// Draw a cylinder. Much like gluCylinder
void gltMakeCylinder(GLTriangleBatch& cylinderBatch, GLfloat baseRadius, GLfloat topRadius,
GLfloat fLength, GLint numSlices, GLint numStacks)
{
float fRadiusStep = (topRadius - baseRadius) / float(numStacks);
GLfloat fStepSizeSlice = (3.1415926536f * 2.0f) / float(numSlices);
M3DVector3f vVertex[4];
M3DVector3f vNormal[4];
M3DVector2f vTexture[4];
cylinderBatch.BeginMesh(numSlices * numStacks * 6);
GLfloat ds = 1.0f / float(numSlices);
GLfloat dt = 1.0f / float(numStacks);
GLfloat s;
GLfloat t;
for (int i = 0; i < numStacks; i++)
{
if(i == 0)
t = 0.0f;
else
t = float(i) * dt;
float tNext;
if(i == (numStacks - 1))
tNext = 1.0f;
else
tNext = float(i+1) * dt;
float fCurrentRadius = baseRadius + (fRadiusStep * float(i));
float fNextRadius = baseRadius + (fRadiusStep * float(i+1));
float theyta;
float theytaNext;
float fCurrentZ = float(i) * (fLength / float(numStacks));
float fNextZ = float(i+1) * (fLength / float(numStacks));
float zNormal = 0.0f;
if(!m3dCloseEnough(baseRadius - topRadius, 0.0f, 0.00001f))
{
// Rise over run...
zNormal = (baseRadius - topRadius);
}
for (int j = 0; j < numSlices; j++)
{
if(j == 0)
s = 0.0f;
else
s = float(j) * ds;
float sNext;
if(j == (numSlices -1))
sNext = 1.0f;
else
sNext = float(j+1) * ds;
theyta = fStepSizeSlice * float(j);
if(j == (numSlices - 1))
theytaNext = 0.0f;
else
theytaNext = fStepSizeSlice * (float(j+1));
// Inner First
vVertex[1][0] = cos(theyta) * fCurrentRadius; // X
vVertex[1][1] = sin(theyta) * fCurrentRadius; // Y
vVertex[1][2] = fCurrentZ; // Z
vNormal[1][0] = vVertex[1][0]; // Surface Normal, same for everybody
vNormal[1][1] = vVertex[1][1];
vNormal[1][2] = zNormal;
m3dNormalizeVector3(vNormal[1]);
vTexture[1][0] = s; // Texture Coordinates, I have no idea...
vTexture[1][1] = t;
// Outer First
vVertex[0][0] = cos(theyta) * fNextRadius; // X
vVertex[0][1] = sin(theyta) * fNextRadius; // Y
vVertex[0][2] = fNextZ; // Z
if(!m3dCloseEnough(fNextRadius, 0.0f, 0.00001f)) {
vNormal[0][0] = vVertex[0][0]; // Surface Normal, same for everybody
vNormal[0][1] = vVertex[0][1]; // For cones, tip is tricky
vNormal[0][2] = zNormal;
m3dNormalizeVector3(vNormal[0]);
}
else
memcpy(vNormal[0], vNormal[1], sizeof(M3DVector3f));
vTexture[0][0] = s; // Texture Coordinates, I have no idea...
vTexture[0][1] = tNext;
// Inner second
vVertex[3][0] = cos(theytaNext) * fCurrentRadius; // X
vVertex[3][1] = sin(theytaNext) * fCurrentRadius; // Y
vVertex[3][2] = fCurrentZ; // Z
vNormal[3][0] = vVertex[3][0]; // Surface Normal, same for everybody
vNormal[3][1] = vVertex[3][1];
vNormal[3][2] = zNormal;
m3dNormalizeVector3(vNormal[3]);
vTexture[3][0] = sNext; // Texture Coordinates, I have no idea...
vTexture[3][1] = t;
// Outer second
vVertex[2][0] = cos(theytaNext) * fNextRadius; // X
vVertex[2][1] = sin(theytaNext) * fNextRadius; // Y
vVertex[2][2] = fNextZ; // Z
if(!m3dCloseEnough(fNextRadius, 0.0f, 0.00001f)) {
vNormal[2][0] = vVertex[2][0]; // Surface Normal, same for everybody
vNormal[2][1] = vVertex[2][1];
vNormal[2][2] = zNormal;
m3dNormalizeVector3(vNormal[2]);
}
else
memcpy(vNormal[2], vNormal[3], sizeof(M3DVector3f));
vTexture[2][0] = sNext; // Texture Coordinates, I have no idea...
