/**
* Apply a perspective projection matrix.
*
* \param left left clipping plane coordinate.
* \param right right clipping plane coordinate.
* \param bottom bottom clipping plane coordinate.
* \param top top clipping plane coordinate.
* \param nearval distance to the near clipping plane.
* \param farval distance to the far clipping plane.
*
* \sa glFrustum().
*
* Flushes vertices and validates parameters. Calls _math_matrix_frustum() with
* the top matrix of the current matrix stack and sets
* __struct gl_contextRec::NewState.
*/
void GLAPIENTRY
_mesa_Frustum( GLdouble left, GLdouble right,
GLdouble bottom, GLdouble top,
GLdouble nearval, GLdouble farval )
{
GET_CURRENT_CONTEXT(ctx);
FLUSH_VERTICES(ctx, 0);
if (nearval <= 0.0 ||
farval <= 0.0 ||
nearval == farval ||
left == right ||
top == bottom)
{
_mesa_error( ctx, GL_INVALID_VALUE, "glFrustum" );
return;
}
_math_matrix_frustum( ctx->CurrentStack->Top,
(GLfloat) left, (GLfloat) right,
(GLfloat) bottom, (GLfloat) top,
(GLfloat) nearval, (GLfloat) farval );
ctx->NewState |= ctx->CurrentStack->DirtyFlag;
}
void
cogl_matrix_frustum (CoglMatrix *matrix,
float left,
float right,
float bottom,
float top,
float z_near,
float z_far)
{
#ifndef USE_MESA_MATRIX_API
float x, y, a, b, c, d;
CoglMatrix frustum;
x = (2.0f * z_near) / (right - left);
y = (2.0f * z_near) / (top - bottom);
a = (right + left) / (right - left);
b = (top + bottom) / (top - bottom);
c = -(z_far + z_near) / ( z_far - z_near);
d = -(2.0f * z_far* z_near) / (z_far - z_near);
frustum.xx = x;
frustum.yx = 0.0f;
frustum.zx = 0.0f;
frustum.wx = 0.0f;
frustum.xy = 0.0f;
frustum.yy = y;
frustum.zy = 0.0f;
frustum.wy = 0.0f;
frustum.xz = a;
frustum.yz = b;
frustum.zz = c;
frustum.wz = -1.0f;
frustum.xw = 0.0f;
frustum.yw = 0.0f;
frustum.zw = d;
frustum.ww = 0.0f;
cogl_matrix_multiply (matrix, matrix, &frustum);
#else
_math_matrix_frustum (matrix, left, right, bottom, top, z_near, z_far);
#endif
_COGL_MATRIX_DEBUG_PRINT (matrix);
}
