return;
}
*nVert = slices*(stacks-1)+2;
+ if ((*nVert) > 65535) /* TODO: must have a better solution than this low limit, at least for architectures where gluint is available */
+ fgWarning("fghGenerateSphere: too many slices or stacks requested, indices will wrap");
/* precompute values on unit circle */
fghCircleTable(&sint1,&cost1,-slices,FALSE);
*nVert = 0;
return;
}
- *nVert = slices*(stacks+1)+1;
+ *nVert = slices*(stacks+2)+1; /* need an extra stack for closing off bottom with correct normals */
+
+ if ((*nVert) > 65535)
+ fgWarning("fghGenerateCone: too many slices or stacks requested, indices will wrap");
/* Pre-computed circle */
fghCircleTable(&sint,&cost,-slices,FALSE);
(*normals )[1] = 0.f;
(*normals )[2] = -1.f;
idx = 3;
+ /* other on bottom (get normals right) */
+ for (j=0; j<slices; j++, idx+=3)
+ {
+ (*vertices)[idx ] = cost[j]*r;
+ (*vertices)[idx+1] = sint[j]*r;
+ (*vertices)[idx+2] = z;
+ (*normals )[idx ] = 0.f;
+ (*normals )[idx+1] = 0.f;
+ (*normals )[idx+2] = -1.f;
+ }
/* each stack */
for (i=0; i<stacks+1; i++ )
free(sint);
free(cost);
}
+
+void fghGenerateCylinder(
+ GLfloat radius, GLfloat height, GLint slices, GLint stacks, /* input */
+ GLfloat **vertices, GLfloat **normals, int* nVert /* output */
+ )
+{
+ int i,j;
+ int idx = 0; /* idx into vertex/normal buffer */
+
+ /* Step in z as stacks are drawn. */
+ GLfloat radf = (GLfloat)radius;
+ GLfloat z;
+ const GLfloat zStep = (GLfloat)height / ( ( stacks > 0 ) ? stacks : 1 );
+
+ /* Pre-computed circle */
+ GLfloat *sint,*cost;
+
+ /* number of unique vertices */
+ if (slices==0 || stacks<1)
+ {
+ /* nothing to generate */
+ *nVert = 0;
+ return;
+ }
+ *nVert = slices*(stacks+3)+2; /* need two extra stacks for closing off top and bottom with correct normals */
+
+ if ((*nVert) > 65535)
+ fgWarning("fghGenerateCylinder: too many slices or stacks requested, indices will wrap");
+
+ /* Pre-computed circle */
+ fghCircleTable(&sint,&cost,-slices,FALSE);
+
+ /* Allocate vertex and normal buffers, bail out if memory allocation fails */
+ *vertices = malloc((*nVert)*3*sizeof(GLfloat));
+ *normals = malloc((*nVert)*3*sizeof(GLfloat));
+ if (!(vertices) || !(normals))
+ {
+ free(*vertices);
+ free(*normals);
+ fgError("Failed to allocate memory in fghGenerateCylinder");
+ }
+
+ z=0;
+ /* top on Z-axis */
+ (*vertices)[0] = 0.f;
+ (*vertices)[1] = 0.f;
+ (*vertices)[2] = 0.f;
+ (*normals )[0] = 0.f;
+ (*normals )[1] = 0.f;
+ (*normals )[2] = -1.f;
+ idx = 3;
+ /* other on top (get normals right) */
+ for (j=0; j<slices; j++, idx+=3)
+ {
+ (*vertices)[idx ] = cost[j]*radf;
+ (*vertices)[idx+1] = sint[j]*radf;
+ (*vertices)[idx+2] = z;
+ (*normals )[idx ] = 0.f;
+ (*normals )[idx+1] = 0.f;
+ (*normals )[idx+2] = -1.f;
+ }
+
+ /* each stack */
+ for (i=0; i<stacks+1; i++ )
+ {
+ for (j=0; j<slices; j++, idx+=3)
+ {
+ (*vertices)[idx ] = cost[j]*radf;
+ (*vertices)[idx+1] = sint[j]*radf;
+ (*vertices)[idx+2] = z;
+ (*normals )[idx ] = cost[j];
+ (*normals )[idx+1] = sint[j];
+ (*normals )[idx+2] = 0.f;
+ }
+
+ z += zStep;
+ }
+
+ /* other on bottom (get normals right) */
+ z -= zStep;
+ for (j=0; j<slices; j++, idx+=3)
+ {
+ (*vertices)[idx ] = cost[j]*radf;
+ (*vertices)[idx+1] = sint[j]*radf;
+ (*vertices)[idx+2] = z;
