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//
// Book: OpenGL(R) ES 2.0 Programming Guide
// Authors: Aaftab Munshi, Dan Ginsburg, Dave Shreiner
// ISBN-10: 0321502795
// ISBN-13: 9780321502797
// Publisher: Addison-Wesley Professional
// URLs: http://safari.informit.com/9780321563835
// http://www.opengles-book.com
//
// ESUtil.c
//
// A utility library for OpenGL ES. This library provides a
// basic common framework for the example applications in the
// OpenGL ES 2.0 Programming Guide.
//
///
// Includes
//
#include "esUtil.h"
#include <math.h>
#include <string.h>
#define PI 3.1415926535897932384626433832795f
void ESUTIL_API
esScale(ESMatrix *result, GLfloat sx, GLfloat sy, GLfloat sz)
{
result->m[0][0] *= sx;
result->m[0][1] *= sx;
result->m[0][2] *= sx;
result->m[0][3] *= sx;
result->m[1][0] *= sy;
result->m[1][1] *= sy;
result->m[1][2] *= sy;
result->m[1][3] *= sy;
result->m[2][0] *= sz;
result->m[2][1] *= sz;
result->m[2][2] *= sz;
result->m[2][3] *= sz;
}
void ESUTIL_API
esTranslate(ESMatrix *result, GLfloat tx, GLfloat ty, GLfloat tz)
{
result->m[3][0] += (result->m[0][0] * tx + result->m[1][0] * ty + result->m[2][0] * tz);
result->m[3][1] += (result->m[0][1] * tx + result->m[1][1] * ty + result->m[2][1] * tz);
result->m[3][2] += (result->m[0][2] * tx + result->m[1][2] * ty + result->m[2][2] * tz);
result->m[3][3] += (result->m[0][3] * tx + result->m[1][3] * ty + result->m[2][3] * tz);
}
void ESUTIL_API
esRotate(ESMatrix *result, GLfloat angle, GLfloat x, GLfloat y, GLfloat z)
{
GLfloat sinAngle, cosAngle;
GLfloat mag = sqrtf(x * x + y * y + z * z);
sinAngle = sinf ( angle * PI / 180.0f );
cosAngle = cosf ( angle * PI / 180.0f );
if ( mag > 0.0f )
{
GLfloat xx, yy, zz, xy, yz, zx, xs, ys, zs;
GLfloat oneMinusCos;
ESMatrix rotMat;
x /= mag;
y /= mag;
z /= mag;
xx = x * x;
yy = y * y;
zz = z * z;
xy = x * y;
yz = y * z;
zx = z * x;
xs = x * sinAngle;
ys = y * sinAngle;
zs = z * sinAngle;
oneMinusCos = 1.0f - cosAngle;
rotMat.m[0][0] = (oneMinusCos * xx) + cosAngle;
rotMat.m[0][1] = (oneMinusCos * xy) - zs;
rotMat.m[0][2] = (oneMinusCos * zx) + ys;
rotMat.m[0][3] = 0.0F;
rotMat.m[1][0] = (oneMinusCos * xy) + zs;
rotMat.m[1][1] = (oneMinusCos * yy) + cosAngle;
rotMat.m[1][2] = (oneMinusCos * yz) - xs;
rotMat.m[1][3] = 0.0F;
rotMat.m[2][0] = (oneMinusCos * zx) - ys;
rotMat.m[2][1] = (oneMinusCos * yz) + xs;
rotMat.m[2][2] = (oneMinusCos * zz) + cosAngle;
rotMat.m[2][3] = 0.0F;
rotMat.m[3][0] = 0.0F;
rotMat.m[3][1] = 0.0F;
rotMat.m[3][2] = 0.0F;
rotMat.m[3][3] = 1.0F;
esMatrixMultiply( result, &rotMat, result );
}
}
void ESUTIL_API
