glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_NORMAL_ARRAY);
}
-/**
- * Draw the geometric shape with filled triangles
+
+/* Draw the geometric shape with filled triangles
*
* - If the shape is naturally triangulated (numEdgePerFace==3), each
* vertex+normal pair is used only once, so no vertex indices.
glDisableClientState(GL_NORMAL_ARRAY);
}
+
+
/* Shape decomposition to triangles
* We'll use glDrawElements to draw all shapes that are not naturally
* composed of triangles, so generate an index vector here, using the
}
}
+static void fghGenerateSphere(GLfloat radius, GLint slices, GLint stacks, GLfloat **vertices, GLfloat **normals, int* nVert)
+{
+ int i,j;
+ int idx = 0; /* idx into vertex/normal buffer */
+ GLfloat x,y,z;
+
+ /* Pre-computed circle */
+ GLfloat *sint1,*cost1;
+ GLfloat *sint2,*cost2;
+
+ /* number of unique vertices */
+ if (slices==0 || stacks<2)
+ {
+ /* nothing to generate */
+ *nVert = 0;
+ return;
+ }
+ *nVert = slices*(stacks-1)+2;
+
+ /* precompute values on unit circle */
+ fghCircleTable(&sint1,&cost1,-slices,FALSE);
+ fghCircleTable(&sint2,&cost2, stacks,TRUE);
+
+ /* 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 fghGenerateSphere");
+ }
+
+ /* top */
+ (*vertices)[0] = 0.f;
+ (*vertices)[1] = 0.f;
+ (*vertices)[2] = radius;
+ (*normals )[0] = 0.f;
+ (*normals )[1] = 0.f;
+ (*normals )[2] = 1.f;
+ idx = 3;
+
+ /* each stack */
+ for( i=1; i<stacks; i++ )
+ {
+ for(j=0; j<slices; j++, idx+=3)
+ {
+ x = cost1[j]*sint2[i];
+ y = sint1[j]*sint2[i];
+ z = cost2[i];
+
+ (*vertices)[idx ] = x*radius;
+ (*vertices)[idx+1] = y*radius;
+ (*vertices)[idx+2] = z*radius;
+ (*normals )[idx ] = x;
+ (*normals )[idx+1] = y;
+ (*normals )[idx+2] = z;
+ }
+ }
+
+ /* bottom */
+ (*vertices)[idx ] = 0.f;
+ (*vertices)[idx+1] = 0.f;
+ (*vertices)[idx+2] = -radius;
+ (*normals )[idx ] = 0.f;
+ (*normals )[idx+1] = 0.f;
+ (*normals )[idx+2] = -1.f;
+
+ /* Done creating vertices, release sin and cos tables */
+ free(sint1);
+ free(cost1);
+ free(sint2);
+ free(cost2);
+}
+
/* -- INTERNAL DRAWING functions --------------------------------------- */
#define _DECLARE_INTERNAL_DRAW_DO_DECLARE(name,nameICaps,nameCaps,vertIdxs)\
free(normals );
}
}
-#endif /* GL_ES_VERSION_2_0 */
-/* -- INTERFACE FUNCTIONS ---------------------------------------------- */
-
-
-#ifndef EGL_VERSION_1_0
-/*
- * Draws a solid sphere
- */
-void FGAPIENTRY glutSolidSphere(double radius, GLint slices, GLint stacks)
+static void fghSphere( double radius, GLint slices, GLint stacks, GLboolean useWireMode )
{
- int i,j;
+ int i,j,idx, nVert;
+ GLfloat *vertices, *normals;
- /* Adjust z and radius as stacks are drawn. */
- GLfloat radf = (GLfloat)radius;
- GLfloat z0,z1;
- GLfloat r0,r1;
-
- /* Pre-computed circle */
+ /* Generate vertices and normals */
+ fghGenerateSphere((GLfloat)radius,slices,stacks,&vertices,&normals,&nVert);
+
+ if (nVert==0)
+ /* nothing to draw */
+ return;
- GLfloat *sint1,*cost1;
- GLfloat *sint2,*cost2;
+ if (useWireMode)
+ {
+ GLuint *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.
