void Mtx_Ortho(C3D_Mtx* mtx, float left, float right, float bottom, float top, float near, float far, bool isLeftHanded)
{
Mtx_Zeros(mtx);
// Standard orthogonal projection matrix, with a fixed depth range of [-1,0] (required by PICA)
// http://www.wolframalpha.com/input/?i={{1,0,0,0},{0,1,0,0},{0,0,0.5,-0.5},{0,0,0,1}}{{2/(r-l),0,0,(l%2Br)/(l-r)},{0,2/(t-b),0,(b%2Bt)/(b-t)},{0,0,2/(n-f),(n%2Bf)/(n-f)},{0,0,0,1}}
mtx->r[0].x = 2.0f / (right - left);
mtx->r[0].w = (left + right) / (left - right);
mtx->r[1].y = 2.0f / (top - bottom);
mtx->r[1].w = (bottom + top) / (bottom - top);
if (isLeftHanded)
mtx->r[2].z = 1.0f / (far - near);
else
mtx->r[2].z = 1.0f / (near - far);
mtx->r[2].w = 0.5f*(near + far) / (near - far) - 0.5f;
mtx->r[3].w = 1.0f;
}
void Mtx_Ortho(C3D_Mtx* mtx, float left, float right, float top, float bottom, float near, float far) {
C3D_Mtx mp;
Mtx_Zeros(&mp);
// Build standard orthogonal projection matrix
mp.r[0].x = 2.0f / (right - left);
mp.r[0].w = (left + right) / (left - right);
mp.r[1].y = 2.0f / (top - bottom);
mp.r[1].w = (bottom + top) / (bottom - top);
mp.r[2].z = 2.0f / (far - near);
mp.r[2].w = (near + far) / (near - far);
mp.r[3].w = 1.0f;
// Fix depth range to [-1, 0]
C3D_Mtx mp2;
Mtx_Identity(&mp2);
mp2.r[2].z = 0.5;
mp2.r[2].w = -0.5;
Mtx_Multiply(mtx, &mp2, &mp);
}
void Mtx_Identity(C3D_Mtx* out)
{
Mtx_Zeros(out);
out->r[0].x = out->r[1].y = out->r[2].z = out->r[3].w = 1.0f;
}
