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/* glframe.c
*
* Camera
*
* notes: we could make these functions to be inlined, but they would need
* to be moved into a header
*
*/
#include "glframe.h"
#include "math3d.h"
void glframe_reset(GLFrame *frame)
{
frame->v_location[0] = 0.0f;
frame->v_location[1] = 0.0f;
frame->v_location[2] = 0.0f;
frame->v_forward[0] = 0.0f;
frame->v_forward[1] = 0.0f;
frame->v_forward[2] = -1.0f;
frame->v_up[0] = 0.0f;
frame->v_up[1] = 1.0f;
frame->v_up[2] = 0.0f;
}
/* get a 4x4 transformation matrix that describes the ccamera orientation */
void glframe_get_camera_orientation(GLFrame *frame, M3DMatrix44f m)
{
M3DVector3f x, z;
/* make rotation matrix, z vector is reversed */
z[0] = -frame->v_forward[0];
z[1] = -frame->v_forward[1];
z[2] = -frame->v_forward[2];
/* x vector = y cross z */
m3dCrossProductf(x, frame->v_up, z);
/* matrix has no translation information and is transposed */
#define M(row,col) m[col*4+row]
M(0, 0) = x[0];
M(0, 1) = x[1];
M(0, 2) = x[2];
M(0, 3) = 0.0;
M(1, 0) = frame->v_up[0];
M(1, 1) = frame->v_up[1];
M(1, 2) = frame->v_up[2];
M(1, 3) = 0.0;
M(2, 0) = z[0];
M(2, 1) = z[1];
M(2, 2) = z[2];
M(2, 3) = 0.0;
M(3, 0) = 0.0;
M(3, 1) = 0.0;
M(3, 2) = 0.0;
M(3, 3) = 1.0;
#undef M
}
/* perform viewing or modeling transformations */
/* some of the code is unimplemented */
void glframe_apply_camera_transform(GLFrame *frame)
{
/* XXX: rotation only, should passed in as a parameter */
int rot_only = 0;
M3DMatrix44f m;
glframe_get_camera_orientation(frame, m);
glMultMatrixf(m);
/* if Rotation only, then do not do the translation */
if (!rot_only)
glTranslatef(-frame->v_location[0], -frame->v_location[1], -frame->v_location[2]);
#if 0
gluLookAt(v_location[0], v_location[1], v_location[2],
v_location[0] + v_forward[0],
v_location[1] + v_forward[1],
v_location[2] + v_forward[2],
v_up[0], v_up[1], v_up[2]);
#endif
}
void glframe_move_forward(GLFrame *frame, float delta)
{
// Move along direction of front direction
frame->v_location[0] += frame->v_forward[0] * delta;
frame->v_location[1] += frame->v_forward[1] * delta;
frame->v_location[2] += frame->v_forward[2] * delta;
}
void glframe_rotate_local_y(GLFrame *frame, float angle)
{
M3DMatrix44f rotMat;
/* just Rotate around the up vector */
/* create a rotation matrix around my Up (Y) vector */
m3dRotationMatrix44f(rotMat, angle, frame->v_up[0], frame->v_up[1], frame->v_up[2]);
M3DVector3f newVect;
/* rotate forward pointing vector (inlined 3x3 transform) */
newVect[0] = rotMat[0] * frame->v_forward[0] + rotMat[4] * frame->v_forward[1] + rotMat[8] * frame->v_forward[2];
newVect[1] = rotMat[1] * frame->v_forward[0] + rotMat[5] * frame->v_forward[1] + rotMat[9] * frame->v_forward[2];
newVect[2] = rotMat[2] * frame->v_forward[0] + rotMat[6] * frame->v_forward[1] + rotMat[10] * frame->v_forward[2];
m3dCopyVector3f(frame->v_forward, newVect);
}
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