+ (*normals )[idx ] = 0.f;
+ (*normals )[idx+1] = 0.f;
+ (*normals )[idx+2] = 1.f;
+ }
+
+ /* bottom */
+ (*vertices)[idx ] = 0.f;
+ (*vertices)[idx+1] = 0.f;
+ (*vertices)[idx+2] = height;
+ (*normals )[idx ] = 0.f;
+ (*normals )[idx+1] = 0.f;
+ (*normals )[idx+2] = 1.f;
+
+ /* Release sin and cos tables */
+ free(sint);
+ free(cost);
+}
#endif
/* -- INTERNAL DRAWING functions --------------------------------------- */
int i,j,idx, nVert;
GLfloat *vertices, *normals;
- if (slices * stacks > 65535)
- fgWarning("fghSphere: too many slices or stacks requested, indices will wrap");
-
/* Generate vertices and normals */
fghGenerateSphere((GLfloat)radius,slices,stacks,&vertices,&normals,&nVert);
int i,j,idx, nVert;
GLfloat *vertices, *normals;
- if (slices * stacks > 65535)
- fgWarning("fghCone: too many slices or stacks requested, indices will wrap");
-
/* Generate vertices and normals */
+ /* Note, (stacks+1)*slices vertices for side of object, slices+1 for top and bottom closures */
fghGenerateCone((GLfloat)base,(GLfloat)height,slices,stacks,&vertices,&normals,&nVert);
if (nVert==0)
}
/* generate for each stack */
- for (i=0,idx=0; i<stacks+1; i++)
+ for (i=0,idx=0; i<stacks; i++)
{
- GLushort offset = 1+i*slices; /* start at 1 (0 is top vertex), and we advance one stack down as we go along */
+ GLushort offset = 1+(i+1)*slices; /* start at 1 (0 is top vertex), and we advance one stack down as we go along */
for (j=0; j<slices; j++, idx++)
{
stackIdx[idx] = offset+j;
for (i=0,idx=0; i<slices; i++)
{
GLushort offset = 1+i; /* start at 1 (0 is top vertex), and we advance one slice as we go along */
- sliceIdx[idx++] = offset;
- sliceIdx[idx++] = offset+stacks*slices;
+ sliceIdx[idx++] = offset+slices;
+ sliceIdx[idx++] = offset+(stacks+1)*slices;
}
/* draw */
GLushort offset;
/* Allocate buffers for indices, bail out if memory allocation fails */
- stripIdx = malloc((slices+1)*2*(stacks+1)*sizeof(GLushort));
+ stripIdx = malloc((slices+1)*2*(stacks+1)*sizeof(GLushort)); /*stacks +1 because of closing off bottom */
if (!(stripIdx))
{
free(stripIdx);
/* Strip indices are relative to first index belonging to strip, NOT relative to first vertex/normal pair in array */
for (i=0; i<stacks; i++, idx+=2)
{
- offset = 1+i*slices; /* triangle_strip indices start at 1 (0 is top vertex), and we advance one stack down as we go along */
+ offset = 1+(i+1)*slices; /* triangle_strip indices start at 1 (0 is top vertex), and we advance one stack down as we go along */
for (j=0; j<slices; j++, idx+=2)
{
stripIdx[idx ] = offset+j;
free(normals);
}
+static void fghCylinder( double radius, double height, GLint slices, GLint stacks, GLboolean useWireMode )
+{
+ int i,j,idx, nVert;
+ GLfloat *vertices, *normals;
+
+ /* Generate vertices and normals */
+ /* Note, (stacks+1)*slices vertices for side of object, 2*slices+2 for top and bottom closures */
+ fghGenerateCylinder((GLfloat)radius,(GLfloat)height,slices,stacks,&vertices,&normals,&nVert);
+
+ if (nVert==0)
+ /* nothing to draw */
+ return;
+
+ if (useWireMode)
+ {
+ GLushort *sliceIdx, *stackIdx;
+ /* First, generate vertex index arrays for drawing with glDrawElements
+ * We have a bunch of line_loops to draw for each stack, and a
+ * bunch for each slice.
