Detailed Description

Describes the properties of a view that is being rendered.

These are properties such as the type of view (parallel or perspective), its clipping distances, width, height, zoom factor, field-of-view, etc.

Data Members:

Matrix3 prevAffineTM;

This is the world space to camera space transformation matrix computed 2 ticks before the affineTM matrix below.

Matrix3 affineTM;

This matrix will take a point in world space and convert it to camera space (or world to view space if it's a viewport). The camera coordinates are set up looking down the -Z axis, X is to the right, and Y is up.

int projType;

One of the following values:

PROJ_PERSPECTIVE

The view is a perspective projection.

PROJ_PARALLEL

The view is a parallel projection.

float hither, yon;

The hither and yon clipping distances.

float distance;

This data member is available in release 3.0 and later only.

The distance from the view point to the image (view) plane.

float zoom;

The zoom factor of the viewport for parallel projection. The zoom factor gives the amount of magnification relative to a standard view width of 400 pixels. This is best explained via the following code fragment: ComputeViewParams() computes the projection factors for a given view, and MapToScreen() applies these factors to map a point from 3D camera coordinates to 2D screen coordinates.

#define VIEW_DEFAULT_WIDTH ((float)400.0)
void SRendParams::ComputeViewParams(const ViewParams&vp)
{
    if (vp.projType == PROJ_PERSPECTIVE) {
        float fac = -(float)(1.0 / tan(0.5*(double)vp.fov));
        xscale = fac*dw2;        // dw2 = float(devWidth)/2.0
        yscale = -devAspect*xscale;
    }
    else {
        xscale = (float)devWidth/(VIEW_DEFAULT_WIDTH*vp.zoom);
        yscale = -devAspect*xscale;
    }
}

Point2 SRendParams::MapToScreen(Point3 p)
{
    Point2 s;
    if (proj_type==PROJ_PERSPECTIVE) {
        s.x = dw2 + xscale*p.x/p.z;
        s.y = dh2 + yscale*p.y/p.z;
    }
    else {
        s.x = dw2 + xscale*p.x;
        s.y = dh2 + yscale*p.y;
    }
    return s;
}

float fov;

Field of view in radians for perspective projections.

float nearRange;

This data member is available in release 2.0 and later only.

The near environment range setting (used for fog effects).

float farRange;

This data member is available in release 2.0 and later only.

The far environment setting (used for fog effects).

See also:: Class Matrix3, Class Renderer, Class RendParams.

#include <render.h>

Inheritance diagram for ViewParams:

[legend]

List of all members.

Public Member Functions
virtual INT_PTR	Execute (int cmd, ULONG_PTR arg1=0, ULONG_PTR arg2=0, ULONG_PTR arg3=0)
	This is a general purpose function that allows the API to be extended in the future.
Public Attributes
Matrix3	prevAffineTM
Matrix3	affineTM
int	projType
float	hither
float	yon
float	distance
float	zoom
float	fov
float	nearRange
float	farRange

Member Function Documentation

virtual INT_PTR Execute	(	int	cmd,
		ULONG_PTR	arg1 = `0`,
		ULONG_PTR	arg2 = `0`,
		ULONG_PTR	arg3 = `0`
	)		`[inline, virtual]`

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This is a general purpose function that allows the API to be extended in the future.

The 3ds Max development team can assign new cmd numbers and continue to add functionality to this class without having to 'break' the API.

Parameters:: int cmd

The index of the command to execute.

ULONG_PTR arg1=0

Optional argument 1. See the documentation where the cmd option is discussed for more details on these parameters.

ULONG_PTR arg2=0

Optional argument 2.

ULONG_PTR arg3=0

Optional argument 3.