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# theJuniorOne

Member Since 14 Mar 2012
Offline Last Active Mar 26 2012 12:06 PM

### Camera Rotation problems

26 March 2012 - 01:20 AM

Hey so I have spent the past weekend trying to get my Camera to rotate in opengl, using quaternions. From what I understand the Math appears to be correct but when it runs, the camera just rotates to apparently wherever it feels like. Anyways here is the code hopefully some one can help me out here.

```void Camera:: RotateCamera(double Angle, double _x, double _y, double _z)
{
std::cout<<" before point of focus ("<<pointOfFocus.x<<","<<pointOfFocus.y<<","<<pointOfFocus.z<<")"<<std::endl;
//create a quaternion given the angle and vector
Quaternion4f temp,temp2, Dist, result;
//get both sides of the rotation quaternion
temp.FromAxis(Vector3f(_x,_y,_z), Angle);
temp2 = temp.getConjugate();
//make the quaternion out of the direction vector
Dist = Quaternion4f(0,direction.x,direction.y,direction.z);
//rotate the DIST quaternion by temp
result = (temp * Dist) * temp2;
//set the new direction to be the result
direction.set(result.x, result.y, result.z);
//solve for new point of focus
pointOfFocus = direction + position;
//normalize the direction
direction.normalize();
std::cout<<" after point of focus ("<<pointOfFocus.x<<","<<pointOfFocus.y<<","<<pointOfFocus.z<<")"<<std::endl;
}```

```void Camera:: Render()
{
gluLookAt(
position.x,
position.y,
position.z,
pointOfFocus.x,
pointOfFocus.y,
pointOfFocus.z,
up.x,
up.y,
up.z);
}```

### Texture Mapping Issues

14 March 2012 - 04:03 AM

Hi, I have been working on a project for school and I am having some problems with texturing a model after I load it from a file. The models seem to all be load and drawn fine, but the textures appear to just be placed anywhere they want on the model itself. as see below.

below is the code involved aswell

```ObjectModelType * LoadObjectModel(char *data, int datasize)
{
Vector3f objboundingboxmin(9999,9999,9999);
Vector3f objboundingboxmax(0,0,0);
char *memoryPositionPtr, *endOfMemoryPtr;
int c=0, polyCtr=0, vertexCtr=0, uvCtr=0, normalCtr=0;
ObjectModelType *theModel;
theModel = (ObjectModelType *)calloc(1,sizeof(ObjectModelType));
memoryPositionPtr = data;						   // current position and end location pointers
endOfMemoryPtr = data + datasize;
while (memoryPositionPtr != endOfMemoryPtr)
{
if (*memoryPositionPtr == 'v')
//	   theModel->VertexCount++;	  // removed
if (*(memoryPositionPtr+1) == 't') // added
else if (*(memoryPositionPtr+1) == 'n')
theModel->NormalCount++;
else if (*memoryPositionPtr == 'f')
theModel->PolygonCount++;
while (*memoryPositionPtr++ != 0x0A)
;
}
//allocate memory for the model data
theModel->VertexArray = (ObjectVertexType *)malloc(sizeof(ObjectVertexType)*theModel->VertexCount);
theModel->NormalArray = (ObjectNormalType *)malloc(sizeof(ObjectNormalType)*theModel->NormalCount);// now allocate the arrays
theModel->UVArray = (ObjectUVType *)malloc(sizeof(ObjectUVType)*theModel->UVvertexCount);   // added
theModel->PolygonArray = (ObjectPolygonType *)malloc(sizeof(ObjectPolygonType)*theModel->PolygonCount);

memoryPositionPtr = data;		  // finally, go back and scan the values
vertexCtr = 1;
polyCtr = uvCtr = 0;	  // reset values	 // added  modified
while (memoryPositionPtr != endOfMemoryPtr)
{
if (*memoryPositionPtr=='v')	// might be a vertex or a uv coord
{
if (*(memoryPositionPtr+1) == 't') // it's a uv coord
{
sscanf(memoryPositionPtr,"vt %f %f",&theModel->UVArray[uvCtr].u,
&theModel->UVArray[uvCtr].v);
uvCtr++;
}
else if (*(memoryPositionPtr+1) == 'n') // it's a normal coord
{
sscanf(memoryPositionPtr,"v %f %f %f",&theModel->NormalArray[normalCtr].x,
&theModel->NormalArray[normalCtr].y,
&theModel->NormalArray[normalCtr].z);
normalCtr++;
}
else							  // no, it's a vertex
{
sscanf(memoryPositionPtr,"v %f %f %f",&theModel->VertexArray[vertexCtr].x,
&theModel->VertexArray[vertexCtr].y,
&theModel->VertexArray[vertexCtr].z);
if (objboundingboxmin.x > theModel->VertexArray[vertexCtr].x)
{
objboundingboxmin.x = theModel->VertexArray[vertexCtr].x;
theModel->bbminx = objboundingboxmin.x;
}
if (objboundingboxmin.y > theModel->VertexArray[vertexCtr].y)
{
objboundingboxmin.y = theModel->VertexArray[vertexCtr].y;
}
if (objboundingboxmin.z > theModel->VertexArray[vertexCtr].z)
{
objboundingboxmin.z = theModel->VertexArray[vertexCtr].z;
}
if (objboundingboxmax.x < theModel->VertexArray[vertexCtr].x)
{
objboundingboxmax.x = theModel->VertexArray[vertexCtr].x;
}
if (objboundingboxmax.y < theModel->VertexArray[vertexCtr].y)
{
objboundingboxmax.y = theModel->VertexArray[vertexCtr].y;
}
if (objboundingboxmax.z < theModel->VertexArray[vertexCtr].z)
{
objboundingboxmax.z = theModel->VertexArray[vertexCtr].z;
}
theModel->bbminx = objboundingboxmin.x;
theModel->bbminy = objboundingboxmin.y;
theModel->bbminz = objboundingboxmin.z;
theModel->bbmaxx = objboundingboxmax.x;
theModel->bbmaxy = objboundingboxmax.y;
theModel->bbmaxz = objboundingboxmax.z;
vertexCtr++;
}
}
else if (*memoryPositionPtr=='f')
{
sscanf(memoryPositionPtr,"f %d/%d/%d %d/%d/%d %d/%d/%d ",
polyCtr++;
}

while (*memoryPositionPtr++ != (char) 0x0A)
;
}
return theModel;
}
//#include <direct.h>  /* supports _getcwd to get the current working directory if their are problems finding the file */
long LoadObjectFile(const char* filename, char** data)
{
long bytes = 0;
FILE* theFile;
//   char buffer[_MAX_PATH];  _getcwd( buffer, _MAX_PATH ); /* Get the current working directory: */
theFile = fopen(filename, "rt");
if (theFile != NULL)
{
fseek(theFile, 0, SEEK_END);
long end = ftell(theFile);
fseek(theFile, 0, SEEK_SET);

*data = (char*) malloc(end);
bytes = (long)fread(*data, sizeof(char), (size_t)end, theFile);
fclose(theFile);
}
return bytes;
}```