+ */
+
+ stackIdx = malloc(slices*(stacks+1)*sizeof(GLushort));
+ sliceIdx = malloc(slices*2 *sizeof(GLushort));
+ if (!(stackIdx) || !(sliceIdx))
+ {
+ free(stackIdx);
+ free(sliceIdx);
+ fgError("Failed to allocate memory in fghGenerateCylinder");
+ }
+
+ /* generate for each stack */
+ for (i=0,idx=0; i<stacks+1; i++)
+ {
+ GLushort offset = 1+(i+1)*slices; /* start at 1 (0 is top vertex), and we advance one stack down as we go along */
+ for (j=0; j<slices; j++, idx++)
+ {
+ stackIdx[idx] = offset+j;
+ }
+ }
+
+ /* generate for each slice */
+ for (i=0,idx=0; i<slices; i++)
+ {
+ GLushort offset = 1+i; /* start at 1 (0 is top vertex), and we advance one slice as we go along */
+ sliceIdx[idx++] = offset+slices;
+ sliceIdx[idx++] = offset+(stacks+1)*slices;
+ }
+
+ /* draw */
+ glEnableClientState(GL_VERTEX_ARRAY);
+ glEnableClientState(GL_NORMAL_ARRAY);
+
+ glVertexPointer(3, GL_FLOAT, 0, vertices);
+ glNormalPointer(GL_FLOAT, 0, normals);
+ /*draw slices*/
+ glDrawElements(GL_LINES,slices*2,GL_UNSIGNED_SHORT,sliceIdx);
+ /*draw stacks*/
+ for (i=0; i<stacks+1; i++)
+ glDrawElements(GL_LINE_LOOP, slices,GL_UNSIGNED_SHORT,stackIdx+i*slices);
+
+ glDisableClientState(GL_VERTEX_ARRAY);
+ glDisableClientState(GL_NORMAL_ARRAY);
+
+ /* cleanup allocated memory */
+ free(sliceIdx);
+ free(stackIdx);
+ }
+ else
+ {
+ /* First, generate vertex index arrays for drawing with glDrawElements
+ * All stacks, including top and bottom are covered with a triangle
+ * strip.
+ */
+ GLushort *stripIdx;
+ /* Create index vector */
+ GLushort offset;
+
+ /* Allocate buffers for indices, bail out if memory allocation fails */
+ stripIdx = malloc((slices+1)*2*(stacks+2)*sizeof(GLushort)); /*stacks +2 because of closing off bottom and top */
+ if (!(stripIdx))
+ {
+ free(stripIdx);
+ fgError("Failed to allocate memory in fghGenerateCylinder");
+ }
+
+ /* top stack */
+ for (j=0, idx=0; j<slices; j++, idx+=2)
+ {
+ stripIdx[idx ] = 0;
+ stripIdx[idx+1] = j+1; /* 0 is top vertex, 1 is first for first stack */
+ }
+ stripIdx[idx ] = 0; /* repeat first slice's idx for closing off shape */
+ stripIdx[idx+1] = 1;
+ idx+=2;
+
+ /* middle stacks: */
+ /* Strip indices are relative to first index belonging to strip, NOT relative to first vertex/normal pair in array */
+ for (i=0; i<stacks; i++, idx+=2)
+ {
+ offset = 1+(i+1)*slices; /* triangle_strip indices start at 1 (0 is top vertex), and we advance one stack down as we go along */
+ for (j=0; j<slices; j++, idx+=2)
+ {
+ stripIdx[idx ] = offset+j;
+ stripIdx[idx+1] = offset+j+slices;
+ }
+ stripIdx[idx ] = offset; /* repeat first slice's idx for closing off shape */
+ stripIdx[idx+1] = offset+slices;
+ }
+
+ /* top stack */
+ offset = 1+(stacks+2)*slices;
+ for (j=0; j<slices; j++, idx+=2)
+ {
+ stripIdx[idx ] = offset+j;
+ stripIdx[idx+1] = nVert-1; /* zero based index, last element in array (bottom vertex)... */
+ }
+ stripIdx[idx ] = offset;
+ stripIdx[idx+1] = nVert-1; /* repeat first slice's idx for closing off shape */
+
+ /* draw */
+ glEnableClientState(GL_VERTEX_ARRAY);
