void mat_perspective(
float *matrix, float fov, float aspect,
float znear, float zfar)
{
float ymax, xmax;
ymax = znear * tanf(fov * PI / 360.0);
xmax = ymax * aspect;
mat_frustum(matrix, -xmax, xmax, -ymax, ymax, znear, zfar);
}
static void
Reshape(int width, int height)
{
float ar = (float) width / height;
WinWidth = width;
WinHeight = height;
glViewport(0, 0, width, height);
mat_frustum(Projection, -ar, ar, -1, 1, 3, 25);
/* pass viewport dims to the shader */
{
GLfloat viewport[4];
glGetFloatv(GL_VIEWPORT, viewport);
glUniform2f(uViewportSize, viewport[2], viewport[3]);
}
}