2] - ref.z); */
/* glVertex3d(nodes[i][0] - ref.x + 1000*normals[i][0], */
/* nodes[i][1] - ref.y + 1000*normals[i][1], */
/* nodes[i][2] - ref.z + 1000*normals[i][2]); */
/* } */
/* glEnd(); */
glEndList(); glEndList();
fclose(f); fclose(f);
@ -216,9 +250,14 @@ GLint fgObjLoad(char *path) {
/* $Log$ /* $Log$
/* Revision 1.6 1997/11/25 19:25:35 curt /* Revision 1.7 1997/12/08 22:51:17 curt
/* Changes to integrate Durk's moon/sun code updates + clean up. /* Enhanced to handle ccw and cw tri-stripe winding. This is a temporary
/* admission of defeat. I will eventually go back and get all the stripes
/* wound the same way (ccw).
/* /*
* Revision 1.6 1997/11/25 19:25:35 curt
* Changes to integrate Durk's moon/sun code updates + clean up.
*
* Revision 1.5 1997/11/15 18:16:39 curt * Revision 1.5 1997/11/15 18:16:39 curt
* minor tweaks. * minor tweaks.
* *

11
Scenery/scenery.c
View file

@ -80,16 +80,21 @@ void fgSceneryUpdate(double lon, double lat, double elev) {
/* Render out the current scene */ /* Render out the current scene */
void fgSceneryRender() { void fgSceneryRender() {
/* glCallList(area_terrain); */ glCallList(area_terrain);
fgAstroRender(); fgAstroRender();
} }
/* $Log$ /* $Log$
/* Revision 1.23 1997/11/25 19:25:37 curt /* Revision 1.24 1997/12/08 22:51:18 curt
/* Changes to integrate Durk's moon/sun code updates + clean up. /* Enhanced to handle ccw and cw tri-stripe winding. This is a temporary
/* admission of defeat. I will eventually go back and get all the stripes
/* wound the same way (ccw).
/* /*
* Revision 1.23 1997/11/25 19:25:37 curt
* Changes to integrate Durk's moon/sun code updates + clean up.
*
* Revision 1.22 1997/10/28 21:00:22 curt * Revision 1.22 1997/10/28 21:00:22 curt
* Changing to new terrain format. * Changing to new terrain format.
* *