『觸屏坐標』『x,y』坐標轉『正交投影』坐標, 『視錐體解像』寬高, 比例需手機解像寬高比壹致.
計屏幕寬高比
| float aspect_ratio = (float)cam->real_width / (float)cam->real_height; |
『視錐體解像』寬高,此時定義『高』800pix
| float frustum_width = 800 *aspect_ratio; |
| float frustum_height = 800 ; |
『正交投影』代碼
重置視區尺寸, 值係手機解像寬高
| ::glViewport(0,0,real_width,real_height); |
設定投影矩陣
| ::glMatrixMode(GL_PROJECTION); |
載入單位矩陣
| ::glLoadIdentity(); |
正交投影, 游戲坐標原點(0,0,0)為於屏幕中心
| glOrthof(frustum_width / 2, frustum_width / 2, -frustum_height / 2, frustum_height / 2, pos.y – 10, far_clip_z); |
設定模型視圖矩陣
| ::glMatrixMode(GL_MODELVIEW); |
載入單位矩陣
| ::glLoadIdentity(); |
手指触摸手機屏幕onTouch() 所得坐標需轉游戲世界坐標,正交投影OpenGL游㱆+Z軸指向屏幕深處.
| float touch3Dx = (touch2Dx / real_width) * frustum_width ; |
| float touch3Dz = (touch2Dy /real_height) * frustum_height ; |
計3D相機位置
| touch3Dx = touch3Dx + camPosX; |
| touch3Dz = touch3Dz + camPosX; |
游戲坐標原點(0,0,0)為於屏幕中心
| touch3Dx = touch3Dx – (frustum_width / 2.0f); |
| touch3Dz = touch3Dz – (frustum_height / 2.0f); |