```void Entity::loadImage(const char* filename)
{
ILuint ilimg;
ilGenImages(1, &ilimg);
ilBindImage(ilimg);
{
printf("Error: Could load image %s\n", filename);
return;
}
glGenTextures(1, &image);
glBindTexture(GL_TEXTURE_2D, image);
ILuint bpp = ilGetInteger(IL_IMAGE_BPP);
ILuint width = ilGetInteger(IL_IMAGE_WIDTH);
ILuint height = ilGetInteger(IL_IMAGE_HEIGHT);
ILuint format = ilGetInteger(IL_IMAGE_FORMAT);
ILubyte *data = ilGetData();
glPixelStorei(GL_UNPACK_ALIGNMENT,1);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, bpp, width, height, 0, format,
GL_UNSIGNED_BYTE, data);
ilDeleteImages(1, &ilimg);
}
void Entity :: ApplyTexture()
{
glEnable(GL_NORMALIZE);
glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBindTexture(GL_TEXTURE_2D,image);
glEnable(GL_REPEAT);
}```

Drawing the model
```void Entity::draw()
{
/*draw the object in opengl to current location*/
glPushMatrix();
glColor3f(1,1,1);
glTranslatef(
currentAnimState->position.x,
currentAnimState->position.y,
currentAnimState->position.z);

//ApplyTexture();
for(long i=0; i<currentPose->PolygonCount;i++)
{
long v1 =  currentPose->PolygonArray[i].Vertex[0];
long v2 =  currentPose->PolygonArray[i].Vertex[1];
long v3 =  currentPose->PolygonArray[i].Vertex[2];
long uv1 =  currentPose->PolygonArray[i].UV[0];
long uv2 =  currentPose->PolygonArray[i].UV[1];
long uv3 =  currentPose->PolygonArray[i].UV[2];
long vn1 =  currentPose->PolygonArray[i].Normal[0];
long vn2 =  currentPose->PolygonArray[i].Normal[1];
long vn3 =  currentPose->PolygonArray[i].Normal[2];
ApplyTexture();
glBegin(GL_TRIANGLES);

//point 1
glNormal3f(currentPose->NormalArray[vn1].x,currentPose->NormalArray[vn1].y,currentPose->NormalArray[vn1].z);
glTexCoord2f(currentPose->UVArray[uv1].u,currentPose->UVArray[uv1].v);
glVertex3f(currentPose->VertexArray[v1].x,currentPose->VertexArray[v1].y,currentPose->VertexArray[v1].z );

//point 2
glNormal3f(currentPose->NormalArray[vn2].x,currentPose->NormalArray[vn2].y,currentPose->NormalArray[vn2].z);
glTexCoord2f(currentPose->UVArray[uv2].u,currentPose->UVArray[uv2].v);
glVertex3f(currentPose->VertexArray[v2].x,currentPose->VertexArray[v2].y,currentPose->VertexArray[v2].z );

//point 3
glNormal3f(currentPose->NormalArray[vn3].x,currentPose->NormalArray[vn3].y,currentPose->NormalArray[vn3].z);
glTexCoord2f(currentPose->UVArray[uv3].u,currentPose->UVArray[uv3].v);
glVertex3f(currentPose->VertexArray[v3].x,currentPose->VertexArray[v3].y,currentPose->VertexArray[v3].z );
glEnd();
}

glPopMatrix();
}```

any help would really be appreciated, I have spent many long nights trying to figure this out, also let me know If you want to me to include any other code. Thanks in advance.

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