commonMain.cameras.RelativeTargetCamera.kt Maven / Gradle / Ivy

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/*
 * Copyright 2020-2021 Slawomir Czerwinski
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package graphics.glimpse.cameras

import graphics.glimpse.types.Angle
import graphics.glimpse.types.Mat4
import graphics.glimpse.types.Vec3
import graphics.glimpse.types.lookAt

/**
 * A camera pointed at the given [target], and located at the given [distance] from it,
 * with the given [longitude] and [latitude] angles, while preserving the defined [upVector].
 */
data class RelativeTargetCamera(

    /**
     * Position of the camera target.
     */
    val target: Vec3,

    /**
     * Distance from the target.
     */
    val distance: Float,

    /**
     * Camera longitude relative to the target.
     */
    val longitude: Angle,

    /**
     * Camera latitude relative to the target.
     */
    val latitude: Angle,

    /**
     * Up-vector preserved for the camera.
     */
    val upVector: Vec3 = Vec3.unitZ
) : Camera {

    /**
     * Position of the camera eye.
     */
    override val eye = target + Vec3.fromSphericalCoordinates(distance, longitude, latitude)

    /**
     * View matrix defined by the camera.
     */
    override val viewMatrix: Mat4 = lookAt(eye, target, upVector)
}