void DrawGeometry(final GL gl) {
// Cache the sphere positions, normals, texture coordinates, and
// vertex indices in a local array; we only need to fill them in the
// first time through this function.
final int nu = 30, nv = 30;
final int nTris = 2 * (nu - 1) * (nv - 1), nVerts = nu * nv;
if (P == null) {
int u, v;
P = BufferUtil.newFloatBuffer(3 * nVerts);
N = BufferUtil.newFloatBuffer(3 * nVerts);
uv = BufferUtil.newFloatBuffer(2 * nVerts);
// Fill in the position, normal, and texture coordinate arrays.
// Just loop over all of the vertices, compute their parametreic
// (u,v) coordinates (which we use for texture coordinates as
// well), and call the ParametricEval() function, which turns (u,v)
// coordinates into positions and normals on the surface of the
// object.
int pp = 0, np = 0, uvp = 0;
for (v = 0; v < nv; ++v) {
final float fv = (float) v / (float) (nv - 1);
for (u = 0; u < nu; ++u) {
final float fu = (float) u / (float) (nu - 1);
uv.put(uvp, fu);
uv.put(uvp + 1, fv);
ParametricEval(fu, fv, pp, P, np, N);
pp += 3;
np += 3;
uvp += 2;
}
}
// Now fill in the vertex index arrays
indices = BufferUtil.newIntBuffer(3 * nTris);
int ip = 0;
for (v = 0; v < nv - 1; ++v)
for (u = 0; u < nu - 1; ++u) {
indices.put(ip++, VERTEX(u, v, nu));
indices.put(ip++, VERTEX(u + 1, v, nu));
indices.put(ip++, VERTEX(u + 1, v + 1, nu));
indices.put(ip++, VERTEX(u, v, nu));
indices.put(ip++, VERTEX(u + 1, v + 1, nu));
indices.put(ip++, VERTEX(u, v + 1, nu));
}
// Tell Cg which of these data pointers are associated with which
// parameters to the vertex shader, so that when we call
// cgGLEnableClientState() and then glDrawElements(), the shader
// gets the right input information.
CGparameter param = CgGL.cgGetNamedParameter(vertexProgram, "Pobject");
CgGL.cgGLSetParameterPointer(param, 3, GL.GL_FLOAT, 0, P);
param = CgGL.cgGetNamedParameter(vertexProgram, "Nobject");
CgGL.cgGLSetParameterPointer(param, 3, GL.GL_FLOAT, 0, N);
param = CgGL.cgGetNamedParameter(vertexProgram, "TexUV");
CgGL.cgGLSetParameterPointer(param, 2, GL.GL_FLOAT, 0, uv);
}
// And now, each time through, enable the bindings to the parameters
// that we set up the first time through
CGparameter param = CgGL.cgGetNamedParameter(vertexProgram, "Pobject");
CgGL.cgGLEnableClientState(param);
param = CgGL.cgGetNamedParameter(vertexProgram, "Nobject");
CgGL.cgGLEnableClientState(param);
param = CgGL.cgGetNamedParameter(vertexProgram, "TexUV");
CgGL.cgGLEnableClientState(param);
// Enable the texture parameter as well.
param = CgGL.cgGetNamedParameter(fragmentProgram, "diffuseMap");
CgGL.cgGLEnableTextureParameter(param);
// And now, draw the geometry.
gl.glDrawElements(GL.GL_TRIANGLES, 3 * nTris, GL.GL_UNSIGNED_INT, indices);
// Be a good citizen and disable the various bindings we set up above.
param = CgGL.cgGetNamedParameter(vertexProgram, "Pobject");
CgGL.cgGLDisableClientState(param);
param = CgGL.cgGetNamedParameter(vertexProgram, "Nobject");
CgGL.cgGLDisableClientState(param);
param = CgGL.cgGetNamedParameter(vertexProgram, "TexUV");
CgGL.cgGLDisableClientState(param);
param = CgGL.cgGetNamedParameter(fragmentProgram, "diffuseMap");
CgGL.cgGLDisableTextureParameter(param);
}
