138 lines
3.4 KiB
C++
138 lines
3.4 KiB
C++
#include<hgl/math/Matrix.h>
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// Vulkan Cookbook
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// ISBN: 9781786468154
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// Packt Publishing Limited
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// git: https://github.com/PacktPublishing/Vulkan-Cookbook.git
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//
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// Author: Pawel Lapinski
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// LinkedIn: https://www.linkedin.com/in/pawel-lapinski-84522329
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//
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// Chapter: 10 Helper Recipes
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// Recipe: 04 Preparing a perspective projection matrix
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// Recipe: 05 Preparing an orthographic projection matrix
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namespace hgl
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{
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Matrix4f ortho( float left,
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float right,
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float bottom,
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float top,
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float znear,
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float zfar )
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{
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return Matrix4f(
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2.0f / (right - left),
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0.0f,
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0.0f,
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0.0f,
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0.0f,
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2.0f / (bottom - top),
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0.0f,
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0.0f,
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0.0f,
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0.0f,
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1.0f / (znear - zfar),
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0.0f,
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-(right + left) / (right - left),
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-(bottom + top) / (bottom - top),
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znear / (znear - zfar),
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1.0f
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);
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}
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/**
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* 生成一个正角视图矩阵
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* @param width 宽
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* @param height 高
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* @param znear 近平面z值
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* @param zfar 远平台z值
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*/
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Matrix4f ortho(float width,float height,float znear,float zfar)
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{
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return ortho(0.0f,width,height,0.0f,znear,zfar);
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}
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/**
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* 生成一个正角视图矩阵
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* @param width 宽
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* @param height 高
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*/
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Matrix4f ortho(float width,float height)
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{
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return ortho(width,height,0.0f,1.0f);
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}
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/**
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* 生成一个透视矩阵
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* @param field_of_view 视野(角度)
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* @param aspect_ratio 宽高比
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* @param znear 近截面
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* @param zfar 远截面
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*/
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Matrix4f perspective( float field_of_view,
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float aspect_ratio,
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float znear,
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float zfar)
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{
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float f = 1.0f / tanf( deg2rad( 0.5f * field_of_view ) );
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return Matrix4f(
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f / aspect_ratio,
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0.0f,
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0.0f,
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0.0f,
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0.0f,
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-f,
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0.0f,
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0.0f,
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0.0f,
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0.0f,
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zfar/(znear-zfar),
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-1.0f,
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0.0f,
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0.0f,
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-(znear * zfar) / (zfar-znear),
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0.0f
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);
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//经查证，此代码等于glm::perspectiveRH_ZO之后将[1][1]乘-1，在SaschaWillems的范例中，如果反转Y轴，则[1][1]确实要乘-1。
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}
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Matrix4f lookat(const Vector3f &eye,const Vector3f &target,const Vector3f &up)
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{
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Vector3f forward=normalize(target-eye);
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Vector3f right =normalize(cross(forward,up));
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Vector3f nup =cross(right,forward);
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return Matrix4f( right.x,
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nup.x,
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-forward.x,
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0.0f,
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right.y,
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nup.y,
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-forward.y,
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0.0f,
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right.z,
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nup.z,
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-forward.z,
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0.0f,
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-dot(eye,right ),
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-dot(eye,nup ),
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dot(eye,forward),
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1.0f
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);
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//经查证，此代码完全等于glm::lookAtRH，无任何差别
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}
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}//namespace hgl
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