vTexture[2][1] = tNext;
cylinderBatch.AddTriangle(vVertex, vNormal, vTexture);
// Rearrange for next triangle
memcpy(vVertex[0], vVertex[1], sizeof(M3DVector3f));
memcpy(vNormal[0], vNormal[1], sizeof(M3DVector3f));
memcpy(vTexture[0], vTexture[1], sizeof(M3DVector2f));
memcpy(vVertex[1], vVertex[3], sizeof(M3DVector3f));
memcpy(vNormal[1], vNormal[3], sizeof(M3DVector3f));
memcpy(vTexture[1], vTexture[3], sizeof(M3DVector2f));
cylinderBatch.AddTriangle(vVertex, vNormal, vTexture);
}
}
cylinderBatch.End();
}
/////////////////////////////////////////////////////////////////////////////////////////////////
// Make a sphere
void gltMakeSphere(GLTriangleBatch& sphereBatch, GLfloat fRadius, GLint iSlices, GLint iStacks)
{
GLfloat drho = (GLfloat)(3.141592653589) / (GLfloat) iStacks;
GLfloat dtheta = 2.0f * (GLfloat)(3.141592653589) / (GLfloat) iSlices;
GLfloat ds = 1.0f / (GLfloat) iSlices;
GLfloat dt = 1.0f / (GLfloat) iStacks;
GLfloat t = 1.0f;
GLfloat s = 0.0f;
GLint i, j; // Looping variables
sphereBatch.BeginMesh(iSlices * iStacks * 6);
for (i = 0; i < iStacks; i++)
{
GLfloat rho = (GLfloat)i * drho;
GLfloat srho = (GLfloat)(sin(rho));
GLfloat crho = (GLfloat)(cos(rho));
GLfloat srhodrho = (GLfloat)(sin(rho + drho));
GLfloat crhodrho = (GLfloat)(cos(rho + drho));
// Many sources of OpenGL sphere drawing code uses a triangle fan
// for the caps of the sphere. This however introduces texturing
// artifacts at the poles on some OpenGL implementations
s = 0.0f;
M3DVector3f vVertex[4];
M3DVector3f vNormal[4];
M3DVector2f vTexture[4];
for ( j = 0; j < iSlices; j++)
{
GLfloat theta = (j == iSlices) ? 0.0f : j * dtheta;
GLfloat stheta = (GLfloat)(-sin(theta));
GLfloat ctheta = (GLfloat)(cos(theta));
GLfloat x = stheta * srho;
GLfloat y = ctheta * srho;
GLfloat z = crho;
vTexture[0][0] = s;
vTexture[0][1] = t;
vNormal[0][0] = x;
vNormal[0][1] = y;
vNormal[0][2] = z;
vVertex[0][0] = x * fRadius;
vVertex[0][1] = y * fRadius;
vVertex[0][2] = z * fRadius;
x = stheta * srhodrho;
y = ctheta * srhodrho;
z = crhodrho;
vTexture[1][0] = s;
vTexture[1][1] = t - dt;
vNormal[1][0] = x;
vNormal[1][1] = y;
vNormal[1][2] = z;
vVertex[1][0] = x * fRadius;
vVertex[1][1] = y * fRadius;
vVertex[1][2] = z * fRadius;
theta = ((j+1) == iSlices) ? 0.0f : (j+1) * dtheta;
stheta = (GLfloat)(-sin(theta));
ctheta = (GLfloat)(cos(theta));
x = stheta * srho;
y = ctheta * srho;
z = crho;
s += ds;
vTexture[2][0] = s;
vTexture[2][1] = t;
vNormal[2][0] = x;
vNormal[2][1] = y;
vNormal[2][2] = z;
vVertex[2][0] = x * fRadius;
vVertex[2][1] = y * fRadius;
vVertex[2][2] = z * fRadius;
x = stheta * srhodrho;
y = ctheta * srhodrho;
z = crhodrho;
vTexture[3][0] = s;
vTexture[3][1] = t - dt;
vNormal[3][0] = x;
vNormal[3][1] = y;
vNormal[3][2] = z;
vVertex[3][0] = x * fRadius;
vVertex[3][1] = y * fRadius;
vVertex[3][2] = z * fRadius;
sphereBatch.AddTriangle(vVertex, vNormal, vTexture);
// Rearrange for next triangle
memcpy(vVertex[0], vVertex[1], sizeof(M3DVector3f));
memcpy(vNormal[0], vNormal[1], sizeof(M3DVector3f));
memcpy(vTexture[0], vTexture[1], sizeof(M3DVector2f));
memcpy(vVertex[1], vVertex[3], sizeof(M3DVector3f));
memcpy(vNormal[1], vNormal[3], sizeof(M3DVector3f));
memcpy(vTexture[1], vTexture[3], sizeof(M3DVector2f));
sphereBatch.AddTriangle(vVertex, vNormal, vTexture);
}
t -= dt;
}
sphereBatch.End();
}
void gltMakeDisk(GLTriangleBatch& diskBatch, GLfloat innerRadius, GLfloat outerRadius, GLint nSlices, GLint nStacks)
{
// How much to step out each stack
GLfloat fStepSizeRadial = outerRadius - innerRadius;
if(fStepSizeRadial < 0.0f) // Dum dum...