+ */
- FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutSolidSphere" );
+ sliceIdx = malloc(slices*(stacks+1)*sizeof(GLuint));
+ stackIdx = malloc(slices*(stacks-1)*sizeof(GLuint));
- fghCircleTable(&sint1,&cost1,-slices,FALSE);
- fghCircleTable(&sint2,&cost2, stacks,TRUE);
+ /* generate for each stack */
+ for (i=0,idx=0; i<slices; i++)
+ {
+ GLuint offset = 1+i; /* start at 1 (0 is top vertex), and we advance one slice as we go along */
+ sliceIdx[idx++] = 0; /* vertex on top */
+ for (j=0; j<stacks-1; j++, idx++)
+ {
+ sliceIdx[idx] = offset+j*slices;
+ }
+ sliceIdx[idx++] = nVert-1; /* zero based index, last element in array... */
+ }
- /* The top stack is covered with a triangle fan */
+ /* generate for each stack */
+ for (i=0,idx=0; i<stacks-1; i++)
+ {
+ GLuint offset = 1+i*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;
+ }
+ }
- z0 = 1;
- z1 = cost2[(stacks>0)?1:0];
- r0 = 0;
- r1 = sint2[(stacks>0)?1:0];
+ /* draw */
+ glEnableClientState(GL_VERTEX_ARRAY);
+ glEnableClientState(GL_NORMAL_ARRAY);
- glBegin(GL_TRIANGLE_FAN);
+ glVertexPointer(3, GL_FLOAT, 0, vertices);
+ glNormalPointer(GL_FLOAT, 0, normals);
+ /*draw slices*/
+ for (i=0; i<slices; i++)
+ glDrawElements(GL_LINE_STRIP,stacks+1,GL_UNSIGNED_INT,sliceIdx+i*(stacks+1));
+ /*draw stacks*/
+ for (i=0; i<stacks-1; i++)
+ glDrawElements(GL_LINE_LOOP, slices,GL_UNSIGNED_INT,stackIdx+i*slices);
- glNormal3f(0,0,1);
- glVertex3f(0,0,radf);
+ glDisableClientState(GL_VERTEX_ARRAY);
+ glDisableClientState(GL_NORMAL_ARRAY);
- for (j=slices; j>=0; j--)
+ /* cleanup allocated memory */
+ free(sliceIdx);
+ free(stackIdx);
+ }
+ else
+ {
+ GLuint *topIdx, *bottomIdx, *stripIdx;
+ /* First, generate vertex index arrays for drawing with glDrawElements
+ * Top and bottom are covered with a triangle fan
+ * Each other stack with triangle strip. Only need to generate on
+ * of those as we'll have to draw each stack separately, and can
+ * just use different offsets in glDrawElements.
+ */
+
+ /* Allocate buffers for indices, bail out if memory allocation fails */
+ topIdx = malloc((slices+2)*sizeof(GLuint));
+ bottomIdx = malloc((slices+2)*sizeof(GLuint));
+ stripIdx = malloc((slices+1)*2*(stacks-2)*sizeof(GLuint));
+ if (!(topIdx) || !(bottomIdx) || !(stripIdx))
{
- glNormal3f(cost1[j]*r1, sint1[j]*r1, z1 );
- glVertex3f(cost1[j]*r1*radf, sint1[j]*r1*radf, z1*radf);
+ free(topIdx);
+ free(bottomIdx);
+ free(stripIdx);
+ fgError("Failed to allocate memory in fghGenerateSphere");
}
- glEnd();
+ topIdx[0]=0;
+ topIdx[1] = 1; /* repeat first slice's idx for closing off shape */
+ for (j=slices, idx=2; j>0; j--, idx++)
+ topIdx[idx] = j;
- /* Cover each stack with a quad strip, except the top and bottom stacks */
-
- for( i=1; i<stacks-1; i++ )
- {
- z0 = z1; z1 = cost2[i+1];
- r0 = r1; r1 = sint2[i+1];
-
- glBegin(GL_QUAD_STRIP);
+ bottomIdx[0]=nVert-1; /* zero based index, last element in array... */
+ for (j=0, idx=1; j<slices; j++, idx++)
+ bottomIdx[idx] = nVert-(slices+1)+j;
+ bottomIdx[idx] = nVert-(slices+1); /* repeat first slice's idx for closing off shape */
- for(j=0; j<=slices; j++)
+ /* Strip indices are relative to first index belonging to strip, NOT relative to first vertex/normal pair in array */
