Implement Matrix4x4::OpenGLPerspProjLH

include/J3ML/LinearAlgebra/Matrix4x4.h

@@ -209,10 +209,10 @@ namespace J3ML::LinearAlgebra {
         static Matrix4x4 D3DPerspProjLH(float nearPlane, float farPlane, float hViewportSize, float vViewportSize);
         static Matrix4x4 D3DPerspProjRH(float nearPlane, float farPlane, float hViewportSize, float vViewportSize);
 
-        static Matrix4x4 OpenGLOrthoProjLH(float nearPlane, float farPlane, float hViewportSize, float vViewportSize);
-        static Matrix4x4 OpenGLOrthoProjRH(float nearPlane, float farPlane, float hViewportSize, float vViewportSize);
-        static Matrix4x4 OpenGLPerspProjLH(float nearPlane, float farPlane, float hViewportSize, float vViewportSize);
-        static Matrix4x4 OpenGLPerspProjRH(float nearPlane, float farPlane, float hViewportSize, float vViewportSize);
+        static Matrix4x4 OpenGLOrthoProjLH(float n, float f, float h, float v);
+        static Matrix4x4 OpenGLOrthoProjRH(float n, float f, float h, float v);
+        static Matrix4x4 OpenGLPerspProjLH(float n, float f, float h, float v);
+        static Matrix4x4 OpenGLPerspProjRH(float n, float f, float h, float v);
 
         Vector4 operator[](int row);
 

src/J3ML/LinearAlgebra/Matrix4x4.cpp

@@ -514,4 +514,50 @@ namespace J3ML::LinearAlgebra {
         At(row, 2) *= scalar;
         At(row, 3) *= scalar;
     }
+
+    Matrix4x4 Matrix4x4::OpenGLOrthoProjLH(float n, float f, float h, float v) {
+        /// Same as OpenGLOrthoProjRH, except that the camera looks towards +Z in view space, instead of -Z.
+        using f32 = float;
+        f32 p00 = 2.f / h; f32 p01 = 0;           f32 p02 = 0;       float p03 = 0.f;
+        f32 p10 = 0;       f32 p11 = 2.f / v; f32 p12 = 0;           float p13 = 0.f;
+        f32 p20 = 0;       f32 p21 = 0;       f32 p22 = 2.f / (f-n); float p23 = (f+n) / (n-f);
+        f32 p30 = 0;       f32 p31 = 0;       f32 p32 = 0;           float p33 = 1.f;
+
+        return {p00, p01, p02, p03, p10, p11, p12, p13, p20, p21, p22, p23, p30, p31, p32, p33};
+
+    }
+
+    Matrix4x4 Matrix4x4::OpenGLOrthoProjRH(float n, float f, float h, float v) {
+        using f32 = float;
+        f32 p00 = 2.f / h; f32 p01 = 0;       f32 p02 = 0;           f32 p03 = 0.f;
+        f32 p10 = 0;       f32 p11 = 2.f / v; f32 p12 = 0;           f32 p13 = 0.f;
+        f32 p20 = 0;       f32 p21 = 0;       f32 p22 = 2.f / (n-f); f32 p23 = (f+n) / (n-f);
+        f32 p30 = 0;       f32 p31 = 0;       f32 p32 = 0;           f32 p33 = 1.f;
+
+        return {p00, p01, p02, p03, p10, p11, p12, p13, p20, p21, p22, p23, p30, p31, p32, p33};
+    }
+
+    Matrix4x4 Matrix4x4::OpenGLPerspProjLH(float n, float f, float h, float v) {
+        // Same as OpenGLPerspProjRH, except that the camera looks towards +Z in view space, instead of -Z.
+        using f32 = float;
+        f32 p00 = 2.f *n / h;  f32 p01 = 0;           f32 p02 = 0;              f32 p03 = 0.f;
+        f32 p10 = 0;           f32 p11 = 2.f * n / v; f32 p12 = 0;              f32 p13 = 0.f;
+        f32 p20 = 0;           f32 p21 = 0;           f32 p22 = (n+f) / (f-n);  f32 p23 = 2.f*n*f / (n-f);
+        f32 p30 = 0;           f32 p31 = 0;           f32 p32 = 1.f;            f32 p33 = 0.f;
+
+        return {p00, p01, p02, p03, p10, p11, p12, p13, p20, p21, p22, p23, p30, p31, p32, p33};
+    }
+
+    Matrix4x4 Matrix4x4::OpenGLPerspProjRH(float n, float f, float h, float v) {
+        // In OpenGL, the post-perspective unit cube ranges in [-1, 1] in all X, Y and Z directions.
+        // See http://www.songho.ca/opengl/gl_projectionmatrix.html , unlike in Direct3D, where the
+        // Z coordinate ranges in [0, 1]. This is the only difference between D3DPerspProjRH and OpenGLPerspProjRH.
+        using f32 = float;
+        float p00 = 2.f *n / h;  float p01 = 0;           float p02 = 0;              float p03 = 0.f;
+        float p10 = 0;           float p11 = 2.f * n / v; float p12 = 0;              float p13 = 0.f;
+        float p20 = 0;           float p21 = 0;           float p22 = (n+f) / (n-f);  float p23 = 2.f*n*f / (n-f);
+        float p30 = 0;           float p31 = 0;           float p32 = -1.f;           float p33 = 0.f;
+
+        return {p00, p01, p02, p03, p10, p11, p12, p13, p20, p21, p22, p23, p30, p31, p32, p33};
+    }
 }