Member interpolateVertex (const SRPVertexShaderOut *a, const SRPVertexShaderOut *b, float t, const SRPShaderProgram *sp, SRPVertexShaderOut *out): this is disgusting
Member mat4ConstructPerspectiveProjection (float x_min_near, float x_max_near, float y_min_near, float y_max_near, float z_near, float z_far): Avoid matmul here?