fStepSizeRadial *= -1.0f;
fStepSizeRadial /= float(nStacks);
GLfloat fStepSizeSlice = (3.1415926536f * 2.0f) / float(nSlices);
diskBatch.BeginMesh(nSlices * nStacks * 6);
M3DVector3f vVertex[4];
M3DVector3f vNormal[4];
M3DVector2f vTexture[4];
float fRadialScale = 1.0f / outerRadius;
for(GLint i = 0; i < nStacks; i++) // Stacks
{
float theyta;
float theytaNext;
for(GLint j = 0; j < nSlices; j++) // Slices
{
float inner = innerRadius + (float(i)) * fStepSizeRadial;
float outer = innerRadius + (float(i+1)) * fStepSizeRadial;
theyta = fStepSizeSlice * float(j);
if(j == (nSlices - 1))
theytaNext = 0.0f;
else
theytaNext = fStepSizeSlice * (float(j+1));
// Inner First
vVertex[0][0] = cos(theyta) * inner; // X
vVertex[0][1] = sin(theyta) * inner; // Y
vVertex[0][2] = 0.0f; // Z
vNormal[0][0] = 0.0f; // Surface Normal, same for everybody
vNormal[0][1] = 0.0f;
vNormal[0][2] = 1.0f;
vTexture[0][0] = ((vVertex[0][0] * fRadialScale) + 1.0f) * 0.5f;
vTexture[0][1] = ((vVertex[0][1] * fRadialScale) + 1.0f) * 0.5f;
// Outer First
vVertex[1][0] = cos(theyta) * outer; // X
vVertex[1][1] = sin(theyta) * outer; // Y
vVertex[1][2] = 0.0f; // Z
vNormal[1][0] = 0.0f; // Surface Normal, same for everybody
vNormal[1][1] = 0.0f;
vNormal[1][2] = 1.0f;
vTexture[1][0] = ((vVertex[1][0] * fRadialScale) + 1.0f) * 0.5f;
vTexture[1][1] = ((vVertex[1][1] * fRadialScale) + 1.0f) * 0.5f;
// Inner Second
vVertex[2][0] = cos(theytaNext) * inner; // X
vVertex[2][1] = sin(theytaNext) * inner; // Y
vVertex[2][2] = 0.0f; // Z
vNormal[2][0] = 0.0f; // Surface Normal, same for everybody
vNormal[2][1] = 0.0f;
vNormal[2][2] = 1.0f;
vTexture[2][0] = ((vVertex[2][0] * fRadialScale) + 1.0f) * 0.5f;
vTexture[2][1] = ((vVertex[2][1] * fRadialScale) + 1.0f) * 0.5f;
// Outer Second
vVertex[3][0] = cos(theytaNext) * outer; // X
vVertex[3][1] = sin(theytaNext) * outer; // Y
vVertex[3][2] = 0.0f; // Z
vNormal[3][0] = 0.0f; // Surface Normal, same for everybody
vNormal[3][1] = 0.0f;
vNormal[3][2] = 1.0f;
vTexture[3][0] = ((vVertex[3][0] * fRadialScale) + 1.0f) * 0.5f;
vTexture[3][1] = ((vVertex[3][1] * fRadialScale) + 1.0f) * 0.5f;
diskBatch.AddTriangle(vVertex, vNormal, vTexture);
// Rearrange for next triangle
memcpy(vVertex[0], vVertex[1], sizeof(M3DVector3f));
memcpy(vNormal[0], vNormal[1], sizeof(M3DVector3f));
memcpy(vTexture[0], vTexture[1], sizeof(M3DVector2f));
memcpy(vVertex[1], vVertex[3], sizeof(M3DVector3f));
memcpy(vNormal[1], vNormal[3], sizeof(M3DVector3f));
memcpy(vTexture[1], vTexture[3], sizeof(M3DVector2f));
diskBatch.AddTriangle(vVertex, vNormal, vTexture);
}
}
