Matrix.c

/******************************************************************
*
* Matrix.c
*
* Description: Helper routine for matrix computations.
* 	
*
* Computer Graphics Proseminar SS 2014
* 
* Interactive Graphics and Simulation Group
* Institute of Computer Science
* University of Innsbruck
*
*******************************************************************/

/* Standard includes */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

// Needed for VisualStudioCompiler
#define _USE_MATH_DEFINES
#include <math.h>

/******************************************************************
*
* SetIdentityMatrix
*
*******************************************************************/

void SetIdentityMatrix(float* result)  
{
    float identity[16] = {
        1.0, 0.0, 0.0, 0.0,
	0.0, 1.0, 0.0, 0.0,
	0.0, 0.0, 1.0, 0.0,
	0.0, 0.0, 0.0, 1.0,
    };

    memcpy(result, identity, 16*sizeof(float));
}

void SetIdentityMatrix3x3(float* result)
{
    float identity[9] = {
    1.0, 0.0, 0.0,
	0.0, 1.0, 0.0,
	0.0, 0.0, 1.0,
    };

    memcpy(result, identity, 9*sizeof(float));
}

/******************************************************************
*
* SetRotationX
*
*******************************************************************/

void SetRotationX(float anglex, float* result)
{
    anglex = M_PI/180 * anglex;   /* Conversion angle from degree to radians */

    float temp[16] = 
    {  
        1.0,           0.0,          0.0, 0.0,
	0.0,  cosf(anglex),-sinf(anglex), 0.0,
	0.0,  sinf(anglex), cosf(anglex), 0.0,
	0.0,           0.0,          0.0, 1.0  
    };

    memcpy(result, temp, 16*sizeof(float));
}


/******************************************************************
*
* SetRotationY
*
*******************************************************************/

void SetRotationY(float angley, float* result)
{
    angley = M_PI/180 * angley;   /* Conversion angle from degree to radians */

    float temp[16] = 
    {
        cosf(angley),  0.0,   sinf(angley),  0.0,
	         0.0,  1.0,            0.0,  0.0,
       -sinf(angley),  0.0,   cosf(angley),  0.0,
	         0.0,  0.0,            0.0,  1.0   
    };
  
    memcpy(result, temp, 16*sizeof(float));
}


/******************************************************************
*
* SetRotationZ
*
*******************************************************************/

void SetRotationZ(float anglez, float* result)
{
    anglez = M_PI/180 * anglez;   /* Conversion angle from degree to radian */

    float temp[16] = 
    {	
        cosf(anglez), -sinf(anglez),  0.0,  0.0,
        sinf(anglez),  cosf(anglez),  0.0,  0.0,          
                 0.0,           0.0,  1.0,  0.0,
                 0.0,           0.0,  0.0,  1.0   
    };

    memcpy(result, temp, 16*sizeof(float));
}


/******************************************************************
*
* SetTranslation
*
*******************************************************************/

void SetTranslation(float x, float y, float z, float* result)
{
  float temp[16] = 
  {
      1.0,  0.0,  0.0,    x,
      0.0,  1.0,  0.0,    y,
      0.0,  0.0,  1.0,    z,
      0.0,  0.0,  0.0,  1.0
  };

  memcpy(result, temp, 16*sizeof(float));
}

/******************************************************************
*
* SetScale
*
*******************************************************************/

void SetScaling(float x, float y, float z, float* result)
{
  float temp[16] = 
  {
      x  ,  0.0,  0.0,  0.0,
      0.0,  y  ,  0.0,  0.0,
      0.0,  0.0,  z  ,  0.0,
      0.0,  0.0,  0.0,  1.0
  };

  memcpy(result, temp, 16*sizeof(float));
}


/******************************************************************
*
* MultiplyMatrix
*
*******************************************************************/

void MultiplyMatrix(float* m1, float* m2, float* result)
{
    int i;
    float temp[16];

    for (i = 0; i < 16; i++)
        temp[i] = 0.0;
    
    temp[0] = m1[0]*m2[0] + m1[1]*m2[4] + m1[2]*m2[8] + m1[3]*m2[12];
    temp[1] = m1[0]*m2[1] + m1[1]*m2[5] + m1[2]*m2[9] + m1[3]*m2[13];
    temp[2] = m1[0]*m2[2] + m1[1]*m2[6] + m1[2]*m2[10] + m1[3]*m2[14];
    temp[3] = m1[0]*m2[3] + m1[1]*m2[7] + m1[2]*m2[11] + m1[3]*m2[15];

    temp[4] = m1[4]*m2[0] + m1[5]*m2[4] + m1[6]*m2[8] + m1[7]*m2[12];
    temp[5] = m1[4]*m2[1] + m1[5]*m2[5] + m1[6]*m2[9] + m1[7]*m2[13];
    temp[6] = m1[4]*m2[2] + m1[5]*m2[6] + m1[6]*m2[10] + m1[7]*m2[14];
    temp[7] = m1[4]*m2[3] + m1[5]*m2[7] + m1[6]*m2[11] + m1[7]*m2[15];

    temp[8] = m1[8]*m2[0] + m1[9]*m2[4] + m1[10]*m2[8] + m1[11]*m2[12];
    temp[9] = m1[8]*m2[1] + m1[9]*m2[5] + m1[10]*m2[9] + m1[11]*m2[13];
    temp[10] = m1[8]*m2[2] + m1[9]*m2[6] + m1[10]*m2[10] + m1[11]*m2[14];
    temp[11] = m1[8]*m2[3] + m1[9]*m2[7] + m1[10]*m2[11] + m1[11]*m2[15];

    temp[12] = m1[12]*m2[0] + m1[13]*m2[4] + m1[14]*m2[8] + m1[15]*m2[12];
    temp[13] = m1[12]*m2[1] + m1[13]*m2[5] + m1[14]*m2[9] + m1[15]*m2[13];
    temp[14] = m1[12]*m2[2] + m1[13]*m2[6] + m1[14]*m2[10] + m1[15]*m2[14];
    temp[15] = m1[12]*m2[3] + m1[13]*m2[7] + m1[14]*m2[11] + m1[15]*m2[15];

    memcpy(result, temp, 16*sizeof(float));
}


/******************************************************************
*
* SetPerspectiveMatrix
*
*******************************************************************/

void SetPerspectiveMatrix(float fov, float aspect, float nearPlane, 
                          float farPlane, float* result) 
{   
    float f = 1.0 / tan(fov * 3.1415926/360.0);
    float c1 = -(farPlane + nearPlane) / (farPlane - nearPlane);
    float c2 = -(2.0 * farPlane * nearPlane) / (farPlane - nearPlane);

    float temp[16] = 
    {
        f/aspect,  0.0,   0.0,  0.0,
	     0.0,    f,   0.0,  0.0,
	     0.0,  0.0,    c1,   c2,
             0.0,  0.0,  -1.0,  0.0
    };

    memcpy(result, temp, 16*sizeof(float));
}