esFrustum(ESMatrix *result, float left, float right, float bottom, float top, float nearZ, float farZ)
{
float deltaX = right - left;
float deltaY = top - bottom;
float deltaZ = farZ - nearZ;
ESMatrix frust;
if ( (nearZ <= 0.0f) || (farZ <= 0.0f) ||
(deltaX <= 0.0f) || (deltaY <= 0.0f) || (deltaZ <= 0.0f) )
return;
frust.m[0][0] = 2.0f * nearZ / deltaX;
frust.m[0][1] = frust.m[0][2] = frust.m[0][3] = 0.0f;
frust.m[1][1] = 2.0f * nearZ / deltaY;
frust.m[1][0] = frust.m[1][2] = frust.m[1][3] = 0.0f;
frust.m[2][0] = (right + left) / deltaX;
frust.m[2][1] = (top + bottom) / deltaY;
frust.m[2][2] = -(nearZ + farZ) / deltaZ;
frust.m[2][3] = -1.0f;
frust.m[3][2] = -2.0f * nearZ * farZ / deltaZ;
frust.m[3][0] = frust.m[3][1] = frust.m[3][3] = 0.0f;
esMatrixMultiply(result, &frust, result);
}
void ESUTIL_API
esPerspective(ESMatrix *result, float fovy, float aspect, float nearZ, float farZ)
{
GLfloat frustumW, frustumH;
frustumH = tanf( fovy / 360.0f * PI ) * nearZ;
frustumW = frustumH * aspect;
esFrustum( result, -frustumW, frustumW, -frustumH, frustumH, nearZ, farZ );
}
void ESUTIL_API
esOrtho(ESMatrix *result, float left, float right, float bottom, float top, float nearZ, float farZ)
{
float deltaX = right - left;
float deltaY = top - bottom;
float deltaZ = farZ - nearZ;
ESMatrix ortho;
if ( (deltaX == 0.0f) || (deltaY == 0.0f) || (deltaZ == 0.0f) )
return;
esMatrixLoadIdentity(&ortho);
ortho.m[0][0] = 2.0f / deltaX;
ortho.m[3][0] = -(right + left) / deltaX;
ortho.m[1][1] = 2.0f / deltaY;
ortho.m[3][1] = -(top + bottom) / deltaY;
ortho.m[2][2] = -2.0f / deltaZ;
ortho.m[3][2] = -(nearZ + farZ) / deltaZ;
esMatrixMultiply(result, &ortho, result);
}
void ESUTIL_API
esMatrixMultiply(ESMatrix *result, ESMatrix *srcA, ESMatrix *srcB)
{
ESMatrix tmp;
int i;
for (i=0; i<4; i++)
{
tmp.m[i][0] = (srcA->m[i][0] * srcB->m[0][0]) +
(srcA->m[i][1] * srcB->m[1][0]) +
(srcA->m[i][2] * srcB->m[2][0]) +
(srcA->m[i][3] * srcB->m[3][0]) ;
tmp.m[i][1] = (srcA->m[i][0] * srcB->m[0][1]) +
(srcA->m[i][1] * srcB->m[1][1]) +
(srcA->m[i][2] * srcB->m[2][1]) +
(srcA->m[i][3] * srcB->m[3][1]) ;
tmp.m[i][2] = (srcA->m[i][0] * srcB->m[0][2]) +
(srcA->m[i][1] * srcB->m[1][2]) +
(srcA->m[i][2] * srcB->m[2][2]) +
(srcA->m[i][3] * srcB->m[3][2]) ;
tmp.m[i][3] = (srcA->m[i][0] * srcB->m[0][3]) +
(srcA->m[i][1] * srcB->m[1][3]) +
(srcA->m[i][2] * srcB->m[2][3]) +
(srcA->m[i][3] * srcB->m[3][3]) ;
}
memcpy(result, &tmp, sizeof(ESMatrix));
}
void ESUTIL_API
esMatrixLoadIdentity(ESMatrix *result)
{
memset(result, 0x0, sizeof(ESMatrix));
result->m[0][0] = 1.0f;
result->m[1][1] = 1.0f;
result->m[2][2] = 1.0f;
result->m[3][3] = 1.0f;
}
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