+ glEnableClientState(GL_NORMAL_ARRAY);
+
+ glVertexPointer(3, GL_FLOAT, 0, vertices);
+ glNormalPointer(GL_FLOAT, 0, normals);
+ /*draw stacks*/
+ for (i=0; i<stacks+2; i++)
+ glDrawElements(GL_TRIANGLE_STRIP,(slices+1)*2,GL_UNSIGNED_SHORT,stripIdx+i*(slices+1)*2);
+
+ glDisableClientState(GL_VERTEX_ARRAY);
+ glDisableClientState(GL_NORMAL_ARRAY);
+
+ /* cleanup allocated memory */
+ free(stripIdx);
+ }
+
+ /* cleanup allocated memory */
+ free(vertices);
+ free(normals);
+}
+
/* -- INTERFACE FUNCTIONS ---------------------------------------------- */
*/
void FGAPIENTRY glutSolidCylinder(double radius, double height, GLint slices, GLint stacks)
{
- int i,j;
-
- /* Step in z and radius as stacks are drawn. */
- GLfloat radf = (GLfloat)radius;
- GLfloat z0,z1;
- const GLfloat zStep = (GLfloat)height / ( ( stacks > 0 ) ? stacks : 1 );
-
- /* Pre-computed circle */
-
- GLfloat *sint,*cost;
-
FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutSolidCylinder" );
- fghCircleTable(&sint,&cost,-slices,FALSE);
-
- /* Cover the base and top */
-
- glBegin(GL_TRIANGLE_FAN);
- glNormal3f(0, 0, -1 );
- glVertex3f(0, 0, 0 );
- for (j=0; j<=slices; j++)
- glVertex3f(cost[j]*radf, sint[j]*radf, 0);
- glEnd();
-
- glBegin(GL_TRIANGLE_FAN);
- glNormal3f(0, 0, 1 );
- glVertex3f(0, 0, (GLfloat)height);
- for (j=slices; j>=0; j--)
- glVertex3f(cost[j]*radf, sint[j]*radf, (GLfloat)height);
- glEnd();
-
- /* Do the stacks */
-
- z0 = 0;
- z1 = zStep;
-
- for (i=1; i<=stacks; i++)
- {
- if (i==stacks)
- z1 = (GLfloat)height;
-
- glBegin(GL_TRIANGLE_STRIP);
- for (j=0; j<=slices; j++ )
- {
- glNormal3f(cost[j], sint[j], 0 );
- glVertex3f(cost[j]*radf, sint[j]*radf, z0 );
- glVertex3f(cost[j]*radf, sint[j]*radf, z1 );
- }
- glEnd();
-
- z0 = z1; z1 += zStep;
- }
-
- /* Release sin and cos tables */
-
- free(sint);
- free(cost);
+ fghCylinder( radius, height, slices, stacks, FALSE );
}
/*
*/
void FGAPIENTRY glutWireCylinder(double radius, double height, GLint slices, GLint stacks)
{
- int i,j;
-
- /* Step in z and radius as stacks are drawn. */
- GLfloat radf = (GLfloat)radius;
- GLfloat z = 0;
- const GLfloat zStep = (GLfloat)height / ( ( stacks > 0 ) ? stacks : 1 );
-
- /* Pre-computed circle */
-
- GLfloat *sint,*cost;
-
FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutWireCylinder" );
- fghCircleTable(&sint,&cost,-slices,FALSE);
-
- /* Draw the stacks... */
-
- for (i=0; i<=stacks; i++)
- {
- if (i==stacks)
- z = (GLfloat)height;
-
- glBegin(GL_LINE_LOOP);
-
- for( j=0; j<slices; j++ )
- {
- glNormal3f(cost[j], sint[j], 0);
- glVertex3f(cost[j]*radf, sint[j]*radf, z);
- }
-
- glEnd();
-
- z += zStep;
- }
-
- /* Draw the slices */
-
- glBegin(GL_LINES);
-
- for (j=0; j<slices; j++)
- {
- glNormal3f(cost[j], sint[j], 0 );
- glVertex3f(cost[j]*radf, sint[j]*radf, 0 );
- glVertex3f(cost[j]*radf, sint[j]*radf, (GLfloat)height);
- }
-
- glEnd();
-
- /* Release sin and cos tables */
-
- free(sint);
- free(cost);
+ fghCylinder( radius, height, slices, stacks, TRUE );
}
/*
projects / freeglut / commitdiff