+ for (i=0,idx=0; i<stacks-2; i++, idx+=2)
+ {
+ GLuint offset = 1+i*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)
{
- glNormal3d(cost1[j]*r1, sint1[j]*r1, z1 );
- glVertex3d(cost1[j]*r1*radf, sint1[j]*r1*radf, z1*radf);
- glNormal3d(cost1[j]*r0, sint1[j]*r0, z0 );
- glVertex3d(cost1[j]*r0*radf, sint1[j]*r0*radf, z0*radf);
+ stripIdx[idx ] = offset+j+slices;
+ stripIdx[idx+1] = offset+j;
}
+ stripIdx[idx ] = offset+slices; /* repeat first slice's idx for closing off shape */
+ stripIdx[idx+1] = offset+0;
+ }
- glEnd();
- }
- /* The bottom stack is covered with a triangle fan */
+ /* draw */
+ glEnableClientState(GL_VERTEX_ARRAY);
+ glEnableClientState(GL_NORMAL_ARRAY);
- z0 = z1;
- r0 = r1;
+ glVertexPointer(3, GL_FLOAT, 0, vertices);
+ glNormalPointer(GL_FLOAT, 0, normals);
+ /*draw top*/
+ glDrawElements(GL_TRIANGLE_FAN,slices+2,GL_UNSIGNED_INT,topIdx);
+ /*draw stacks*/
+ for (i=0; i<stacks-2; i++)
+ glDrawElements(GL_TRIANGLE_STRIP,(slices+1)*2,GL_UNSIGNED_INT,stripIdx+i*(slices+1)*2);
+ /*draw bottom*/
+ glDrawElements(GL_TRIANGLE_FAN,slices+2,GL_UNSIGNED_INT,bottomIdx);
- glBegin(GL_TRIANGLE_FAN);
+ glDisableClientState(GL_VERTEX_ARRAY);
+ glDisableClientState(GL_NORMAL_ARRAY);
- glNormal3d(0,0,-1);
- glVertex3d(0,0,-radius);
+ /* cleanup allocated memory */
+ free(topIdx);
+ free(bottomIdx);
+ free(stripIdx);
+ }
+
+ /* cleanup allocated memory */
+ free(vertices);
+ free(normals);
+}
- for (j=0; j<=slices; j++)
- {
- glNormal3d(cost1[j]*r0, sint1[j]*r0, z0 );
- glVertex3d(cost1[j]*r0*radf, sint1[j]*r0*radf, z0*radf);
- }
+#endif /* GL_ES_VERSION_2_0 */
- glEnd();
- /* Release sin and cos tables */
+/* -- INTERFACE FUNCTIONS ---------------------------------------------- */
- free(sint1);
- free(cost1);
- free(sint2);
- free(cost2);
+
+#ifndef EGL_VERSION_1_0
+/*
+ * Draws a solid sphere
+ */
+void FGAPIENTRY glutSolidSphere(double radius, GLint slices, GLint stacks)
+{
+ FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutSolidSphere" );
+
+ fghSphere( radius, slices, stacks, FALSE );
}
/*
*/
void FGAPIENTRY glutWireSphere(double radius, GLint slices, GLint stacks)
{
- int i,j;
-
- /* Adjust z and radius as stacks and slices are drawn. */
- GLfloat radf = (GLfloat)radius;
- GLfloat r;
- GLfloat x,y,z;
-
- /* Pre-computed circle */
-
- GLfloat *sint1,*cost1;
- GLfloat *sint2,*cost2;
-
FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutWireSphere" );
- fghCircleTable(&sint1,&cost1,-slices,FALSE);
- fghCircleTable(&sint2,&cost2, stacks,TRUE);
-
- /* Draw a line loop for each stack */
-
- for (i=1; i<stacks; i++)
- {
- z = cost2[i];
- r = sint2[i];
-
- glBegin(GL_LINE_LOOP);
-
- for(j=0; j<=slices; j++)
- {
- x = cost1[j];
- y = sint1[j];
-
- glNormal3f(x,y,z);
- glVertex3f(x*r*radf,y*r*radf,z*radf);
- }
-
- glEnd();
- }
-
- /* Draw a line loop for each slice */
-
- for (i=0; i<slices; i++)
- {
- glBegin(GL_LINE_STRIP);
-
- for(j=0; j<=stacks; j++)
- {
- x = cost1[i]*sint2[j];
- y = sint1[i]*sint2[j];
- z = cost2[j];
-
- glNormal3f(x,y,z);
- glVertex3f(x*radf,y*radf,z*radf);
- }
-
- glEnd();
- }
-
- /* Release sin and cos tables */
-
- free(sint1);
- free(cost1);
- free(sint2);
- free(cost2);
+ fghSphere( radius, slices, stacks, TRUE );
+
}
/*
projects / freeglut / commitdiff