68 lines
2.2 KiB
C++
68 lines
2.2 KiB
C++
// Copyright 2017 The Dawn Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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class Camera {
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public:
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Camera()
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: _azimuth(glm::radians(45.f)),
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_altitude(glm::radians(30.f)),
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_radius(10.f),
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_center(0, 0, 0),
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_dirty(true) {
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recalculate();
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}
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void rotate(float dAzimuth, float dAltitude) {
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_dirty = true;
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_azimuth = glm::mod(_azimuth + dAzimuth, glm::radians(360.f));
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_altitude = glm::clamp(_altitude + dAltitude, glm::radians(-89.f), glm::radians(89.f));
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}
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void pan(float dX, float dY) {
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recalculate();
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glm::vec3 vX = glm::normalize(glm::cross(-_eyeDir, glm::vec3(0, 1, 0)));
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glm::vec3 vY = glm::normalize(glm::cross(_eyeDir, vX));
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_center += vX * dX * _radius + vY * dY * _radius;
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}
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void zoom(float factor) {
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_dirty = true;
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_radius = _radius * glm::exp(-factor);
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}
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glm::mat4 view() {
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if (_dirty) {
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recalculate();
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}
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return _view;
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}
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private:
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void recalculate() {
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glm::vec4 eye4 = glm::vec4(1, 0, 0, 1);
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eye4 = glm::rotate(glm::mat4(), _altitude, glm::vec3(0, 0, 1)) * eye4;
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eye4 = glm::rotate(glm::mat4(), _azimuth, glm::vec3(0, 1, 0)) * eye4;
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_eyeDir = glm::vec3(eye4);
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_view = glm::lookAt(_center + _eyeDir * _radius, _center, glm::vec3(0, -1, 0));
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_dirty = false;
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}
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float _azimuth;
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float _altitude;
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float _radius;
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glm::vec3 _center;
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glm::vec3 _eyeDir;
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bool _dirty;
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glm::mat4 _view;
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};
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