diskBatch.End();
}
// Draw a torus (doughnut) at z = fZVal... torus is in xy plane
void gltMakeTorus(GLTriangleBatch& torusBatch, GLfloat majorRadius, GLfloat minorRadius, GLint numMajor, GLint numMinor)
{
double majorStep = 2.0f*M3D_PI / numMajor;
double minorStep = 2.0f*M3D_PI / numMinor;
int i, j;
torusBatch.BeginMesh(numMajor * (numMinor+1) * 6);
for (i=0; i<numMajor; ++i)
{
double a0 = i * majorStep;
double a1 = a0 + majorStep;
GLfloat x0 = (GLfloat) cos(a0);
GLfloat y0 = (GLfloat) sin(a0);
GLfloat x1 = (GLfloat) cos(a1);
GLfloat y1 = (GLfloat) sin(a1);
M3DVector3f vVertex[4];
M3DVector3f vNormal[4];
M3DVector2f vTexture[4];
for (j=0; j<=numMinor; ++j)
{
double b = j * minorStep;
GLfloat c = (GLfloat) cos(b);
GLfloat r = minorRadius * c + majorRadius;
GLfloat z = minorRadius * (GLfloat) sin(b);
// First point
vTexture[0][0] = (float)(i)/(float)(numMajor);
vTexture[0][1] = (float)(j)/(float)(numMinor);
vNormal[0][0] = x0*c;
vNormal[0][1] = y0*c;
vNormal[0][2] = z/minorRadius;
m3dNormalizeVector3(vNormal[0]);
vVertex[0][0] = x0 * r;
vVertex[0][1] = y0 * r;
vVertex[0][2] = z;
// Second point
vTexture[1][0] = (float)(i+1)/(float)(numMajor);
vTexture[1][1] = (float)(j)/(float)(numMinor);
vNormal[1][0] = x1*c;
vNormal[1][1] = y1*c;
vNormal[1][2] = z/minorRadius;
m3dNormalizeVector3(vNormal[1]);
vVertex[1][0] = x1*r;
vVertex[1][1] = y1*r;
vVertex[1][2] = z;
// Next one over
b = (j+1) * minorStep;
c = (GLfloat) cos(b);
r = minorRadius * c + majorRadius;
z = minorRadius * (GLfloat) sin(b);
// Third (based on first)
vTexture[2][0] = (float)(i)/(float)(numMajor);
vTexture[2][1] = (float)(j+1)/(float)(numMinor);
vNormal[2][0] = x0*c;
vNormal[2][1] = y0*c;
vNormal[2][2] = z/minorRadius;
m3dNormalizeVector3(vNormal[2]);
vVertex[2][0] = x0 * r;
vVertex[2][1] = y0 * r;
vVertex[2][2] = z;
// Fourth (based on second)
vTexture[3][0] = (float)(i+1)/(float)(numMajor);
vTexture[3][1] = (float)(j+1)/(float)(numMinor);
vNormal[3][0] = x1*c;
vNormal[3][1] = y1*c;
vNormal[3][2] = z/minorRadius;
m3dNormalizeVector3(vNormal[3]);
vVertex[3][0] = x1*r;
vVertex[3][1] = y1*r;
vVertex[3][2] = z;
torusBatch.AddTriangle(vVertex, vNormal, vTexture);
// Rearrange for next triangle
memcpy(vVertex[0], vVertex[1], sizeof(M3DVector3f));
memcpy(vNormal[0], vNormal[1], sizeof(M3DVector3f));
memcpy(vTexture[0], vTexture[1], sizeof(M3DVector2f));
memcpy(vVertex[1], vVertex[3], sizeof(M3DVector3f));
memcpy(vNormal[1], vNormal[3], sizeof(M3DVector3f));
memcpy(vTexture[1], vTexture[3], sizeof(M3DVector2f));
torusBatch.AddTriangle(vVertex, vNormal, vTexture);
}
}
torusBatch.End();
}